CN201253215Y - X-ray CT device - Google Patents
X-ray CT device Download PDFInfo
- Publication number
- CN201253215Y CN201253215Y CNU2008201228316U CN200820122831U CN201253215Y CN 201253215 Y CN201253215 Y CN 201253215Y CN U2008201228316 U CNU2008201228316 U CN U2008201228316U CN 200820122831 U CN200820122831 U CN 200820122831U CN 201253215 Y CN201253215 Y CN 201253215Y
- Authority
- CN
- China
- Prior art keywords
- ray
- rotating
- angle
- mrow
- rotating device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000002591 computed tomography Methods 0.000 claims abstract description 70
- 238000000034 method Methods 0.000 claims abstract description 42
- 238000012545 processing Methods 0.000 claims abstract description 21
- 238000001514 detection method Methods 0.000 claims description 22
- 238000013170 computed tomography imaging Methods 0.000 abstract description 12
- 230000005540 biological transmission Effects 0.000 abstract description 8
- 238000004891 communication Methods 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 12
- 230000033001 locomotion Effects 0.000 description 10
- 238000003384 imaging method Methods 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 4
- 230000008054 signal transmission Effects 0.000 description 4
- 239000002356 single layer Substances 0.000 description 4
- 230000005672 electromagnetic field Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 210000000214 mouth Anatomy 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000002583 angiography Methods 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 230000000747 cardiac effect Effects 0.000 description 1
- 230000003788 cerebral perfusion Effects 0.000 description 1
- 210000002455 dental arch Anatomy 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 238000001959 radiotherapy Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001356 surgical procedure Methods 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
Images
Landscapes
- Apparatus For Radiation Diagnosis (AREA)
Abstract
The utility model discloses an X-ray CT instrument, an image rebuilding method for X-ray CT imaging and an X-ray CT imaging method using the image rebuilding method, wherein the X-ray CT instrument comprises a supporter, a rotator which can be rotatably supported on the supporter, an X-ray generator which is arranged on the rotator and used for radiating X-rays to a checked object, a detector which is fixed on the rotator, corresponds to the X-ray generator and is used for detecting the X-rays passing through the checked object by transmission to be used as a projection data, a driver which is connected with the rotator and drives the rotator to enable the rotator to continuously rotate in the degrees not higher than 360 in a reciprocating mode, a controller which controls the X-ray CT scanning process and a data processor which is in cable communication with the detector and is used for receiving and processing the projection data transmitted from the detector by a cable so as to rebuild the three dimensional image of the checked object.
Description
Technical Field
The utility model relates to an X ray CT equipment, be used for the image reconstruction method of X ray CT formation of image and use the X ray CT imaging method of this image reconstruction method, especially relate to one kind and can shorten the X ray CT equipment, the image reconstruction method and the X ray CT imaging method of formation of image time, improvement formation of image precision.
Background
In 1989, spiral CT (computed tomography) began to be put into clinical medical use, which gradually replaced the previous tomographic CT due to its great advantages. The advantages of spiral CT over tomographic CT are: the spiral CT can continuously acquire projection data and obtain three-dimensional data of an object through a specially designed reconstruction algorithm, so that the CT scanning time is greatly shortened, the Z-axis resolution of a reconstructed image is provided, and motion artifacts are reduced. In 1991, the Elscint company firstly introduced the double-layer spiral CT on the basis of the single-layer spiral CT, and then revealed the rapid development of the multilayer spiral CT.
The main difference between the multilayer spiral CT and the single-layer spiral CT is that the detector of the single-layer spiral CT is single-row, only one layer of fan-beam projection data can be collected each time, while the detectors of the multilayer spiral CT are multi-row, and can simultaneously collect multilayer cone-beam projection data; therefore, compared with the single-layer spiral CT, the performance of the multi-layer spiral CT is greatly improved, the coverage area of an X-ray beam is greatly increased, the utilization rate of the X-ray is effectively improved, the scanning time is shortened, and a three-dimensional reconstruction image with higher quality can be obtained. In 1998, the companies GE, Siemens, Toshiba, Philips introduced 4-layer spiral CT; in 2001, the GE company introduced 8 layers first; in 2002, 16-layer spiral CT was introduced by GE, Siemens, Toshiba and Philips respectively; in 2005, Toshiba introduced 256-layer spiral CT; in 2007, Toshiba published its newly introduced 320-layer spiral CT product at the 93 rd north american radiology conference in chicago, usa. The current multi-layer spiral CT scanning speed exceeds 3 weeks per second, and the method is widely applied to the fields of human body three-dimensional imaging, angiography imaging, cardiac imaging, cerebral perfusion imaging and the like. New technologies such as computer-assisted surgery, virtual endoscopy and assisted radiotherapy are also developed on the multi-slice spiral CT technology.
Although the multi-slice helical CT technique has been clinically successful, it still has its inherent drawbacks: because the multilayer spiral CT adopts a continuous rotating slip ring technology, power supplies required by an X-ray generating device on the ring and a multi-row detector are supplied through a high-speed slip ring, and particularly, a large amount of projection data generated by the multi-row detector in the scanning process needs to be transmitted to a computer under the ring at a high speed through a radio frequency technology, so that the data transmission speed is low and the data is easily subjected to electromagnetic interference. As a result, the technical difficulty and cost of the slip ring and the telex are greatly increased, so that the price of the multilayer spiral CT product is kept high, and the popularization of the product is limited.
SUMMERY OF THE UTILITY MODEL
The present invention has thus been made to at least partially overcome the above-mentioned problems occurring in the prior art.
An object of the utility model is to provide an X ray CT equipment, be used for the image reconstruction method of X ray CT formation of image and use the X ray CT imaging method of this image reconstruction method can shorten the formation of image time, improve the formation of image precision.
According to an aspect of the present invention, there is provided an X-ray CT apparatus, comprising: a support device; a rotating device rotatably supported on the supporting device; the X-ray generating device is arranged on the rotating device and used for radiating X-rays to the detected object; a detecting device fixed on the rotating device and opposite to the X-ray generating device for detecting the X-ray transmitted through the detected object as projection data; the driving device is connected with the rotating device and is used for driving the rotating device to continuously and reciprocally rotate for less than or equal to 360 degrees; a control device for controlling the X-ray CT scanning process; and the data processing device is communicated with the detection device through a cable and is used for receiving and processing the projection data transmitted from the detection device through the cable so as to reconstruct a three-dimensional stereo image of the detected object.
Different with traditional multilayer spiral CT, the utility model discloses an X ray CT equipment has abandoned current spiral CT universal use's messenger rotary device along the technique of same direction continuous rotation. The utility model discloses in, the scanning path of the X ray CT equipment that combines together the rotary path of the rotary device of X ray CT equipment and the at uniform velocity linear motion route of the detected object and obtain is not a continuous smooth helix, but a circumference or a continuous non-smooth spiral broken line of constituteing by the continuous smooth helix pitch arc of multistage. All required projection data can be obtained through uniform linear motion of the detected object and reciprocating rotation scanning of the X-ray generating device by less than or equal to 360 degrees, and a three-dimensional tomographic image of the irradiated part is obtained through reconstruction.
Because the rotating device does not need to rotate for a plurality of circles continuously, the cable is not twisted together due to the rotation of the plurality of circles continuously, and therefore, mass projection data collected on the detection device can be transmitted to the data processing device at the rear end through optical cables, network cables and other lines. Compared with wireless transmission, the data signal transmission speed of wired transmission is higher, the signal-to-noise ratio is higher, the anti-electromagnetic interference capability of the data signal transmission device is stronger, and therefore imaging can be faster, the quality of the data signal is improved, and imaging precision is improved.
According to another aspect of the present invention, there is provided an image reconstruction method for performing X-ray CT imaging on a detected object by using the aforementioned X-ray CT apparatus, comprising: (a) setting the layer number i of the tomographic image for reconstructing the detected object: 1-N, wherein N is a positive integer; (b) filtering the acquired projection data; (c) selecting projection data in a complete unidirectional spiral scanning angle of the ith fault, wherein the unidirectional spiral scanning angle is less than or equal to 360 degrees; (d) back projecting the projection data of the selected ith fault onto a corresponding pixel point of the ith fault image to complete image reconstruction of the ith fault; (e) and (d) repeating the steps (c) - (d) until i is equal to N, thereby completing the reconstruction of the whole image of the detected object.
According to a further aspect of the present invention, there is provided an X-ray CT imaging method, comprising the steps of: the rotating device is driven to continuously reciprocate for rotating motion of less than or equal to 360 degrees; providing X-ray radiation to the detected object by an X-ray generating device rotating with the rotating device, and detecting X-rays passing through the detected object as projection data; transmitting the detected projection data to a data processing device by using a cable; and processing the transmitted projection data at the data processing device to reconstruct a three-dimensional stereoscopic image of the object.
Drawings
Fig. 1 is a schematic block diagram of an X-ray CT apparatus according to an embodiment of the present invention;
fig. 2 is a scanning schematic view of an X-ray CT apparatus according to an embodiment of the present invention;
fig. 3 is an example of an X-ray CT apparatus according to an embodiment of the present invention;
fig. 4 is a schematic diagram of an X-ray scanning path of an X-ray CT apparatus according to an embodiment of the present invention;
fig. 5 is a schematic view of the operation of the pulse type X-ray generating device, the rotation of the rotating device, and the data acquisition of the detecting device in the X-ray CT apparatus according to the embodiment of the present invention;
FIG. 6 is an example of a method of selecting projection data for reconstructing one of the slices in a case where a reciprocating rotational scan of ≦ 360 degrees is performed to detect the detected object;
FIG. 7 is a flow diagram of an exemplary reconstruction method for performing a reciprocating rotational scan at ≦ 360 degrees for detecting the detected object; and
fig. 8 is a schematic diagram of an application of the X-ray CT apparatus according to an embodiment of the present invention to an oral cavity site scanning.
Detailed Description
The present invention will be described below with reference to the accompanying drawings. In the drawings, like reference numerals denote like parts. The description of the specific embodiments of the present invention is intended to be illustrative of the invention and is not intended to limit the scope of the invention.
As shown in fig. 1-2, an X-ray CT apparatus according to an embodiment of the present invention includes a supporting device 1, a rotating device 2, an X-ray generating device 3, a detecting device 4, a driving device 5, a control device 6, and a data processing device 7. The rotating device 2 is rotatably supported on the supporting device 1. The X-ray generating device 3 is disposed on the rotating device 2 for radiating X-rays to the detected object P, wherein the X-ray generating device 3 may take any suitable form such as an X-ray accelerator, an X-ray machine, or a radioactive isotope. The X-ray generating device 3 can also adopt an arc-shaped target surface, and the electromagnetic field is used for controlling the electron beam to rapidly scan and target, so that an X-ray beam scanned along the arc-shaped target surface is generated, and the X-ray generating device 3 which rotates along the rotating device 2 is replaced. The X-ray generating device can complete quick circular scanning because the electron beam controlled by the electromagnetic field can realize quick scanning and target shooting.
Furthermore, in the case of the X-ray generating device 3 in the form of an X-ray machine, preferably a pulsed operation is possible. That is, a trigger (not shown) is provided in the X-ray CT apparatus. Only when the trigger triggers the X-ray generating device 3 is the pulsed X-ray emitted, and at the same time the detecting device 4 is triggered for data acquisition. The working mode can greatly reduce the X-ray irradiation dose to the detected object.
The detection device 4 is fixed on the rotating device 2 and is arranged opposite to the X-ray generating device 3 by 180 degrees. During the CT scan, the object P placed on the bed 8 passes through the space between the X-ray generator 3 and the detector 4 in a straight line at a constant speed by the movement of the bed 8, and the detector 4 detects the X-rays emitted from the X-ray generator 3 and transmitted through the object P as projection data. The detection means 4 may take any suitable form, such as a flat panel detector or detector array, and may be a solid state detector, a scintillator detector, a gas detector or a semiconductor detector.
The driving device 5 is connected with the rotating device 2 and is used for driving the rotating device 2 to continuously reciprocate for rotating for less than or equal to 360 degrees. The control device 6 is used for controlling the X-ray CT scanning process. The data processing device 7 is in communication with the detection device 4 through a cable, and is used for receiving and processing the projection data transmitted from the detection device 4 through the cable so as to reconstruct a three-dimensional stereo image of the detected object.
According to the utility model discloses an X ray CT equipment still includes and is used for bearing the cable bear device 9, cable bear device 9 is fixed on rotary device 2 to along with rotary device 2's rotation and motion. In a simple example, the cable carrier 9 is in the form of a rubber hose, which can wrap not only the cables connected between the data processing device 7 and the detection device 4, but also all cables associated with components that are fixed to the rotation device 2 and are to be rotated together with the rotation device 2, such as power supply cables associated with the X-ray generating device 3 and the detection device 4 fixed to the rotation device 2, etc. In another example, as shown in fig. 1, the cable carrier 9 takes the form of a drag chain. The tow chain is hollow for accommodating the various cables described above. Furthermore, the drag chain has a certain rigidity and strength, however, it can also be installed bent as desired. One end of the drag chain is fixed on the rotating device 2 (as shown by a point a in fig. 1), and the drag chain and the respective cables accommodated therein are dragged along with the rotation of the rotating device 2. The other end of the drag chain is fixed to the support device 1 (as indicated by point B in fig. 1), and this fixed end of the drag chain remains different during the rotation of the rotating device 2, and each cable accommodated in the drag chain is connected to other corresponding devices, such as a data processing device, etc., through this fixed end. It should be noted that although in fig. 1 two fixed points are shown at the a and B point positions, the two fixed points may be provided at any suitable points on the rotation means 2 and the support means 1, respectively. It should also be noted that the length between the two fixed ends of the drag chain is any suitable length that can follow the rotation of the rotation device 2 through at least 360 degrees without affecting the rotation of the rotation device 2.
Fig. 3 shows an example of an X-ray CT apparatus according to an embodiment of the present invention, wherein in the shown example, in addition to the above-mentioned devices, an angle measuring device 10 fixed on the supporting device 1 and in communication connection with the control device 6 is further included for detecting an angle rotated by the rotating device 2 around a rotation center. The drive means 5 comprise an electric motor 51 and a drive member 52. The driving part 52 is connected between a driving shaft (not shown) of the motor 51 and the rotating device 2 to rotate the rotating device 2 by the rotation of the driving shaft of the motor 51. Wherein the control means controls the drive shaft of the motor 51 and thereby the direction and angle of rotation of the rotating means 2, based on the detection result of the angle measuring means 10. The drive member 52 is shown in fig. 3 in the form of a drive belt, however, one of ordinary skill in the art will appreciate that the drive member 52 may also take the form of a drive gear. For example, a first gear is provided on the outer periphery of the rotating device, and a second gear that meshes with the first gear is provided on the drive shaft of the motor, so that the driving force is transmitted from the motor to the rotating device by the meshing between the gears, thereby driving the rotating device to rotate.
It should be noted that the drive means 5 may also be implemented in other suitable forms. For example, the angle measuring device 10 may be attached to the motor 51, and measure the angle rotated by the rotating device 2 indirectly by measuring the angle rotated by the drive shaft of the motor 51. Furthermore, it will be appreciated that the angle measurement device 10 may be any suitable device capable of performing angle measurements, such as an encoder, which is known in the art.
The process of performing X-ray CT imaging using the X-ray CT apparatus of the present invention will be described with reference to fig. 2 and 4 to 5.
First, as shown in fig. 2, the drive rotating means 2 makes a circular rotating motion of less than or equal to 360 degrees continuously and reciprocally. While the rotating device 2 performs a circular rotation motion, the bed 8 carries the object P to be detected (in the example of fig. 2, the object to be detected is a human body) to move linearly at a constant speed and to pass through between the X-ray generating device 3 and the detecting device 4 at a constant speed. During the process that the detected object P passes between the X-ray generating device 3 and the detecting device 4 at a constant speed, the X-ray emitted by the X-ray generating device 3 is transmitted through the detected object P and then reaches the detecting device 4. The detection device 4 receives X-rays containing detected information as projection data. In the process, the scanning path of the X-ray generating device shown in fig. 4 is formed by the combination of the moving path of the detected object P passing through the detecting device 4 and the X-ray generating device 3 at a constant speed and the circular rotation moving path of the rotating device 2 which continuously reciprocates for 360 degrees or less. The scanning path is not a continuous smooth spiral line as disclosed in the prior art, but a circle (in the case where the object P to be detected can be covered by one scan, and thus does not need to be moved at a constant speed along a straight line) or a continuous non-smooth spiral broken line composed of a plurality of continuous smooth spiral arcs.
Instead of the above-described X-ray transmission and reception manner, in one example, the X-ray CT apparatus is provided with a trigger, and the rotating means 2 (or the driving means 5) is provided with an angle measuring means 10 such as an encoder. While the rotating means 2 is rotating, the angle measuring means 10 detects the angle through which the rotating means 2 (or the angle through which the driving means 5 is rotated, thereby indirectly obtaining the angle through which the rotating means 2 is rotated). When detecting that the rotating device 2 rotates through a predetermined angle (the value of the angle can be set according to the requirements of practical application), the trigger triggers the X-ray generating device 3 to emit X-rays, and simultaneously triggers the detecting device 4 to detect, that is, a pulse type emitting and receiving mode is adopted.
Alternatively, as shown in fig. 5, a schematic diagram illustrating a synchronization example between the operation of the X-ray generating device using the pulse method, the rotation of the rotating device, and the data acquisition of the detecting device in the X-ray CT apparatus according to the embodiment of the present invention is shown, where fig. 5(a) is a connection manner of the signal control transmission line among the position trigger, the X-ray generating device, the detecting device, and the data processing device mounted on the rotating device 2, and fig. 5(b) is a diagram of the timing sequence of one X-ray exposure and data acquisition during the scanning process. When the rotating device 2 rotates a preset angle, the position trigger sends a narrow trigger signal I, the falling edge of the signal informs the X-ray generating device 3 and the detecting device 4, so that the X-ray generating device 3 sends a pulse X-ray II with a certain time length, meanwhile, the detecting device 4 carries out data acquisition III on exposure, the falling edge of the exposure signal II of the X-ray generating device informs the detecting device 4 that the exposure is finished, and the detecting device 4 transmits acquired data to the data processing device 6 in a time sequence IV.
In the case of using a pulse type X-ray generating device in the CT scanning process, only in the X-ray exposure process, X-rays are incident on the human body, and therefore, compared with a CT apparatus in which X-rays are continuously incident, an unnecessary X-ray radiation dose can be reduced to a great extent. Moreover, because the exposure process under each scanning angle can be controlled to be very small (for example, several milliseconds of exposure time), the range of the rotation angle of the rotating device is very small in a single exposure time, so that the motion artifact in the exposure adopting process is greatly reduced, and the resolution of the CT sectional image is improved.
Next, after the detection device 4 transmits projection data to the data processing device 7 through a cable connected between the detection device 4 and the data processing device 7, the data processing device 7 processes the projection data to reconstruct a three-dimensional stereoscopic image of the object P to be detected. The data processing means 7 may take the form of a computer workstation or may be a high-performance PC. Also, the three-dimensional tomographic image of the object to be detected can be reconstructed by the following two methods:
(1) under the condition that the detection of the detected object can be completed only by one-way rotation, the following single circular orbit CT reconstruction algorithm is adopted. When the detected object can be completely covered by the detection device and the X-ray beam in one circumferential CT scanning, the scanning track at the moment is a circular track; the tomographic image can be reconstructed in the following manner. The reconstruction formula is as follows:
wherein,
wherein, gm(λ, u, v) represents projection data acquired by a flat panel detector (i.e. the detection means 4 takes the form of a flat panel detector); λ represents the angular parameter of the projection sample, the integration range λ1～λ2，λ1Denotes the starting angle, λ, of the scan2Indicating the end angle of the scan. When lambda is2-λ1When the angle is 360 degrees, scanning is carried out on a complete circular track; when lambda is2-λ1When the angle is 180 degrees + fan beam angle, CT half scanning and short scanning are performed; when the angle is 180 degrees + fan beam fan angle<λ2-λ1<When the scanning angle is 360 degrees, the scanning angle is larger than CT half scanning and short scanning; when lambda is2-λ1<When the angle is 180 degrees plus the fan angle of the fan beam, CT ultra-short scanning is performed. In the four scanning situations, the above formula can complete the reconstruction of the CT image.
(u, v) represents the rectangular coordinates of the projection data on the flat panel detector. h isR(. represents a Ramp filter, h)h(. cndot.) denotes a Hilbert filter.
The X-ray image reconstruction method is a back projection weight function, and the value of the function ensures that each X-ray only contributes once to the back projection operation of a reconstructed image, namely when a certain X-ray is acquired for 2 times or more than 2 times, the weight function value corresponding to the X-ray is the reciprocal of the acquisition times. One special case is that when scanning a closed circular orbit, the reconstruction weight function at this time takes values for all rays as follows: <math> <mrow> <mi>w</mi> <mrow> <mo>(</mo> <mi>λ</mi> <mo>,</mo> <mover> <mi>u</mi> <mo>~</mo> </mover> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>/</mo> <mn>2</mn> <mo>.</mo> </mrow></math>
the above-mentioned method for reconstructing an image of a detected object is disclosed in the article published in 2004 by the utility model entitled "a New Super-Short-Scan Algorithm for fan-beam and con-beam recovery" (image recovery from incorporated Data III, proc.of SPIE, vol.5562, Pages80-87, 2004), which is hereby incorporated by reference in its entirety.
(2) In the case of performing reciprocating rotational scanning of ≦ 360 degrees to detect the detected object, the following reconstruction algorithm is employed. Performing tomographic image reconstruction in this scanning mode first requires selecting projection data at which angles are required for the tomographic reconstruction, which is a key issue. The utility model discloses the people reachs through the research: the projection data in the complete one-way spiral scanning angle of the fault are selected to reconstruct the fault image, and a better reconstruction effect can be obtained.
Specifically, as shown in fig. 6, an example of a method for selecting projection data for reconstructing one of the slices when reciprocating rotational scanning is performed to detect an object to be detected at ≦ 360 degrees is shown. The fault plane to be reconstructed and the X-ray scanning path of the X-ray CT apparatus have only one intersection point W, the projection data within the complete one-directional helical scanning angle where the intersection point W is located is selected as reconstruction data, and the dotted line in the fault plane to be reconstructed in fig. 6 is the projection of the complete one-directional helical scanning trajectory required by the selected reconstructed fault image on the fault.
Fig. 7 shows a flowchart of an exemplary reconstruction method in case of performing ≦ 360 degree reciprocal rotation scanning for detecting the detected object. Specifically, in step S1, the number of layers i of the tomographic image in which the detected object is reconstructed is set: 1-N, wherein N is a positive integer. The number of layers of the tomographic image can be selected by those skilled in the art according to the need and the practical situation and experience. Next, in step S2, the projection data that has been obtained is filtered. The acquired projection data may be filtered using any suitable prior art technique, for example, line-by-line filtering may be used.
Next, in step S3, projection data within a complete unidirectional helical scan angle at which the ith slice is located is selected, wherein the unidirectional helical scan angle is less than or equal to 360 degrees. Specifically, as shown in fig. 4 and 6, when the detecting device 4 and the X-ray generating device 3 continuously reciprocate with a rotational motion of less than or equal to 360 degrees, an X-ray scanning path as shown in fig. 4 is formed. When one of the slices is selected (for example, the ith slice), the slice has only one intersection point W with the X-ray scanning path, and projection data within a complete unidirectional scanning angle of the intersection point W is selected.
Continuing to step S4, backprojecting the projection data of the selected ith tomographic image to the corresponding pixel point of the ith tomographic image, thereby completing image reconstruction of the ith tomographic image. Such back projection methods are well known in the art and will not be described in detail herein.
Repeating the steps (S3) — (S4) until i ═ N, thereby completing the reconstruction of the entire image of the object to be detected, and then completing the X-ray CT imaging.
An X-ray CT apparatus and an application example of X-ray CT imaging according to an embodiment of the present invention are shown in fig. 8, and are used for scanning a dental arch part of a human mouth.
According to the above, the present invention discloses an X-ray CT apparatus, an image reconstruction method for performing X-ray CT imaging on a subject to be detected by using the X-ray CT apparatus, and an X-ray CT imaging method using the reconstruction method, wherein compared with the prior art, because the rotation device of the X-ray CT apparatus does not need to rotate continuously for multiple cycles, there is no need to worry about twisting cables together due to the rotation of the continuous multiple cycles, and thus, mass projection data collected on a detection device can be transmitted to a data processing device at the rear end through optical cables, network cables, and other lines. Compared with wireless transmission, the data signal transmission speed of wired transmission is higher, the signal-to-noise ratio is higher, the anti-electromagnetic interference capability of the data signal transmission device is stronger, and therefore imaging can be faster, the quality of the data signal is improved, and imaging precision is improved.
It is to be noted that the above description is intended to be illustrative, and not restrictive. Accordingly, it will be appreciated by those skilled in the art that modifications may be made to the invention without departing from the scope of the appended claims.
Claims (11)
1. An X-ray CT apparatus comprising:
a support device;
a rotating device rotatably supported on the supporting device;
the X-ray generating device is arranged on the rotating device and used for radiating X-rays to the detected object;
a detecting device fixed on the rotating device and opposite to the X-ray generating device for detecting the X-ray transmitted through the detected object as projection data;
the driving device is connected with the rotating device and is used for driving the rotating device to continuously and reciprocally rotate for less than or equal to 360 degrees;
control device for controlling an X-ray CT scanning process, and
and the data processing device is communicated with the detection device through a cable and is used for receiving and processing the projection data transmitted from the detection device through the cable so as to reconstruct an image of the detected object.
2. The X-ray CT apparatus according to claim 1, wherein the drive means includes:
an electric motor;
the driving part is connected between a driving shaft of the motor and the rotating device so as to drive the rotating device to rotate through the rotation of the driving shaft of the motor; and
an angle measuring device mounted on the motor and communicatively connected to the control device for detecting an angle through which a drive shaft of the motor rotates;
wherein, the control device controls the rotation direction and the angle of the rotating device according to the detection result of the angle measuring device.
3. The X-ray CT apparatus according to claim 1, further comprising an angle measuring device fixed to the supporting device and communicatively connected to the control device for detecting an angle rotated by the rotating device about a rotation center.
4. The X-ray CT apparatus according to claim 2 or 3, the angle measuring device being an encoder.
5. The X-ray CT apparatus according to claim 3, said drive means comprising:
an electric motor; and
a driving part connected between a driving shaft of the motor and the rotating device to drive the rotating device to rotate;
and the control device controls the rotating direction and the angle of the rotating device according to the detection result of the angle measuring device.
6. The X-ray CT apparatus according to claim 2 or 5, wherein the drive means is a drive belt or a drive gear.
7. The X-ray CT apparatus according to claim 1, further comprising a cable carrying device for carrying the cable, the cable carrying device being fixed to the rotating device and moving with rotation of the rotating device.
8. The X-ray CT apparatus of claim 7 wherein the cable carrier is a rubber hose.
9. An X-ray CT apparatus according to claim 7 wherein the cable carrying means is a flexible hollow drag chain having one end fixed to the rotating means and the other end fixed to the supporting means.
10. The X-ray CT apparatus according to claim 2 or 3, further comprising a trigger which triggers the X-ray generating means to emit X-rays and simultaneously triggers the detector to detect the X-rays passing through the object to be detected when the rotating means rotates through a predetermined angle.
11. The X-ray CT apparatus of claim 1 wherein the detection device is a flat panel detector or a detector array.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201228316U CN201253215Y (en) | 2008-09-28 | 2008-09-28 | X-ray CT device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201228316U CN201253215Y (en) | 2008-09-28 | 2008-09-28 | X-ray CT device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201253215Y true CN201253215Y (en) | 2009-06-10 |
Family
ID=40736524
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008201228316U Expired - Fee Related CN201253215Y (en) | 2008-09-28 | 2008-09-28 | X-ray CT device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201253215Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105496444A (en) * | 2015-12-01 | 2016-04-20 | 苏州佳世达光电有限公司 | Scan control method and scanning device |
| WO2019128523A1 (en) * | 2017-12-28 | 2019-07-04 | 清华大学 | Ct inspection system and ct imaging method |
| WO2020087935A1 (en) * | 2018-11-01 | 2020-05-07 | 苏州瑞派宁科技有限公司 | Ct device |
-
2008
- 2008-09-28 CN CNU2008201228316U patent/CN201253215Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105496444A (en) * | 2015-12-01 | 2016-04-20 | 苏州佳世达光电有限公司 | Scan control method and scanning device |
| CN105496444B (en) * | 2015-12-01 | 2018-06-26 | 苏州佳世达光电有限公司 | Scan control method and scanning means |
| WO2019128523A1 (en) * | 2017-12-28 | 2019-07-04 | 清华大学 | Ct inspection system and ct imaging method |
| US11327198B2 (en) | 2017-12-28 | 2022-05-10 | Tsinghua University | CT inspection system and CT imaging method for a reciprocating swinging process of a radioactive source device and a detection device around an object at non-uniform speed to collect effective detection data |
| WO2020087935A1 (en) * | 2018-11-01 | 2020-05-07 | 苏州瑞派宁科技有限公司 | Ct device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101683271B (en) | X-ray CT equipment, image reconstructing method and X-ray imaging method | |
| US8284894B2 (en) | Fast tomosynthesis scanner apparatus and CT-based method based on rotational step-and-shoot image acquistion without focal spot motion during continuous tube movement for use in cone-beam volume CT mammography imaging | |
| US9380984B2 (en) | Computer tomography imaging device and method | |
| CN100563573C (en) | CT formation method and system | |
| EP2049918B1 (en) | Stereo tube computed tomography | |
| US7251523B2 (en) | Tomogram creating device and radiation examining apparatus | |
| US20060115040A1 (en) | Cone-beam filtered backprojection image reconstruction method for short trajectories | |
| CN101325911B (en) | Systems and methods for scanning and data acquisition in computed tomography (CT) applications | |
| US6751283B2 (en) | Reconstruction method for tilted-gantry computed tomography | |
| CN102860838A (en) | Equipment and method for dental X-ray tomography | |
| JP2009533086A (en) | Patient positioning using tomosynthesis technology | |
| CN104198506B (en) | Low-angle is from pendulum-type large-sized multiple layer helical CT device and inspection method | |
| JP2007000408A (en) | X-ray ct apparatus | |
| US7702063B2 (en) | CT method for the examination of cyclically moving object | |
| WO2008024584A2 (en) | Artifact correction for motion artifacted images | |
| Endo et al. | Four-dimensional computed tomography (4D CT)-concepts and preliminary development | |
| JP2004160218A (en) | X-ray computerized tomographic apparatus, x-ray computerized tomographic apparatus control method, and x-ray computerized tomography program | |
| EP1815438A1 (en) | Reconstruction method for computer tomograph and computer tomograph | |
| CN201253215Y (en) | X-ray CT device | |
| JP2003180676A (en) | Method for reconstituting computerized tomographic image | |
| JP2004113785A (en) | Image formation method and ct unit for implementing the same in computerized tomography | |
| CN111317496A (en) | CT imaging device and imaging method | |
| US7142628B2 (en) | Computed tomography method | |
| CN105828717B (en) | Projection data acquisitions device | |
| US7418075B2 (en) | Subtle dynamic helical scan for uniform z-resolution and noise |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090610 Termination date: 20150928 |
|
| EXPY | Termination of patent right or utility model |