Compton Camera with a Segmented Detection Module

Abstract

A Compton camera for medical imaging is divided into segments (11), where each segment (11) includes a part of a scatter detector (12), a part of a capture detector (13), and a part of electronic equipment (14). Different segments (11) can be positioned together to form a Compton camera that is arcuate around a part of a patient space. By using segments (11), any number of segments (11) can be used to cooperate with a multimodal imaging system.

Description

Background Art

[0001] This embodiment relates to a Compton medical imaging system. The Compton imaging system is configured as a test platform, such as assembling a scattering ring, and subsequently, assembling a catcher ring mounted to a large frame. Electronic devices are connected to detect Compton-based events from a phantom. The Compton imaging system fails to meet the design and constraint requirements for practical use in any commercial clinical environment. Current solutions lack the ability to be integrated into an imaging platform in a clinic or lack the design and constraint requirements (i.e., flexibility and scalability) to address commercial needs. Summary of the Invention

[0002] As an introduction, the preferred embodiments described below include methods, systems, and Compton cameras for medical imaging. The Compton camera is divided into a plurality of segments, where each segment includes a portion of a scattering detector, a portion of a catcher detector, and a portion of electronic devices. Different segments can be positioned together to form a Compton camera that is arcuate around a portion of a patient space. By using segments, any number of segments can be used to cooperate with a multimodal imaging system.

[0003] In a first aspect, a Compton camera for medical imaging is provided. A first module has a wedge-shaped profile formed by a first housing, a first scattering detector connected to the first housing, and a first catcher detector connected to the first housing and spaced apart from the first scattering detector. A second module has the same wedge-shaped profile formed by a second housing, a second scattering detector connected to the second housing, and a second catcher detector connected to the second housing and spaced apart from the second scattering detector. The first module can be connected to and disconnected from the second module.

[0004] In a second aspect, a medical imaging system includes solid-state detector modules, each having a scattering detector and a catcher detector of a Compton sensor. The solid-state detector modules are shaped to be stacked together as a ring or partial ring of a configurable number of the solid-state detector modules.

[0005] In a third aspect, a method for forming a Compton camera is provided. Pairs of scattering detectors and catcher detectors are housed in separate housings shaped to be adjacent, where the pairs of scattering detectors and catcher detectors of different ones of the housings are non-planar. The housings are adjacent in a ring or partial ring around a patient space.

[0006] The present invention is defined by the appended claims, and nothing in this section should be taken as a limitation on those claims. Other aspects and advantages of the invention are discussed below in connection with the preferred embodiments, and may later be claimed independently or in combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The components and the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In addition, in the drawings, like reference numerals designate corresponding parts throughout the different views.

[0008] Figure 1 is a perspective view of multiple modules of a Compton camera according to one embodiment;

[0009] Figure 2 illustrates an exemplary scattering detector;

[0010] Figure 3 illustrates an exemplary capture detector;

[0011] Figure 4A is a side view of one embodiment of a Compton camera, Figure 4B is Figure 4A a front view of the Compton camera of Figure 4C is Figure 4B a detail view of a portion of the Compton camera of

[0012] Figure 5 is a perspective view of one embodiment of a Compton camera in a medical imaging system;

[0013] Figure 6 is a perspective view of one embodiment of a full-ring Compton camera in a medical imaging system;

[0014] Figure 7 is a perspective view of one embodiment of a partial-ring Compton camera in a medical imaging system;

[0015] Figure 8 is a perspective view of one embodiment of a full-ring Compton camera in a medical imaging system having a partial ring with an axial extension;

[0016] Figure 9 is a perspective view of one embodiment of a single-module-based Compton camera in a medical imaging system; and

[0017] Figure 10 is a flowchart of an exemplary embodiment of a method for forming a Compton camera. DETAILED DESCRIPTION

[0018] A medical imaging system includes a multi-modal compatible Compton camera having a segmented detection module. A Compton camera, such as a Compton camera ring, is segmented into modules that house detection units. Each module is independent, and when assembled into a ring or partial ring, these modules can communicate with each other. These modules are independent, but can be assembled into a multi-module unit that generates an image based on Compton scattering. Cylindrically symmetric modules or spherical shell segmented modules can be used.

[0019] The scatter-catcher pair, modular arrangement allows for efficient manufacturing, can be repaired on-site, and is cost- and energy-effective. These modules allow for design freedom to vary the radius of each radial detection unit, the angular span, and / or the axial span of a module. The scatter-catcher pair modules are multi-modal compatible and / or form a modular ring Compton camera for clinical radiography. This design allows for flexibility so that the Compton camera can be added to an existing computed tomography (CT), magnetic resonance (MR), positron emission tomography (PET), or other medical imaging platform, either as an axially separated system or a fully integrated system. Each module can address heat dissipation, data collection, calibration, and / or allow for efficient assembly and repair.

[0020] Each scatter-catcher pair module is formed from a commercially suitable solid-state detector module (e.g., Si, CZT, CdTe, HPGe, or the like), allowing for an energy range of 100 - 3000 keV. A greater range of isotope energies (>2 MeV) can be provided for Compton imaging, enabling new tracers / markers to be achieved by selecting the scatter-capture detector. Modularity allows for the removal or replacement of individual modules, allowing for time- and cost-effective repair. These modules can operate independently and be isolated, or can be linked for cross-talk, enabling improved image quality and higher efficiency when detecting Compton events using the scatter detector of one module and the capture detector of another module.

[0021] Modularity allows for flexible design geometries optimized for individual requirements, such as partial rings for integration with CT systems (e.g., connected between the X-ray source and detector), some modules (e.g., tiled) for integration with single photon emission computed tomography gamma cameras or other space-constrained imaging systems, or full rings. Functional imaging based on Compton detection events can be added to other imaging systems (e.g., CT, MR, or PET). Multiple full rings or partial rings can be placed adjacent to each other to achieve greater axial coverage of the Compton camera. A dedicated or stand-alone Compton-based imaging system can be formed. In one embodiment, these modules include collimators for lower energies (e.g., < 300 keV), thus providing multi-channel and multi-path imaging (e.g., for Compton events, using the high energy of the scatter-capture detector, and for SPECT or PET imaging, using the low energy of one of the detectors). These modules can be fixed or rapidly rotating (0.1 rpm << 𝜔 << 240 rpm). Size, mounting, servicing, and / or cost constraints are addressed by the modules of the scatter-capturer pairings.

[0022] Figure 1 An embodiment of a module 11 for a Compton camera is shown. Four modules 11 are shown, but additional or fewer modules can also be used. The Compton camera is formed by one or more modules, depending on the desired design of the Compton camera.

[0023] The Compton camera is used for medical imaging. The space for the patient relative to these modules is arranged such that the modules are positioned to detect photons emitted from the patient. The radiopharmaceutical in the patient includes a radioisotope. Due to the decay of the radioisotope, photons are emitted from the patient. The energy from the radioisotope can be 100 - 3000 keV, depending on the material and structure of the detector. Any of a variety of radioisotopes can be used to image the patient.

[0024] Each module 11 includes the same components or many components among the same components. The scatter detector 12, the capture detector 13, the circuit board 14, and the baffle 15 are disposed in the same housing 21. Additional, different, or fewer components can be provided. For example, the scatter detector 12 and the capture detector 13 are disposed in the housing 21 without other components. As another example, fiber optic data lines 16 are disposed in all of the modules 11 or a subset of the modules 11.

[0025] Module 11 is shaped to be stacked together. Modules 11 match each other, for example having matching recesses and extensions, locking members, tenons and grooves, or clips. In other embodiments, flat surfaces or other surfaces are provided for abutting against each other or against separators. Locking members, clips, bolts, tenons and grooves, or other attachment mechanisms are provided for attaching module 11 to any adjacent module 11. In other embodiments, module 11 is attached to a gantry or other frame, with or without a direct connection to any adjacent module 11.

[0026] One or more connections to other modules 11 or to the gantry may be releasable. Module 11 is connected and disconnectable. The connection can be releasable, allowing one module 11 or a group of modules 11 to be removed without removing all of the modules 11.

[0027] To form a Compton camera from more than one module 11, the outer shape of housing 21 and / or module 11 is a wedge shape. Due to this wedge shape, modules 11 can be stacked around an axis to form a ring or a partial ring. The portion closer to the axis has a width dimension such that the width dimension is narrower along a dimension perpendicular to the axis than the width dimension of the portion farther from the axis. In Figure 1 module 11, housing 21 has the widest portion farthest from the axis. In other embodiments, the widest portion is closer to the axis, but is spaced apart from the narrowest portion closest to the axis. In the wedge shape, scatter detector 12 is closer to the narrower portion of the wedge shape than capture detector 13. The wedge shape in a cross-section along a plane normal to the axis allows modules 11 to be stacked and / or connected adjacent to each other in an abutting position to form at least a portion of a ring around the axis.

[0028] The tapering of the wedge provides a number N of modules 11 to form a complete ring around the axis. Any number N can be used, for example N = 10 - 30 modules. The number N can be configurable, for example using different housings 21 for different numbers N. The number of modules 11 for a given Compton camera can vary, depending on the design of the Compton camera (e.g., partial ring). The wedge shape can be provided along other dimensions, for example having a wedge shape in a cross-section parallel to the axis.

[0029] The stacked modules 11 are cylindrically symmetric when connected to the gantry of a medical imaging system. The narrowest end of the wedge cross-section is closest to the patient space of the medical imaging system, and the widest end of the wedge cross-section can be farthest from the patient space. In alternative embodiments, other shapes than a wedge can be provided, which allow stacking together to provide a ring or a generally curved shape of the stack.

[0030] The housing 21 is made of metal, plastic, fiberglass, carbon (e.g., carbon fiber), and / or other materials. In one embodiment, different parts of the housing 21 have different materials. For example, tin is used for the housing around the circuit board 14. Aluminum is used to hold the scatter detector 12 and / or the capture detector 13. In another example, the housing 12 has the same material, such as aluminum.

[0031] The housing 21 can be formed of different structures, such as an end plate having a wedge shape, a ground plane sheet housing the circuit board 14, and a separate structure of walls for holding the scatter detector 12 and the capture detector 13, wherein the separate structure is formed of a material through which photons of a desired energy from Compton events can pass (e.g., aluminum or carbon fiber). In an alternative embodiment, for the region where the scatter detector 12 and / or the capture detector 13 are located, no walls are provided for the module 11 between the end plates, thereby avoiding interference of photons transmitted from the scatter detector 12 of one module 11 to the capture detector 13 of another module 11. Because of and / or in order to hold the detectors 12, 13, the housing 21 is made of a low attenuation material, such as aluminum or carbon fiber.

[0032] The housing 21 can seal the module or include openings. For example, openings for air flow are provided, such as at the top of the widest part of the wedge shape provided at the circuit board 14. The housing 21 can include holes, slots, tongues, locking members, clips, supports, buffers, or other structures for mounting, mating, and / or stacking.

[0033] Each solid-state detector module 11 includes both a scatter detector 12 and a capture detector 13 of a Compton sensor. By stacking each module, the size of the Compton sensor increases. A given module 11 itself can be a Compton sensor because both the scatter detector 12 and the capture detector 13 are included in the module.

[0034] The module 11 can be individually removed and / or added to the Compton sensor. For a given module 11, the scatter detector 12 and / or the capture detector 13 can be removed from the module 11. For example, the module 11 is removed for repair. One or both of the faulty detectors 12, 13 are removed from the module 11 for replacement. Once replaced, the refurbished module 11 is put back into the medical imaging system. Bolts, clips, locking members, tenons and grooves, or other releasable connectors can connect the detectors 12, 13 or the parts of the housing 21 for the detectors 12, 13 to the rest of the module 11.

[0035] The scatter detector 12 is a solid-state detector. Any material can be used, such as Si, CZT, CdTe, HPGe, and / or other materials. The scatter detector 12 is fabricated using wafers to any thickness, for example, the thickness is about 4 mm for CZT. Any size can be used, such as about 5x5 cm. Figure 2 The square shape of the scatter detector 12 is shown. Other shapes than square can be used, such as rectangular. For Figure 1 the module 11, the scatter detector 12 can be rectangular extending between two wedge-shaped end plates.

[0036] In the module 11, the scatter detector 12 has any range. For example, the scatter detector 12 extends from one wedge-shaped end wall to the other wedge-shaped end wall. Smaller or larger ranges can be set, such as extending between the mounts within the module 11 or axially extending beyond one or both end walls. In one embodiment, the scatter detector 12 is at, on, or beside one end wall without extending to the other end wall.

[0037] The scatter detector 12 forms a sensor array. For example, Figure 2 the 5x5 cm scatter detector 12 is a 21x21 pixel array with a pixel pitch of about 2.2 mm. Other numbers of pixels, pixel pitch, and / or sizes of the array can be used.

[0038] The scatter detector 12 includes semiconductors formatted for processing. For example, the scatter detector 12 includes an application-specific integrated circuit (ASIC) that is used to sense photon interactions with electrons in the scatter detector 12. The ASIC is juxtaposed with the pixels of the scatter detector 12. The ASIC has any thickness. Multiple ASICs can be set, such as 9 ASICs in a 3x3 grid of the scatter detector 12.

[0039] The scatter detector 12 can operate at any count rate, such as >100 kcps / mm. Due to the interaction, the pixels generate electricity. The electricity is sensed by the application-specific integrated circuit. The position, time, and / or energy are sensed. The sensed signals can be conditioned, such as amplified, and sent to one or more of the circuit boards 14. Flexible circuits, wires, or other communication paths transfer these signals from the ASIC to the circuit board 14.

[0040] Compton sensing operates without collimation. Instead, the fixed relationship between the energy, position, and angle of the photon interactions at the scatter detector 12 relative to the photon interactions at the capture detector 13 is used to determine the angle of the photons entering the scatter detector 12. The Compton process is applied using the scatter detector 12 and the capture detector 13.

[0041] The capture detector 13 is a solid-state detector. Any material can be used, such as Si, CZT, CdTe, HPGe, and / or other materials. The capture detector 13 is fabricated using wafers to any thickness, for example, the thickness is about 10 mm for CZT. Any size can be used, such as about 5x5 cm. Due to the wedge shape and separated positions of the scatter detector 12 and the capture detector 13, this size can be greater than the scatter detector 12 along at least one dimension. Figure 3 The rectangular shape of the capture detector 13 is shown, but other shapes can also be used. For Figure 1 module 11, the capture detector 13 can be a rectangle extending between two end plates, where the length is the same as the scatter detector 12 and the width is greater than the scatter detector 12.

[0042] The capture detector 12 forms a sensor array. For example, Figure 3 a 5x6 cm capture detector 13 is a 14x18 pixel array with a pixel pitch of about 3.4 mm. This pixel size is greater than the pixel size of the scatter detector 12. The number of pixels is less than the number of pixels of the scatter detector 12. Other numbers of pixels, pixel pitches, and / or array sizes can be used. Other relative pixel sizes and / or pixel numbers can be used.

[0043] In module 11, the capture detector 13 has any range. For example, the capture detector 13 extends from one wedge-shaped end wall to another wedge-shaped end wall. Smaller or larger ranges can be set, such as extending between mounts within module 11 or axially extending beyond one or both end walls. In one embodiment, the capture detector 13 is at, on, or beside one end wall without extending to the other end wall.

[0044] The capture detector 13 includes a semiconductor formatted for processing. For example, the capture detector 13 includes an ASIC for sensing photon interactions with electrons in the capture detector 13. The ASIC is juxtaposed with the pixels of the capture detector 13. The ASIC has any thickness. Multiple ASICs can be provided, such as 6 ASICs in a 2x3 grid of the capture detector 13.

[0045] The capture detector 13 can operate at any count rate, such as >100 kcps / mm. Due to this interaction, the pixels generate electricity. This electricity is sensed by the ASIC. The position, time, and / or energy are sensed. The sensed signal can be conditioned, such as amplified, and sent to one or more of the circuit boards 14. Flexible circuits, wires, or other communication paths transfer these signals from the ASIC to the circuit board 14.

[0046] The capture detector 13 is spaced from the scatter detector 12 at any distance along a radial line from the axis or normal to the parallel scatter detector 12 and capture detector 13. In one embodiment, the spacing is about 20 cm, but greater or lesser spacings can be set. The space between the capture detector 13 and the scatter detector 12 is filled with air, other gases, and / or other materials having low attenuation for photons of the desired energy.

[0047] The circuit board 14 is a printed circuit board, but a flexible circuit or other materials can also be used. Any number of circuit boards 14 can be used for each module. For example, one circuit board 14 is provided for the scatter detector 12 and another circuit board 14 is provided for the capture detector 13.

[0048] The circuit board 14 is within the housing 21, but can also extend beyond the housing 21. The housing 21 can be grounded and thus serve as a ground plane for the circuit board 14. The circuit boards 14 are mounted parallel to each other or not parallel, for example, spread out in a wedge shape. These circuit boards are positioned generally orthogonally to the capture detector 13. This is generally used to account for any spreading due to the wedge shape. Brackets, bolts, screws, and / or supports from each other and / or the housing 21 are used to hold the circuit boards 14 in place.

[0049] The circuit board 14 is connected to the ASICs of the scatter detector 12 and the capture detector 13 by a flexible circuit or wires. These ASICs output the detected signals. The circuit board 14 is acquisition electronics that processes the detected signals to provide parameters to the Compton processor 19 (e.g., an image processor). Any parameterization of the detected signals can be used. In one embodiment, the output energy, arrival time, and three-dimensional position are provided. Other acquisition processing can be provided.

[0050] The circuit board 14 outputs to each other, for example, through current connections within the module 11, outputs to the data bridge 17, and / or outputs to the fiber optic data link 16. The fiber optic data link 16 is a fiber optic interface for converting an electrical signal into an optical signal. One or more fiber optic cables provide the acquisition parameters of the events detected by the scatter detector 12 and the capture detector 13 to the Compton processor 19.

[0051] The data bridge 17 is a circuit board, wires, a flexible circuit, and / or other materials for current connections to allow communication between the modules 11. A housing or a protective plate can cover the data bridge 17. The data bridge 17 is releasably connected to one or more modules 11. For example, the plug or mating connector of the data bridge 17 mates with the corresponding plug or mating connector on the housing 21 and / or the circuit board 14. A locking member, a clip, a tenon and groove, screws, and / or bolts can be used to releasably hold the data bridge 17 in place with the module 11.

[0052] The data bridge 17 allows communication between modules. For example, an optical fiber data link 16 is provided in one module 11 and not in another module 11. The cost of the optical fiber data link 16 in each module 11 is avoided. Instead, parameters output by another module 11 are provided to the module 11 having the optical fiber data link 16 via the data bridge 17. One or more circuit boards 14 of the module 11 having the optical fiber data link 16 route the parameter output to the optical fiber data link 16, thereby using the optical fiber data link 16 to report detected events from more than one module 11. In an alternative embodiment, each module 11 includes an optical fiber data link 16, so the data bridge 17 is not provided or the data bridge 17 conveys other information.

[0053] The data bridge 17 can connect other signals between the modules 11. For example, the data bridge 17 includes conductors for power. Alternatively, different bridges supply power to the modules 11 or the modules 11 are powered separately. As another example, the data bridge 17 is used to convey clock and / or synchronization signals between the modules 11.

[0054] In Figure 1 an embodiment, a separate clock and / or synchronization bridge 18 is provided. The clock and / or synchronization bridge 18 is a circuit board, wire, flexible circuit, and / or other material for current connection to allow the conveyance of clock and / or synchronization signals between the modules 11. A housing or protective plate may cover the clock and / or synchronization bridge 18. The clock and / or synchronization bridge 18 is releasably connected to one or more modules 11. For example, the plug or mating connector of the clock and / or synchronization bridge 18 mates with the corresponding plug or mating connector on the housing 21 and / or the circuit board 14. A locking member, clip, tongue and groove, screw, and / or bolt connection can be used to releasably hold the clock and / or synchronization bridge 18 in place with the module 11.

[0055] The clock and / or synchronization bridge 18 can be connected in a group with the data bridge 17 to the same or different modules 11. In Figure 1 the embodiment shown, the data bridge 17 is connected between pairs of modules 11, and the clock and / or synchronization bridge 18 is connected across a group of four modules 11.

[0056] The clock and / or synchronization bridge 18 provides a common clock signal and / or synchronization signal for synchronizing the clocks of the modules 11. One of the parameters formed by the circuit board 14 of each module 11 is the detection time of an event. Compton detection relies on event pairs, namely, a scattering event and a capture event. Timing is used to pair events from different detectors 12, 13. Common clock timing and / or synchronization allows precise pairing where the event pairs are detected in different modules 11. In an alternative embodiment, only scattering and capture events detected in the same module 11 are used, so the clock and / or synchronization bridge 18 may not be provided.

[0057] Other links or bridges between different modules 11 can be provided. Since the bridges 17, 18 are removable, each module 11 can be removed for repair while leaving the remaining modules 11 in the gantry.

[0058] Each module 11 is air-cooled. Holes (i.e., inlet and outlet holes) can be provided for promoting air flow through the module 11. One or more baffles 15 can be provided to direct the air within the module 11. Alternatively or additionally, water, conduction transfer, and / or other cooling can be provided.

[0059] In one embodiment, the top portion of the wedge-shaped module 11 or housing 21 is open (i.e., there is no cover on the side farthest from the patient area). One or more baffles 15 are provided along one or more circuit boards 14 and / or the center of the housing 21. A fan and a heat exchanger 20 are arranged at a position separated from the capture detector 13 (e.g., at the top of the module 11) to promote cooled or ambient-temperature air into each module 11, for example, along half of the module 11. The baffle 15 and / or the circuit board 14 direct at least some of the air to the airspace between the scatter detector 12 and the capture detector 13. Then, the air passes over the baffle 15 and / or the circuit board 14 on another part (e.g., the other half) of the module 11 to exit to the heat exchanger 20. Other air routes can be provided.

[0060] The heat exchanger and the fan 20 are provided for each individual module 11 and can thus be fully or partially within the module 11. In other embodiments, ducts, baffles, or other structures direct air to multiple modules 11. For example, a group of four modules 11 share a common heat exchanger and fan 20, which are mounted to the gantry or other frame for cooling the group of modules 11.

[0061] To form a Compton sensor, one or more modules 11 are used. For example, two or more modules 11 are positioned relative to the patient bed or the imaging space to detect photon emissions from the patient. The arrangement of a larger number of modules 11 can allow for the detection of a larger number of emissions. By using the wedge shape, the modules 11 can be positioned against, adjacent to, and / or connected to each other to form an arc around the patient space. The arc can have any range. The modules 11 are in direct contact with each other or contact through spacers or the gantry, with a small gap (e.g., 10 cm or less) between the modules 11.

[0062] In one example, four modules 11 are positioned together such that they share a clock and / or synchronization bridge 18, one or more data bridges 17, and a heat exchanger and fan 20. One, two, or four fiber optic data links 16 are provided for the set of modules 11. For the same patient space, multiple such sets of modules 11 can be positioned separately or adjacent to each other.

[0063] Due to the modular approach, any number of modules 11 can be used. Although any given module 11 is used in a different arrangement structure from other modules used in the module 11, manufacturing is more efficient and less expensive by building multiple identical components.

[0064] The fiber optic data link 16 of the module 11 or the set of modules 11 is connected to a Compton processor 19. The Compton processor 19 receives values of parameters of different events. Using energy and timing parameters, scatter events and capture events are paired. For each pair, the spatial position and energy of the pair of events are used to find the angle of incidence of the photon on the scatter detector 12. In one embodiment, the event pairs are limited to events within the same module 11. In another embodiment, capture events from the same or different modules 11 can be paired with scatter events from a given module 11. More than one Compton processor 19 can be used, for example, for pairing events from different parts of the partial ring 40.

[0065] Once the paired events are linked, the Compton processor 19 or another processor can perform computed tomography to reconstruct the two-dimensional or three-dimensional distribution of the detected radiation. The angle of incidence or the incident ray of each event is used in the reconstruction. The reconstructed distribution of the detected Compton events is used to render a Compton image.

[0066] The display 22 is a CRT, LCD, projector, printer, or other display. The display 22 is configured to display Compton images. One or more images are stored in a display plane buffer and read out to the display 22. These images can be displayed individually or combined, for example, to display a Compton image overlaid or adjacent to a SPECT image.

[0067] Figure 4A - 6 An exemplary arrangement of the module 11 is shown. The modules 11 form a ring 40 around the patient space. Figure 4A Four such rings 40 stacked axially are shown. Figure 4B The scatter detector 12 and the corresponding capture detector 13 of the module 11 in the ring 40 are shown. Figure 4CDetails of a portion of the ring 40 are shown. Three modules 11 provide corresponding pairs of scatter detectors 12 and capture detectors 13. Other sizes than those shown may be used. Any number of modules 11 may be used to form the ring 40. The ring 40 completely surrounds the patient space. Within the housing of the medical imaging system, the ring 40 is connected to the gantry 50 or another frame, as Figure 5 shown therein. The ring 40 may be positioned to allow the patient bed 60 to move a patient into and / or through the ring 40. Figure 6 An example of this configuration is shown.

[0068] This ring may be used for Compton-based imaging of radiation from a patient. Figure 7 An example is shown using the same type of module 11 but in a different configuration. A partial ring 40 is formed. One or more gaps 70 are provided in the ring 40. This may allow other components to be used in the gap and / or to manufacture a less expensive system by using fewer modules 11.

[0069] Figure 8 Another configuration of the module 11 is shown. The ring 40 is a full ring. Additional partial rings 80 are axially stacked relative to the bed 60 or the patient space, thereby extending the axial range of the detected radiation. The partial rings 80 are distributed at every Nth module 11 or every group of N modules 11 (e.g., N = 4), rather than Figure 7 the partial ring 40 with two gaps 70. The additional rings may be full rings. The full ring 40 may be a partial ring 80. Different rings 40 and / or partial rings 80 are axially stacked without separation or with a small separation (e.g., less than 1 / 2 of the axial range of the module 11). Wider spacings may be provided, such as gaps having more than one module 11's axial range.

[0070] Figure 9 Yet another configuration of the module 11 is shown. One module 11 or a single group of modules 11 is positioned through the patient space or the bed 60. Multiple separated single modules 11 or groups (e.g., groups of four) may be provided at different positions relative to the bed 60 and / or the patient space.

[0071] In any configuration, the modules 11 are held in place by attachment to one gantry, multiple gantries, and / or other frames. This holding is releasable, for example, using bolts or screws. The desired number of modules 11 is used to assemble the desired configuration for a given medical imaging system. The collected modules 11 are installed in the medical imaging system so as to define the patient space or be installed relative to the patient space. The result is a Compton sensor for imaging a patient.

[0072] The bed 60 enables the patient to be moved to scan different parts of the patient at different times. Alternatively or additionally, the gantry 50 moves to form the module 11 of the Compton sensor. The gantry 50 translates the Compton sensor along the patient space axis and / or rotates it around the patient space (i.e., rotates around the long axis of the bed 60 and / or the patient). Other rotations and / or translations may be provided, such as rotating the module 11 around an axis not parallel to the long axis of the bed 60 or the patient. Combinations of different translations and / or rotations may be provided.

[0073] A medical imaging system having a Compton sensor is used as a stand-alone imaging system. Compton sensing is used to measure the distribution of a radiopharmaceutical in a patient. For example, the full ring 40, partial ring 40, and / or axially stacked rings 40, 80 are used as a Compton-based imaging system.

[0074] In other embodiments, the medical imaging system is a multimodal imaging system. The Compton sensor formed by the module 11 is one modality and another modality is also provided. For example, the other modality is a single photon emission computed tomography (SPECT), PET, CT, or MR imaging system. The full ring 40, partial ring 40, axially stacked rings 40, 80, and / or a single module 11 or group of modules 11 are combined with sensors for another type of medical imaging. The Compton sensor may share the bed 60 with another modality, for example, positioned along the long axis of the bed 60, where the bed positions the patient in the Compton sensor in one direction and in the other modality in another direction.

[0075] The Compton sensor may share an outer housing with another modality. For example, the full ring 40, partial ring 40, axially stacked rings 40, 80, and / or a single module 11 or group of modules 11 are arranged within the same imaging system housing for one or more sensors of another modality. The bed 60 positions the patient relative to the desired sensors within the imaging system housing. The Compton sensor may be positioned adjacent to other sensors axially and / or in a gap at the same axial position. In one embodiment, the partial ring 40 is used in a computed tomography system. The gantry holding the X-ray source and X-ray detector also holds the module 11 of the partial ring 40. The X-ray source is in one gap 70 and the detector is in another gap 70. In another embodiment, a single module 11 or sparsely distributed modules 11 are connected to the gantry of a SPECT system. The module 11 is placed adjacent to a gamma camera such that the gantry of the gamma camera moves the module 11. Alternatively, a collimator may be located between the module 11 and the patient or between the scatter detector 12 and the capture detector 13, allowing the scatter and / or capture detectors 12, 13 of the module 11 to be used for photoelectric event detection in SPECT imaging as an alternative or supplement to Compton event detection.

[0076] Module-based segmentation of the Compton sensor allows the same design of module 11 to be used in any different configuration. Thus, different numbers of module 11, module positions, and / or configurations of module 11 can be used for different medical imaging systems. For example, one arrangement is set up for use with one type of CT system, and different arrangements (e.g., the number and / or position of module 11) are used for different types of CT systems.

[0077] Module-based segmentation of the Compton sensor allows for more efficient and less expensive repairs. Instead of replacing the entire Compton sensor, any module 11 can be disconnected, fixed, or replaced. Module 11 can be connected and disconnected from each other and / or the gantry 50 individually. Remove any bridge, and then module 11 can be removed from the medical imaging system while the other module 11 remains. Replacing a single module 11 is less expensive. The amount of time for repairs can be reduced. Individual components of the defective module 11 can be easily replaced, such as replacing the scatter detector 12 or the capture detector 13 while leaving the other one. By using the corresponding detectors 12, 13, module 11 can be configured to operate with different radioisotopes (i.e., different energies).

[0078] Figure 10 An embodiment of a flowchart of a method for forming, using, and repairing a Compton camera is shown. The Compton camera is formed in a segmented method. Instead of manually assembling the entire camera in place, the scatter detector and capture detector pairs are positioned relative to each other to form the desired configuration of the Compton camera. This segmented method can allow for different configurations of the same parts, easy assembly, easy repair, and / or integration with other imaging modalities.

[0079] The method is implemented by Figure 1 a system to assemble a Compton sensor as shown in any one of FIGS. 4-9. Compton sensors of other systems, modules, and / or configurations can be used.

[0080] These actions are performed in the order shown (i.e., from top to bottom or according to the numbers) or in other orders. For example, action 108 can be performed as part of action 104.

[0081] Additional, different, or fewer actions can be provided. For example, actions 102 and 104 are provided for assembling the Compton camera without performing actions 106 and 108. As another example, action 106 is performed without the other actions.

[0082] In action 102, the scatter detector and capture detector pairs are housed in separate housings. Modules are assembled, where each module includes both a scatter detector and a capture detector. These housings are manufactured by machines and / or people.

[0083] These modules are shaped to be adjacent, where the scatter detectors and capture detector pairs of different housings among these housings are non-planar. For example, a wedge shape is set and / or positioned such that the detector pairs form an arc, such as Figure 4C as shown in. When these modules are positioned against each other, this shape allows and / or enforces this arcuate shape.

[0084] In operation 104, the housings are made adjacent. A person or a machine assembles a Compton sensor from these housings. By stacking these housings adjacent to each other in direct contact or in contact through a spacer, gantry or frame, the adjacent housings form an arc. A full ring or a partial ring is formed around and at least partially defines a patient space. Based on the design of the Compton camera, any number of housings with corresponding scatter detector and capture detector pairs are positioned together to form a Compton camera.

[0085] The housings can be made adjacent as part of a multimodal system or for creating a single Compton imaging system. For a multimodal system, the housings are located in the same outer housing as sensors for other modalities and / or are positioned relative to the same bed, such other modalities as SPECT, PET, CT or MR imaging systems. The same or different gantries or support frames can be used for the housings of the Compton camera and for sensors for other modalities.

[0086] The construction or design of the Compton camera defines the number and / or position of the housings. Once adjacent, the housings can be connected for communication, for example, by communicating through one or more bridges. The housings can be connected to other components, such as an air cooling system and / or a Compton processor.

[0087] In operation 106, the assembled Compton camera detects radiation. A given radiation photon interacts with a scatter detector. The result is that another photon scatters at a specific angle with respect to the incident ray of the radiation photon. This secondary photon has less energy. This secondary photon is detected by a capture detector. Based on both the energy and time of the detected scatter event and capture event, the events are paired. The position and energy of the paired events provide a line and a scatter angle between the detectors. As a result, the incident ray of the radiation photon is determined.

[0088] To increase the likelihood of detecting this secondary photon, a capture event from one housing can be paired with a scatter event from another housing. Due to the angle, the scatter from one scatter detector may be incident on the paired capture detector in the same housing or on a capture detector in another housing. By making the housings open in the detector region and / or using low photon attenuation materials, a greater number of Compton events can be detected.

[0089] Detected events are counted or collected. Response lines or lines along which different Compton events occur are used in the reconstruction. A three-dimensional distribution of radiation from a patient can be reconstructed based on Compton sensing. This reconstruction does not require a collimator because Compton sensing interprets or provides the incident angle of radiation photons.

[0090] Detected events are reconstructed into object space. An image can be rendered to a display device based on the reconstructed events. The image represents the radiation distribution within the patient.

[0091] In operation 108, a human or machine (e.g., a robot) removes one of the housings. The housing can be removed when one of the detectors or associated electronics in the housing fails or is to be replaced to detect at a different energy. The other housings are left in the medical imaging system. This allows for easier repair and / or replacement of the housing and / or detector without the cost of greater disassembly and / or replacement of the entire Compton camera.

[0092] Although the invention has been described above with reference to various embodiments, it should be understood that many changes and modifications can be made without departing from the scope of the invention. Accordingly, the foregoing detailed description is to be considered illustrative rather than restrictive, and it is understood that the appended claims, including all equivalents, are intended to define the spirit and scope of the invention.

Claims

1. A Compton camera for medical imaging, the Compton camera comprising: A first module (11) having a wedge-shaped cross-section formed by a first housing (21), a first scatter detector (12) connected to the first housing (21), and a first capture detector (13), the first capture detector (13) being connected to the first housing (21) and spaced apart from the first scatter detector (12); And A second module (11) having the same wedge-shaped cross-section formed by a second housing (21), a second scatter detector (12) connected to the second housing (21), and a second capture detector (13), the second capture detector (13) being connected to the second housing (21) and spaced apart from the second scatter detector (12); Wherein the first module (11) can be directly connected and disconnected from the second module (11) through a releasable attachment mechanism of the first module and the second module, Wherein the first module (11) further includes a circuit board (14) within the first housing (21), the circuit board (14) being orthogonal to the first capture detector (13), wherein the first module (11) further includes a baffle (15) for air with air flow cooling, the air entering through the circuit board (14) and being separated from the first scatter detector (12) and the first capture detector (13), passing between the first scatter detector (12) and the first capture detector (13), and leaving through the circuit board (14).

2. The Compton camera according to claim 1, wherein The first module (11) and the second module (11) are cylindrically symmetric when connected to a gantry (50) of a medical imaging system, the narrowest end of the wedge-shaped cross-section being closest to the patient space of the medical imaging system, the widest end of the wedge-shaped cross-section being farthest from the patient space, and the first module (11) can be removed from the medical imaging system while the second module (11) remains in the medical imaging system.

3. The Compton camera according to claim 1, wherein The first module (11) further includes an application-specific integrated circuit having the first scatter detector (12) and the first capture detector (13), and further includes a flexible circuit connecting the application-specific integrated circuit to the circuit board (14).

4. The Compton camera according to claim 1, further comprising a heat exchanger and a fan (20), the heat exchanger and the fan (20) being shared by the first module (11) and the second module (11) for the air flow cooling.

5. The Compton camera according to claim 1, wherein, A power and data bridge (17) is connected between the first module (11) and the second module (11), and wherein the first module (11) includes an optical fiber data link for outputting data from the first module (11) and the second module (11), and the second module (11) does not have any optical fiber data links.

6. The Compton camera according to claim 1 further includes a third module (11) and a fourth module (11), and a clock bridge (18) that links the first module (11), the second module (11), the third module (11), and the fourth module (11).

7. The Compton camera according to claim 1, wherein, The first module (11) and the second module (11) form a ring (40) or a part of a partial ring around the patient space of the medical imaging system.

8. The Compton camera according to claim 7, wherein, The ring (40) or the partial ring shares the outer housing (21) of the medical imaging system with another modality of medical imaging.

9. The Compton camera according to claim 7, wherein, The ring (40) or the partial ring is connected to a gantry (50) for moving the ring or the partial ring relative to the patient space.

10. The Compton camera according to claim 7 further includes an additional ring (40) or partial ring of modules (11) that is axially adjacent to the ring or the partial ring having the first module (11) and the second module (11).

11. The Compton camera according to claim 1, wherein, The first module (11) and the second module (11) are connected to a single photon emission computed tomography, positron emission tomography, computed tomography, or magnetic resonance imaging system.

12. The Compton camera according to claim 1 further includes a Compton processor (19) communicatively connected to the first module (11) and the second module (11), the Compton processor (19) being configured to link the scattering events of the first module (11) with the capture events of the second module (11).

13. A medical imaging system includes: Solid state detector modules (11), each having a scattering detector and a capture detector (13) of a Compton sensor; The solid state detector modules (11) are shaped to be stacked together as a ring or a partial ring of a configurable number of the solid state detector modules (11), the solid state detector modules having a wedge-shaped cross-section formed by corresponding housings (21), wherein each of the solid state detector modules (11) is capable of being directly connected to and disconnected from another of the solid state detector modules (11) through an attachment mechanism of the solid state detector module, wherein the solid state detector module (11) further includes a circuit board (14) within the corresponding housing (21), the circuit board (14) being orthogonal to the capture detector (13), and wherein the solid state detector module (11) further includes a baffle (15) with air flow cooling for air, the air entering through the circuit board (14) and being separated from the scattering detector (12) and the capture detector (13), passing between the scattering detector (12) and the capture detector (13), and leaving through the circuit board (14).

14. The medical imaging system according to claim 13, wherein, Each of the solid state detector modules (11) has a wedge shape, wherein the scattering detector (12) is closer to the narrower part of the wedge shape than the capture detector (13), and an air region separates the scattering detector (12) from the capture detector (13).

15. The medical imaging system according to claim 13, further comprising a single photon emission computed tomography, positron emission tomography, computed tomography or magnetic resonance imaging system imager that shares a housing (21) or a table (60) with the solid state detector module (11).

16. The medical imaging system according to claim 13, wherein, When stacked together, the solid state detector module (11) can be individually removed from the ring or the partial ring.

17. A method for forming a Compton camera according to any one of claims 1 to 12, the method comprising: accommodating (102) pairs of a scatter detector and a capture detector (13) in separate wedge-shaped housings (21); and adjacenting (104) and directly connecting the housings (21) in a ring or a partial ring around a patient space.

18. The method according to claim 17, wherein, Adjacenting (104) includes forming the ring or the partial ring as part of a multimodal system including the Compton camera and a single photon emission computed tomography, positron emission tomography, computed tomography or magnetic resonance imaging system.

19. The method according to claim 17, further comprising detecting (106) radiation using a scatter detector (12) of one housing (21) and a capture detector (13) of another housing (21).

20. The method according to claim 17, further comprising removing (108) one housing (21) from the ring or the partial ring while leaving other housings in the separate housings (21) in the ring or the partial ring.

Images