EP3215830A1 - Système d'imagerie radiographique et procédé de positionnement d'un tel système - Google Patents
Système d'imagerie radiographique et procédé de positionnement d'un tel systèmeInfo
- Publication number
- EP3215830A1 EP3215830A1 EP15804885.0A EP15804885A EP3215830A1 EP 3215830 A1 EP3215830 A1 EP 3215830A1 EP 15804885 A EP15804885 A EP 15804885A EP 3215830 A1 EP3215830 A1 EP 3215830A1
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- EP
- European Patent Office
- Prior art keywords
- channels
- unit
- coordinates
- image
- plate
- 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.)
- Withdrawn
Links
- 238000003384 imaging method Methods 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims description 19
- 238000012545 processing Methods 0.000 claims abstract description 42
- 239000000463 material Substances 0.000 claims abstract description 8
- 239000011159 matrix material Substances 0.000 claims description 36
- 230000005540 biological transmission Effects 0.000 claims description 21
- 230000009466 transformation Effects 0.000 claims description 20
- 238000004846 x-ray emission Methods 0.000 claims description 5
- 230000005855 radiation Effects 0.000 description 11
- 241001397173 Kali <angiosperm> Species 0.000 description 8
- 238000006073 displacement reaction Methods 0.000 description 7
- 238000004422 calculation algorithm Methods 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 5
- 230000005484 gravity Effects 0.000 description 5
- 238000009792 diffusion process Methods 0.000 description 3
- 239000003550 marker Substances 0.000 description 3
- 230000011664 signaling Effects 0.000 description 3
- 238000013519 translation Methods 0.000 description 3
- 238000012937 correction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000013598 vector Substances 0.000 description 2
- 238000011976 chest X-ray Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000003708 edge detection Methods 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002601 radiography Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/44—Constructional features of apparatus for radiation diagnosis
- A61B6/4429—Constructional features of apparatus for radiation diagnosis related to the mounting of source units and detector units
- A61B6/4452—Constructional features of apparatus for radiation diagnosis related to the mounting of source units and detector units the source unit and the detector unit being able to move relative to each other
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/40—Arrangements for generating radiation specially adapted for radiation diagnosis
- A61B6/4035—Arrangements for generating radiation specially adapted for radiation diagnosis the source being combined with a filter or grating
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/44—Constructional features of apparatus for radiation diagnosis
- A61B6/4405—Constructional features of apparatus for radiation diagnosis the apparatus being movable or portable, e.g. handheld or mounted on a trolley
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/50—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications
- A61B6/51—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications for dentistry
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/58—Testing, adjusting or calibrating thereof
- A61B6/587—Alignment of source unit to detector unit
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/58—Testing, adjusting or calibrating thereof
- A61B6/588—Setting distance between source unit and detector unit
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
- G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
- A61B6/4291—Arrangements for detecting radiation specially adapted for radiation diagnosis the detector being combined with a grid or grating
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2223/00—Investigating materials by wave or particle radiation
- G01N2223/30—Accessories, mechanical or electrical features
- G01N2223/301—Accessories, mechanical or electrical features portable apparatus
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2223/00—Investigating materials by wave or particle radiation
- G01N2223/40—Imaging
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2223/00—Investigating materials by wave or particle radiation
- G01N2223/60—Specific applications or type of materials
- G01N2223/612—Specific applications or type of materials biological material
Definitions
- the invention relates to radiographic imaging, especially X-ray imaging, and more particularly to mobile radiographic imaging in the medical field, in particular dental.
- mobile X-ray systems are used to make X-ray images, particularly X-ray images in a patient's bed.
- These mobile systems comprise an X-ray unit and an X-ray unit, and these elements are placed on either side of an object, such as a patient, a container, or any other object. for which it is desired to make a radiographic image in order to examine the object.
- These mobile systems are manipulated by an operator and can misalign, which can produce an image with contrast and / or deformation defects of the object. In this case, the image is difficult to exploit.
- Some X-ray systems provide means for aligning the transmitting unit with the receiving unit.
- US2002 / 0150215 discloses an X-ray imaging system using an optical, or ultrasonic, or magnetic camera, located on the X-ray unit and markers placed on the receiving unit. .
- the camera produces an image of the markers to determine the position of the receiving unit.
- the field of view of an optical or ultrasonic camera can be obstructed by the object to be analyzed.
- magnetic cameras may be disturbed by nearby metal objects.
- US patent application US2007 / 0223657 discloses a method of aligning a transmitter and an X-ray detector displaceable by motorized moving means.
- the method includes placing the detector in an initial position and, with the aid of the detector, generating a map, in one or more dimensions, of the radiation profile including regions of interest that are identifiable by their intensity level. radiation. Then, the detector is moved to other positions and the new radiation profiles and their coordinates in space are recorded. Once the radiation profile map is obtained, it can be used to align the source and detector.
- U.S. Patent Application US2002 / 0080922 discloses an X-ray radiographic method using a receiving unit comprising an X-ray detector and an anti-scattering gate located on the detector, the grid comprising pairs of radiopaque alignment bars.
- a first image of the object is produced, with a radiation delivering a low dose of X-rays, then the relative position of the alignment bars in the first image is measured, the relative angle of the detector with respect to the emission unit, and a second image is produced with radiation delivering a high dose of X-rays, for a radiographic image.
- the image is displayed using a screen and a distance is measured between the edge of the pattern and the edge of the screen to determine if the receiving unit is centered relative to the unit of the screen. program.
- the document gives no information on the X-ray dose delivered.
- the system only allows to center the receiving unit and does not offer the possibility of precisely positioning the receiving unit.
- An object of the invention is to overcome the drawbacks mentioned above, and in particular to provide means for facilitating the positioning of the receiving unit with respect to the transmission unit of a radiographic imaging system X-ray.
- Another object is to limit the X-ray doses used when positioning the reception unit with respect to the emission unit.
- a radiographic imaging system comprising:
- a plate made of an X-ray opaque material and located between the emission unit and the reception unit.
- the plate has at least four channels, each channel allowing part of the X-rays emitted by the transmitting unit to pass through the channel; the receiving unit generates an alignment radiographic image having a projected pattern of each channel; and the system includes an image processing unit configured to determine the coordinates of the projected patterns in the alignment image and to calculate a position of the reception unit from the coordinates of the projected patterns in the image of the image. alignment and channel coordinates.
- the image processing unit may further comprise a memory for storing parameters of a first geometric transformation matrix connecting coordinates of the reference patterns with respectively the coordinates of the channels, each reference pattern corresponding to a projection of a channel in a reference radiographic image generated when the receiving unit is located at a reference distance from the receiving unit, the processing unit being further configured to identify the projected pattern in the radiographic image of aligning each channel, to match the projected patterns in the alignment radiographic image with the channels of the plate respectively, to calculate parameters of a second geometric transformation matrix connecting the coordinates of the projected patterns in the radiographic image with the coordinates of the reference patterns, and to calculate the position of the unit of r receipt from the parameters of the first and second matrices.
- the plate may comprise several channels forming an asymmetric figure.
- the plate may comprise at least two channels aligned along a first axis, at least two channels aligned along a second axis perpendicular to the first, and at least three channels aligned along a third axis inclined relative to the first and second axes.
- the transmitting unit and the receiving unit can be mobile.
- a mobile X-ray imaging system is provided which is particularly suitable for chest radiography performed in a patient's bed and for dental X-ray.
- the channels may have a cylindrical shape.
- the sections of the channels may have different diameters between them.
- a radiographic imaging system comprising an X-ray emission unit and an X-ray receiving unit, the method comprising the steps of:
- the plate comprising at least four channels, each channel allowing part of the X-rays emitted by the unit issue to pass through the channel;
- the calculation step may further comprise a calibration step in which a reference radiographic image is generated by the reception unit located at a reference distance from the transmission unit, and includes a projected reference pattern of each channel, the coordinates of the reference patterns are determined, and parameters of a first geometric transformation matrix connecting the coordinates of the reference patterns to the coordinates of the channels are calculated, a step of identifying the projected pattern in the image radiographic alignment of each channel, a step of matching the projected patterns in the alignment radiographic image with respectively the channels of the plate, a step of calculating the parameters of a second geometrical transformation matrix connecting the coordinates of the projected patterns in the alignment radiographic image with the coordinates of the reference patterns, the position of the unit of reception being determined from the parameters of the first and second matrices.
- the calculation step may further comprise a calculation of the orientation angles of the receiving unit from the parameters of the first and second matrices.
- FIG. 1 schematically illustrates an embodiment of a radiographic imaging system according to the invention.
- FIG. 2 to 8 schematically illustrate embodiments of a plate according to the invention.
- FIG. 1 shows a radiographic imaging system 1, comprising an X-ray emission unit 2, an X-ray reception unit 3, a plate 1 1, and an image processing unit 4
- the imaging system 1 is intended to produce a radiographic image of an object 5, for example a patient, a bottle, a portion of a tube, and in particular an area of interest of the object 5 to be examined.
- the emission unit 2 can be, for example, an X-ray tube.
- the emission unit 2 comprises a housing 6 in which are housed a source 7 of X-rays and a diaphragm 8.
- the diaphragm 8 delimits a irradiated zone 8a generally having a rectangular, circular or octagonal shape.
- the diaphragm 8 can open and close to vary the amount of X-radiation to the receiving unit 3.
- the source 7 produces X-ray radiation, which passes through the irradiated zone 8a of the diaphragm 8, towards the The reception unit 3.
- the X-ray beam is shown schematically by the reference A3.
- the reception unit 3 comprises an X-ray detector 9, and may comprise an anti-diffusion gate 10 for reducing the scattered X-rays and improving the contrast of the images.
- the grid 10 may be focused, i.e. it may comprise bars oriented towards a focal point, or it may be unfocused when it comprises parallel bars.
- the reception unit 3 can be positioned so that the incidence of X-rays is normal to the reception unit 3.
- a longitudinal axis A1 of the reception unit 3 is perpendicular to an axis of propagation. A2 of the X-radiation emitted.
- the longitudinal axis A1 is inclined by an angle A different from 90 ° with respect to the axis of propagation A2.
- the receiving unit 3 may be tilted to view certain areas of the object 5 that are masked when using a 90 ° X-ray angle.
- the transmission unit 2 and the reception unit 3 are movable in translation and in rotation, and are displaceable manually, or by displacement means, respectively represented by the references 12 and 13.
- the displacement means 12, 13 may be manual or automated micrometric actuators for moving the emission 2 and reception 3 units of the imaging system 1.
- the transmission unit 2 can be moved in an automated manner and the reception unit 3 can be moved manually by an operator.
- the processing unit 4 cooperates with the plate 1 1 so as to improve the alignment of the reception unit 3 with respect to the emission unit 2. It is understood by aligning the reception unit 3, the operation which consists in positioning and orienting the reception unit 3 with respect to the emission unit 2, or vice versa, so as to produce an exploitable radiographic image, that is to say an image whose level of contrast allows a user to view the areas of interest of the object 5 to be analyzed.
- the object 5 to be examined is placed between the reception unit 3 and the emission unit 2, and then the plate is placed. 1 1 on the emission unit 2, and a first IR radiographic image, noted alignment image.
- the embodiment of the IR alignment image consists in emitting an X-ray radiation, by the emission unit 2, in the direction of the reception unit 3, and then detecting, by the reception unit 3, the X-radiation to generate the IR alignment image.
- the obtained IR alignment image makes it possible to determine the position and the orientation of the reception unit 3 with respect to the emission unit 2.
- the plate 1 1 Since the realization of the IR alignment image is carried out when the object 5 is placed between the reception unit 3 and the emission unit 2, it is advantageous to make a plate 1 1 which limits the X-radiation received by the object 5 during the step of alignment of the elements 2, 3 of the imaging system 1. In addition, the plate 1 1 must make it possible to generate an exploitable IR alignment image to precisely determine the position and the orientation of the reception unit 3.
- the plate 1 1 is made of an X-ray opaque material, by example lead or tungsten.
- the plate 11 has, for example, a thickness of at least 3 mm to stop the quasi-totality of the photons having an energy used in conventional radiology.
- the plate 11 is located between the emission unit 2 and the reception unit 3, on the path A3 of the X-rays emitted by the emission unit 2. More particularly, the plate 1 1 is located between the X-ray source 7 and the reception unit 3.
- the plate 1 1 is preferably mounted on the X-ray tube 2.
- the plate 1 1 is housed in the housing 6 of the tube 2.
- the plate 1 1 is located in the housing 6 so that the diaphragm 8 is placed between the plate 1 1 and the source 7 of X-rays.
- the plate 1 1 is intended to receive an X-radiation emitted by the emission unit 2 in order to be able to align the reception unit 3 with the emission unit 2.
- the plate 1 1 comprises at least four channels 20 to 23.
- Each channel 20 to 23 allows part of the X-rays emitted by the emission unit 2 to pass through the channel 20 to 23.
- a channel 20 to 23 may be an opening, such as a hole or a slot, filled with or not filled with an X-ray transparent material. In any case, the channels allow X-rays to pass.
- the plate 11 comprises only four channels 20 to 23, thus reducing the quantity of X-rays emitted. towards the object 5.
- the diameter of the channels 20 to 23 is less than the length of the plate 11.
- the diameter of at least one channel may be greater than that of the other channels of the plate 1 1.
- the plate 11 is located perpendicular to the axis of propagation A2 of the X-rays so that the channels 20 to 23 are oriented towards the source 7 to obtain a projection of the channels in the image of alignment IR which is not not distorted.
- the plate 11 may comprise a single panel in which at least four channels 20 to 23 are formed.
- the plate 1 1 may also comprise several panels 40 to 43, each panel 40 to 43 comprising at least one of said at least four channels 20 to 23.
- Each panel 40 to 43 is made of an X-ray opaque material.
- the plate 1 1 may comprise two panels each having at least two channels 20 to 23.
- the plate 1 1 may comprise three panels including at least one panel comprises at least two channels 20 to 23.
- the plate 1 1 may comprise four panels 40 to 43.
- the panels 40 to 43 may be mounted mobile on the emission unit 2 between a closed position in which the channels 20 to 23 are located inside the X-ray beam A3, and an open position in which the channels 20 to 23 are located outside the X-ray beam A3. In FIG.
- the channels 20 to 23 can interact or not interact with the beam A3.
- X It is advantageous that the channels 20 to 23 do not interact in order to reduce the disturbances during the production of the radiographic image of the object 5.
- the patterns formed by the channels allow additional control of the X-ray image of the object 5.
- the receiving unit and the transmitting unit are correctly placed relative to the object 5. It is then possible to detect an offset from a prior positioning phase where the plates were in closed positions to generate the IR alignment image. In the open position, the X-ray flux is larger than in the closed position so as to make the X-ray image and not an alignment image.
- the movable panels 40 to 43 make it possible to move rapidly from the open position to the closed position, in other words to quickly generate the IR alignment image and then the exploitable radiographic image of the object 5, and vice versa.
- panels 40 to 43 are mounted movable in translation along axes perpendicular to the axis of propagation A2 (the axis of propagation A2 is perpendicular to the plane of the sheet of Figures 6 and 7) to separate them from each other to the open position, and to bring them together others to the closed position.
- the panels 40 to 43 In the closed position the panels 40 to 43 can be in contact with each other, or be partially juxtaposed with respect to each other, with or without contact between them.
- the plate 11 can be mounted on a transmission unit 2 which does not include a diaphragm 8.
- FIGS. 2 to 6 show several embodiments of the plate 11.
- a front view of the plate 1 1 having four channels 20 to 23, preferably four openings of circular section, that is to say that the channels 20 to 23 have a cylindrical shape.
- the channels 20 to 23 are located at specific positions in the plate 1 1 so that the figure formed by the four channels 20 to 23 is asymmetrical.
- the channels 20 to 23 are cylindrical and their sections have different diameters between them.
- the channels 20 to 23 have the same cylindrical shape and have different diameters.
- the channels 20 to 23 are differentiated by their size.
- the channels 20 to 23 have a shape of a truncated cone.
- the top of each truncated cone may be located in front of the X-ray source 7, their bases being located opposite the reception unit 3.
- the plate 11 may be situated at an optimal position with respect to the source 7, so that the top of the truncated cones is located on the axis of propagation A2 X-rays.
- the top of the truncated cones is located on the source 7 X-rays.
- the plate 1 1 comprises four channels 20 to 23, in particular four openings with circular section.
- the channels 20 to 23 are located at specific positions in the plate 1 1 so that the figure formed by the four channels 20 to 23 is asymmetrical.
- the channels 20 to 23 have the same length L, that is to say that their sections have the same diameter.
- the channels 20 to 23 are differentiated by their position on the plate 11.
- the plate has four channels 20 to 23 cylindrical arranged to form an asymmetrical figure.
- the distances separating the channels 20 to 23 are distinct so as to move a channel 22 away from the first two 20, 21.
- the arrangement of the channels 20 to 26 within the plate 1 1 forms an asymmetrical figure.
- An asymmetrical pattern makes it possible to obtain, in the IR alignment image, projected patterns from the channels that are located at distinct distances from one another. The distinct distances obtained may facilitate the matching of the projected patterns with the channels of the plate 1 1.
- the plate 11 comprises three zones Z1 to Z3, each zone comprising several channels, and a cylindrical channel 23 distinct from those of the zones.
- the three zones Z1 to Z3 each comprise six cylindrical channels arranged symmetrically to form a circle.
- a zone Z1 to Z3 comprising six channels makes it possible to reduce the dose of x-rays emitted with respect to a single channel that would surround the six channels. It may be noted that each zone Z1 to Z3 forms a symmetrical figure, however, the arrangement of the zones Z1 to Z4 forms an asymmetric figure.
- the plate 11 comprises fourteen channels 20 to 33.
- the plate 11 comprises a first group of seven channels 20 to 26 aligned along a first axis B1, a second group of four channels 27 to 30 aligned. according to a second axis B2 perpendicular to the first axis B1, and a third group of three channels 31 to 33 aligned along a third axis B3 inclined at an angle B relative to the first and second axes B1, B2.
- the four channels 27 to 30 of the second group are aligned along the second axis B2 with the third channel 22 of the first group, starting from the left in FIG. 5.
- the three channels 31 to 33 of the third group are also aligned.
- each line of channels may comprise several channels.
- the channels 20 to 33 have a circular section and have the same diameter.
- the plate 11 comprises more than four channels when it is desired to align the transmission unit 2 with the reception unit 3 in complex situations, for example in the case where the object 5 is bulky, or when the amount of X-radiation emitted is low.
- the fact of aligning channels along three distinct axes B1 to B3 makes it possible to improve the robustness of the image processing by improving the determination of the coordinates of the patterns projected in the image.
- the image processing unit 4 makes it possible to determine the position and the orientation of the reception unit 3 of the imaging system 1.
- the image processing unit 4 is coupled to the reception unit 3.
- the processing unit 4 is either integrated within the detector 9, or located outside the detector 9 while being electrically connected to the detector 9 by wired or wireless link.
- the image processing unit 4 is, for example, a computer.
- the detector 9 receives the X-radiation emitted by the emission unit 2, and generates an X-ray image of IR alignment corresponding to the X-radiation received by the detector 9.
- the IR alignment image generated by the detector 9 comprises the respective projections of the channels 20 to 23 of the plate 1 1, that is to say the projected patterns M1 to M4 of the channels 20 to 23.
- the detector 9 transmits the images generated, by electrical signal, to the processing unit 4 which determines the position and orientation of the reception unit 3 with respect to the transmission unit 2.
- the determination of the position and the orientation of the reception unit 3 is carried out on the basis of known processing algorithms. integrated image in the processing unit 4.
- the processing unit 4 determines the coordinates of the projected patterns M1 to M4 in the IR alignment image, then determines a position of the reception unit 3 from the determined coordinates and coordinates of the channels 20 to 23.
- the processing unit 4 can also determine an inclination of the receiving unit 3 with respect to an axis perpendicular to the plate January 1.
- the processing unit 4 comprises a memory for storing parameters of a first geometric transformation matrix Kref.
- the geometric transformation associated with the first matrix Kref corresponds to a projection of the coordinates of the channels 20 to 23 of the plate 11 in a reference radiographic image.
- the first matrix Kref makes it possible to connect the coordinates of a projected pattern in the reference image with those of the channel 20 to 23 of the plate 11 which has generated the projected pattern.
- the patterns projected in the reference image are also referred to as reference patterns.
- the reference patterns are obtained by positioning the reception unit 3 at a reference distance Dref of the reception unit, and by generating the reference radiographic image of the plate 1 1.
- the receiving unit 3 in a reference orientation in which the plane of the receiving unit 3 is parallel to the plane of the plate 1 1, and perpendicular to the axis of propagation A2 X-rays.
- the radiographic image is also generated reference with the plate 1 1 located in the housing 6 of the emission unit 2 and without the object 5 to be studied.
- P a matrix of the coordinates of a channel 20 to 23 of the plate 1 1;
- - Qref a matrix of the coordinates of the reference pattern corresponding to the projection of the channel 20 to 23 in the reference radiographic image.
- the processing unit 4 can also calculate the parameters of the first matrix Kref, for each reference pattern and for each channel associated with the reference pattern, and compare the values of the parameters obtained for each calculation.
- the coordinates of a point in a radiographic image, reference or alignment are expressed according to a two-dimensional image reference defined by two orthonormal vectors U, V and an origin point O.
- the reference image is linked to radiographic reference and alignment images.
- a three-dimensional object marker is also defined comprising three orthonormal vectors X, Y, Z and an origin point I, in which the coordinates of the channels are expressed.
- the object marker is linked to the source 7.
- the plate 11 is secured to the source 7, and the object marker is also connected to the plate 11.
- the coordinates of the channels 20 to 23 of the plate 11 are expressed in the object reference.
- the coordinates of the channels 20 to 23 are previously recorded in the memory of the processing unit 4.
- the coordinates of a channel 20 to 23 correspond to the coordinates of the center of gravity of a section of the channel 20 to 23.
- the center of gravity chosen to determine the coordinates of the channel 20 to 23 is the center of gravity of a section of the channel located at the surface of the plate 1 1 placed opposite the source 7.
- the coordinates of a channel 20 to 23 correspond to the coordinates, expressed in the object reference of a representative point of the channel 20 to 23.
- the representative point of a channel 20 to 23 is located at the periphery of a section of the channel 20 to 23.
- the representative point of a channel 20 to 23 is located inside the channel 20 to 23, that is to say on a straight line connecting the center of gravity and a point located at the periphery of the section of the channel 20 to 23.
- the orientation of the plate 1 1 in the object repository is also stored in the memory.
- the plate 1 1 has a 90 ° orientation with respect to the X-ray propagation axis.
- the Kref matrix can be written in the following way: o ⁇
- - k a conversion factor from meter to pixel, the value of which depends on the type of detector 9 and whose unit is in pixels per meter;
- U0, V0 coordinates, in the image frame, of a point of the reference image corresponding to the orthogonal projection of the source 7 of the radii
- Um1, Vm1 the coordinates of a reference pattern in the image reference
- Xc1, Yc1, Zc1 the coordinates of a channel in the object reference.
- the IR alignment image is generated with the same plate 1 1 for which the parameters of the first geometric transformation matrix Kref have been determined, and with the object 5 to analyze located between the reception unit 3 and the emission unit 2.
- the processing unit 4 identifies the projected patterns M1 to M4 in the alignment image IR using image processing algorithms known to detect the contours of the projected patterns M1 to M4.
- image processing algorithms known to detect the contours of the projected patterns M1 to M4.
- the same algorithms can be applied to the reference image to identify the reference patterns. For example, Canny filters can be used.
- the gray alignment thresholding algorithm can be pre-applied to the IR alignment image to provide a simplified image for improved edge detection.
- filtering may be applied to the IR alignment image to suppress the isolated pixels, i.e., to suppress the noise of the image.
- image processing algorithms configured to determine the characteristics of each projected pattern can be applied to identify the patterns.
- Features include, but are not limited to, the shape, length, and coordinates of the projected pattern in the IR alignment image.
- a Hough transform function can be applied to determine the characteristics of the projected patterns M1 to M4.
- the Projected patterns M1 to M4 are circles or ellipses.
- the coordinates of the pattern are those of the center of the circle or ellipse.
- the coordinates of a pattern correspond to the coordinates of the centroid of the pattern.
- the coordinates of a projected pattern M1 to M4 correspond to the coordinates, expressed in the image frame, of a point representative of the projected pattern M1 to M4.
- the representative point of a projected pattern M1 to M4 is located at the periphery of the projected pattern M1 to M4, that is to say situated on the contour of the projected pattern M1 to M4.
- the representative point of a projected pattern M1 to M4 is located inside the projected pattern M1 to M4, that is to say on a straight line connecting the center of gravity and a point located on the contour. of the projected motif M1 to M4.
- the other characteristics of the patterns M1 to M4 are the diameters of the circles, the small and large axes of the ellipses.
- the processing unit 4 matches the identified patterns M1 to M4 with the associated channels 20 to 23 of the plate 11.
- the processing unit 4 matches the projected patterns M1 to M4 by means of a feature table stored in the memory of the processing unit 4.
- the table includes the characteristics of the channels 20 to 23 of the plate 1 1, namely their shape, their length and their position in the plate 1 1.
- the pairing consists in traversing the IR alignment image to identify the projected patterns M1 to M4, and for each identified projected pattern, the processing unit 4 calculates the characteristics of the pattern, such as, for example, its shape, its length, and its position in the IR image. Then the processing unit 4 compares the calculated characteristics with those of the table and locates the channel of the plate that corresponds to the projected pattern.
- a projected pattern corresponds to a channel of the plate when the calculated characteristics are proportional to those of the table.
- the proportionality corresponds to an enlargement or a narrowing, as a function of the position of the detector 9.
- the channels 20 to 23 have the same size, for example the same diameter, the pairing is performed according to the position of the sensors. reasons projected in the image, because the position of the patterns in the image makes it possible to differentiate them from each other. On the contrary, when the channels have different sizes, the matching is done according to the sizes of the projected patterns, because they are different from each other.
- the processing unit 4 calculates, by known image processing algorithms, parameters of a second geometric transformation matrix H connecting the coordinates of the reference patterns with the coordinates of the projected patterns M1 to M4 in the Radiographic image of IR alignment.
- the second matrix H corresponds to a planar homography between the reference radiographic image and the radiographic image of IR alignment. This planar homography is mathematically represented by the second matrix H.
- Qref the coordinate matrix of the reference pattern corresponding to the projection of the channel 20 to 23 in the reference radiographic image
- Qali a coordinate matrix of the channel 20 to 23 projected in the alignment radiographic image.
- the projected pattern in the alignment image and the associated reference pattern being generated by the same channel of the plate 1 1.
- the third geometric transformation associated with the third matrix Kali corresponds to a projection of the coordinates of a channel 20 to 23 of the plate 11 in the IR alignment image.
- the third matrix Kali makes it possible to connect the coordinates of a projected pattern in the IR alignment image with those of the channel 20 to 23 of the plate 11 which has generated the projected pattern.
- Kali the third matrix corresponding to the third geometrical transformation
- k ' another conversion factor from meter to pixel, the value of which depends on the type of detector 9 and whose unit is in pixels per meter;
- D a distance between the reception unit 3 and the transmission unit 2, expressed in meters, during the generation of the IR alignment image.
- the processing unit 4 calculates, from the product between the first and second matrices Kref, and H, the parameters of the matrices Kali and Rali. Then, the processing unit 4 calculates the position and orientation of the receiving unit from the calculated parameters. More particularly, the processing unit 4 calculates the distance D between the reception unit 3 and the emission unit 2. Furthermore, the rotation matrix Rali can be decomposed into three matrices, that is, say three other matrices each representing a rotation of the reception unit 3 with respect to an axis X, Y, Z of the object reference.
- the user can furthermore enter, by means of a graphic interface 14, a position, or a distance between the transmission unit 2 and the reception unit 3, and a desired inclination.
- the processing unit 4 then calculates the difference in position between the desired position and the determined position, as well as the difference in orientation between the desired orientation and the determined orientation. Using the calculated differences, the processing unit can provide position correction and orientation information.
- the imaging system 1 may comprise a signaling unit 15, for example a screen, coupled to the processing unit. 4 to indicate to the operator the values of the position and the orientation determined.
- the signaling unit 15 may further indicate the initial distance determined by the processing unit 4.
- the signaling unit 15 may also indicate a displacement information, in translation and in rotation, to align the transmission unit. 2.
- the displacement information corresponds to the displacement of the transmission unit 2 necessary to align it with respect to the reception unit 3.
- the displacement information is that which makes it possible to move the transmission unit 2 so that the distance between the receiving unit 3 and the transmitting unit 2 is equal to an optimum distance provided by the manufacturer of the receiving unit 3.
- the optimum distance may be the focal length of the anti-diffusion gate 10 in the case where the reception unit 3 is equipped with such a gate.
- the housing 6 of the transmission unit 2 may further comprise displacement means 16 for placing and removing the plate 1 1 in an automated manner. When the reception unit 3 and the emission unit 2 are aligned, the plate 11 is removed, and a normal radiographic image of the object 5, denoted diagnostic image, is produced.
- the projected patterns M1 to M4 of the IR alignment image must have a minimum diameter of 1 mm.
- the reception unit 3 located at a distance from the transmission unit 2 for which the enlargement factor of the channels 20 to 23 of the plate 1 1 is equal, for example, to 10
- there will be made a plate January 1 whose channels have a diameter greater than 100 ⁇ .
- projected patterns M1 to M4 having a diameter of about 1 mm are obtained, which allows their detection.
- a plate 1 1 may have channels 20 to 23 having an identical shape, however, the diameter of each channel is less than 100 ⁇ .
- the magnification factor may be 4 and the plate 11 used then has channels 20 to 23 each having a diameter equal to 50 ⁇ .
- the size of the channels is adapted to the type of detector, in particular according to the size of the pixels.
- the alignment image is performed with a low dose of X-rays.
- This low dose corresponds to about ten times less than a normal dose for producing a diagnostic X-ray image.
- the surface ratio between a plate-free irradiation field with open diaphragms, for example 20 cm x 20 cm, and the plate-field area where X-rays pass only through the channels is For example, for a diagnostic X-ray image requiring a PDS dose area product of the order of 100 cGy.cm2, the additional dose given to the patient during the alignment step is 10 x 10000 times less. or 10 microGy.cm2 in terms of PDS, which is negligible.
- a succession of radiographic images is carried out beforehand, in the presence of calibrated objects and in the absence of a patient to be analyzed. Simulation is performed by varying the diameter of the channels and recording the delivered X-ray dose required for detection of the projected patterns formed in the radiographic images obtained. In addition, the signal-to-noise ratio can be recorded according to the size of the object and the dose delivered.
- a set of plates 1 1 respectively associated with different clinical situations, for example situations that require different doses of X-rays. This game includes plates 1 1 optimized for making a radiographic image specific from a given imaging system.
- the imaging system 1 makes it possible to place a plate 1 1 according to the distance between the reception unit and the emission unit, and therefore the enlargement factor of the reception unit 3.
- Other parameters can be taken into account, for example the thickness of the area of interest of the object 5, the sensitivity of the reception unit 3, the contrast of the desired image ...
- the method of positioning the reception unit 3 with respect to the transmission unit, or vice versa can be implemented by the imaging system 1 defined above.
- the reception unit 3 and the transmission unit 2 are arranged so that the object 5 to be analyzed is located between the transmission unit 2 and the detector 9.
- the method further comprises the steps of:
- the plate 1 1 made of an X-ray opaque material, between the emission unit 2 and the reception unit 3, the plate 1 1 comprising at least four channels 20 to 23, each channel allowing a part X-rays emitted by the transmitting unit 2 to pass through the channel;
- a radiographic imaging system and a system positioning method that minimizes the quantities of X-rays emitted while allowing radiographic images to be made without distortion.
- the number of images is reduced so as to limit a patient's exposure to X-rays.
- Such an imaging system is particularly suitable for environments comprising metallic objects that can disturb electromagnetic measurement systems. classic distances.
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Application Number | Priority Date | Filing Date | Title |
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FR1460687A FR3028039B1 (fr) | 2014-11-05 | 2014-11-05 | Systeme d'imagerie radiographique et procede de positionnement d'un tel systeme |
PCT/FR2015/052998 WO2016071645A1 (fr) | 2014-11-05 | 2015-11-05 | Système d'imagerie radiographique et procédé de positionnement d'un tel système |
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EP3215830A1 true EP3215830A1 (fr) | 2017-09-13 |
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US (1) | US10758204B2 (fr) |
EP (1) | EP3215830A1 (fr) |
FR (1) | FR3028039B1 (fr) |
WO (1) | WO2016071645A1 (fr) |
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DE102014210897B4 (de) * | 2014-06-06 | 2022-01-13 | Siemens Healthcare Gmbh | Verfahren und Vorrichtung zur Strahlerpositionierung |
WO2016081881A1 (fr) | 2014-11-20 | 2016-05-26 | Heuresis Corporation | Système de balayage par rayons x |
US10631799B2 (en) * | 2016-12-07 | 2020-04-28 | Harris Corporation | Dental image collection device providing optical alignment features and related system and methods |
US10770195B2 (en) | 2017-04-05 | 2020-09-08 | Viken Detection Corporation | X-ray chopper wheel assembly |
US11172908B2 (en) * | 2019-07-30 | 2021-11-16 | GE Precision Healthcare LLC | Method and systems for correcting x-ray detector tilt in x-ray imaging |
FR3099832B1 (fr) | 2019-08-09 | 2021-10-08 | Univ Grenoble Alpes | Collimateur tournant pour un système de détection de rayons X |
CN115698774A (zh) | 2020-06-02 | 2023-02-03 | 维肯检测公司 | X射线成像设备和方法 |
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US20040057556A1 (en) * | 2002-09-20 | 2004-03-25 | Koninklijke Philips Electronics N.V. | Method and apparatus for alignment of anti-scatter grids for computed tomography detector arrays |
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US6973202B2 (en) * | 1998-10-23 | 2005-12-06 | Varian Medical Systems Technologies, Inc. | Single-camera tracking of an object |
US6422750B1 (en) | 2000-12-22 | 2002-07-23 | Ge Medical Systems Global Technology Company, Llc | Digital x-ray imager alignment method |
US6702459B2 (en) | 2001-04-11 | 2004-03-09 | The Uab Research Foundation | Mobile radiography system and process |
US7006594B2 (en) | 2002-02-25 | 2006-02-28 | Ge Medical Systems Global Technology Company, Llc | Method and apparatus for reconstruction calibration of detector position and source motion based on a multi-pin phantom |
US7344304B2 (en) | 2005-06-14 | 2008-03-18 | Varian Medical Systems Technologies, Inc. | Self-alignment of radiographic imaging system |
US7950849B2 (en) * | 2005-11-29 | 2011-05-31 | General Electric Company | Method and device for geometry analysis and calibration of volumetric imaging systems |
US7341376B2 (en) | 2006-03-23 | 2008-03-11 | General Electric Company | Method for aligning radiographic inspection system |
FR2899349B1 (fr) | 2006-04-04 | 2009-05-01 | Pierre Tranchant | Reglage de position d'une installation de radiologie mobile |
JP2010178914A (ja) * | 2009-02-05 | 2010-08-19 | Hitachi Medical Corp | 移動型x線撮影装置 |
JP2011019707A (ja) * | 2009-07-15 | 2011-02-03 | Fujifilm Corp | X線撮影装置、x線撮影装置の制御方法、及びプログラム |
US8262288B2 (en) * | 2010-01-21 | 2012-09-11 | Analogic Corporation | Focal spot position determiner |
ES2646819T3 (es) | 2010-05-12 | 2017-12-18 | Trophy | Aparato de alineación para radiografía intrabucal dental |
US8821015B2 (en) | 2011-03-08 | 2014-09-02 | Carestream Health, Inc. | Alignment apparatus for X-ray imaging system |
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2014
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2015
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- 2015-11-05 WO PCT/FR2015/052998 patent/WO2016071645A1/fr active Application Filing
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US20040057556A1 (en) * | 2002-09-20 | 2004-03-25 | Koninklijke Philips Electronics N.V. | Method and apparatus for alignment of anti-scatter grids for computed tomography detector arrays |
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See also references of WO2016071645A1 * |
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WO2016071645A1 (fr) | 2016-05-12 |
US10758204B2 (en) | 2020-09-01 |
FR3028039B1 (fr) | 2016-12-30 |
FR3028039A1 (fr) | 2016-05-06 |
US20170332986A1 (en) | 2017-11-23 |
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