EP3987312A1 - Camera compton et procede d'imagerie 3d campton - Google Patents
Camera compton et procede d'imagerie 3d camptonInfo
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- EP3987312A1 EP3987312A1 EP20800005.9A EP20800005A EP3987312A1 EP 3987312 A1 EP3987312 A1 EP 3987312A1 EP 20800005 A EP20800005 A EP 20800005A EP 3987312 A1 EP3987312 A1 EP 3987312A1
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Classifications
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- 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
- G01N23/20—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 using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/20066—Measuring inelastic scatter of gamma rays, e.g. Compton effect
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/1603—Measuring radiation intensity with a combination of at least two different types of detector
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/29—Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation
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- G01N2223/00—Investigating materials by wave or particle radiation
- G01N2223/40—Imaging
- G01N2223/401—Imaging image processing
Definitions
- the present application relates to the field of imaging and more particularly to the imaging of sources of gamma rays.
- the present application relates to a device, system and methods for imaging by detector of the Compton Camera type.
- the present application relates to a device, system and methods for imaging by Compton Camera called “multi-capture” (at least “bi-capture”), that is to say using at least two captures.
- Compton imaging performed from at least two different locations (either different locations of the same Compton Camera, or different locations of several separate Compton Cameras).
- the present application therefore details a new technology for detecting gamma rays combining several captures of Compton images and improvements made to cameras and / or image reconstruction methods using this type of multiple captures.
- the invention further relates to the use of such imaging and / or detection in the fields in particular of astronomy, the nuclear industry and the medical field.
- Such a capture center makes it possible, thanks to the photons detected, to obtain Compton images following the interaction between an incident Gamma ray with the capture center, for example as shown in FIG. 1.
- the image reconstruction mode used by Compton cameras is fundamentally ambiguous. Indeed, we typically measure a vector corresponding to the characteristics of a first interaction (11) (or “diffusion”), which has a given energy (E1), then a vector corresponding to a second interaction (I2) (or “absorption ").
- E1 first interaction
- I2 second interaction
- the incident gamma radiation is then localized on a cone whose apex is 11 and the opening angle is given by the ratio between the measured energies of the two interactions (E1 / E2).
- a first interaction (11) of a gamma ray with a scintillator will generate photons detectable by the capture center (CC) and deviate its trajectory
- a second interaction (I2) with a scintillator (identical or different from the first) will also generate photons detectable by the capture center (CC)
- Compton imaging defining a Reconstruction Cone (CR) whose vertex is in the capture center ( CC) and whose base is a reconstruction ellipse (DR) formed by the intersection between the reconstruction cone (CR) and a reconstruction plane perpendicular to the imaging axis of the capture center (CC).
- the reconstruction plan can be defined using various means, such as for example telemetry, laser measurement or even by three-dimensional reconstruction of the Compton images. It will be noted that in the latter case, it is not necessary to make an assumption on the identification of the source with an optical object.
- the object of the present invention is therefore to provide a Compton imaging device, system and method making it possible to overcome at least part of the drawbacks of the prior art.
- the terms "present invention” or “the invention” in fact designate, in the present application, simply possible embodiments and examples of implementation. These various embodiments, as well as their particular technical characteristics, could of course be isolated from each other or combined together by a person skilled in the art, in particular thanks to the functional considerations provided in the present application and according to the needs imposed by them. targeted applications according to the fields of application.
- the invention relates to a device, a system and a method for using a Compton camera, characterized by the use of at least two centers for capturing distinct positions. [0012]
- the invention makes it possible to reduce the calculation time and / or to limit the number of photons necessary to obtain reliable imaging, unlike the prior art using only Compton images obtained from the same center. capture.
- a second relates to a 3D imaging method using said Compton cameras and some of the various applications which result therefrom.
- the present application proposes to use "Compton images” from different “Compton capture” positions.
- the term “Compton image” (or simply “image”) designates in the present application the imagery obtained from the vectors calculated on the basis of the data collected by a single determined “capture center” (of determined position, whatever the its technical specifications).
- the term “Compton capture” designates in the present application the imagery obtained from the vectors calculated on the basis of the data collected by several determined “capture centers”, whether it is acts of the same capture center displaced in space between two successive images or of two distinct capture centers (CC1, CC2) producing independent images from different positions.
- the present application therefore provides various embodiments for its physical implementation in terms of device, system or method.
- the same camera will preferably be used in two successive positions or two identical cameras located in two different positions, but the present application also provides for the possibility of using two different cameras in two different positions.
- the invention is characterized in that the distinct positions are separated by a distance less than or equal to twice the resolution. position (for example 1 ° or 2 °, even 3 °) (by preference to the angular resolution between two sources which is clearly superior: for example 6 ° to 8 °) of the capture center of the Compton camera in order to obtain a stereoscopic vision in a compact portable instrument.
- the invention is characterized in that the distinct positions are separated by a distance less than but close to twice the angular resolution of the capture center of the Compton camera, in particular at the desired range for the camera.
- the invention is characterized in that the separate positions are arranged in an arc centered on the position of the gamma ray source.
- FIG. 2 illustrates the two possible reconstruction disks (DR) obtained by a single capture center (CC1) from two successive images (n and n + 1). These two reconstruction discs (DR) make it possible to estimate the real position of the source (S) by the intersection of the two reconstruction cones (CR), but the estimated position is ambiguous.
- the present application proposes to use Compton captures from at least two different capture centers (CC1, CC2). They can be several Compton images of the same camera or images of several separate cameras, or even cameras moving in space between different locations of capture centers. All that is said for a multi-capture camera can be reproduced with a monocular camera by moving the camera from a precisely known distance and by performing identical poses on condition of also knowing precisely the relative positions and the orientation of the optical axis of the camera.
- a multi-capture camera consists of two Compton C1 and C2 heads (each can be made up of a pair of diffuser + absorber plates). These two heads are ideally identical in terms of optical configuration / design, their optical axes are preferably parallel, the two heads being separated by a precisely known distance. These two cameras look at the same field of view.
- the precision of the position of a point radioactive source obtained with a Compton camera is between 1 ° and 2 °. It is this parameter which is important for the design of a multi-capture camera.
- the distance between the two heads must under tend an angle greater than the angular accuracy of locating a source within the range of the camera. (For example a separation of 10 centimeters (cm) between the heads if the position accuracy is 1 ° and the target range is 10 meters)
- the distance between the two heads will be relatively small, for example 20 cm and this camera can operate in multi-capture mode up to at least 5 to 10 meters (m).
- the distance between the heads is not too great, for example less than 10 ° ( ⁇ 10 °) so that the observed field of view is not too different between the two images.
- an angular distance between the heads greater than 30 ° (> 30 °) has a different utility, that of giving a three-dimensional image of an extended object.
- the multi-capture camera is particularly suitable for the analysis of low contamination, or even of natural radioactivity. Indeed in this case the photon flux is low (a few photons / hour). It takes hours for the source to pass the detection threshold (50 photons / point source) and the natural background noise disturbs the measurement. On the other hand, if we have an estimate of the distance from the source, triangulation makes it possible to obtain detection with certainty.
- This phenomenon is amplified by the fact that the dimension of the detector, in the case of a monocular camera, is small compared to the distance from the source, therefore the areas of intersection are extended objects (due to the uncertainties on the measurement of the various parameters) distributed around two lines by pair of cones.
- the images can be improved and we can hope for a gain of a factor of 2 to 3 on the angular resolution of our camera and find the angular resolution that is expected according to the diameter of an isolated spot as well that we would get it with an optical camera.
- This mode is therefore particularly advantageous for the detection of very low contamination.
- This method proceeds by successive iterations (between 10 and 30 in most situations). On the other hand, if we apply a large number of "smoothings" to the image of an extended object, the image is greatly degraded.
- a factory calibration is carried out with a point source in different angular positions in the field of the camera.
- PSF Point spread function
- the number of photons present in the source is estimated
- the maximum number of smoothing to be applied in this case is determined as a function of the extent of the source and of the number of photons present.
- the Compton camera repeatedly provides the number of photons which have contributed to building a given image. It is therefore possible to use it to estimate a flux of gamma rays.
- the Compton image must be reconstructed over the entire space (4 Pi steradians). It is then necessary to identify the parasitic sources and exclude from the reconstruction the cones which pass through these parasitic sources. In this way, the disturbance of the counting rate is limited, which provides an electronic collimation of the signal collected by the device according to certain embodiments of the present application.
- the present application also provides for the integration of at least one measurement of the flow of a screened source.
- the intense sources of radiation are located in a container which may be a metal barrel, a concrete enclosure, lead protection or any other type of material or radiation protection device.
- the image is reconstructed on 4 Pi and all the cones passing through sources or intense artefacts located outside the area of interest are removed from the reconstruction. In most cases, an initial estimate is available, even accurate to 10% of the distance from the source (visible multi-capture camera, physical measurement, laser range finder, etc.).
- FIG. 2 represents an example of a conventional monocular Compton camera.
- the direction of incidence of each gamma photon performing a Compton effect in the detector is positioned on a cone.
- there are one or two possible solutions which are two generating lines of the cone.
- there are generally two solutions only one of which represents the position of the source.
- the solution is degenerated into Z (i.e. uncertain as to the depth of the source, i.e. its distance from the camera) because whatever the position of the reconstruction plane, the two solutions appear angularly in the same place.
- the second solution (that which does not contain the source) is that which generates artefacts (false concentrations) on reconstruction.
- Figure 4 shows the multi-capture camera (or the effect of a movement relative to the known trajectory of a monocular camera)
- the possible solutions are a conical arc (ellipse, parabola, etc.) .
- the solution is no longer degenerated into Z: beyond a certain distance there is no longer any solution.
- the angular position of the solutions is dependent on the reconstruction plan. However, the real source has a fixed angular direction, so the real source will emerge from the noise very quickly.
- the present application therefore aims to further protect:
- At least one Compton multi-capture camera consisting of 2 neighboring detection sets observing the same field of view, characterized in that the two detection sets are separated by an angular distance greater than 1 ° at the maximum range of the camera in order to allow observation of a movement of a point source at the maximum range between two images taken simultaneously.
- the present application also aims to protect, alternatively or in combination: - use of this type of camera to estimate the distance from a radioactive source by triangulation of gamma rays; - elimination of artefacts by keeping only the points which are preserved between the two images (coherent distance);
- a reconstruction method using a multi-capture camera which consists in considering for the reconstruction only the intersections of the cones coming from the camera C1 with those coming from the camera C2;
- the invention also relates to a method making it possible to create a three-dimensional and / or tomographic image of an object in Compton imaging gamma radiation, characterized in that it comprises one or more Compton cameras producing at least three views from of three known positions distributed each on one of the three axes (X, Y, Z) of a trihedron, the acquisition fields of said views having at least one overlap zone covering the object to be imaged.
- the invention further relates to a Compton imaging method which comprises a reconstruction method using less than 10 photons / voxel per view to reconstruct the 3D image.
- the invention relates to a Compton imaging method which comprises an electronic collimation step capable of excluding sources or photons originating from the areas that it is desired to exclude from the image.
- said views can be acquired either simultaneously by three separate Compton cameras, or sequentially by moving at least one Compton camera on said 3 axes of the trihedron.
- said trihedron is a trihedron with orthogonal X, Y and Z axes defining three directions of space, the source to be imaged being at the origin of the trihedron.
- said Compton imaging method contains a method of tomographic reconstruction of said object to be imaged from at least two Compton views, the fields of view of which are distributed in three dimensions (X, Y, Z ) from space.
- said Compton imaging method contains a Compton reconstruction method in which only the intersections of cones from different views are retained.
- said Compton imaging method contains a Compton analysis process, used in the case where the intensity of the source is identical between several views, to filter the parasitic events for which said intensity of the source does not satisfy the law of the inverse of squared distances, not varying like 1 / d 2 on each of the views, d being the distance from the source to the camera on each of the views.
- the invention further relates to a Compton imager comprising at least one Compton camera, producing at least three successive or simultaneous views by implementing the method according to at least one of the features described above.
- one of said Compton cameras is mounted on a frame defining said trihedron.
- At least one of said Compton cameras is mounted on at least one articulated arm capable of successively and simultaneously moving in all directions in space and being oriented along Euler angles, or in mode automatic, or in manual mode.
- the invention also relates to the use of said Compton imager according to one of the features described above in various fields (medical, veterinary, industrial, security, etc.)
- the invention further relates to a Compton imager comprising at least one CT-Scan head enabling a computed tomography image to be produced for attenuation correction in the images produced by Compton imaging.
- the invention also relates to a Compton imager coupled to a medical accelerator.
- the invention further relates to a Compton imager, all of the detection heads of which are facing each other around a bench, said bench being able to perform translational and rotational movements in a plane.
- the invention further relates to the use of the Compton imager to improve the control of radiotherapy and hadron therapy treatments.
- the invention further relates to the use of the Compton imager to improve the radiation protection of patients, staff, animals and the environment in the presence of one or more radioactive sources.
- the invention further relates to the use of the Compton imager for obtaining a tomographic image in gamma radiation of a living being with an injected dose of less than 20 MBq in less than 20 minutes for applications in the fields of medical, veterinary and preclinical imaging, to perform non-destructive testing.
- FIG. 1 is a schematic representation of classic Compton imaging of the prior art
- Fig. 2 is a schematic representation of the reconstructions from two successive Compton images in the prior art
- FIG. 3 is a schematic representation of reconstructions from four successive Compton images in the prior art.
- FIG. 4 is a schematic representation of the reconstructions from two Compton images obtained from two separate Compton captures, according to certain embodiments of the present application.
- FIG. 5 is a schematic representation of reconstructions from three Compton images obtained by a first Compton capture and from two successive images obtained by a second Compton capture, according to certain embodiments of the present application.
- FIG. 6 is a schematic representation of the reduction in the target volume of reconstructions from several Compton captures from a position close to angular resolution.
- FIG. 7 is a schematic representation of the reduction in target volume of reconstructions from multiple Compton captures when the captures are moved in an arc centered on the source.
- FIG. 9 a is a schematic representation of two cones in two separate views.
- FIG. 9. b is the schematic representation of the area of intersection of these two cones and of its volume.
- FIG. 9.c and [Fig. 9.d] are the images of two sources ( 22 Na and 137 Cs) detected by two separate views according to one embodiment of the invention (reconstructed image (MLM / MLEM) from said two views along the axis X [Fig. 9.c], along the Z axis [Fig. 9.d]:
- FIG. 10 is a schematic representation of three Compton cameras distributed over the three axes (X, Y, Z) of a trihedron centered in O
- FIG. 11.a is a schematic representation of three cones in three distinct views.
- FIG. 11.b is a schematic representation of the area of intersection of said three cones and of its volume.
- the [Fig. 12] represents an embodiment of the invention comprising two sources of 30 kBq, one of 137 Cs, the other of 22 Na separated by 15 cm and observed from a distance of 50 cm.
- FIG. 12. a] represents the XZ section obtained by “classical” 3D reconstruction by considering all the intersections between Compton cones. The position of the 2 sources is clearly visible but the image shows many artefacts.
- FIG. 12. b] represents the same section XZ obtained by reconstruction according to certain embodiments of the invention using only the multi-view intersections and clearly showing the position of the two sources and the virtual disappearance of the artefacts. DETAILED DESCRIPTION
- the object of the present invention is therefore to provide a Compton 3D reconstruction method, uses and a Compton imager making it possible to overcome at least part of the drawbacks of the prior art.
- the invention relates to a Compton imaging method using one or more Compton cameras.
- Said Compton cameras produce at least three views [Fig. 10], [Fig. January 1 .c] (containing CCi capture centers, CC2, CC3 [Fig. 10]) from three known positions distributed over the three axes (X, Y, Z) each passing through a catch centers one of the Compton cameras.
- the implementation of said method allows the 3D reconstruction of the image of an object from a minimum of views, preferably three.
- An advantage of using the method of the present invention is that it makes it possible to reduce the number of views necessary for the reconstruction of the image which imposes constraints (time, dose, cost, etc.). For example, multiplying the number of views has a cost, either in pause time if you have to move the camera to get enough views, or in equipment cost if you use equipment that takes multiple views simultaneously.
- the implementation of the method of the present invention makes it possible to combine the advantages of the detection mode of Compton cameras, of the original and novel method of selection of the photons required to reconstruct 3D image.
- the method of the present invention comprises a 3D Compton reconstruction step requiring less than 10 photons / voxels to reconstruct the image. This is partly due to the finesse of our photon selection method which, by reducing the positional uncertainty by acquisition, improves the localization accuracy of the reconstruction gamma photons.
- said method makes it possible, with very few photons compared to current conventional tomographic imagers, to reconstruct three-dimensional (3D) images of better or at least equivalent quality.
- the electronic collimation of Compton cameras improves sensitivity, compared for example with Anger cameras because it accepts photons regardless of their respective angles of incidence. It is also much more robust to disturbances from secondary and / or off-screen sources. Indeed, it is possible to exclude from the reconstruction cones which contain a source secondary to the one to be studied, for example a source outside the measurement field. By performing such processing we obtain an image and a count rate of the main source very similar to what we get in the absence of a secondary source. This electronic collimation is therefore able to exclude unwanted sources or photons and retain only those useful for reconstructing the image for a gain in quality and time.
- the method of the present invention comprises a 3D Compton reconstruction step requiring less than 10 photons / voxels to reconstruct the image. This is in part due to the finesse of our photon selection method which improves the localization accuracy of reconstructing gamma photons for a better image with fewer hits compared to conventional imagers of the same type.
- a Compton 3D reconstruction is carried out from three views, each sampling one of the three directions of space. Acquisition times and number of moves according to each view defined at the user's discretion.
- H and are the two points of interaction and the direction of diffusion is given by the line d (l 2 ) passing through h and I2.
- the point of absorption I2 apex of the Compton cone is the reference point locating the position of one of the views on one of the axes, the three axes forming a trihedron whose origin O [Fig. 10.] is the point of intersection of said axes.
- the 1 D, 2D, 3D modes described below must be understood as being the number of spatial directions of view (s).
- two gamma photons coming from the same source are detected by a Compton camera along one of the axes of the trihedron (1 D mode).
- a Compton camera along one of the axes of the trihedron (1 D mode).
- the intersection volumes of the cones are quite large. For example, 2240 cm 3 for the intersection volume following a view [Fig. 8.c]
- the two gamma photons are detected either by two different Compton cameras, each along one of the three axes of the trihedron, or by a single Compton camera capable of successively producing two views, each along two different axes of the trihedron ([Fig. 9. a]; [Fig. 9. b]).
- Such an arrangement of Compton cameras makes it possible to have two separate shots along two axes of a plane passing through the object to be imaged, the details of the object to be imaged are better circumscribed, better defined and better resolved than in 1 D mode.
- With two views along X and Y at 90 ° to each other there is an interaction volume of the Compton cones of 1327 cm 3 [Fig. 9. b]. Lower than that obtained from the intersection of the Compton cones in acquisition 1 D.
- many values of X and Y are excluded, the solution is no longer degenerate along the observation axes.
- An advantage of this embodiment is to accelerate the convergence of the reconstruction algorithm.
- the [Fig. 9.c] and [Fig. 9.d] are the views and images obtained from the classical 2D reconstruction from views along X and along Y at 90 ° to each other. All intersections between cones are considered valid. The views are taken along the X and Y axes and the image shown along the Z axis where no observations are available.
- One of the advantages of this embodiment is to highlight three problems, an artefact line along the axis of view, the image of the point source is not spherical and has a distortion along the same axes as the artifact, the image computation time is very long.
- an observation along the Z axis further reduces artifacts. Indeed, with this complete observation there is no longer a particular direction according to a view and the artifact is much less marked.
- one solution offered by the method is, to limit this problem, to observe the system along the Z axis.
- three gamma photons from the same source are detected, either by three different Compton cameras, each along one of the three axes of the trihedron ([Fig. 10]; [Fig. 12]), or by a single Compton camera capable of producing three views, each along three different axes of the trihedron, or by two cameras, one producing a view along one of the axes of the trihedron and the other successively producing the other two views respectively on the other two axes of the trihedron.
- the purpose of these different Compton camera layout options is to cover all the possible configurations to ultimately make it possible to obtain three distinct shots along the three axes of a trihedron.
- the views can be acquired, either simultaneously by three separate Compton cameras, or sequentially by a displacement of at least one Compton camera on said 3 axes X, Y and Z of the trihedron.
- the place of emission (S) of the detected photon coincides with the point of intersection (O) of the X, Y and Z origin axes of the trihedron [Fig. 10.].
- said trihedron is a trihedron with orthogonal X, Y and Z axes defining three directions of space.
- Three views following the three directions of space constitute optimal observation conditions for a given source located at the origin of said trihedron, If the field of view is transparent to radiation, the views above and below are equivalent in information, and are those where the axes joining the source to the camera constitute an orthogonal trihedron.
- the source is simultaneously observed along the 3 axes of the trihedron and only the intersections which include the three viewing angles are considered, in the most general case there are only 8 possible point solutions for the source in space, 8 restricted zones if the cones have a certain thickness due to uncertainties [Fig. 9.a]
- the method contains a Compton reconstruction method in which only the intersections of cones from different views are retained.
- One of the advantages being by example, improving the source location accuracy which allows better reduction of ghost source artifacts in the reconstructed image.
- a voxel is generally defined as a unit of volume image the geometry of which is variable (cubic, cylindrical, spherical, etc.) and that this term should not be understood in a limiting manner.
- Another advantage of imposing the presence of cones from the 3 views to consider an intersection zone as valid, is that this will considerably accelerate the convergence of the rear projection algorithm by removing the irrelevant zones to locate the source.
- Another advantage is that this reduction in uncertainties leads to reducing the dimensions of the task which contains the image of the source. With three views we have a better angular resolution of the Compton camera.
- said Compton imaging method further contains a Compton scanning process, used in the case where the intensity of the source is identical between several views, to filter the parasitic events for which said intensity of the source does not satisfy the law of the inverse of squared distances, not varying as 1 / d 2 on each of the views, d being the distance from the source to the camera on each of the views.
- a Compton scanning process used in the case where the intensity of the source is identical between several views, to filter the parasitic events for which said intensity of the source does not satisfy the law of the inverse of squared distances, not varying as 1 / d 2 on each of the views, d being the distance from the source to the camera on each of the views.
- the attenuation due to the scattered radiation is not a problem since it is possible to obtain quantified images of the scattered radiation. It is therefore advantageous to use these images to correct the number of photons emitted.
- the present invention further relates to a Compton imager comprising at least one Compton camera, capable of producing at least three successive or simultaneous views and implementing the Compton imaging method according to the particularities described above.
- said Compton imager comprises a Compton camera mounted on a frame defining the trihedron.
- At least one of the Compton cameras of said Compton imager is mounted on at least one articulated arm which can successively and simultaneously move in all directions in space and be oriented along the angles of Euler, either in automatic mode or in manual mode.
- This facilitates the deployment of the cameras around the object to be imaged and also makes it possible to consider and achieve all types of possible and desired orientations for different arrangements of the view heads of each of the cameras.
- Another advantage is to make it possible to bring the detection heads closer to the area to be imaged and thus reduce the acquisition time and at the same time the dose and, to improve the spatial resolution of the image, to be able to achieve the various view positions desired regardless of the geometric constraints.
- the automatic mode is controlled remotely. So for some use it is not necessary to have an operator near the object to be imaged.
- said Compton camera are mounted on aircraft (for example a drone, etc.) or on a land drone thus making it possible to produce views of an object to be imaged located in a zone of particularly restrictive access (at sea, space, contaminated area, ).
- the present invention relates to the use of the Compton imager according to the particularities described above in many fields (health, industry, environment, safety).
- PET imaging In the field of health for example, one of the main interests of Compton 3D imaging compared to other imaging modalities, PET imaging for example, it makes it possible to obtain tomographic images, which are certainly less resolved. , but on the one hand with a dose injected by a factor of 10 to 20 lower, and contributes significantly to improving the radiation protection of patients, staff, animals and the environment.
- the low cost of the device of the present invention compared to a PET scan makes it more accessible.
- the present invention relates to the use of the Compton imager for medical imaging, for veterinary imaging, for preclinical checks.
- One of the advantages of the Compton imager of the present invention is that it is particularly suitable for imaging large animals (horses, cows, elephant, giraffe ).
- the Compton method and imager of the present application also relates to the field of pharmacokinetic studies (diffusion of the tracer in the body). Scanning of potentially cancerous patients to locate hot spots, the injected dose being so low (and therefore cheap) that it does not pose a risk to the patient. It also makes it possible to increase the number of frequent post-treatment images for better patient follow-up with a severely restricted dose.
- the use of the Compton imager of the present invention allows a patient to accumulate advantages in terms of quality of care, cost and treatment time, better post-treatment follow-up.
- the present invention relates to the use of the Compton imager in industry, for example for the detection of faults in various types of structures, for performing non-destructive testing, etc.
- the present invention relates to the use of the Compton imager to obtain the image of radioactivity distributions, in deduce the activity of one or more sources in industry, locate (place of emission of the photon) the sources in the containers. Indeed, with a precise measurement of the broadcast, we have a good estimate of the real activity of a source.
- the implementation of the method on a storage drum of dimensions 600 x 925 mm leads to an image (MLM / MLEM) in 20 minutes at 1.3 meters from the center with a dose of only 4.5 MBq of 60 Co using the Compton 3D reconstruction method described in the present invention.
- MLM / MLEM image
- 250 MBq is injected, with the PET detectors placed less than 40 cm from the center of the object to be imaged.
- FIG.12 shows an embodiment of the invention where two sources ( 137 Cs and 22 Na) of 30 kBq each, separated by 15 cm are observed (3 views in three directions distinct) at a distance of 50 cm from the origin of the trihedron.
- the Compton imager described is applied to humans, with the same field of view, three Compton cameras being 40 cm from the center of the area of interest.
- the number of photons detected increases by a factor of 10.
- a tomographic image is obtained in 2 minutes, either by injecting only 0.5 MBq, or a better resolved image by posing longer.
- the three parameters can be adjusted depending on the relevance, the analysis, generally depending on the information sought.
- the invention relates to the use of the Compton imager to produce tomographic images in gamma radiation (of a living being, of an animal, etc.) with an injected dose. less than 20 MBq for a time t less than 20 minutes.
- the many advantages in quality of care, cost, treatment time, ALARA, etc. made available by the device are thus combined for a patient.
- Compton cameras offer to take views with large field sizes. Compared to PET cameras the difference in field of view is significant (8100 square degrees versus 25 square degrees if PET modules of the same size as Compton modules were used).
- Another advantage for using Compton cameras is that in Compton imagery, a probability density is imaged. The image is sensitive to the neighborhood, which speeds up the convergence of the reconstruction. Unlike the pointillist PET image, each LOR is independent.
- the Compton method and imager of the present application is suitable and just as effective in the case of sources whose intensity is constant or weakly variable over time.
- the camera it is possible by moving the camera and by performing at least 3 poses (views) of the same object so that the vector joining the source and the camera has projections of at least 50% (in total or 50% along each axis) according to the 3 axes of an orthogonal trihedron.
- the case where the 3 observations take place according to a trihedron (X, Y, Z) with respect to the source is optimal.
- This can be done for example by installing a camera according to the invention on a robotic arm or a land or air drone. The goal is to have all the necessary configurations to avoid having missing views.
- the source is variable (medical applications) or if it is desired to have an image acquisition period as short as possible, it is advantageous to simultaneously acquire the 3 views along X, Y, Z during one and the same pose.
- the invention relates to the application of the method and of the Compton imager described in the field of the nuclear industry.
- to perform a 3D tomography of containers of radioactive substances for example waste drums
- the Compton imager of the present invention comprises at least one CT-Scan head enabling a tomodensitometric image to be produced.
- An advantage of this embodiment is that it allows the user to make attenuation corrections.
- the CT-scan head provides an image of the skeleton and further improves the localization of an organ in the body relative to the bone landmark.
- the CT-Scan head of the present invention includes any type of detector X-ray tube combination making it possible to determine the attenuation maps or to produce X-ray images.
- the Compton imager is coupled to a medical accelerator to perform dosimetry-in vivo measurements and thus makes it possible to check that the treatment actually delivered is indeed that which has been planned.
- medical accelerator here designates any type of medical treatment device that generates gamma or X photons in any way, with energies within the range of said Compton cameras greater than 200 keV.
- the coupling is carried out using articulated arms facilitating the optimum positioning desired for the measurement to be carried out.
- the detection heads are each facing one another around a bench, said bench capable of performing translational and rotational movements in a plane.
- the bench described above can be a bed, a table or any other device of the same type allowing the correct positioning of the area to be imaged in the field (s) of view of the Compton cameras.
- the scanning mode described above comprises a displacement of the bench in the desired direction to make it possible to image areas beyond the range of the fields of view of the Compton cameras (for example in medicine a whole body acquisition to see the distribution of 'a radionuclide throughout the body).
- the invention further relates to the use of the Compton imager of the present invention for improving the control of hadron therapy treatments.
- the correlation between the position of emission of the prompt gamma rays and the position of the Bragg peak makes it possible to control the quality of hadron therapy treatments.
- the energy of the prompt gammas varies from some hundred keV to several MeV favoring Compton scattering.
- the Compton imager of the present invention allows with unequaled localization precision the place of emission of each prompt gamma photons. Thus the correlation can be made and facilitates the monitoring of treatments.
- Another advantage of using said Compton imager is its very good energy resolution enabling it to detect and discriminate the entire spectrum of said prompt gammas.
- An additional advantage of the invention is the temporal resolution of the detectors employed (less than 200 picoseconds / ps) making it possible to attribute the photons detected to a particular phase of the pulsed flux of photons detected (for example rising edge of the pulse of photons emitted by the device) [00199]
- the present invention relates to the use of the Compton imager to improve the radiation protection of patients, staff, animals and the environment in the presence of one or more radioactive sources.
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Abstract
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Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US16/446,471 US20200400593A1 (en) | 2019-06-19 | 2019-06-19 | Camera compton multi-capture et procede d'imagerie |
FR2001009A FR3097656B1 (fr) | 2019-06-19 | 2020-01-31 | Camera Compton et procédé d’imagerie 3D COMPTON |
FR2001010A FR3097655B1 (fr) | 2019-06-19 | 2020-01-31 | Procede d’imagerie utilisant conjointement une reconstruction pet et une reconstruction compton, de preference en compton 3d |
PCT/EP2020/067238 WO2020254653A1 (fr) | 2019-06-19 | 2020-06-19 | Camera compton et procede d'imagerie 3d campton |
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EP20737365.5A Pending EP3987314A1 (fr) | 2019-06-19 | 2020-06-19 | Procede d'imagerie utilisant conjointement une reconstruction pet et une reconstruction compton, de preference en compton 3d |
EP20800005.9A Pending EP3987312A1 (fr) | 2019-06-19 | 2020-06-19 | Camera compton et procede d'imagerie 3d campton |
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EP (2) | EP3987314A1 (fr) |
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FR3130367B1 (fr) * | 2021-12-13 | 2023-12-08 | Agence Nat Pour La Gestion Des Dechets Radioactifs | Procédé d’estimation d’une distance entre un dispositif du type caméra Compton et une source de rayonnement gamma, programme d’ordinateur et ensemble d’imagerie Compton. |
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US7550738B1 (en) * | 2005-04-28 | 2009-06-23 | Utah State University | Nuclear material identification and localization |
US8461547B2 (en) * | 2005-04-28 | 2013-06-11 | Utah State University | Suppressed correlation method for identifying radioactive sources |
US8515011B2 (en) * | 2009-06-02 | 2013-08-20 | Mayo Foundation For Medical Education And Research | System and method for dose verification radiotherapy |
FR2997766B1 (fr) | 2012-11-08 | 2015-06-12 | Alain Iltis | Systeme et procede de detection de rayonnement gamma de type gamma camera |
FR3013125A1 (fr) | 2013-11-08 | 2015-05-15 | Alain Iltis | Procede pour ameliorer la resolution en energie de detecteurs de rayons gamma a scintillation, systeme, composant et application associes |
FR3036500B1 (fr) | 2015-05-18 | 2017-06-23 | Alain Iltis | Systeme et procede de detection de rayonnement gamma de type camera compton. |
ES2629092B1 (es) | 2015-11-04 | 2018-07-04 | Consejo Superior De Investigaciones Científicas (Csic) | Sistema de cámara compton de rayos gamma con medida de tiempo de vuelo |
JP6842694B2 (ja) * | 2017-02-20 | 2021-03-17 | 国立研究開発法人量子科学技術研究開発機構 | 部分リングpet装置及びpet装置 |
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- 2020-01-31 FR FR2001009A patent/FR3097656B1/fr active Active
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- 2020-06-19 EP EP20800005.9A patent/EP3987312A1/fr active Pending
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WO2020254673A1 (fr) | 2020-12-24 |
WO2020254649A1 (fr) | 2020-12-24 |
WO2020254653A1 (fr) | 2020-12-24 |
FR3097656B1 (fr) | 2022-07-22 |
FR3097655B1 (fr) | 2022-01-28 |
US20220357291A1 (en) | 2022-11-10 |
EP3987314A1 (fr) | 2022-04-27 |
US11898972B2 (en) | 2024-02-13 |
US20200400593A1 (en) | 2020-12-24 |
FR3097656A1 (fr) | 2020-12-25 |
FR3097655A1 (fr) | 2020-12-25 |
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