WO2020096300A1 - Method for measuring spatial magnetic field distribution of magnet and device for measuring spatial magnetic field distribution of magnet by using same - Google Patents

Method for measuring spatial magnetic field distribution of magnet and device for measuring spatial magnetic field distribution of magnet by using same Download PDF

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WO2020096300A1
WO2020096300A1 PCT/KR2019/014812 KR2019014812W WO2020096300A1 WO 2020096300 A1 WO2020096300 A1 WO 2020096300A1 KR 2019014812 W KR2019014812 W KR 2019014812W WO 2020096300 A1 WO2020096300 A1 WO 2020096300A1
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magnetic field
magnet
spatial
measuring
field distribution
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PCT/KR2019/014812
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French (fr)
Korean (ko)
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이상갑
장재영
황영진
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한국기초과학지원연구원
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
    • G01R33/387—Compensation of inhomogeneities
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
    • A61B5/055—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/24—Arrangements or instruments for measuring magnetic variables involving magnetic resonance for measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/246—Spatial mapping of the RF magnetic field B1
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/30—Sample handling arrangements, e.g. sample cells, spinning mechanisms
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
    • G01R33/385—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field using gradient magnetic field coils

Definitions

  • the present invention relates to a method for measuring a spatial magnetic field distribution of a magnet, and more specifically, for example, a magnetic resonance imaging (hereinafter, also referred to as "MRI") or nuclear magnetic field.
  • MRI magnetic resonance imaging
  • NMR Nuclear Magnetic Resonance
  • the measurement of the spatial magnetic field around the magnet takes a long measurement time, and
  • the magnetic field distribution of the magnetic field and A method for measuring the distribution of a spatial magnetic field of a magnet configured to measure the spatial uniformity quickly and accurately, and a spatial magnet of the magnet using the method Distribution relates to a measuring device.
  • the present invention in the conventional, for example, MRI, in a shimming operation performed to improve the magnetic field uniformity of a device using a magnet, in response to RF applied through an RF coil Because it is configured to receive magnetic resonance (MR) signals generated by the human body and analyze spatial magnetic field distribution, the longer the human body is exposed to high-power RF environments that may be harmful to safety, or the higher the magnetic field equipment, the so-called SAR (Specific Absorption Rate) In order to solve the problems of the magnetic field distribution measuring method and devices of the prior art magnet, which has a problem that can cause fatal damage to the safety of the human body by generating a local heat called a hotspot, It is configured to accurately measure the spatial magnetic field distribution of the magnet provided in the equipment without directly applying high-power RF.
  • the present invention relates to a method for measuring a spatial magnetic field distribution of a magnet and an apparatus for measuring the spatial magnetic field distribution of a magnet using the same.
  • the present invention in order to improve the magnetic field uniformity, it takes a long measurement time when measuring the spatial magnetic field distribution of the magnet, and while the human body or an object occupies the magnetic field utilization space around the magnet, the direct Measurement is impossible, therefore, to analyze the spatial magnetic field distribution, it is necessary to apply high-power RF directly to the human body.
  • a magnetic field value measured by arranging a plurality of conventional magnetometers at a location where coordinates of a space to be analyzed is known, or a magnetic resonance from each sample by arranging a plurality of MR samples and RF coils ( MR)
  • MR MR
  • a person who receives a signal and obtained through spectral analysis of the received signal It is configured to calculate the magnetic field uniformity in the virtual sphere space located in the center of the cylinder using the field value and the field gradients calculated from these values, so that high-power RF is not applied to the human body when measuring the distribution of the magnetic field in the magnet
  • the present invention relates to a method for measuring a spatial magnetic field distribution of a magnet and a device for measuring the spatial magnetic field distribution of a magnet using
  • NMR nuclear magnetic resonance spectroscopy
  • MRI magnetic resonance imaging
  • Research equipment capable of analyzing pathological mechanisms and diagnostic equipment configured to visually view the inside of the human body are widely used.
  • the above-described MRI device reacts with applying a magnetic field to the human body using a magnet to resonate hydrogen atom nuclei in the body. It is used to diagnose soft tissue diseases such as muscles and cartilage or cancer by receiving signals.
  • the RF coil unit for a magnetic resonance imaging system Volumetric RF of a magnetic resonance imaging system by forming a dielectric structure inside an RF coil element, including at least one RF coil element formed on a cylindrical base having a circular or elliptical cross-section and a dielectric structure formed inside the base.
  • the magnetic field generated by the coil unit can apply a uniform magnetic field to the subject as a whole, and by applying a uniform magnetic field to the subject as a whole, so that a high-resolution magnetic resonance image can be obtained without deteriorating the quality of the magnetic resonance image according to the position.
  • An RF coil unit including a dielectric structure, and a magnetic resonance imaging system including the same, have been proposed. have.
  • a plurality of receiving coils positioned to be in close contact with the body; And a plurality of transmission coils spaced apart from the body and RF-resonated with the reception coil, the reception coil comprising: a first coil portion in a strip shape curved between both ends; And a second coil portion that is curved in shape between both ends and installed to be spaced apart from the first coil portion, and one end of the first and second coil portions is spaced apart from each other to form a first capacitor, and the first and second coil portions are formed.
  • the other ends of the spacers are spaced apart from each other to form a second capacitor, and one of the ends and the other ends of the wiring part is formed to be extended, and the first and second coil parts are configured to be curved in a semicircle, respectively, in an ultra-high magnetic field MRI field such as 7T.
  • MRI field such as 7T.
  • a homogeneous magnetic field and a high-resolution image can be obtained.
  • a RF resonator has been proposed in a magnetic resonance imaging system that is configured to be able to observe the brain more accurately and in detail as close as possible to the head.
  • devices such as the MRI of the prior art as described above require a shimming operation that corrects the uniformity of the magnetic field by measuring the distribution of the magnetic field at the time of first use, and thus the image of the image in MRI is required.
  • a process of applying a pulse to the RF coil surrounding the human body is essential.
  • MRI requires the process of measuring the magnetic field uniformity to increase the resolution even after the human body enters the magnetic field space for imaging and correcting the magnetic field uniformity through the shing operation accordingly, but the magnetic field distribution measuring device of the prior art
  • the magnetic field spatial uniformity cannot be calculated because the measuring device cannot access the region of interest while an object such as a human body or a probe occupies the magnetic field utilization space around the magnets.
  • the conventional magnetic field spatial uniformity measurement method uses a magnetic field
  • the measurement takes a long time due to the measurement while rotating the distribution measuring device mechanically.
  • the present invention is intended to solve the problems of the prior art as described above, and therefore the object of the present invention is to improve the magnetic field uniformity in various equipment using magnets, for example, NMR or MRI.
  • magnets for example, NMR or MRI.
  • the object of the present invention is to improve the magnetic field uniformity in various equipment using magnets, for example, NMR or MRI.
  • another object of the present invention is a magnetic resonance (MR) signal generated in the human body in response to RF applied through an RF coil in a shimmering operation performed to improve the magnetic field uniformity of a device using a magnet such as an MRI.
  • MR magnetic resonance
  • the spatial magnetic field distribution of the magnet provided in the corresponding equipment was accurately measured without applying high power RF directly to the human body.
  • Another object of the present invention in order to improve the magnetic field uniformity, it takes a long measurement time when measuring the spatial magnetic field distribution of the magnet, while the human body or an object occupies the magnetic field utilization space around the magnet. It is not possible to measure the magnetic field directly.
  • the method and apparatus for measuring the spatial magnetic field distribution of a prior art magnet which had a problem that could have a detrimental effect on the human body due to the direct application of high power RF to the human body
  • the magnetic field value measured by arranging a plurality of conventional magnetometers at a location where the coordinates of the space to analyze the magnetic field distribution of the magnet is known, or, by arranging a plurality of MR samples and RF coils, each sample Magnetic resonance (MR) signal from the spectral analysis of the received signal
  • MR Magnetic resonance
  • a method for measuring a spatial magnetic field distribution of a magnet comprising: a placement step of arranging a plurality of magnetic resonance (MR) samples in a magnetic field space around the magnet, respectively; A detection step of applying a current (RF pulse) of a predetermined value to each of the MR samples and detecting an MR signal generated from each of the MR samples according to the applied current value; A magnetic field calculation step of calculating a magnetic field value corresponding to each coordinate value of each MR sample based on the MR signal detected for each MR sample in the MR signal detection step; And a magnetic field uniformity calculating step of calculating a spatial uniformity degree of the magnetic field of the magnet based on the magnetic field values calculated for each MR sample coordinate in the magnetic field calculating step.
  • a method for measuring the spatial magnetic field distribution of a magnet is provided.
  • the placement step using a non-magnetic material including stainless steel (Stainless steel) or aluminum to form a hollow cylindrical structure, the RF coil is wound at a plurality of locations where the spatial coordinates on the structure are known
  • a plurality of MR samples are disposed at respective spatial coordinate positions, and each MR sample is fixed at the spatial coordinate positions of the cylindrical structure using an attachment means including a non-magnetic adhesive, and then the cylindrical It is characterized in that, by placing the structure in a magnetic field space around the magnet, a process of placing a plurality of the MR samples in a magnetic field space around the magnet is performed.
  • the detecting step is characterized in that it is configured to detect the MR signal including the MR spectrum and the magnetic field value from each of the MR samples.
  • each MR signal detected in the MR signal detection step is performed to calculate a value of the X-axis (frequency) corresponding to the maximum value in the spectrum as a magnetic field value for the corresponding MR sample.
  • a virtual gradient is set in the center of the space of the cylindrical structure, and a field gradient is used using coordinate values (x, y, z) for each of the MR samples and magnetic field values calculated from the MR signal. (Field gradients) is calculated, and a process of calculating a magnetic field in the virtual sphere space is performed by calculating a magnetic field value corresponding to a coordinate value of each MR sample using each calculated field gradient. It is characterized by being configured.
  • the maximum and minimum values of the magnetic field values calculated for each coordinate with respect to the virtual sphere space in the magnetic field calculation step are used to calculate the magnetic sphere uniformity using the following equation. It is characterized in that it is configured to perform a process for calculating the magnetic field uniformity for.
  • Bmax is the maximum value of the magnetic field calculated for each coordinate
  • Bmin represents the minimum value of the magnetic field calculated for each coordinate
  • a basic setting including an initial value is input through a user interface (UI)
  • processing of the MR signal detection step, the magnetic field calculation step, and the magnetic field uniformity calculation step is automatically performed. It is characterized by being configured to be performed.
  • a plurality of magnetometers are respectively disposed in place of the MR sample in the arrangement step, and in the detection step, magnetic field values are measured through each magnetometer, and the magnetic field calculation step and the magnetic field uniformity are measured.
  • a process of calculating the magnetic field uniformity in the virtual sphere space and the magnetic field uniformity in the virtual sphere space is performed based on the coordinate values of each magnetometer and the magnetic field values measured through each magnetometer. It is characterized by being configured as possible.
  • the MR sample contains a predetermined amount of water (H2O) or heavy water (D2O) or a liquid of a molecule containing hydrogen or deuterium in a container made of hydrogen or deuterium, or a material containing no hydrogen and deuterium. After sealing, it is characterized by being configured to wind the RF coil a predetermined number of times outside the container.
  • H2O water
  • D2O heavy water
  • the magnetic field of the magnet is determined in advance A plurality of magnetometers or a plurality of MR samples arranged at intervals, respectively; A current supply for applying a current of a predetermined value; A signal detector for receiving an MR signal generated by the current applied through the current supply; And a control unit configured to control the overall operation of the measuring device and analyze the MR signal detected through the signal detector to perform the process of calculating the spatial magnetic field distribution and magnetic field uniformity of the magnet.
  • An apparatus for measuring the spatial magnetic field distribution of a magnet is provided.
  • a shimmering system for improving the magnetic field uniformity of the magnet, there is provided a shimmering system characterized in that it comprises a spatial magnetic field distribution measuring device of the magnet described above.
  • a magnetic resonance (MR) signal is received from each sample, and a magnetic sphere value obtained through spectral analysis on the received signal and field gradients calculated from these values are used in a virtual sphere space located in the center of the cylinder.
  • a magnetic field distribution measuring method of a magnet configured to calculate the magnetic field uniformity of a magnet and a spatial magnetic field distribution measuring device using the magnet are provided, thereby ensuring safety by preventing high-power RF from being applied to the human body when measuring the magnetic field distribution of the magnet At the same time, even if a human body or an object occupies a magnetic field space, it is quick and accurate.
  • the magnetic field uniformity may be even if the magnetic field uniformity changes during recording by the magnetic field uniformity can be measured at the center to compensate for the magnetic field uniformity in real time.
  • the present invention by providing a method for measuring the spatial magnetic field distribution of a magnet constituted as described above and a device for measuring the spatial magnetic field distribution of a magnet using the same, for example, NMR or MRI, to various equipment using a magnet
  • a method for measuring the spatial magnetic field distribution of a magnet constituted as described above
  • a device for measuring the spatial magnetic field distribution of a magnet using the same for example, NMR or MRI
  • the magnetic field uniformity of a device using a magnet is performed.
  • a magnetic resonance (MR) signal generated in the human body is received and analyzed to analyze the spatial magnetic field distribution in response to the RF applied through the RF coil, so that the human body is in a high-power RF environment that may be harmful to safety.
  • FIG. 1 is a view schematically showing the configuration of a prior art MRI device.
  • FIG. 2 is a conceptual diagram schematically showing a process of acquiring an MR spectrum signal without applying high power RF directly to a human body in a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
  • FIG. 3 is a conceptual diagram schematically showing a process of calculating magnetic field uniformity based on values obtained from respective MR samples in a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
  • FIG. 4 is a flowchart schematically showing the overall configuration of a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
  • FIG. 5 is a view schematically showing the overall configuration of a magnetic field distribution measuring device of a magnet using a method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
  • the present invention as described later, for example, in NMR or MRI, in various equipment using magnets, in order to improve the magnetic field uniformity, it takes a long measurement time to measure the spatial magnetic field distribution of the magnet, the magnet
  • the magnetic field distribution of the magnet was unable to measure the spatial magnetic field distribution of the magnet while the human body or the object occupied the surrounding magnetic field.
  • the present invention relates to a method for measuring a spatial magnetic field distribution of a magnet and a device for measuring the spatial magnetic field distribution of a magnet using the same, which is configured to quickly and accurately measure distribution and spatial uniformity.
  • the present invention in the reaming operation performed to improve the magnetic field uniformity of the equipment using a magnet, such as MRI, magnetic resonance (MR) generated in the human body corresponding to the RF applied through the RF coil ) Because it is configured to receive signals and analyze the distribution of the spatial magnetic field, the longer the human body is exposed to a high-power RF environment that may be harmful to safety, or the higher the magnetic field equipment, the so-called local heating called SAR hotspot, resulting in human safety
  • SAR hotspot local heating
  • the present invention takes a long measurement time when measuring the spatial magnetic field distribution of a magnet in order to improve the magnetic field uniformity, while the human body or an object occupies the magnetic field utilization space around the magnet, Direct measurement is not possible. Therefore, in order to analyze the distribution of the spatial magnetic field, it is necessary to apply high-power RF directly to the human body.
  • MR MR
  • It is configured to calculate the magnetic field uniformity in the virtual sphere space located in the center of the cylinder using the magnetic field value and the field gradients calculated from these values, so that high-power RF is not applied to the human body when measuring the magnetic field distribution of the magnet
  • the present invention relates to a method for measuring the spatial magnetic field distribution of a magnet and a device for measuring the spatial magnetic field distribution of a magnet using the same, which is capable of measuring the magnetic field
  • the present invention has been described taking the case where the method for measuring the spatial magnetic field distribution of the magnet according to the present invention is applied to MRI, but the present invention is limited only to the case of MRI.
  • the present invention can be applied in various forms as necessary to a method and apparatus for measuring a spatial magnetic field distribution of a magnet in order to improve the uniformity of a magnetic field in various equipment equipped with a magnet as well as silk MRI. You should keep in mind.
  • FIG. 1 is a diagram schematically showing the configuration of a prior art MRI device.
  • the conventional MRI device applies RF pulses directly to the human body through single and few RF coils, and spaces through magnetic resonance (MR) signals received from the human body in response to the applied RF pulses. It is configured to uniformize the magnetic field distribution by analyzing the magnetic field distribution.
  • MR magnetic resonance
  • MRI requires a process of measuring the magnetic field uniformity to increase the resolution and correcting the magnetic field uniformity through the shing operation according to the prior art magnetic field distribution measuring device, even after the human body enters the magnetic field space for imaging While an object such as a human body or a probe occupies the magnetic field utilization space around the magnet, there is a problem that the magnetic field spatial uniformity cannot be calculated because the measuring device cannot access the region of interest, and in addition, the existing magnetic field spatial uniformity measurement The method has a disadvantage in that it takes a long measurement time by measuring while rotating the magnetic field distribution measuring device mechanically.
  • the present inventors secure safety by preventing high-power RF from being applied to the human body when measuring the magnetic field distribution of the magnet, as described later, and quickly and accurately even when a human body or an object occupies the magnetic field space.
  • a new configuration that can measure the spatial magnetic field distribution of the magnet and calculate the magnetic field uniformity, and at the same time, even when the magnetic field uniformity changes during diagnostic imaging, can measure the magnetic field uniformity in the center to correct the magnetic field uniformity in real time.
  • a method for measuring the spatial magnetic field distribution of a magnet and a measuring device for the spatial magnetic field distribution of a magnet using the same are proposed.
  • FIG. 2 is a conceptual diagram schematically showing a process of acquiring an MR spectrum signal without applying high power RF directly to a human body in a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention. to be.
  • the method for measuring the distribution of a spatial magnetic field of a magnet unlike the prior art spatial magnetic field distribution measuring apparatus and methods for receiving an MR signal by applying high-power RF directly to the human body, Assuming a cylinder-shaped space at the site to be measured, and assuming a helical path on the surface of the cylinder space, a plurality of MR samples 22 in which the RF coil 21 is wound at regular intervals on the path After placing each, using a multiplexer, the RF coil 21 is supplied with an RF pulse to each of the MR samples 22 wound, MR spectrum and magnetic field values (B1, B2, B3, B4, ...), and is configured to calculate magnetic field and uniformity through spectrum analysis.
  • each MR sample 22 is similarly provided through a multiplexer. Since MR signals, such as MR spectrums generated from the fields, can be received almost simultaneously, the MR spectrum is located at each RF sample 22 position without the need to position the RF coil directly in the human body, as in prior art MRI devices and methods. And magnetic field values.
  • each of the MR samples 22 is for generating an MR spectrum signal on behalf of the human body, so that each part of the human body can be replaced according to a position where each MR sample 22 is disposed, for example For example, using water (H2O), it may be suitably configured to exhibit the same or similar MR spectral characteristics as the corresponding site.
  • H2O water
  • the MR sample 22 described above comprises water (H2O) or heavy water (D2O) or hydrogen or deuterium in a sealed spherical or cylindrical container made of a material that does not contain hydrogen and / or deuterium. It can be composed by wrapping the RF coil on the outside of the container after containing the liquid of the appropriate molecule, wherein the amount of liquid of the appropriate molecule including water (H2O) or heavy water (D2O) or hydrogen or deuterium and the number of coil windings is appropriate. It can be configured by adjustment.
  • the nuclear spin of the hydrogen or deuterium of a suitable molecule including hydrogen or deuterium in the water molecule or deuterium in the heavy molecule, or the MR magnetometer It is the source of the MR signal of the magnetic field sensor.
  • the MR magnetometer it is not necessary to use the MR magnetometer, for example, a Hall magnetometer or an atomic magnetometer may be used depending on the level of precision of the required magnetic field uniformity.
  • a non-magnetic material such as stainless steel or aluminum is used to form a cylindrical structure. Then, assuming a helical path on the surface of the structure of the cylinder, the MR samples 22 in which the RF coils 21 are wound at regular intervals are disposed along the helical paths, respectively, using a non-magnetic adhesive. It can be configured to attach the MR sample 22 of the non-magnetic structure.
  • the distance between each MR sample 22 should be the same, and in this way, by placing the cylinder in which the plurality of MR samples 22 are placed inside the MRI, the RF coils are disposed in each part of the human body. Can replace the way.
  • the cylinders are based on the x, y, and z coordinate values for each MR sample 22 and the magnetic field values and MR spectra received from each MR sample 22. It may be configured to assume a virtual spherical space in the center of the interior and calculate field gradients to calculate magnetic field uniformity.
  • FIG. 3 schematically shows a process of calculating the magnetic field uniformity based on values obtained from each MR sample 22 in the method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention It is a conceptual diagram.
  • each MR sample obtained by assuming a virtual spherical space in the center of the cylinder and as shown in Fig. 2 is obtained.
  • the process of calculating the magnetic field uniformity for a virtual sphere space by calculating field gradients using the x, y, z coordinate values for (22) and the corresponding magnetic field values and MR spectrum It can be configured to be performed.
  • a magnetic field at a specific point can be expressed as a series of sums of various components, for example, as shown in Equation 1 below, and a set of coordinates and magnetic field values from various samples Using (set), you can calculate each coefficient (Field Gradients).
  • B is a value of a magnetic field at a specific coordinate (x, y, z), and each coefficient (A, B, X, Y, Z, etc.) indicated by a square field is a field.
  • A, B, X, Y, Z, etc. indicated by a square field is a field.
  • the magnetic field values corresponding to the corresponding coordinate values can be directly obtained by using them, so that the magnetic field values for all spaces in the virtual sphere can be derived.
  • the virtual sphere The spatial uniformity of the magnetic field with respect to space can be calculated.
  • a magnetic field mapping database can be constructed by matching the magnetic field values corresponding to the coordinate values (x, y, z).
  • Bmax represents the maximum value of the magnetic field calculated for each coordinate
  • Bmin represents the minimum value of the magnetic field calculated for each coordinate
  • the uniformity of the magnetic field in the sphere can be calculated through the above-described process, and the spatial uniformity in the sphere thus obtained corresponds to an object function required when performing the shimmering operation.
  • the magnetic field at a specific point is displayed as a series containing a plurality of field gradients, and each coefficient is calculated to calculate a magnetic field value corresponding to the corresponding coordinate value, thereby spatial uniformity. Since the details of the method for calculating the contents are self-evident to those skilled in the art with reference to literatures of the prior art, for this reason, in the present invention, as described above, with reference to the literatures of the prior art, etc. It should be noted that the detailed description of the contents that can be easily understood and practiced by those skilled in the art has been omitted.
  • FIG. 4 measures the spatial magnetic field distribution of a magnet according to an embodiment of the present invention It is a flow chart schematically showing the overall configuration of the method.
  • the method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention is divided into a large number and, first, a plurality of MR samples in which RF coils are wound at regular intervals in a magnetic field space inside the magnet are respectively arranged.
  • a virtual sphere-shaped space is assumed in the center of the cylinder, and a field gradient (Field) using the MR spectrum and magnetic field values detected for each MR sample and the x, y, and z coordinate values for each MR sample Gradients) to calculate a magnetic field value corresponding to each coordinate value in a virtual sphere space for each current value set (S43), and calculated for each coordinate
  • a magnetic field uniformity calculation step (S44) for calculating a spatial uniformity in the virtual space, obtain, for each set of current values.
  • the MR sample placement step (S41) instead of placing the RF coil in each part of the human body, for example, the MR sample in which the RF coil is wound at regular intervals along a helical path on the surface of a cylindrical structure. It can be configured to place each, and in this way a cylinder in which a plurality of MR samples are disposed is placed inside the MRI on behalf of the human body.
  • H2O water
  • D2O heavy water
  • a liquid of a molecule containing hydrogen or deuterium After containing and sealing, it may be configured to wind the RF coil a predetermined number of times outside the container, and at this time, it is configured to exhibit the same or similar MR spectrum characteristics as each part of the human body by appropriately adjusting the amount of liquid and the number of coil windings. Can be.
  • the MR is generated from the MR sample according to the applied current value by applying a predetermined value of current (ie, RF pulse) through the RF coil to each MR sample Processing may be performed to detect MR signals each including spectral and magnetic field values.
  • a predetermined value of current ie, RF pulse
  • the magnetic field for space is derived from field gradients obtained by substituting the magnetic field values obtained through respective MR samples into the Harmonic Analysis equation. And coordinate information (x, y, z).
  • the above-described magnetic field uniformity calculation step (S44), as described above with reference to Figure 3 and [Equation 2], the maximum and minimum values of the magnetic field values derived from a combination of field gradients (Field gradients) and coordinate information By calculating the uniformity of the magnetic field with respect to the virtual sphere space, a process of deriving an objective function representing the spatial uniformity of the magnetic field with respect to the virtual sphere space can be performed.
  • the method for measuring the spatial magnetic field distribution of a magnet includes a program configured to execute a processing process of each step configured as described above with reference to FIG. 4 by a computer or dedicated hardware. It can be implemented in the form.
  • the method for measuring the spatial magnetic field distribution of a magnet is configured such that the processing as shown in FIG. 4 is automatically performed with a simple operation of inputting basic settings such as an initial value, thereby being a skilled technician. Without the need for a simple configuration and low cost, the magnetic field distribution measurement of the magnet can be performed safely and accurately.
  • the present invention by using the method for measuring the spatial magnetic field distribution of the magnet according to the embodiment of the present invention configured as described above, by preventing the RF pulse from being applied to the human body when measuring the spatial magnetic field distribution of the magnet In addition to ensuring safety, it is possible to quickly and accurately measure the spatial magnetic field distribution of a magnet and calculate the magnetic field uniformity even when a human body or an object occupies the magnetic field space. In addition, even when the magnetic field uniformity changes during shooting, It is possible to easily measure a magnetic field uniformity measurement device to measure the magnetic field uniformity so that the magnetic field uniformity can be corrected in real time.
  • FIG. 5 is a diagram schematically showing the overall configuration of a magnetic field distribution measuring device 50 of a magnet configured to perform a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
  • the magnetic field distribution measuring device 50 of a magnet is divided into a large number and is fixed along a spiral path on an outer surface of a cylinder-shaped space formed in a magnetic field space inside the magnet. It is configured to include a plurality of MR samples 52 arranged at intervals and an RF coil 53 wound on the surface of each MR sample 52 to generate a magnetic field of a corresponding value according to the supplied current value, wherein ,
  • the above-described cylinder-shaped space is external to the outside by a plurality of shim coils 51 formed to generate a magnetic field having a corresponding value according to the supplied current value, for example, inside the MRI. And surrounding surfaces.
  • the spatial magnetic field distribution measuring apparatus 50 of the above-described magnet although not shown, the current supply 54 for applying a current to each of the shim coil 51 and the RF coil 53, and each MR
  • the signal detector 55 for receiving the MR signal generated from the sample 52 and the current value applied to each of the shim coil 51 and the RF coil 53 are controlled and obtained from each MR sample 52
  • the overall operation of the process of calculating the spatial magnetic field distribution and the spatial uniformity by analyzing the values is controlled, and a control unit 56 configured to control the overall operation of the measurement device 50 may be further included.
  • the above-described current supplier 54 supplies current of a predetermined value to the simcoil 51 and the RF coil 53 under the control of the control unit 56, and the signal detector 55 according to the applied current value Each is configured to measure the generated magnetic field signal and transmit it to the control unit 56. Since it can be suitably configured using the configuration of an existing magnetic field distribution measuring device or a shimmering device, in the present invention, detailed descriptions are provided to simplify the description. It should be noted that the explanation has been omitted.
  • control unit 56 may be configured as a processor that controls the current applied to the simcoil 51 and the RF coil 53 in real time, as described above with reference to FIGS. 2 to 4.
  • a series of processes that measure the spatial magnetic field distribution of the magnet and calculate the magnetic field uniformity are configured to be automatically performed through software processing, thereby ensuring safety by preventing RF pulses from being applied to the human body when measuring the magnetic field distribution of the magnet.
  • the magnetic field uniformity in the center even when the magnetic field uniformity changes during shooting
  • the ball of the magnet that can be measured to correct the magnetic field uniformity in real time.
  • the magnetic field distribution measuring apparatus 50 can be easily implemented.
  • the magnetic field distribution measuring device 50 of the magnet configured as described above, when measuring the spatial magnetic field distribution of the magnet, safety is prevented by applying an RF pulse to the human body.
  • the magnetic field uniformity in the center even when a human body or an object occupies the magnetic field space, the magnetic field uniformity in the center even when the magnetic field uniformity changes during shooting It is possible to measure the magnetic field uniformity in real time, and it is possible to easily implement an MRI device and a shimmering system.
  • the present invention has been described by taking a case in which a plurality of MR samples are arranged to calculate a magnetic field and spatial uniformity by arranging a plurality of MR samples in the magnetic field space of the magnet,
  • the present invention is not necessarily limited to the case of the above-described embodiment, that is, the present invention can be configured by using a general magnetometer, instead of using the MR sample described above.
  • a hollow cylinder-like structure is formed using a non-magnetic material including stainless steel or aluminum, and a magnetometer is used by using a non-magnetic adhesive at a plurality of locations where spatial coordinates on the structure are known.
  • the cylindrical structure is placed in the magnetic field space around the magnet, and the magnetic field values and the coordinate values of each magnetometer measured through each magnetometer are used to simulate the magnetic field in the virtual sphere space and the virtual sphere space.
  • the magnetic field uniformity distribution method is configured to be performed so that a plurality of MR samples are separately manufactured, and a magnetic field distribution measuring method of a magnet according to the present invention and a magnetic field spatial magnetic field distribution measuring device using the same are used. It can be implemented.
  • the method for measuring the distribution of the spatial magnetic field of a magnet according to the present invention and the apparatus for measuring the distribution of the spatial magnetic field of a magnet using the same can be implemented.
  • the coordinates of the space for analyzing the magnetic field distribution of the magnet A magnetic field value measured by placing a plurality of conventional magnetometers at a known location, or a plurality of MR samples and RF coils are arranged to receive a magnetic resonance (MR) signal from each sample, and spectrum analysis of the received signal
  • MR magnetic resonance
  • a magnetic field distribution method of a magnet configured to calculate the magnetic field uniformity in a virtual sphere space located in the center of the cylinder using the magnetic field values obtained through and the field gradients calculated from these values, and the space of the magnet using the magnetic field value
  • magnetic field uniformity during shooting in addition to being able to quickly and accurately measure the spatial magnetic field distribution of a magnet and calculate magnetic field uniformity even when a human body or an object occupies a magnetic field space Even when is changed, it is possible to measure the magnetic field uniformity in the center, and the magnetic field uniformity can be corrected in real time.
  • the present invention by providing a method for measuring the spatial magnetic field distribution of a magnet configured as described above and a device for measuring the spatial magnetic field distribution of a magnet using the same, for example, NMR or MRI, to various equipment using a magnet
  • a method for measuring the spatial magnetic field distribution of a magnet configured as described above
  • a device for measuring the spatial magnetic field distribution of a magnet using the same for example, NMR or MRI
  • the magnetic field uniformity of a device using a magnet is performed.
  • a magnetic resonance (MR) signal generated in the human body is received and analyzed to analyze the spatial magnetic field distribution in response to the RF applied through the RF coil, so that the human body is in a high-power RF environment that may be harmful to safety.
  • the details of the method for measuring the spatial magnetic field distribution of a magnet according to the present invention and the apparatus for measuring the spatial magnetic field distribution of a magnet using the same have been described through the embodiments of the present invention as described above.
  • the present invention is not limited to the contents described, and thus the present invention is capable of various modifications, changes, combinations, and replacements according to design needs and various other factors by those skilled in the art to which the present invention pertains. It is natural that it will.

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Abstract

The present invention relates to a method for measuring the spatial magnetic field distribution of a magnet (superconduction magnet). Provided are a method for measuring the spatial magnetic field distribution of a magnet and a device for measuring the spatial magnetic field distribution of a magnet by using same, which: can ensure security by preventing a high-power RF from being applied to a human body during measurement of the spatial magnetic field distribution of a magnet; can quickly and accurately measure the spatial magnetic field distribution of the magnet and calculate the magnetic field homogeneity of the magnet even when the magnetic field space is occupied by a human body or an object; and can measure the magnetic field homogeneity in the center portion even when the magnetic field homogeneity changes during imaging, and thus correct the magnetic field homogeneity in real time.

Description

자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치Method for measuring spatial magnetic field distribution of magnet and measuring device for spatial magnetic field distribution of magnet using the same
본 발명은 자석(magnet)의 공간 자기장 분포를 측정하기 위한 방법에 관한 것으로, 더 상세하게는, 예를 들면, 자기공명영상(Magnetic Resonance Imaging) 장치(이하, "MRI"라고도 함)나 핵자기공명(Nuclear Magnetic Resonance) 분광장치(이하, "NMR"이라고도 함)와 같이, 자석을 이용한 각종 장비에 있어서 자기장 균일도를 개선하기 위해 자석 주위의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 자석의 공간 자기장 분포를 측정할 수 없는 단점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 자석의 공간 자기장 분포 및 공간 균일도를 신속하고 정확하게 측정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치에 관한 것이다.The present invention relates to a method for measuring a spatial magnetic field distribution of a magnet, and more specifically, for example, a magnetic resonance imaging (hereinafter, also referred to as "MRI") or nuclear magnetic field. Resonance (Nuclear Magnetic Resonance) spectroscopy (hereinafter, also referred to as "NMR"), in various equipment using magnets, in order to improve the magnetic field uniformity, the measurement of the spatial magnetic field around the magnet takes a long measurement time, and In order to solve the problems of the magnetic field spatial magnetic field distribution measuring method and devices of the prior art, which had the disadvantage of being unable to measure the spatial magnetic field distribution of the magnet while the human body or object occupied the magnetic field utilization space, the magnetic field distribution of the magnetic field and A method for measuring the distribution of a spatial magnetic field of a magnet configured to measure the spatial uniformity quickly and accurately, and a spatial magnet of the magnet using the method Distribution relates to a measuring device.
또한, 본 발명은, 종래, 예를 들면, MRI와 같이, 자석을 이용한 장비의 자기장 균일도를 개선하기 위해 행해지는 쉬밍(shimming) 작업에 있어서, RF 코일(coil)을 통해 인가된 RF에 대응하여 인체에서 발생하는 자기공명(magnetic resonance ; MR) 신호를 수신하여 공간 자기장 분포를 분석하도록 구성됨으로 인해, 안전에 유해할 수 있는 고출력 RF 환경에 인체가 더 오래 많이 노출되거나 또는 고자기장 장비일수록 이른바 SAR(Specific Absorption Rate) 핫스팟(hotspot)이라는 국부적인 발열이 발생하여 인체의 안전에 치명적인 데미지를 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 인체에 직접 고출력 RF를 인가하지 않고 해당 장비에 구비된 자석의 공간 자기장 분포를 정확하게 측정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치에 관한 것이다.In addition, the present invention, in the conventional, for example, MRI, in a shimming operation performed to improve the magnetic field uniformity of a device using a magnet, in response to RF applied through an RF coil Because it is configured to receive magnetic resonance (MR) signals generated by the human body and analyze spatial magnetic field distribution, the longer the human body is exposed to high-power RF environments that may be harmful to safety, or the higher the magnetic field equipment, the so-called SAR (Specific Absorption Rate) In order to solve the problems of the magnetic field distribution measuring method and devices of the prior art magnet, which has a problem that can cause fatal damage to the safety of the human body by generating a local heat called a hotspot, It is configured to accurately measure the spatial magnetic field distribution of the magnet provided in the equipment without directly applying high-power RF. The present invention relates to a method for measuring a spatial magnetic field distribution of a magnet and an apparatus for measuring the spatial magnetic field distribution of a magnet using the same.
아울러, 본 발명은, 상기한 바와 같이 자기장 균일도를 개선하기 위하여 자석의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석 주위의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 점유부에 대한 직접 측정이 불가능하며, 따라서 공간 자기장 분포를 분석하기 위해서는 인체에 직접 고출력 RF를 인가해야 함으로 인해 인체에 유해한 영향을 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 자석의 자기장 분포를 분석하고자 하는 공간의 좌표가 알려진 위치에 복수의 통상적인 자력계를 배치하여 측정된 자기장값, 또는, 복수의 MR 샘플 및 RF 코일을 배치하여 각각의 샘플로부터 자기공명(MR) 신호를 수신하고, 수신된 신호에 대한 스펙트럼 분석을 통해 얻어진 자기장값 및 이 값들로 계산된 필드 그라디언트(Field Gradients)를 이용하여 실린더 중앙에 위치한 가상의 구 공간에서의 자기장 균일도를 계산하도록 구성됨으로써, 자석의 공간 자기장 분포 측정시 고출력 RF가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도 측정이 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치에 관한 것이다.In addition, the present invention, as described above, in order to improve the magnetic field uniformity, it takes a long measurement time when measuring the spatial magnetic field distribution of the magnet, and while the human body or an object occupies the magnetic field utilization space around the magnet, the direct Measurement is impossible, therefore, to analyze the spatial magnetic field distribution, it is necessary to apply high-power RF directly to the human body. In order to analyze the magnetic field distribution of a magnet, a magnetic field value measured by arranging a plurality of conventional magnetometers at a location where coordinates of a space to be analyzed is known, or a magnetic resonance from each sample by arranging a plurality of MR samples and RF coils ( MR) A person who receives a signal and obtained through spectral analysis of the received signal It is configured to calculate the magnetic field uniformity in the virtual sphere space located in the center of the cylinder using the field value and the field gradients calculated from these values, so that high-power RF is not applied to the human body when measuring the distribution of the magnetic field in the magnet In addition to ensuring safety, it is possible to quickly and accurately measure the spatial magnetic field distribution of a magnet and calculate the magnetic field uniformity even when a human body or an object occupies the magnetic field space, and even when the magnetic field uniformity changes during shooting. The present invention relates to a method for measuring a spatial magnetic field distribution of a magnet and a device for measuring the spatial magnetic field distribution of a magnet using the magnetic field uniformity measurement in the center so that the magnetic field uniformity can be corrected in real time.
최근, 여러가지 질병 여부나 병변을 보다 명확하게 확인하고 판단하기 위해, 예를 들면, 핵자기공명 분광장치(NMR)나 자기공명 영상장치(MRI)와 같이, 자석 및 자기공명 현상을 이용하여 약, 병리 기작을 분석할 수 있는 연구장비와 인체 내부를 시각적으로 볼 수 있도록 구성되는 진단장비들이 널리 사용되고 있다. Recently, in order to more clearly identify and determine whether various diseases or lesions, for example, nuclear magnetic resonance spectroscopy (NMR) or magnetic resonance imaging (MRI), using a magnet and magnetic resonance phenomenon, Research equipment capable of analyzing pathological mechanisms and diagnostic equipment configured to visually view the inside of the human body are widely used.
즉, 상기한 MRI 장치는, X선을 이용하는 기존의 X-ray 검사나 컴퓨터 단층촬영(Computerized Tomography ; CT) 등과 달리, 자석을 이용하여 인체에 자기장을 인가하는 것에 반응하여 체내의 수소 원자핵이 공명하는 신호를 수신하여 영상을 얻는 것으로, 근육이나 연골 등 연부 조직 질환이나 암 진단을 위해 주로 사용되고 있다. That is, unlike the conventional X-ray examination or computerized tomography (CT) using X-rays, the above-described MRI device reacts with applying a magnetic field to the human body using a magnet to resonate hydrogen atom nuclei in the body. It is used to diagnose soft tissue diseases such as muscles and cartilage or cancer by receiving signals.
여기서, 상기한 바와 같이 자석을 이용한 영상진단장비에 대한 종래기술의 예로는, 예를 들면, 먼저, 한국 공개특허공보 제10-2016-0026567호에 따르면, 자기공명영상 시스템용 RF 코일부에 있어서, 원형 또는 타원 형상의 단면을 지닌 원통형상의 베이스 상에 형성된 적어도 하나의 RF 코일 요소 및 베이스 내부에 형성된 유전 구조체를 포함하여, RF 코일 요소 내부에 유전 구조체를 형성함으로써 자기공명영상 시스템의 체적형 RF 코일부에 의해 발생하는 자기장이 피검체에 전체적으로 균일한 자기장을 인가할 수 있으며, 피검체 전체적으로 균일한 자기장을 인가함으로써 위치에 따른 자기공명영상의 질 저하없이 고해상도의 자기공명영상을 획득할 수 있도록 구성되는 유전 구조체를 포함하는 RF 코일부 및 이를 포함하는 자기공명영상 시스템이 제시된 바 있다. Here, as an example of the prior art for the imaging equipment using a magnet as described above, for example, first, according to Korean Patent Publication No. 10-2016-0026567, in the RF coil unit for a magnetic resonance imaging system Volumetric RF of a magnetic resonance imaging system by forming a dielectric structure inside an RF coil element, including at least one RF coil element formed on a cylindrical base having a circular or elliptical cross-section and a dielectric structure formed inside the base. The magnetic field generated by the coil unit can apply a uniform magnetic field to the subject as a whole, and by applying a uniform magnetic field to the subject as a whole, so that a high-resolution magnetic resonance image can be obtained without deteriorating the quality of the magnetic resonance image according to the position. An RF coil unit including a dielectric structure, and a magnetic resonance imaging system including the same, have been proposed. have.
또한, 상기한 바와 같이 자석을 이용한 영상진단장비에 대한 종래기술의 다른 예로는, 예를 들면, 한국 등록특허공보 제10-1860228호에 따르면, 신체에 밀착되도록 위치하는 복수개의 수신코일; 및 신체와 이격되어 설치되며 수신코일과 RF 공진되는 복수개의 송신코일을 포함하고, 상기 수신코일은, 양단부 사이가 만곡된 스트립 형상의 제 1 코일부; 및 양단부 사이가 만곡된 스트립 형상이고 제 1 코일부와 이격되게 설치되는 제 2 코일부로 구성되며, 제 1, 2 코일부의 일단부가 상호 이격되어 제 1 캐패시터를 형성하고, 제 1, 2 코일부의 타단부가 상호 이격되어 제 2 캐패시터를 형성하며, 일단부와 타단부중 한곳에는 배선부가 연장형성되고, 제 1, 2 코일부는 각각 반원형으로 만곡되도록 구성됨으로써, 7T와 같은 초고자기장 MRI 분야에서 균질한 자기장과 고해상도의 영상을 얻을 수 있으며, 특히, 머리에 최대한 밀착하여 뇌를 보다 정확하고 상세하게 관찰할 수 있도록 구성되는 자기공명 영상시스템에서의 송수신 RF 공진기가 제시된 바 있다. In addition, as another example of the prior art for the image diagnosis equipment using a magnet as described above, for example, according to Korean Patent Publication No. 10-1860228, a plurality of receiving coils positioned to be in close contact with the body; And a plurality of transmission coils spaced apart from the body and RF-resonated with the reception coil, the reception coil comprising: a first coil portion in a strip shape curved between both ends; And a second coil portion that is curved in shape between both ends and installed to be spaced apart from the first coil portion, and one end of the first and second coil portions is spaced apart from each other to form a first capacitor, and the first and second coil portions are formed. The other ends of the spacers are spaced apart from each other to form a second capacitor, and one of the ends and the other ends of the wiring part is formed to be extended, and the first and second coil parts are configured to be curved in a semicircle, respectively, in an ultra-high magnetic field MRI field such as 7T. A homogeneous magnetic field and a high-resolution image can be obtained. In particular, a RF resonator has been proposed in a magnetic resonance imaging system that is configured to be able to observe the brain more accurately and in detail as close as possible to the head.
상기한 바와 같이, 종래, 자석을 이용한 영상진단장비에 대하여 여러 가지 기술내용들이 제시된 바 있으나, 상기한 바와 같은 종래기술의 장치들은 다음과 같은 문제점이 있는 것이었다. As described above, in the related art, various technical contents have been proposed for the image diagnosis equipment using a magnet, but the devices of the prior art as described above have the following problems.
즉, 일반적으로, 상기한 바와 같은 종래기술의 MRI와 같은 장치들은, 최초 사용시 자석의 공간 자기장 분포를 측정하여 자기장의 균일도를 보정하는 쉬밍(shimming) 작업이 필요하고, 이와 같이 MRI에서 영상이미지를 취득하거나 또는 자기장 균일도를 개선하기 위한 쉬밍작업을 수행하기 위하여는 인체를 감싸고 있는 RF 코일에 펄스를 인가하는 과정이 필수적이다. That is, in general, devices such as the MRI of the prior art as described above require a shimming operation that corrects the uniformity of the magnetic field by measuring the distribution of the magnetic field at the time of first use, and thus the image of the image in MRI is required. In order to acquire or perform a shimmering operation to improve the magnetic field uniformity, a process of applying a pulse to the RF coil surrounding the human body is essential.
여기서, 일반적으로, MRI의 자기장 세기가 강할수록 영상의 정확도가 개선되나 자기장이 강해질수록 RF 코일에 의한 전자기파 세기 분포도 불균일해짐으로 인해, 고자기장 MRI일수록 이른바 SAR(Specific Absorption Rate) 핫스팟(hotspot)이라는 국부적인 발열이 발생하여 인체의 안전에 유해한 영향을 미칠 수 있는 문제점이 있었다. Here, in general, as the magnetic field strength of the MRI increases, the accuracy of the image improves, but as the magnetic field increases, the electromagnetic wave intensity distribution by the RF coil becomes non-uniform, and the higher the magnetic field MRI, the so-called SAR (Specific Absorption Rate) hotspot. There was a problem that local fever occurred and could have a detrimental effect on the safety of the human body.
아울러, 최근에는, 초전도자석 기술 및 MRI 영상장치 기술의 발전으로 고자기장 MRI의 실현 가능성이 높아짐으로 인해 현재 7 테슬라(T) MRI의 병원 설치가 임박하였고, 이에 더하여 14T MRI의 필요성도 대두되고 있으나, 상기한 바와 같은 종래기술의 MRI 장치들은 고자기장 MRI로 갈수록 인체에 치명적인 대미지를 미칠 수 있는 위험성이 더욱 심각해진다는 문제점도 있다. In addition, in recent years, due to the development of superconducting magnet technology and MRI imaging device technology, the possibility of realizing a high magnetic field MRI is increasing, and the establishment of a hospital for 7 Tesla (T) MRI is imminent, and in addition, the need for 14T MRI is emerging. , As described above, the MRI devices of the prior art have a problem that the risk of fatal damage to the human body becomes more serious as the MRI of the high magnetic field increases.
더욱이, 일반적으로, MRI는 영상촬영을 위해 인체가 자기장 공간으로 들어간 후에도 해상도 증가를 위하여 자기장 균일도를 측정하고 그에 따른 쉬밍작업을 통해 자기장 균일도를 보정하는 과정이 필요하나, 종래기술의 자기장 분포 측정장치들은 자석 주위의 자기장 활용공간을 인체나 프로브 등과 같은 물체가 점유하고 있는 동안에는 측정장치가 관심영역으로 접근할 수 없으므로 자기장 공간균일도를 산출할 수 없으며, 이에 더하여, 기존의 자기장 공간균일도 측정방식은 자기장 분포 측정장치를 기계적으로 회전시키면서 측정함으로 인해 측정시간이 오래 걸리는 단점도 있었다. Moreover, in general, MRI requires the process of measuring the magnetic field uniformity to increase the resolution even after the human body enters the magnetic field space for imaging and correcting the magnetic field uniformity through the shing operation accordingly, but the magnetic field distribution measuring device of the prior art The magnetic field spatial uniformity cannot be calculated because the measuring device cannot access the region of interest while an object such as a human body or a probe occupies the magnetic field utilization space around the magnets. In addition, the conventional magnetic field spatial uniformity measurement method uses a magnetic field There is also a disadvantage that the measurement takes a long time due to the measurement while rotating the distribution measuring device mechanically.
이에, 상기한 바와 같이, 인체에 직접 고출력 RF가 인가됨으로 인해 인체의 안전에 유해한 영향을 미칠 수 있는 문제점과, 자석의 자기장 활용공간에 물체가 위치되어 있는 동안에는 자기장 공간균일도를 산출할 수 없는 문제점 및 측정시간이 오래 걸리는 단점이 있었던 종래기술의 자석의 공간 자기장 분포 측정장치 및 방법들의 문제점을 해결하기 위해서는, 자석의 공간 자기장 분포 측정시 고출력 RF가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하고, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 동시에, 진단영상 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도를 측정 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 새로운 구성의 자석의 공간 자기장 분포 측정방법 및 장치를 제시하는 것이 바람직하나, 아직까지 그러한 요구를 모두 만족시키는 장치나 방법은 제시되지 못하고 있는 실정이다.Thus, as described above, a problem that may have a detrimental effect on the safety of the human body due to the application of high-power RF directly to the human body, and the problem that the magnetic field spatial uniformity cannot be calculated while an object is located in the magnetic field using the magnetic field And in order to solve the problems of the magnetic field distribution measuring device and methods of the prior art magnet, which had the disadvantage of taking a long measurement time, ensure safety by preventing high-power RF from being applied to the human body when measuring the magnetic field distribution of the magnet. , Even if a human body or an object occupies a magnetic field space, it is possible to quickly and accurately measure the magnetic field distribution of the magnet and calculate the magnetic field uniformity, and at the same time, measure the magnetic field uniformity in the center even when the magnetic field uniformity changes during the imaging of a diagnostic image. Possible to correct magnetic field uniformity in real time One may be desirable to present the spatial magnetic field distribution measuring method and apparatus of the magnets of the new configuration, the device or the method of yet to meet all such requirements is configured to have a situation that does not present.
본 발명은 상기한 바와 같은 종래기술의 문제점을 해결하고자 하는 것으로, 따라서 본 발명의 목적은, 예를 들면, NMR이나 MRI와 같이, 자석을 이용한 각종 장비에 있어서, 자기장 균일도를 개선하기 위해 자석의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석 주위의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 자석의 공간 자기장 분포를 측정할 수 없는 단점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 자석의 공간 자기장 분포 및 공간 균일도를 신속하고 정확하게 측정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치를 제공하고자 하는 것이다. The present invention is intended to solve the problems of the prior art as described above, and therefore the object of the present invention is to improve the magnetic field uniformity in various equipment using magnets, for example, NMR or MRI. When measuring the spatial magnetic field distribution, it took a long time to measure, and while the human body or object occupied the magnetic field utilization space around the magnet, it was impossible to measure the spatial magnetic field distribution of the magnet. And to solve the problems of the devices, to provide a magnetic field distribution measurement method of a magnet and a spatial magnetic field distribution measurement device of the magnet using the same, which is configured to quickly and accurately measure the spatial magnetic field distribution and spatial uniformity of the magnet.
또한, 본 발명의 다른 목적은, MRI와 같이 자석을 이용한 장비의 자기장 균일도를 개선하기 위해 행해지는 쉬밍 작업에 있어서, RF 코일을 통해 인가된 RF에 대응하여 인체에서 발생하는 자기공명(MR) 신호를 수신하여 공간 자기장 분포를 분석하도록 구성됨으로 인해, 안전에 유해할 수 있는 고출력 RF 환경에 인체가 더 오래 많이 노출되거나 또는 고자기장 장비일수록 이른바 SAR 핫스팟이라는 국부적인 발열이 발생하여 인체의 안전에 치명적인 데미지를 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 인체에 직접 고출력 RF를 인가하지 않고 해당 장비에 구비된 자석의 공간 자기장 분포를 정확하게 측정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치를 제공하고자 하는 것이다. In addition, another object of the present invention is a magnetic resonance (MR) signal generated in the human body in response to RF applied through an RF coil in a shimmering operation performed to improve the magnetic field uniformity of a device using a magnet such as an MRI. Because it is configured to receive and analyze the spatial magnetic field distribution, the longer the human body is exposed to a high power RF environment that may be harmful to safety, or the higher the magnetic field equipment, the more local heat called SAR hotspot occurs, which is fatal to human safety. In order to solve the problems of the method and devices for measuring the spatial magnetic field distribution of the prior art magnet, which had a problem that could cause damage, the spatial magnetic field distribution of the magnet provided in the corresponding equipment was accurately measured without applying high power RF directly to the human body. Method for measuring the spatial magnetic field distribution of a magnet that is configured to Liver intended to provide a magnetic field distribution measuring apparatus.
아울러, 본 발명의 또 다른 목적은, 상기한 바와 같이 자기장 균일도를 개선하기 위하여 자석의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석 주위의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 점유부에 대한 직접 측정이 불가능하며, 따라서 공간 자기장 분포를 분석하기 위해서는 인체에 직접 고출력 RF를 인가해야 함으로 인해 인체에 유해한 영향을 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 자석의 자기장 분포를 분석하고자 하는 공간의 좌표가 알려진 위치에 복수의 통상적인 자력계를 배치하여 측정된 자기장값, 또는, 복수의 MR 샘플 및 RF 코일을 배치하여 각각의 샘플로부터 자기공명(MR) 신호를 수신하고, 수신된 신호에 대한 스펙트럼 분석을 통해 얻어진 자기장값 및 이 값들로 계산된 필드 그라디언트(Field Gradients)를 이용하여 실린더 중앙에 위치한 가상의 구 공간에서의 자기장 균일도를 계산하도록 구성됨으로써, 자석의 공간 자기장 분포 측정시 고출력 RF가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도 측정이 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치를 제공하고자 하는 것이다.In addition, another object of the present invention, as described above, in order to improve the magnetic field uniformity, it takes a long measurement time when measuring the spatial magnetic field distribution of the magnet, while the human body or an object occupies the magnetic field utilization space around the magnet. It is not possible to measure the magnetic field directly. Therefore, in order to analyze the spatial magnetic field distribution, the method and apparatus for measuring the spatial magnetic field distribution of a prior art magnet, which had a problem that could have a detrimental effect on the human body due to the direct application of high power RF to the human body In order to solve the problem, the magnetic field value measured by arranging a plurality of conventional magnetometers at a location where the coordinates of the space to analyze the magnetic field distribution of the magnet is known, or, by arranging a plurality of MR samples and RF coils, each sample Magnetic resonance (MR) signal from the spectral analysis of the received signal It is configured to calculate the magnetic field uniformity in a virtual sphere space located in the center of the cylinder by using the magnetic field value obtained through and the field gradients calculated from these values, so that high power RF is applied to the human body when measuring the distribution of the magnetic field in the magnetic field In addition to ensuring safety by not being prevented, even when a human body or an object occupies a magnetic field space, it is possible to quickly and accurately measure the spatial magnetic field distribution of the magnet and calculate the magnetic field uniformity, and also changes the magnetic field uniformity during shooting In order to provide a magnetic field uniformity measurement in the center, a magnetic field uniformity distribution method of a magnet configured to correct the magnetic field uniformity in real time, and a magnetic field distribution magnetic field distribution measuring apparatus using the same.
상기한 바와 같은 목적을 달성하기 위해, 본 발명에 따르면, 자석의 공간 자기장 분포 측정방법에 있어서, 자석 주위의 자기장 공간에 복수의 MR(magnetic resonance) 샘플을 각각 배치하는 배치단계; 각각의 상기 MR 샘플에 미리 정해진 값의 전류(RF 펄스)를 인가하고, 인가된 전류값에 따라 각각의 상기 MR 샘플로부터 발생되는 MR 신호를 검출하는 검출단계; 상기 MR 신호 검출단계에서 각각의 상기 MR 샘플에 대하여 검출된 상기 MR 신호에 근거하여 각각의 상기 MR 샘플의 각 좌표값에 대응하는 자기장 값을 산출하는 자기장 산출단계; 및 상기 자기장 산출단계에서 각각의 상기 MR 샘플의 좌표별로 산출된 자기장 값에 근거하여 상기 자석의 자기장에 대한 공간균일도를 산출하는 자기장 균일도 산출단계를 포함하는 처리과정이 컴퓨터나 전용의 하드웨어에 의해 수행되도록 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법이 제공된다. In order to achieve the above object, according to the present invention, a method for measuring a spatial magnetic field distribution of a magnet, comprising: a placement step of arranging a plurality of magnetic resonance (MR) samples in a magnetic field space around the magnet, respectively; A detection step of applying a current (RF pulse) of a predetermined value to each of the MR samples and detecting an MR signal generated from each of the MR samples according to the applied current value; A magnetic field calculation step of calculating a magnetic field value corresponding to each coordinate value of each MR sample based on the MR signal detected for each MR sample in the MR signal detection step; And a magnetic field uniformity calculating step of calculating a spatial uniformity degree of the magnetic field of the magnet based on the magnetic field values calculated for each MR sample coordinate in the magnetic field calculating step. A method for measuring the spatial magnetic field distribution of a magnet is provided.
여기서, 상기 배치단계는, 스테인리스강(Stainless steel) 또는 알루미늄을 포함하는 비자성물질을 이용하여 속이 빈 통 형태의 구조물을 형성하고, 상기 구조물 상의 공간좌표가 알려진 복수의 위치에 RF 코일이 감겨진 복수의 MR 샘플을 각각의 공간좌표 위치에 배치하며, 비자성 접착제를 포함하는 부착수단을 이용하여 각각의 상기 MR 샘플을 상기 통 형태의 구조물의 공간좌표 위치에 각각 고정시킨 후, 상기 통 형태의 구조물을 상기 자석 주위의 자기장 공간에 위치시키는 것에 의해, 상기 자석 주위의 자기장 공간에 복수의 상기 MR 샘플을 각각 배치하는 처리가 수행되도록 구성되는 것을 특징으로 한다. Here, the placement step, using a non-magnetic material including stainless steel (Stainless steel) or aluminum to form a hollow cylindrical structure, the RF coil is wound at a plurality of locations where the spatial coordinates on the structure are known A plurality of MR samples are disposed at respective spatial coordinate positions, and each MR sample is fixed at the spatial coordinate positions of the cylindrical structure using an attachment means including a non-magnetic adhesive, and then the cylindrical It is characterized in that, by placing the structure in a magnetic field space around the magnet, a process of placing a plurality of the MR samples in a magnetic field space around the magnet is performed.
또한, 상기 검출단계는, 각각의 상기 MR 샘플들로부터 MR 스펙트럼 및 자기장 값을 포함하는 상기 MR 신호를 검출하도록 구성되는 것을 특징으로 한다. In addition, the detecting step is characterized in that it is configured to detect the MR signal including the MR spectrum and the magnetic field value from each of the MR samples.
아울러, 상기 자기장 산출단계는, 상기 MR 신호 검출단계에서 검출된 각각의 상기 MR 신호의 스펙트럼 분석을 행하여 스펙트럼상 최대값에 해당하는 X축상(주파수)의 값을 해당 MR 샘플에 대한 자기장 값으로 산출하며, 상기 통 형태의 구조물의 공간 중앙에 가상의 구 공간을 설정하고, 각각의 상기 MR 샘플들에 대한 좌표값(x, y, z)과 상기 MR 신호로부터 산출된 자기장 값을 이용하여 필드 그라디언트(Field gradients)를 계산하며, 산출된 각각의 필드 그라디언트를 이용하여 각각의 상기 MR 샘플의 좌표값에 대응하는 자기장 값을 계산하는 것에 의해 상기 가상의 구 공간에서의 자기장을 산출하는 처리가 수행되도록 구성되는 것을 특징으로 한다. In addition, in the magnetic field calculation step, spectrum analysis of each MR signal detected in the MR signal detection step is performed to calculate a value of the X-axis (frequency) corresponding to the maximum value in the spectrum as a magnetic field value for the corresponding MR sample. A virtual gradient is set in the center of the space of the cylindrical structure, and a field gradient is used using coordinate values (x, y, z) for each of the MR samples and magnetic field values calculated from the MR signal. (Field gradients) is calculated, and a process of calculating a magnetic field in the virtual sphere space is performed by calculating a magnetic field value corresponding to a coordinate value of each MR sample using each calculated field gradient. It is characterized by being configured.
더욱이, 상기 자기장 균일도 산출단계는, 이하의 수학식을 이용하여, 상기 자기장 산출단계에서 상기 가상의 구 공간에 대하여 각각의 좌표별로 산출된 자기장 값들의 최대치와 최소치를 이용하여 상기 가상의 구 공간에 대한 자기장 균일도를 산출하는 처리가 수행되도록 구성되는 것을 특징으로 한다. Furthermore, in the step of calculating the magnetic field uniformity, the maximum and minimum values of the magnetic field values calculated for each coordinate with respect to the virtual sphere space in the magnetic field calculation step are used to calculate the magnetic sphere uniformity using the following equation. It is characterized in that it is configured to perform a process for calculating the magnetic field uniformity for.
Figure PCTKR2019014812-appb-I000001
Figure PCTKR2019014812-appb-I000001
(여기서,Bmax는 각각의 좌표별로 산출된 자기장의 최대값, Bmin는 각각의 좌표별로 산출된 자기장의 최소값을 각각 나타냄) (Where, Bmax is the maximum value of the magnetic field calculated for each coordinate, Bmin represents the minimum value of the magnetic field calculated for each coordinate)
또한, 상기 측정방법은, 사용자 인터페이스(User Interface ; UI)를 통하여 초기값을 포함하는 기초적인 설정을 입력하면 상기 MR 신호 검출단계, 상기 자기장 산출단계, 상기 자기장 균일도 산출단계의 처리과정이 자동으로 수행되도록 구성되는 것을 특징으로 한다. In addition, in the measurement method, when a basic setting including an initial value is input through a user interface (UI), processing of the MR signal detection step, the magnetic field calculation step, and the magnetic field uniformity calculation step is automatically performed. It is characterized by being configured to be performed.
아울러, 상기 측정방법은, 상기 배치단계에서, 상기 MR 샘플 대신에 복수의자력계를 각각 배치하고, 상기 검출단계에서, 각각의 상기 자력계를 통하여 자기장값을 측정하며, 상기 자기장 산출단계 및 상기 자기장 균일도 산출단계에서, 각각의 상기 자력계의 좌표값 및 각각의 상기 자력계를 통하여 측정된 자기장값에 근거하여 상기 가상의 구 공간에서의 자기장 및 상기 가상의 구 공간에 대한 자기장 균일도를 각각 산출하는 처리가 수행되도록 구성되는 것을 특징으로 한다. In addition, in the measuring step, a plurality of magnetometers are respectively disposed in place of the MR sample in the arrangement step, and in the detection step, magnetic field values are measured through each magnetometer, and the magnetic field calculation step and the magnetic field uniformity are measured. In the calculating step, a process of calculating the magnetic field uniformity in the virtual sphere space and the magnetic field uniformity in the virtual sphere space is performed based on the coordinate values of each magnetometer and the magnetic field values measured through each magnetometer. It is characterized by being configured as possible.
더욱이, 상기 MR 샘플은, 수소나 중수소, 또는, 수소 및 중수소를 포함하지 않는 소재로 이루어진 용기에 미리 정해진 양의 물(H2O)이나 중수(D2O) 또는 수소나 중수소를 포함하는 분자의 액체를 담고 밀봉한 후, 상기 용기 외부에 미리 정해진 횟수로 RF 코일을 감아 구성되는 것을 특징으로 한다. Moreover, the MR sample contains a predetermined amount of water (H2O) or heavy water (D2O) or a liquid of a molecule containing hydrogen or deuterium in a container made of hydrogen or deuterium, or a material containing no hydrogen and deuterium. After sealing, it is characterized by being configured to wind the RF coil a predetermined number of times outside the container.
또한, 본 발명에 따르면, 상기에 기재된 자석의 공간 자기장 분포 측정방법을 이용하여 자석의 공간 자기장 분포 및 자기장 균일도를 산출하도록 구성되는 자석의 공간 자기장 분포 측정장치에 있어서, 자석의 자기장 내부에 미리 정해진 간격으로 각각 배치되는 복수의 자력계 또는 복수의 MR 샘플; 미리 정해진 값의 전류를 인가하기 위한 전류공급기; 상기 전류공급기를 통하여 인가된 전류에 의해 발생되는 MR 신호를 수신하기 위한 신호검출기; 및 상기 측정장치의 전체적인 동작을 제어하고, 상기 신호검출기를 통하여 검출된 상기 MR 신호를 분석하여 상기 자석의 공간 자기장 분포 및 자기장 균일도를 산출하는 처리가 수행되도록 이루어지는 제어부를 포함하여 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정장치가 제공된다. In addition, according to the present invention, in the apparatus for measuring the spatial magnetic field distribution of a magnet, which is configured to calculate the spatial magnetic field distribution and the magnetic field uniformity of the magnet using the method for measuring the spatial magnetic field distribution of the magnet described above, the magnetic field of the magnet is determined in advance A plurality of magnetometers or a plurality of MR samples arranged at intervals, respectively; A current supply for applying a current of a predetermined value; A signal detector for receiving an MR signal generated by the current applied through the current supply; And a control unit configured to control the overall operation of the measuring device and analyze the MR signal detected through the signal detector to perform the process of calculating the spatial magnetic field distribution and magnetic field uniformity of the magnet. An apparatus for measuring the spatial magnetic field distribution of a magnet is provided.
아울러, 본 발명에 따르면, 자석의 자기장 균일도를 개선하기 위한 쉬밍시스템에 있어서, 상기에 기재된 자석의 공간 자기장 분포 측정장치를 포함하여 구성되는 것을 특징으로 하는 쉬밍시스템이 제공된다.In addition, according to the present invention, in the shimmering system for improving the magnetic field uniformity of the magnet, there is provided a shimmering system characterized in that it comprises a spatial magnetic field distribution measuring device of the magnet described above.
상기한 바와 같이, 본 발명에 따르면, 자석의 자기장 분포를 분석하고자 하는 공간의 좌표가 알려진 위치에 복수의 통상적인 자력계를 배치하여 측정된 자기장값, 또는, 복수의 MR 샘플 및 RF 코일을 배치하여 각각의 샘플로부터 자기공명(MR) 신호를 수신하고, 수신된 신호에 대한 스펙트럼 분석을 통해 얻어진 자기장값 및 이 값들로 계산된 필드 그라디언트(Field Gradients)를 이용하여 실린더 중앙에 위치한 가상의 구 공간에서의 자기장 균일도를 계산하도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치가 제공됨으로써, 자석의 공간 자기장 분포 측정시 고출력 RF가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도 측정이 가능하여 자기장 균일도를 실시간으로 보정할 수 있다. As described above, according to the present invention, a magnetic field value measured by arranging a plurality of conventional magnetometers at a location where a coordinate of a space to analyze a magnetic field distribution of a magnet is known, or by arranging a plurality of MR samples and RF coils A magnetic resonance (MR) signal is received from each sample, and a magnetic sphere value obtained through spectral analysis on the received signal and field gradients calculated from these values are used in a virtual sphere space located in the center of the cylinder. A magnetic field distribution measuring method of a magnet configured to calculate the magnetic field uniformity of a magnet and a spatial magnetic field distribution measuring device using the magnet are provided, thereby ensuring safety by preventing high-power RF from being applied to the human body when measuring the magnetic field distribution of the magnet At the same time, even if a human body or an object occupies a magnetic field space, it is quick and accurate. In addition to having to measure the spatial distribution of the magnetic field of the magnet and calculates the magnetic field uniformity may be even if the magnetic field uniformity changes during recording by the magnetic field uniformity can be measured at the center to compensate for the magnetic field uniformity in real time.
또한, 본 발명에 따르면, 상기한 바와 같이 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치가 제공됨으로써, 예를 들면, NMR이나 MRI와 같이, 자석을 이용한 각종 장비에 있어서, 자기장 균일도를 개선하기 위해 자석의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석 주위의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 자석의 공간 자기장 분포를 측정할 수 없는 단점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결할 수 있다. In addition, according to the present invention, by providing a method for measuring the spatial magnetic field distribution of a magnet constituted as described above and a device for measuring the spatial magnetic field distribution of a magnet using the same, for example, NMR or MRI, to various equipment using a magnet In order to improve the magnetic field uniformity, it took a long time to measure the magnetic field distribution of the magnet, and while the human body or object occupied the magnetic field utilization space around the magnet, it was impossible to measure the magnetic field distribution of the magnet. It is possible to solve the problems of the method and devices for measuring the spatial magnetic field distribution of a prior art magnet.
아울러, 본 발명에 따르면, 상기한 바와 같이 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치가 제공됨으로써, MRI와 같이 자석을 이용한 장비의 자기장 균일도를 개선하기 위해 행해지는 쉬밍 작업에 있어서, RF 코일을 통해 인가된 RF에 대응하여 인체에서 발생하는 자기공명(MR) 신호를 수신하여 공간 자기장 분포를 분석하도록 구성됨으로 인해, 안전에 유해할 수 있는 고출력 RF 환경에 인체가 더 오래 많이 노출되거나 또는 고자기장 장비일수록 이른바 SAR 핫스팟이라는 국부적인 발열이 발생하여 인체의 안전에 치명적인 데미지를 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결할 수 있다.In addition, according to the present invention, by providing a method for measuring the spatial magnetic field distribution of a magnet constituted as described above and an apparatus for measuring the spatial magnetic field distribution of a magnet using the same, the magnetic field uniformity of a device using a magnet, such as MRI, is performed. In the shimmering operation, a magnetic resonance (MR) signal generated in the human body is received and analyzed to analyze the spatial magnetic field distribution in response to the RF applied through the RF coil, so that the human body is in a high-power RF environment that may be harmful to safety. The longer the exposure, or the higher the magnetic field equipment, the so-called SAR hot spot, the local heat generated, which can cause fatal damage to the safety of the human body. have.
도 1은 종래기술의 MRI 장치의 구성을 개략적으로 나타내는 도면이다. 1 is a view schematically showing the configuration of a prior art MRI device.
도 2는 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법에서 인체에 직접 고출력 RF를 인가하지 않고 MR 스펙트럼 신호를 취득하는 과정을 개략적으로 나타내는 개념도이다. 2 is a conceptual diagram schematically showing a process of acquiring an MR spectrum signal without applying high power RF directly to a human body in a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
도 3은 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법에서 각각의 MR 샘플들로부터 얻어진 값들에 근거하여 자기장 균일도를 산출하는 과정을 개략적으로 나타내는 개념도이다. 3 is a conceptual diagram schematically showing a process of calculating magnetic field uniformity based on values obtained from respective MR samples in a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
도 4는 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법의 전체적인 구성을 개략적으로 나타내는 플로차트이다. 4 is a flowchart schematically showing the overall configuration of a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
도 5는 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법을 이용한 자석의 공간 자기장 분포 측정장치의 전체적인 구성을 개략적으로 나타내는 도면이다.5 is a view schematically showing the overall configuration of a magnetic field distribution measuring device of a magnet using a method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
이하, 첨부된 도면을 참조하여, 본 발명에 따른 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치의 구체적인 실시예에 대하여 설명한다. Hereinafter, a specific embodiment of a method for measuring a spatial magnetic field distribution of a magnet according to the present invention and a device for measuring a spatial magnetic field distribution of a magnet using the same will be described with reference to the accompanying drawings.
여기서, 이하에 설명하는 내용은 본 발명을 실시하기 위한 하나의 실시예일 뿐이며, 본 발명은 이하에 설명하는 실시예의 내용으로만 한정되는 것은 아니라는 사실에 유념해야 한다. Here, it should be noted that the contents described below are only one embodiment for carrying out the present invention, and the present invention is not limited to the contents of the embodiments described below.
또한, 이하의 본 발명의 실시예에 대한 설명에 있어서, 종래기술의 내용과 동일 또는 유사하거나 당업자의 수준에서 용이하게 이해하고 실시할 수 있다고 판단되는 부분에 대하여는, 설명을 간략히 하기 위해 그 상세한 설명을 생략하였음에 유념해야 한다. In addition, in the following description of the embodiments of the present invention, the same or similar to the contents of the prior art, or a portion determined to be easily understood and practiced at the level of those skilled in the art, for the sake of brevity of the detailed description Note that is omitted.
즉, 본 발명은, 후술하는 바와 같이, 예를 들면, NMR이나 MRI와 같이, 자석을 이용한 각종 장비에 있어서, 자기장 균일도를 개선하기 위해 자석의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석 주위의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 자석의 공간 자기장 분포를 측정할 수 없는 단점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 자석의 공간 자기장 분포 및 공간 균일도를 신속하고 정확하게 측정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치에 관한 것이다. That is, the present invention, as described later, for example, in NMR or MRI, in various equipment using magnets, in order to improve the magnetic field uniformity, it takes a long measurement time to measure the spatial magnetic field distribution of the magnet, the magnet In order to solve the problems of the magnetic field spatial magnetic field distribution measuring method and devices of the prior art, the magnetic field distribution of the magnet was unable to measure the spatial magnetic field distribution of the magnet while the human body or the object occupied the surrounding magnetic field. The present invention relates to a method for measuring a spatial magnetic field distribution of a magnet and a device for measuring the spatial magnetic field distribution of a magnet using the same, which is configured to quickly and accurately measure distribution and spatial uniformity.
아울러, 본 발명은, 후술하는 바와 같이, MRI와 같이 자석을 이용한 장비의 자기장 균일도를 개선하기 위해 행해지는 쉬밍 작업에 있어서, RF 코일을 통해 인가된 RF에 대응하여 인체에서 발생하는 자기공명(MR) 신호를 수신하여 공간 자기장 분포를 분석하도록 구성됨으로 인해, 안전에 유해할 수 있는 고출력 RF 환경에 인체가 더 오래 많이 노출되거나 또는 고자기장 장비일수록 이른바 SAR 핫스팟이라는 국부적인 발열이 발생하여 인체의 안전에 치명적인 데미지를 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 인체에 직접 고출력 RF를 인가하지 않고 해당 장비에 구비된 자석의 공간 자기장 분포를 정확하게 측정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치에 관한 것이다. In addition, the present invention, as described later, in the reaming operation performed to improve the magnetic field uniformity of the equipment using a magnet, such as MRI, magnetic resonance (MR) generated in the human body corresponding to the RF applied through the RF coil ) Because it is configured to receive signals and analyze the distribution of the spatial magnetic field, the longer the human body is exposed to a high-power RF environment that may be harmful to safety, or the higher the magnetic field equipment, the so-called local heating called SAR hotspot, resulting in human safety In order to solve the problems of the methods and devices for measuring the magnetic field distribution of a prior art magnet, which had a problem that could cause fatal damage to the magnetic field, the magnetic field distribution of the magnet provided in the corresponding equipment was not accurately applied to the human body. Method for measuring spatial magnetic field distribution of magnets configured to be measured and using the same It relates to a spatial magnetic field distribution measuring apparatus of a magnet.
더욱이, 본 발명은, 후술하는 바와 같이, 자기장 균일도를 개선하기 위하여 자석의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석 주위의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 점유부에 대한 직접 측정이 불가능하며, 따라서 공간 자기장 분포를 분석하기 위해서는 인체에 직접 고출력 RF를 인가해야 함으로 인해 인체에 유해한 영향을 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결하기 위해, 자석의 자기장 분포를 분석하고자 하는 공간의 좌표가 알려진 위치에 복수의 통상적인 자력계를 배치하여 측정된 자기장값, 또는, 복수의 MR 샘플 및 RF 코일을 배치하여 각각의 샘플로부터 자기공명(MR) 신호를 수신하고, 수신된 신호에 대한 스펙트럼 분석을 통해 얻어진 자기장값 및 이 값들로 계산된 필드 그라디언트(Field Gradients)를 이용하여 실린더 중앙에 위치한 가상의 구 공간에서의 자기장 균일도를 계산하도록 구성됨으로써, 자석의 공간 자기장 분포 측정시 고출력 RF가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도 측정이 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치에 관한 것이다. Moreover, the present invention, as will be described later, takes a long measurement time when measuring the spatial magnetic field distribution of a magnet in order to improve the magnetic field uniformity, while the human body or an object occupies the magnetic field utilization space around the magnet, Direct measurement is not possible. Therefore, in order to analyze the distribution of the spatial magnetic field, it is necessary to apply high-power RF directly to the human body. To solve this, the magnetic field value measured by arranging a plurality of conventional magnetometers at a location where the coordinates of the space to analyze the magnetic field distribution of the magnet is known, or a magnetic resonance from each sample by arranging a plurality of MR samples and RF coils (MR) signal received, obtained through spectral analysis of the received signal It is configured to calculate the magnetic field uniformity in the virtual sphere space located in the center of the cylinder using the magnetic field value and the field gradients calculated from these values, so that high-power RF is not applied to the human body when measuring the magnetic field distribution of the magnet In addition to ensuring safety by doing so, even when a human body or an object occupies a magnetic field space, in addition to being able to quickly and accurately measure the magnetic field distribution of the magnet and calculate the magnetic field uniformity, when the magnetic field uniformity changes during shooting The present invention relates to a method for measuring the spatial magnetic field distribution of a magnet and a device for measuring the spatial magnetic field distribution of a magnet using the same, which is capable of measuring the magnetic field uniformity in the center of Edo and correcting the magnetic field uniformity in real time.
계속해서, 도면을 참조하여, 본 발명에 따른 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치의 구체적인 내용에 대하여 설명한다. Subsequently, with reference to the drawings, a detailed description of a method for measuring a spatial magnetic field distribution of a magnet according to the present invention and a device for measuring a spatial magnetic field distribution of a magnet using the same will be described.
여기서, 이하에 설명하는 본 발명의 실시예에서는, 본 발명에 따른 자석의 공간 자기장 분포 측정방법이 MRI에 적용되는 경우를 예로 하여 본 발명을 설명하였으나, 본 발명은 반드시 MRI의 경우로만 한정되는 것은 아니며, 즉, 본 발명은, 비단 MRI 뿐만 아니라, 자석이 구비되는 각종 장비에서 자기장의 균일도를 개선하기 위해 자석의 공간 자기장 분포를 측정하는 방법 및 장치에 대하여 필요에 따라 다양한 형태로 적용될 수 있는 것임에 유념해야 한다. Here, in the embodiment of the present invention described below, the present invention has been described taking the case where the method for measuring the spatial magnetic field distribution of the magnet according to the present invention is applied to MRI, but the present invention is limited only to the case of MRI. In other words, the present invention can be applied in various forms as necessary to a method and apparatus for measuring a spatial magnetic field distribution of a magnet in order to improve the uniformity of a magnetic field in various equipment equipped with a magnet as well as silk MRI. You should keep in mind.
먼저, 도 1을 참조하면, 도 1은 종래기술의 MRI 장치의 구성을 개략적으로 나타내는 도면이다. First, referring to FIG. 1, FIG. 1 is a diagram schematically showing the configuration of a prior art MRI device.
도 1에 나타낸 바와 같이, 기존의 MRI 장치는, 단일 및 소수의 RF 코일을 통하여 인체에 직접 RF 펄스를 인가하고, 인가된 RF 펄스에 대응하여 인체로부터 수신되는 자기공명(MR) 신호를 통해 공간 자기장 분포를 분석하여 자기장 분포를 균일화하도록 구성된다. As shown in FIG. 1, the conventional MRI device applies RF pulses directly to the human body through single and few RF coils, and spaces through magnetic resonance (MR) signals received from the human body in response to the applied RF pulses. It is configured to uniformize the magnetic field distribution by analyzing the magnetic field distribution.
그러나 종래기술의 MRI 장치들은, 도 1에 나타낸 바와 같이, MR 신호를 얻기 위하여 인체를 감싸고 있는 RF 코일에 펄스를 인가해야 하므로, MRI의 자기장이 강해질수록 인체에 인가되는 RF 펄스도 강해지게 되며, 이는, 이른바 SAR(Specific Absorption Rate) 핫스팟(hotspot)과 같은 국부적인 발열을 발생시켜 인체의 안전에 치명적인 위협이 될 수 있다. However, in the prior art MRI devices, as shown in FIG. 1, since a pulse must be applied to the RF coil surrounding the human body to obtain an MR signal, the stronger the magnetic field of the MRI, the stronger the RF pulse applied to the human body. This may cause a local fever such as a so-called Special Absorption Rate (SAR) hotspot, which can be a fatal threat to human safety.
더욱이, MRI의 자기장 세기가 강해질수록 영상의 정확도가 급상승하는 이점이 있으므로 최근에는 7T MRI의 설치에 더하여 14T MRI의 도입에 대한 필요성도 대두되고 있는 실정이나, 상기한 바와 같이 MRI의 자기장이 강해질수록 인체에 인가되는 RF 펄스도 강해지게 되는 점을 감안하면, 고자기장 MRI일수록 영상이미지를 얻을 때나 쉬밍작업시 RF 펄스에 의한 영향을 최대한 배제하는 것이 요구된다. Moreover, as the magnetic field strength of the MRI increases, the accuracy of the image increases rapidly. Recently, the need for the introduction of the 14T MRI in addition to the installation of the 7T MRI has emerged, but as described above, the magnetic field of the MRI increases. Considering that the RF pulse applied to the human body also becomes stronger, the higher the magnetic field MRI is, the more it is required to exclude as much as possible the effect of the RF pulse when obtaining an image image or during a shimmering operation.
또한, 일반적으로, MRI는 영상촬영을 위해 인체가 자기장 공간으로 들어간 후에도 해상도 증가를 위하여 자기장 균일도를 측정하고 그에 따른 쉬밍작업을 통해 자기장 균일도를 보정하는 과정이 필요하나, 종래기술의 자기장 분포 측정장치들은 자석 주위의 자기장 활용공간을 인체나 프로브 등과 같은 물체가 점유하고 있는 동안에는 측정장치가 관심영역으로 접근할 수 없으므로 자기장 공간균일도를 산출할 수 없는 문제가 있으며, 이에 더하여, 기존의 자기장 공간균일도 측정방식은 자기장 분포 측정장치를 기계적으로 회전시키면서 측정함으로 인해 측정시간이 오래 걸리는 단점도 있었다. In addition, in general, MRI requires a process of measuring the magnetic field uniformity to increase the resolution and correcting the magnetic field uniformity through the shing operation according to the prior art magnetic field distribution measuring device, even after the human body enters the magnetic field space for imaging While an object such as a human body or a probe occupies the magnetic field utilization space around the magnet, there is a problem that the magnetic field spatial uniformity cannot be calculated because the measuring device cannot access the region of interest, and in addition, the existing magnetic field spatial uniformity measurement The method has a disadvantage in that it takes a long measurement time by measuring while rotating the magnetic field distribution measuring device mechanically.
이에, 본 발명자들은, 후술하는 바와 같이 하여, 자석의 공간 자기장 분포 측정시 고출력 RF가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하고, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 동시에, 진단영상 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도 측정이 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 새로운 구성의 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치를 제안하였다. Thus, the present inventors secure safety by preventing high-power RF from being applied to the human body when measuring the magnetic field distribution of the magnet, as described later, and quickly and accurately even when a human body or an object occupies the magnetic field space. A new configuration that can measure the spatial magnetic field distribution of the magnet and calculate the magnetic field uniformity, and at the same time, even when the magnetic field uniformity changes during diagnostic imaging, can measure the magnetic field uniformity in the center to correct the magnetic field uniformity in real time. A method for measuring the spatial magnetic field distribution of a magnet and a measuring device for the spatial magnetic field distribution of a magnet using the same are proposed.
더 상세하게는, 도 2를 참조하면, 도 2는 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법에서 인체에 직접 고출력 RF를 인가하지 않고 MR 스펙트럼 신호를 취득하는 과정을 개략적으로 나타내는 개념도이다. More specifically, referring to FIG. 2, FIG. 2 is a conceptual diagram schematically showing a process of acquiring an MR spectrum signal without applying high power RF directly to a human body in a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention. to be.
도 2에 나타낸 바와 같이, 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법은, 인체에 직접 고출력 RF를 인가하여 MR 신호를 수신하는 종래기술의 공간 자기장 분포 측정장치 및 방법들과 달리, 측정하고자 하는 부위에 실린더 형태의 공간을 가정하고, 이러한 실린더 공간 표면에 나선형 경로(helical path)를 상정하여, 해당 경로상에 일정 간격으로 RF 코일(21)이 감겨진 복수의 MR 샘플(22)을 각각 배치한 다음, 멀티플렉서(Multiplexer)를 이용하여, RF 코일(21)이 감겨진 각각의 MR 샘플(22)들에 RF 펄스를 공급하고 MR 스펙트럼 및 자기장 값(B1, B2, B3, B4, ...)을 각각 획득하여, 스펙트럼 분석을 통해 자기장 및 균일도를 계산하도록 구성되는 것을 특징으로 하는 것이다. As shown in FIG. 2, the method for measuring the distribution of a spatial magnetic field of a magnet according to an embodiment of the present invention, unlike the prior art spatial magnetic field distribution measuring apparatus and methods for receiving an MR signal by applying high-power RF directly to the human body, Assuming a cylinder-shaped space at the site to be measured, and assuming a helical path on the surface of the cylinder space, a plurality of MR samples 22 in which the RF coil 21 is wound at regular intervals on the path After placing each, using a multiplexer, the RF coil 21 is supplied with an RF pulse to each of the MR samples 22 wound, MR spectrum and magnetic field values (B1, B2, B3, B4, ...), and is configured to calculate magnetic field and uniformity through spectrum analysis.
즉, 도 2에 나타낸 바와 같이, 멀티플렉서(Multiplexer)를 이용하여 RF 코일(21)이 감겨진 각각의 MR 샘플(22)들에 RF 펄스를 공급하면, 마찬가지로 멀티플렉서를 통하여 각각의 MR 샘플(22)들로부터 발생되는 MR 스펙트럼 등과 같은 MR 신호가 거의 동시에 수신될 수 있으므로, 종래기술의 MRI 장치 및 방법들과 같이 인체에 직접 RF 코일을 위치시킬 필요 없이 각각의 RF 샘플(22)의 위치마다 MR 스펙트럼 및 자기장 값을 얻을 수 있게 된다. That is, as shown in FIG. 2, when RF pulses are supplied to each MR sample 22 in which the RF coil 21 is wound using a multiplexer, each MR sample 22 is similarly provided through a multiplexer. Since MR signals, such as MR spectrums generated from the fields, can be received almost simultaneously, the MR spectrum is located at each RF sample 22 position without the need to position the RF coil directly in the human body, as in prior art MRI devices and methods. And magnetic field values.
여기서, 상기한 각각의 MR 샘플(22)들은 인체를 대신하여 MR 스펙트럼 신호를 생성하기 위한 것으로, 각각의 MR 샘플(22)이 배치되는 위치에 따라 인체의 각 부위를 대신할 수 있도록, 예를 들면, 물(H2O)을 이용하여, 해당 부위와 동일 내지 유사한 MR 스펙트럼 특성을 나타내도록 적절히 구성될 수 있다. Here, each of the MR samples 22 is for generating an MR spectrum signal on behalf of the human body, so that each part of the human body can be replaced according to a position where each MR sample 22 is disposed, for example For example, using water (H2O), it may be suitably configured to exhibit the same or similar MR spectral characteristics as the corresponding site.
더 상세하게는, 상기한 MR 샘플(22)은, 수소 및/또는 중수소를 포함하지 않는 소재로 만들어진 밀봉된 구형 또는 실린더형 용기에 물(H2O) 또는 중수(D2O) 또는 수소나 중수소를 포함하는 적당한 분자의 액체를 담은 후 용기 외부에 RF 코일을 감아 구성될 수 있으며, 이때, 물(H2O) 또는 중수(D2O) 또는 수소나 중수소를 포함하는 적당한 분자의 액체의 양 및 코일을 감는 수를 적절히 조절하여 구성될 수 있다. More specifically, the MR sample 22 described above comprises water (H2O) or heavy water (D2O) or hydrogen or deuterium in a sealed spherical or cylindrical container made of a material that does not contain hydrogen and / or deuterium. It can be composed by wrapping the RF coil on the outside of the container after containing the liquid of the appropriate molecule, wherein the amount of liquid of the appropriate molecule including water (H2O) or heavy water (D2O) or hydrogen or deuterium and the number of coil windings is appropriate. It can be configured by adjustment.
상기한 바와 같이 하여 구성되는 MR 샘플(22)에 있어서, 물분자 내의 수소 또는 중수분자 내의 중수소, 또는 수소나 중수소를 포함하는 적당한 분자의 수소나 중수소가 가지는 핵스핀(nuclear spin)이 MR 자력계(자기장 센서)의 MR 신호의 근원이 되며, 이때, 반드시 MR 자력계를 이용해야만 하는 것은 아니고, 예를 들면, 요구되는 자기장 균일도의 정밀도 수준에 따라 홀(Hall) 자력계나 원자 자력계 등이 사용될 수도 있다. In the MR sample 22 constructed as described above, the nuclear spin of the hydrogen or deuterium of a suitable molecule including hydrogen or deuterium in the water molecule or deuterium in the heavy molecule, or the MR magnetometer ( It is the source of the MR signal of the magnetic field sensor). At this time, it is not necessary to use the MR magnetometer, for example, a Hall magnetometer or an atomic magnetometer may be used depending on the level of precision of the required magnetic field uniformity.
따라서 상기한 바와 같이 하여 구성되는 MR 샘플(22)을 이용하여, 도 2에 나타낸 바와 같이, 예를 들면, 스테인리스강(Stainless steel) 또는 알루미늄 등과 같은 비자성물질을 이용하여 통 형태의 구조물을 형성하고, 이러한 통 형태의 구조물 표면에 나선형 경로(helical path)를 상정하여 일정한 간격으로 RF 코일(21)이 감겨진 MR 샘플(22)을 나선형 경로를 따라 각각 배치하고, 비자성 접착제를 이용하여 각각의 MR 샘플(22)을 비자성체로 이루어진 구조물에 부착시키도록 구성될 수 있다. Therefore, using the MR sample 22 configured as described above, as shown in FIG. 2, for example, a non-magnetic material such as stainless steel or aluminum is used to form a cylindrical structure. Then, assuming a helical path on the surface of the structure of the cylinder, the MR samples 22 in which the RF coils 21 are wound at regular intervals are disposed along the helical paths, respectively, using a non-magnetic adhesive. It can be configured to attach the MR sample 22 of the non-magnetic structure.
이때, 각각의 MR 샘플(22)들 사이의 거리는 동일해야 하며, 이와 같이 하여 복수의 MR 샘플(22)이 배치된 실린더를 MRI 내부에 위치시키는 것에 의해 인체의 각 부위에 RF 코일을 배치하는 기존의 방식을 대신할 수 있다. At this time, the distance between each MR sample 22 should be the same, and in this way, by placing the cylinder in which the plurality of MR samples 22 are placed inside the MRI, the RF coils are disposed in each part of the human body. Can replace the way.
이어서, 후술하는 바와 같은 처리과정을 통하여, 각각의 MR 샘플(22)들에 대한 x, y, z 좌표값과 각각의 MR 샘플(22)들로부터 수신된 자기장 값 및 MR 스펙트럼에 근거하여, 실린더 내부의 중앙에 가상의 구 형태의 공간을 상정하고 필드 그라디언트(Field Gradients)를 계산하여 자기장 균일도를 산출하는 처리가 수행되도록 구성될 수 있다. Subsequently, through a process as described below, the cylinders are based on the x, y, and z coordinate values for each MR sample 22 and the magnetic field values and MR spectra received from each MR sample 22. It may be configured to assume a virtual spherical space in the center of the interior and calculate field gradients to calculate magnetic field uniformity.
즉, 도 3을 참조하면, 도 3은 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법에서 각각의 MR 샘플(22)들로부터 얻어진 값들에 근거하여 자기장 균일도를 산출하는 과정을 개략적으로 나타내는 개념도이다. That is, referring to FIG. 3, FIG. 3 schematically shows a process of calculating the magnetic field uniformity based on values obtained from each MR sample 22 in the method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention It is a conceptual diagram.
도 3에 나타낸 바와 같이, 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법은, 실린더 내부의 중앙에 가상의 구 형태의 공간을 상정하고, 도 2에 나타낸 바와 같이 하여 얻어진 각각의 MR 샘플(22)들에 대한 x, y, z 좌표값과 이에 대응되는 자기장 값 및 MR 스펙트럼을 이용하여, 필드 그라디언트(Field Gradients)를 계산하는 것에 의해 가상의 구 공간에 대한 자기장 균일도를 산출하는 처리가 수행되도록 구성될 수 있다. As shown in Fig. 3, in the method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention, each MR sample obtained by assuming a virtual spherical space in the center of the cylinder and as shown in Fig. 2 is obtained. The process of calculating the magnetic field uniformity for a virtual sphere space by calculating field gradients using the x, y, z coordinate values for (22) and the corresponding magnetic field values and MR spectrum It can be configured to be performed.
더 상세하게는, 일반적으로, 특정 지점에서의 자기장은, 예를 들면, 이하의 [수학식 1]과 같이, 다양한 성분들의 합인 급수로 표시할 수 있고, 다양한 샘플로부터의 좌표 및 자기장 값의 집합(set)을 이용하면 각각의 계수(Field Gradients)를 계산할 수 있다. More specifically, in general, a magnetic field at a specific point can be expressed as a series of sums of various components, for example, as shown in Equation 1 below, and a set of coordinates and magnetic field values from various samples Using (set), you can calculate each coefficient (Field Gradients).
[수학식 1] [Equation 1]
Figure PCTKR2019014812-appb-I000002
Figure PCTKR2019014812-appb-I000002
여기서, 상기한 [수학식 1]에 있어서, B는 특정 좌표(x, y, z)에서의 자기장의 값이고, 네모칸으로 표시된 각각의 계수(A, B, X, Y, Z 등)가 필드 그라디언트(Field Gradients)에 해당한다. Here, in the above Equation 1, B is a value of a magnetic field at a specific coordinate (x, y, z), and each coefficient (A, B, X, Y, Z, etc.) indicated by a square field is a field. Corresponds to Field Gradients.
즉, 상기한 [수학식 1]에 있어서, 복수의 샘플에 대하여 좌변측 B(청색)에 해당 지점에서의 자기장 값을 대입하고, 우변측에 좌표값(적색)을 각각 대입하면 연립방정식이 도출되고, 이러한 연립방정식의 해를 구하여 각각의 계수(Field Gradients)를 구할 수 있다. That is, in [Equation 1] described above, by substituting a magnetic field value at a corresponding point on the left side B (blue) for a plurality of samples, and substituting a coordinate value (red) on the right side, a simultaneous equation is derived. Then, the solution of this system of equations can be obtained to obtain the respective coefficients (Field Gradients).
또한, 상기한 바와 같이 하여 계수를 모두 계산하면 이를 이용하여 해당 좌표값에 대응되는 자기장 값을 바로 구할 수 있으므로 가상의 구 안의 모든 공간에 대한 자기장 값이 도출 가능하며, 이러한 과정을 통해 가상의 구 공간에 대한 자기장의 공간균일도를 산출할 수 있다. In addition, if all the coefficients are calculated as described above, the magnetic field values corresponding to the corresponding coordinate values can be directly obtained by using them, so that the magnetic field values for all spaces in the virtual sphere can be derived. Through this process, the virtual sphere The spatial uniformity of the magnetic field with respect to space can be calculated.
즉, 예를 들면, 필드매핑(field mapping)과 같이, MRI의 자석 사이에 금속심(ferro shim)을 삽입하고 금속심의 둘레를 따라 나선형으로 이동하면서 일정 간격으로 자기장을 각각 측정하여 자석에 의해 형성되는 자기장의 각각의 위치에 대한 필드 그라디언트(field gradient)를 산출함으로써 각각의 좌표값(x, y, z)에 해당하는 자기장의 값을 대응시켜 자기장 매핑 데이터베이스를 구축할 수 있으며, 이와 같이 하여 구축된 자기장 매핑 데이터를 활용하여 가상의 구 공간의 자기장에 대한 필드 그라디언트를 계산하며, 구해진 필드 그라디언트를 이용하여 구 내의 각 좌표에 대한 자기장 값을 산출하고, 각각의 좌표별로 산출된 자기장 값들의 최대치와 최소치의 차이를 이용하여 상기 가상의 구 공간에 대한 자기장의 공간균일도를 산출하도록 구성될 수 있다. That is, for example, as a field mapping (field mapping), by inserting a metal shim (ferro shim) between the magnets of the MRI and moving in a spiral along the perimeter of the metal shim, each magnetic field is measured at regular intervals and formed by a magnet By calculating the field gradient for each position of the magnetic field, a magnetic field mapping database can be constructed by matching the magnetic field values corresponding to the coordinate values (x, y, z). Calculate the field gradient for the magnetic field in the virtual sphere space using the calculated magnetic field mapping data, calculate the magnetic field value for each coordinate in the sphere using the obtained field gradient, and calculate the maximum value of the magnetic field values calculated for each coordinate It may be configured to calculate the spatial uniformity of the magnetic field with respect to the virtual sphere space by using the difference in minimum values.
더 상세하게는, 이하의 [수학식 2]를 이용하여, 각각의 좌표별로 산출된 자기장 값들의 최대치(Bmax)와 최소치(Bmax)를 이용하여 가상의 구 공간에 대한 자기장의 공간균일도를 산출하도록 구성될 수 있다. More specifically, using the following [Equation 2], to calculate the spatial uniformity of the magnetic field for the virtual sphere space by using the maximum value (Bmax) and the minimum value (Bmax) of the magnetic field values calculated for each coordinate Can be configured.
[수학식 2] [Equation 2]
Figure PCTKR2019014812-appb-I000003
Figure PCTKR2019014812-appb-I000003
여기서, 상기한 [수학식 2]에 있어서, Bmax는 각각의 좌표별로 산출된 자기장의 최대값, Bmin는 각각의 좌표별로 산출된 자기장의 최소값을 각각 나타낸다. Here, in the above Equation 2, Bmax represents the maximum value of the magnetic field calculated for each coordinate, and Bmin represents the minimum value of the magnetic field calculated for each coordinate.
따라서 상기한 바와 같은 과정을 통하여 구 안에서의 자기장 균일도를 계산할 수 있으며, 이와 같이 하여 구해진 구에서의 공간균일도가 쉬밍작업 수행시 필요한 목적함수(object function)에 해당한다. Therefore, the uniformity of the magnetic field in the sphere can be calculated through the above-described process, and the spatial uniformity in the sphere thus obtained corresponds to an object function required when performing the shimmering operation.
여기서, 상기한 [수학식 1]에 나타낸 바와 같이, 특정 지점에서의 자기장을 복수의 필드 그라디언트를 포함하는 급수로 표시하고 각각의 계수를 계산하여 해당 좌표값에 대응되는 자기장 값을 산출하여 공간균일도를 계산하는 방법에 대한 보다 구체적인 내용은 당업자에게 있어 종래기술의 문헌 등을 참조하여 자명한 내용이므로, 이에, 본 발명에서는, 설명을 간략히 하기 위해, 상기한 바와 같이 종래기술의 문헌 등을 참조하여 당업자가 용이하게 이해하고 실시할 수 있는 내용에 대하여는 그 상세한 설명을 생략하였음에 유념해야 한다. Here, as shown in [Equation 1], the magnetic field at a specific point is displayed as a series containing a plurality of field gradients, and each coefficient is calculated to calculate a magnetic field value corresponding to the corresponding coordinate value, thereby spatial uniformity. Since the details of the method for calculating the contents are self-evident to those skilled in the art with reference to literatures of the prior art, for this reason, in the present invention, as described above, with reference to the literatures of the prior art, etc. It should be noted that the detailed description of the contents that can be easily understood and practiced by those skilled in the art has been omitted.
따라서 상기한 바와 같은 내용으로부터 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법을 구현할 수 있으며, 즉, 도 4를 참조하면, 도 4는 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법의 전체적인 구성을 개략적으로 나타내는 플로차트이다. Accordingly, a method for measuring the distribution of the spatial magnetic field of a magnet according to an embodiment of the present invention can be implemented from the above-described contents, that is, referring to FIG. 4, FIG. 4 measures the spatial magnetic field distribution of a magnet according to an embodiment of the present invention It is a flow chart schematically showing the overall configuration of the method.
도 4에 나타낸 바와 같이, 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법은, 크게 나누어, 먼저, 자석 내부의 자기장 공간에 일정 간격으로 RF 코일이 감겨진 복수의 MR 샘플을 각각 배치하는 배치단계(S41)와, 각각의 MR 샘플에 미리 정해진 값의 전류(RF 펄스)를 인가하여 각각의 MR 샘플로부터 발생되는 MR 스펙트럼 및 자기장 값을 포함하는 MR 신호를 검출하는 검출단계(S42)와, 실린더 내부의 중앙에 가상의 구 형태의 공간을 상정하고, 각각의 MR 샘플에 대하여 검출된 MR 스펙트럼과 자기장 값 및 각각의 MR 샘플에 대한 x, y, z 좌표값을 이용하여 필드 그라디언트(Field Gradients)를 계산하는 것에 의해, 각각의 전류값 집합에 대하여 가상의 구 공간에서의 각 좌표값에 대응하는 자기장 값을 산출하는 자기장 산출단계(S43)와, 각각의 좌표별로 산출된 자기장 값에 근거하여 각각의 전류값 집합에 대하여 가상의 구 공간에서의 공간균일도를 산출하는 자기장 균일도 산출단계(S44)를 포함하여 구성될 수 있다. As shown in FIG. 4, the method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention is divided into a large number and, first, a plurality of MR samples in which RF coils are wound at regular intervals in a magnetic field space inside the magnet are respectively arranged. Placement step (S41) and a detection step (S42) of detecting an MR signal including an MR spectrum and a magnetic field value generated from each MR sample by applying a current (RF pulse) of a predetermined value to each MR sample; , A virtual sphere-shaped space is assumed in the center of the cylinder, and a field gradient (Field) using the MR spectrum and magnetic field values detected for each MR sample and the x, y, and z coordinate values for each MR sample Gradients) to calculate a magnetic field value corresponding to each coordinate value in a virtual sphere space for each current value set (S43), and calculated for each coordinate Based on the millet value it can comprise a magnetic field uniformity calculation step (S44) for calculating a spatial uniformity in the virtual space, obtain, for each set of current values.
여기서, 상기한 MR 샘플 배치단계(S41)는, 도 2를 참조하여 상기한 바와 같이, 예를 들면, MRI 내부의 촬영하고자 하는 부위에 실린더 형태의 공간을 형성하고, 실린더 공간 표면에 나선형 경로(helical path)를 상정하여, 해당 경로상에 일정 간격으로 RF 코일이 감겨진 복수의 MR 샘플을 각각 배치하는 처리가 수행되도록 구성될 수 있다. Here, the above-described MR sample placement step (S41), as described above with reference to FIG. 2, for example, to form a space in the form of a cylinder in the area to be photographed inside the MRI, a spiral path ( helical path), a process of arranging a plurality of MR samples in which RF coils are wound at regular intervals on a corresponding path may be performed.
즉, 상기한 MR 샘플 배치단계(S41)는, 인체의 각 부위에 RF 코일을 배치하는 대신에, 예를 들면, 통 형태의 구조물 표면에 나선형 경로를 따라 일정 간격으로 RF 코일이 감겨진 MR 샘플을 각각 배치하고, 이와 같이 하여 복수의 MR 샘플이 배치된 실린더를 인체를 대신하여 MRI 내부에 위치시키도록 구성될 수 있다. That is, in the above-described MR sample placement step (S41), instead of placing the RF coil in each part of the human body, for example, the MR sample in which the RF coil is wound at regular intervals along a helical path on the surface of a cylindrical structure. It can be configured to place each, and in this way a cylinder in which a plurality of MR samples are disposed is placed inside the MRI on behalf of the human body.
또한, 각각의 MR 샘플들은, 수소나 중수소, 또는, 수소 및 중수소를 포함하지 않는 소재로 이루어진 용기에 미리 정해진 적당량의 물(H2O)이나 중수(D2O) 또는 수소나 중수소를 포함하는 분자의 액체를 담고 밀봉한 후, 용기 외부에 미리 정해진 횟수로 RF 코일을 감아 구성될 수 있고, 이때, 액체의 양 및 코일을 감는 수를 적절히 조절하여 인체의 각 부위와 동일 내지 유사한 MR 스펙트럼 특성을 나타내도록 구성될 수 있다. In addition, each of the MR samples, hydrogen or deuterium, or a container of a material containing no hydrogen and deuterium in a predetermined amount of water (H2O) or heavy water (D2O) or a liquid of a molecule containing hydrogen or deuterium After containing and sealing, it may be configured to wind the RF coil a predetermined number of times outside the container, and at this time, it is configured to exhibit the same or similar MR spectrum characteristics as each part of the human body by appropriately adjusting the amount of liquid and the number of coil windings. Can be.
아울러, 상기한 MR 신호 검출단계(S42)는, 각각의 MR 샘플에 RF 코일을 통해 미리 설정된 일정한 값의 전류(즉, RF 펄스)를 인가하여, 인가된 전류값에 따라 MR 샘플로부터 발생되는 MR 스펙트럼 및 자기장 값을 포함하는 MR 신호를 각각 검출하는 처리가 수행되도록 구성될 수 있다. In addition, the above-described MR signal detection step (S42), the MR is generated from the MR sample according to the applied current value by applying a predetermined value of current (ie, RF pulse) through the RF coil to each MR sample Processing may be performed to detect MR signals each including spectral and magnetic field values.
더욱이, 상기한 자기장 산출단계(S43)는, 검출된 MR 신호의 스펙트럼 분석을 행하여 스펙트럼상 최대값에 해당하는 X축상(주파수)의 값을 해당 MR 샘플에 대한 자기장 값으로 산출하고, 가상의 구 공간에 대한 자기장은, 도 3 및 [수학식 1]을 참조하여 상기한 바와 같이, 각각의 MR 샘플들을 통해 얻어진 자기장 값을 조화해석(Harmonic Analysis) 식에 대입하여 도출된 필드 그라디언트(Field gradients)와 좌표정보(x, y, z)의 조합을 통해 계산하는 처리가 수행되도록 구성될 수 있다. Moreover, in the above-described magnetic field calculation step (S43), spectrum analysis of the detected MR signal is performed to calculate the value of the X-axis (frequency) corresponding to the maximum value in the spectrum as the magnetic field value for the corresponding MR sample, and obtain a virtual sphere. As described above with reference to FIG. 3 and [Equation 1], the magnetic field for space is derived from field gradients obtained by substituting the magnetic field values obtained through respective MR samples into the Harmonic Analysis equation. And coordinate information (x, y, z).
또한, 상기한 자기장 균일도 산출단계(S44)는, 도 3 및 [수학식 2]를 참조하여 상기한 바와 같이, 필드 그라디언트(Field gradients)와 좌표정보의 조합으로 도출된 자기장 값들의 최대치와 최소치를 이용하여 가상의 구 공간에 대한 자기장의 균일도를 계산하는 것에 의해, 가상의 구 공간에 대한 자기장의 공간균일도를 나타내는 목적함수를 도출하는 처리가 수행되도록 구성될 수 있다. In addition, the above-described magnetic field uniformity calculation step (S44), as described above with reference to Figure 3 and [Equation 2], the maximum and minimum values of the magnetic field values derived from a combination of field gradients (Field gradients) and coordinate information By calculating the uniformity of the magnetic field with respect to the virtual sphere space, a process of deriving an objective function representing the spatial uniformity of the magnetic field with respect to the virtual sphere space can be performed.
아울러, 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법은, 도 4를 참조하여 상기에 설명한 바와 같이 구성되는 각 단계의 처리과정을 컴퓨터나 전용의 하드웨어에 의해 실행시키도록 구성되는 프로그램의 형태로 구현될 수 있다. In addition, the method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention includes a program configured to execute a processing process of each step configured as described above with reference to FIG. 4 by a computer or dedicated hardware. It can be implemented in the form.
즉, 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법은, 초기값 등의 기초적인 설정을 입력하는 간단한 조작만으로 도 4에 나타낸 바와 같은 처리과정이 자동으로 수행되도록 구성됨으로써, 숙련된 기술자가 필요 없이 간단한 구성 및 저렴한 비용으로 안전하고 정확하게 자석의 공간 자기장 분포 측정이 수행될 수 있다. That is, the method for measuring the spatial magnetic field distribution of a magnet according to an embodiment of the present invention is configured such that the processing as shown in FIG. 4 is automatically performed with a simple operation of inputting basic settings such as an initial value, thereby being a skilled technician. Without the need for a simple configuration and low cost, the magnetic field distribution measurement of the magnet can be performed safely and accurately.
더욱이, 본 발명에 따르면, 상기한 바와 같이 하여 구성되는 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법을 이용하여, 자석의 공간 자기장 분포 측정시 RF 펄스가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도를 측정 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정장치를 용이하게 구현할 수 있다. Moreover, according to the present invention, by using the method for measuring the spatial magnetic field distribution of the magnet according to the embodiment of the present invention configured as described above, by preventing the RF pulse from being applied to the human body when measuring the spatial magnetic field distribution of the magnet In addition to ensuring safety, it is possible to quickly and accurately measure the spatial magnetic field distribution of a magnet and calculate the magnetic field uniformity even when a human body or an object occupies the magnetic field space. In addition, even when the magnetic field uniformity changes during shooting, It is possible to easily measure a magnetic field uniformity measurement device to measure the magnetic field uniformity so that the magnetic field uniformity can be corrected in real time.
즉, 도 5를 참조하면, 도 5는 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정방법을 수행하도록 구성되는 자석의 공간 자기장 분포 측정장치(50)의 전체적인 구성을 개략적으로 나타내는 도면이다. That is, referring to FIG. 5, FIG. 5 is a diagram schematically showing the overall configuration of a magnetic field distribution measuring device 50 of a magnet configured to perform a method for measuring a spatial magnetic field distribution of a magnet according to an embodiment of the present invention.
도 5에 나타낸 바와 같이, 본 발명의 실시예에 따른 자석의 공간 자기장 분포 측정장치(50)는, 크게 나누어, 자석 내부의 자기장 공간에 형성되는 실린더 형태의 공간의 외부 표면에 나선형 경로를 따라 일정 간격으로 배치되는 복수의 MR 샘플(52) 및 공급되는 전류값에 따라 대응하는 값의 자기장을 발생하도록 각각의 MR 샘플(52)의 표면에 감겨져 있는 RF 코일(53)을 포함하여 구성되고, 이때, 상기한 실린더 형태의 공간은, 예를 들면, MRI의 내부와 같이, 공급되는 전류값에 따라 대응하는 값의 자기장을 발생하도록 형성되는 복수의 심(Shim)코일(51)에 의해 외부의 상하 및 둘레면이 둘러싸이도록 구성될 수 있다. As shown in FIG. 5, the magnetic field distribution measuring device 50 of a magnet according to an embodiment of the present invention is divided into a large number and is fixed along a spiral path on an outer surface of a cylinder-shaped space formed in a magnetic field space inside the magnet. It is configured to include a plurality of MR samples 52 arranged at intervals and an RF coil 53 wound on the surface of each MR sample 52 to generate a magnetic field of a corresponding value according to the supplied current value, wherein , The above-described cylinder-shaped space is external to the outside by a plurality of shim coils 51 formed to generate a magnetic field having a corresponding value according to the supplied current value, for example, inside the MRI. And surrounding surfaces.
또한, 상기한 자석의 공간 자기장 분포 측정장치(50)는, 도시되지는 않았으나, 각각의 심코일(51)및 RF 코일(53)에 전류를 인가하기 위한 전류공급기(54)와, 각각의 MR 샘플(52)로부터 발생되는 MR 신호를 수신하기 위한 신호검출기(55) 및 각각의 심코일(51)및 RF 코일(53)에 인가되는 전류값을 제어하고, 각각의 MR 샘플(52)로부터 얻어진 값들을 분석하여 공간 자기장 분포 및 공간균일도를 산출하는 과정의 전체적인 동작을 제어하며, 측정장치(50)의 전체적인 동작을 제어하도록 이루어지는 제어부(56) 등을 더 포함하여 구성될 수 있다. In addition, the spatial magnetic field distribution measuring apparatus 50 of the above-described magnet, although not shown, the current supply 54 for applying a current to each of the shim coil 51 and the RF coil 53, and each MR The signal detector 55 for receiving the MR signal generated from the sample 52 and the current value applied to each of the shim coil 51 and the RF coil 53 are controlled and obtained from each MR sample 52 The overall operation of the process of calculating the spatial magnetic field distribution and the spatial uniformity by analyzing the values is controlled, and a control unit 56 configured to control the overall operation of the measurement device 50 may be further included.
여기서, 상기한 전류공급기(54)는 제어부(56)의 제어에 따라 정해진 값의 전류를 심코일(51) 및 RF 코일(53)에 공급하고, 신호검출기(55)는 인가된 전류값에 따라 발생되는 자기장 신호를 측정하여 제어부(56)에 전달하도록 각각 구성되는 것으로, 기존의 자기장 분포 측정장치나 쉬밍장치의 구성을 이용하여 적절하게 구성될 수 있으므로, 본 발명에서는 설명을 간략히 하기 위해 그 상세한 설명을 생략하였음에 유념해야 한다. Here, the above-described current supplier 54 supplies current of a predetermined value to the simcoil 51 and the RF coil 53 under the control of the control unit 56, and the signal detector 55 according to the applied current value Each is configured to measure the generated magnetic field signal and transmit it to the control unit 56. Since it can be suitably configured using the configuration of an existing magnetic field distribution measuring device or a shimmering device, in the present invention, detailed descriptions are provided to simplify the description. It should be noted that the explanation has been omitted.
아울러, 상기한 제어부(56)는, 심코일(51) 및 RF 코일(53)에 인가되는 전류를 실시간으로 제어하는 프로세서로서 구성될 수 있으며, 도 2 내지 도 4를 참조하여 상기한 바와 같이 하여 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출하는 일련의 처리과정이 소프트웨어적인 처리를 통해 자동으로 수행되도록 구성됨으로써, 자석의 공간 자기장 분포 측정시 RF 펄스가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도를 측정 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 자석의 공간 자기장 분포 측정장치(50)를 용이하게 구현할 수 있다. In addition, the control unit 56 may be configured as a processor that controls the current applied to the simcoil 51 and the RF coil 53 in real time, as described above with reference to FIGS. 2 to 4. A series of processes that measure the spatial magnetic field distribution of the magnet and calculate the magnetic field uniformity are configured to be automatically performed through software processing, thereby ensuring safety by preventing RF pulses from being applied to the human body when measuring the magnetic field distribution of the magnet. At the same time, in addition to being able to quickly and accurately measure the magnetic field distribution of the magnet and calculate the magnetic field uniformity even when a human body or an object occupies the magnetic field space, the magnetic field uniformity in the center even when the magnetic field uniformity changes during shooting The ball of the magnet that can be measured to correct the magnetic field uniformity in real time. The magnetic field distribution measuring apparatus 50 can be easily implemented.
더욱이, 본 발명에 따르면, 상기한 바와 같이 하여 구성되는 자석의 공간 자기장 분포 측정장치(50)를 포함하여 구성됨으로써, 자석의 공간 자기장 분포 측정시 RF 펄스가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도를 측정 가능하여 자기장 균일도를 실시간으로 보정할 수 있도록 구성되는 MRI 장치 및 쉬밍시스템을 용이하게 구현할 수 있다. Moreover, according to the present invention, by including the magnetic field distribution measuring device 50 of the magnet configured as described above, when measuring the spatial magnetic field distribution of the magnet, safety is prevented by applying an RF pulse to the human body. At the same time, in addition to being able to quickly and accurately measure the magnetic field distribution of the magnet and calculate the magnetic field uniformity even when a human body or an object occupies the magnetic field space, the magnetic field uniformity in the center even when the magnetic field uniformity changes during shooting It is possible to measure the magnetic field uniformity in real time, and it is possible to easily implement an MRI device and a shimmering system.
여기서, 도 2 내지 도 5를 참조하여 상기한 본 발명의 실시예에서는, 자석의 자기장 공간에 복수의 MR 샘플을 배치하여 자기장 및 공간균일도를 산출하도록 구성되는 경우를 예로 하여 본 발명을 설명하였으나, 본 발명은 반드시 상기한 실시예의 경우로만 한정되는 것은 아니며, 즉, 본 발명은, 상기한 MR 샘플을 이용하는 대신에, 일반적인 자력계를 이용하여 구성될 수 있다. Here, in the embodiment of the present invention described above with reference to FIGS. 2 to 5, the present invention has been described by taking a case in which a plurality of MR samples are arranged to calculate a magnetic field and spatial uniformity by arranging a plurality of MR samples in the magnetic field space of the magnet, The present invention is not necessarily limited to the case of the above-described embodiment, that is, the present invention can be configured by using a general magnetometer, instead of using the MR sample described above.
더 상세하게는, 스테인리스강(Stainless steel) 또는 알루미늄을 포함하는 비자성물질을 이용하여 속이 빈 통 형태의 구조물을 형성하고, 구조물 상의 공간좌표가 알려진 복수의 위치에 비자성 접착제를 이용하여 자력계를 각각 배치한 후 통 형태의 구조물을 자석 주위의 자기장 공간에 위치시키고, 각각의 자력계를 통하여 측정된 자기장값 및 각각의 자력계의 좌표값을 이용하여 가상의 구 공간에서의 자기장 및 가상의 구 공간에 대한 자기장 균일도를 각각 산출하는 처리가 수행되도록 구성됨으로써, 복수의 MR 샘플을 별도로 제조하지 않고 일반적인 자력계를 이용하여 본 발명에 따른 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치를 구현 가능하다. More specifically, a hollow cylinder-like structure is formed using a non-magnetic material including stainless steel or aluminum, and a magnetometer is used by using a non-magnetic adhesive at a plurality of locations where spatial coordinates on the structure are known. After each arrangement, the cylindrical structure is placed in the magnetic field space around the magnet, and the magnetic field values and the coordinate values of each magnetometer measured through each magnetometer are used to simulate the magnetic field in the virtual sphere space and the virtual sphere space. The magnetic field uniformity distribution method is configured to be performed so that a plurality of MR samples are separately manufactured, and a magnetic field distribution measuring method of a magnet according to the present invention and a magnetic field spatial magnetic field distribution measuring device using the same are used. It can be implemented.
따라서 상기한 바와 같이 하여 본 발명에 따른 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치를 구현할 수 있다. Therefore, as described above, the method for measuring the distribution of the spatial magnetic field of a magnet according to the present invention and the apparatus for measuring the distribution of the spatial magnetic field of a magnet using the same can be implemented.
또한, 상기한 바와 같이 하여 본 발명에 따른 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치를 구현하는 것에 의해, 본 발명에 따르면, 자석의 자기장 분포를 분석하고자 하는 공간의 좌표가 알려진 위치에 복수의 통상적인 자력계를 배치하여 측정된 자기장값, 또는, 복수의 MR 샘플 및 RF 코일을 배치하여 각각의 샘플로부터 자기공명(MR) 신호를 수신하고, 수신된 신호에 대한 스펙트럼 분석을 통해 얻어진 자기장값 및 이 값들로 계산된 필드 그라디언트(Field Gradients)를 이용하여 실린더 중앙에 위치한 가상의 구 공간에서의 자기장 균일도를 계산하도록 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치가 제공됨으로써, 자석의 공간 자기장 분포 측정시 고출력 RF가 인체에 인가되지 않도록 하는 것에 의해 안전성을 확보하는 동시에, 인체나 물체가 자기장 공간을 점유하고 있는 경우에도 신속하고 정확하게 자석의 공간 자기장 분포를 측정하고 자기장 균일도를 산출할 수 있는 데 더하여, 촬영중에 자기장 균일도가 변화하는 경우에도 중심부의 자기장 균일도 측정이 가능하여 자기장 균일도를 실시간으로 보정할 수 있다. In addition, according to the present invention, by implementing the method for measuring the spatial magnetic field distribution of a magnet according to the present invention and the apparatus for measuring the spatial magnetic field distribution of a magnet using the same as described above, according to the present invention, the coordinates of the space for analyzing the magnetic field distribution of the magnet A magnetic field value measured by placing a plurality of conventional magnetometers at a known location, or a plurality of MR samples and RF coils are arranged to receive a magnetic resonance (MR) signal from each sample, and spectrum analysis of the received signal A magnetic field distribution method of a magnet configured to calculate the magnetic field uniformity in a virtual sphere space located in the center of the cylinder using the magnetic field values obtained through and the field gradients calculated from these values, and the space of the magnet using the magnetic field value By providing a magnetic field distribution measuring device, high power RF is used when measuring the magnetic field distribution of a magnet. In addition to ensuring safety by not being applied to, magnetic field uniformity during shooting, in addition to being able to quickly and accurately measure the spatial magnetic field distribution of a magnet and calculate magnetic field uniformity even when a human body or an object occupies a magnetic field space Even when is changed, it is possible to measure the magnetic field uniformity in the center, and the magnetic field uniformity can be corrected in real time.
아울러, 본 발명에 따르면, 상기한 바와 같이 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치가 제공됨으로써, 예를 들면, NMR이나 MRI와 같이, 자석을 이용한 각종 장비에 있어서, 자기장 균일도를 개선하기 위해 자석의 공간 자기장 분포를 측정시 측정시간이 오래 걸리고, 자석 주위의 자기장 활용공간을 인체나 물체가 점유하고 있는 동안에는 자석의 공간 자기장 분포를 측정할 수 없는 단점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결할 수 있다. In addition, according to the present invention, by providing a method for measuring the spatial magnetic field distribution of a magnet configured as described above and a device for measuring the spatial magnetic field distribution of a magnet using the same, for example, NMR or MRI, to various equipment using a magnet In order to improve the magnetic field uniformity, it took a long time to measure the magnetic field distribution of the magnet, and while the human body or object occupied the magnetic field utilization space around the magnet, it was impossible to measure the magnetic field distribution of the magnet. It is possible to solve the problems of the method and devices for measuring the spatial magnetic field distribution of a prior art magnet.
더욱이, 본 발명에 따르면, 상기한 바와 같이 구성되는 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치가 제공됨으로써, MRI와 같이 자석을 이용한 장비의 자기장 균일도를 개선하기 위해 행해지는 쉬밍 작업에 있어서, RF 코일을 통해 인가된 RF에 대응하여 인체에서 발생하는 자기공명(MR) 신호를 수신하여 공간 자기장 분포를 분석하도록 구성됨으로 인해, 안전에 유해할 수 있는 고출력 RF 환경에 인체가 더 오래 많이 노출되거나 또는 고자기장 장비일수록 이른바 SAR 핫스팟이라는 국부적인 발열이 발생하여 인체의 안전에 치명적인 데미지를 미칠 수 있는 문제점이 있었던 종래기술의 자석의 공간 자기장 분포 측정방법 및 장치들의 문제점을 해결할 수 있다. Moreover, according to the present invention, by providing a method for measuring a spatial magnetic field distribution of a magnet and a measuring device for spatial magnetic field distribution of a magnet using the same, the magnetic field uniformity of a device using a magnet, such as MRI, is performed. In the shimmering operation, a magnetic resonance (MR) signal generated in the human body is received and analyzed to analyze the spatial magnetic field distribution in response to the RF applied through the RF coil, so that the human body is in a high-power RF environment that may be harmful to safety. The longer the exposure, or the higher the magnetic field equipment, the so-called SAR hot spot, the local heat generated, which can cause fatal damage to the safety of the human body. have.
이상, 상기한 바와 같은 본 발명의 실시예를 통하여 본 발명에 따른 자석의 공간 자기장 분포 측정방법 및 이를 이용한 자석의 공간 자기장 분포 측정장치의 상세한 내용에 대하여 설명하였으나, 본 발명은 상기한 실시예에 기재된 내용으로만 한정되는 것은 아니며, 따라서 본 발명은, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에 의해 설계상의 필요 및 기타 다양한 요인에 따라 여러 가지 수정, 변경, 결합 및 대체 등이 가능한 것임은 당연한 일이라 하겠다.As described above, the details of the method for measuring the spatial magnetic field distribution of a magnet according to the present invention and the apparatus for measuring the spatial magnetic field distribution of a magnet using the same have been described through the embodiments of the present invention as described above. The present invention is not limited to the contents described, and thus the present invention is capable of various modifications, changes, combinations, and replacements according to design needs and various other factors by those skilled in the art to which the present invention pertains. It is natural that it will.

Claims (10)

  1. 자석의 공간 자기장 분포 측정방법에 있어서, In the method for measuring the spatial magnetic field distribution of a magnet,
    자석 주위의 자기장 공간에 복수의 MR(magnetic resonance) 샘플을 각각 배치하는 배치단계; An arrangement step of arranging a plurality of magnetic resonance (MR) samples in a magnetic field space around the magnet, respectively;
    각각의 상기 MR 샘플에 미리 정해진 값의 전류(RF 펄스)를 인가하고, 인가된 전류값에 따라 각각의 상기 MR 샘플로부터 발생되는 MR 신호를 검출하는 검출단계; A detection step of applying a current (RF pulse) of a predetermined value to each of the MR samples and detecting an MR signal generated from each of the MR samples according to the applied current value;
    상기 MR 신호 검출단계에서 각각의 상기 MR 샘플에 대하여 검출된 상기 MR 신호에 근거하여 각각의 상기 MR 샘플의 각 좌표값에 대응하는 자기장 값을 산출하는 자기장 산출단계; 및 A magnetic field calculation step of calculating a magnetic field value corresponding to each coordinate value of each MR sample based on the MR signal detected for each MR sample in the MR signal detection step; And
    상기 자기장 산출단계에서 각각의 상기 MR 샘플의 좌표별로 산출된 자기장 값에 근거하여 상기 자석의 자기장에 대한 공간균일도를 산출하는 자기장 균일도 산출단계를 포함하는 처리과정이 컴퓨터나 전용의 하드웨어에 의해 수행되도록 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법.In the step of calculating the magnetic field, a process including a magnetic field uniformity calculating step of calculating the spatial uniformity of the magnetic field of the magnet based on the magnetic field values calculated for each MR sample coordinate is performed by a computer or dedicated hardware. Method for measuring the spatial magnetic field distribution of a magnet, characterized in that configured.
  2. 제 1항에 있어서, According to claim 1,
    상기 배치단계는, The placement step,
    스테인리스강(Stainless steel) 또는 알루미늄을 포함하는 비자성물질을 이용하여 속이 빈 통 형태의 구조물을 형성하고, 상기 구조물 상의 공간좌표가 알려진 복수의 위치에 RF 코일이 감겨진 복수의 MR 샘플을 각각의 공간좌표 위치에 배치하며, 비자성 접착제를 포함하는 부착수단을 이용하여 각각의 상기 MR 샘플을 상기 통 형태의 구조물의 공간좌표 위치에 각각 고정시킨 후, 상기 통 형태의 구조물을 상기 자석 주위의 자기장 공간에 위치시키는 것에 의해, 상기 자석 주위의 자기장 공간에 복수의 상기 MR 샘플을 각각 배치하는 처리가 수행되도록 구성되는 것을 특징으로 하는 초전도 자석의 공간 자기장 분포 측정방법.A hollow cylindrical structure is formed using a non-magnetic material including stainless steel or aluminum, and a plurality of MR samples in which RF coils are wound at a plurality of locations where spatial coordinates on the structure are known, respectively. Arranged in the spatial coordinate position, each MR sample is fixed to the spatial coordinate position of the cylindrical structure using an attachment means including a non-magnetic adhesive, and then the cylindrical structure is magnetic field around the magnet. A method for measuring the spatial magnetic field distribution of a superconducting magnet, characterized in that it is configured to perform a process of arranging each of the MR samples in a magnetic field space around the magnet by placing them in the space.
  3. 제 2항에 있어서, According to claim 2,
    상기 검출단계는, The detection step,
    각각의 상기 MR 샘플들로부터 MR 스펙트럼 및 자기장 값을 포함하는 상기 MR 신호를 검출하도록 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법.A method of measuring a spatial magnetic field distribution of a magnet, characterized in that it is configured to detect the MR signal including an MR spectrum and a magnetic field value from each of the MR samples.
  4. 제 3항에 있어서, According to claim 3,
    상기 자기장 산출단계는, The magnetic field calculation step,
    상기 MR 신호 검출단계에서 검출된 각각의 상기 MR 신호의 스펙트럼 분석을 행하여 스펙트럼상 최대값에 해당하는 X축상(주파수)의 값을 해당 MR 샘플에 대한 자기장 값으로 산출하며, Spectral analysis of each MR signal detected in the MR signal detection step is performed to calculate a value of the X-axis (frequency) corresponding to the maximum value in the spectrum as a magnetic field value for the corresponding MR sample,
    상기 통 형태의 구조물의 공간 중앙에 가상의 구 공간을 설정하고, 각각의 상기 MR 샘플들에 대한 좌표값(x, y, z)과 상기 MR 신호로부터 산출된 자기장 값을 이용하여 필드 그라디언트(Field gradients)를 계산하며, A virtual sphere space is set in the center of the space of the cylindrical structure, and field gradients are generated using coordinate values (x, y, z) for each of the MR samples and magnetic field values calculated from the MR signal. gradients),
    산출된 각각의 필드 그라디언트를 이용하여 각각의 상기 MR 샘플의 좌표값에 대응하는 자기장 값을 계산하는 것에 의해 상기 가상의 구 공간에서의 자기장을 산출하는 처리가 수행되도록 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법.It is configured to perform a process of calculating a magnetic field in the virtual sphere space by calculating a magnetic field value corresponding to the coordinate value of each MR sample by using the calculated field gradient. Spatial magnetic field distribution measurement method.
  5. 제 4항에 있어서, The method of claim 4,
    상기 자기장 균일도 산출단계는, The magnetic field uniformity calculation step,
    이하의 수학식을 이용하여, 상기 자기장 산출단계에서 상기 가상의 구 공간에 대하여 각각의 좌표별로 산출된 자기장 값들의 최대치와 최소치를 이용하여 상기 가상의 구 공간에 대한 자기장 균일도를 산출하는 처리가 수행되도록 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법.Using the following equation, a process of calculating the magnetic field uniformity for the virtual sphere space is performed using the maximum and minimum values of the magnetic field values calculated for each coordinate with respect to the virtual sphere space in the step of calculating the magnetic field. Method for measuring the spatial magnetic field distribution of a magnet, characterized in that configured as possible.
    Figure PCTKR2019014812-appb-I000004
    Figure PCTKR2019014812-appb-I000004
    (여기서,Bmax는 각각의 좌표별로 산출된 자기장의 최대값, Bmin는 각각의 좌표별로 산출된 자기장의 최소값을 각각 나타냄)(Where, Bmax is the maximum value of the magnetic field calculated for each coordinate, Bmin represents the minimum value of the magnetic field calculated for each coordinate)
  6. 제 5항에 있어서, The method of claim 5,
    상기 측정방법은, The measurement method,
    사용자 인터페이스(User Interface ; UI)를 통하여 초기값을 포함하는 기초적인 설정을 입력하면 상기 MR 신호 검출단계, 상기 자기장 산출단계, 상기 자기장 균일도 산출단계의 처리과정이 자동으로 수행되도록 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법.When a basic setting including an initial value is input through a user interface (UI), the MR signal detection step, the magnetic field calculation step, and the magnetic field uniformity calculation process are automatically performed. How to measure the spatial magnetic field distribution of a magnet.
  7. 제 6항에 있어서, The method of claim 6,
    상기 측정방법은, The measurement method,
    상기 배치단계에서, 상기 MR 샘플 대신에 복수의 자력계를 각각 배치하고, In the placement step, a plurality of magnetometers are respectively disposed in place of the MR sample,
    상기 검출단계에서, 각각의 상기 자력계를 통하여 자기장값을 측정하며, In the detection step, a magnetic field value is measured through each magnetometer,
    상기 자기장 산출단계 및 상기 자기장 균일도 산출단계에서, 각각의 상기 자력계의 좌표값 및 각각의 상기 자력계를 통하여 측정된 자기장값에 근거하여 상기 가상의 구 공간에서의 자기장 및 상기 가상의 구 공간에 대한 자기장 균일도를 각각 산출하는 처리가 수행되도록 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법.In the magnetic field calculation step and the magnetic field uniformity calculation step, a magnetic field in the virtual sphere space and a magnetic field in the virtual sphere space based on the coordinate values of each magnetometer and the magnetic field values measured through each magnetometer. A method for measuring the spatial magnetic field distribution of a magnet, characterized in that the processing for calculating the uniformity is performed.
  8. 제 1항에 있어서, According to claim 1,
    상기 MR 샘플은, The MR sample,
    수소나 중수소, 또는, 수소 및 중수소를 포함하지 않는 소재로 이루어진 용기에 미리 정해진 양의 물(H2O)이나 중수(D2O) 또는 수소나 중수소를 포함하는 분자의 액체를 담고 밀봉한 후, 상기 용기 외부에 미리 정해진 횟수로 RF 코일을 감아 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정방법.After containing and sealing a predetermined amount of water (H2O) or heavy water (D2O) or a molecule containing hydrogen or deuterium in a container made of hydrogen or deuterium, or a material containing no hydrogen and deuterium, and then sealed outside the container Method for measuring the spatial magnetic field distribution of a magnet, characterized in that configured by winding the RF coil a predetermined number of times.
  9. 청구항 1항 내지 청구항 8항 중 어느 한 항에 기재된 자석의 공간 자기장 분포 측정방법을 이용하여 자석의 공간 자기장 분포 및 자기장 균일도를 산출하도록 구성되는 자석의 공간 자기장 분포 측정장치에 있어서, A method for measuring a spatial magnetic field distribution of a magnet, which is configured to calculate a spatial magnetic field distribution and a magnetic field uniformity of the magnet using the method for measuring the spatial magnetic field distribution of the magnet according to any one of claims 1 to 8,
    자석의 자기장 내부에 미리 정해진 간격으로 각각 배치되는 복수의 자력계 또는 복수의 MR 샘플; A plurality of magnetometers or a plurality of MR samples respectively disposed at predetermined intervals inside the magnetic field of the magnet;
    미리 정해진 값의 전류를 인가하기 위한 전류공급기; A current supply for applying a current of a predetermined value;
    상기 전류공급기를 통하여 인가된 전류에 의해 발생되는 MR 신호를 수신하기 위한 신호검출기; 및 A signal detector for receiving an MR signal generated by the current applied through the current supply; And
    상기 측정장치의 전체적인 동작을 제어하고, 상기 신호검출기를 통하여 검출된 상기 MR 신호를 분석하여 상기 자석의 공간 자기장 분포 및 자기장 균일도를 산출하는 처리가 수행되도록 이루어지는 제어부를 포함하여 구성되는 것을 특징으로 하는 자석의 공간 자기장 분포 측정장치.And controlling the overall operation of the measuring device, and analyzing the MR signal detected through the signal detector to perform a process for calculating the spatial magnetic field distribution and magnetic field uniformity of the magnet. A device for measuring the spatial magnetic field distribution of a magnet.
  10. 자석의 자기장 균일도를 개선하기 위한 쉬밍시스템에 있어서, In the shimmering system for improving the magnetic field uniformity of the magnet,
    청구항 9항에 기재된 자석의 공간 자기장 분포 측정장치를 포함하여 구성되는 것을 특징으로 하는 쉬밍시스템.A shimmering system comprising the magnetic field distribution measuring device of the magnet according to claim 9.
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