JPWO2020032922A5 - - Google Patents

Description

The present embodiments relate to nuclear imaging , such as single photon emission tomography (SPECT) imaging .

Slow- rotating , wide -field SPECT systems rely heavily on the presence of a physical collimator. A parallel bore collimator forms an image in combination with a position sensitive detector . Because the radiation from patient radioisotopes is detected by the photoelectric effect, this collimated SPECT system is limited to low-energy photon-emitting isotopes such as Tc99m . Image quality and efficiency are important parameters in SPECT medical imaging systems. Newer SPECT imaging systems add the possibility of imaging higher photon energies, with increased sensitivity and image quality being desirable features .

The Compton effect allows higher energy imaging . The Compton imaging system was built as a test platform, assembling a scattering ring followed by a trapping ring attached to a large framework, and so on . Electronics are also connected to detect Compton-based events from the phantom emissions. However, the Compton imaging system fails to meet the design and restrictive requirements for practical use in commercial clinical settings . Current proposals either lack the ability to integrate clinically into imaging platforms or lack the design and constraint requirements (ie, flexibility and scalability) to address commercial needs.

To begin with , the preferred embodiments described below include methods and systems for medical imaging. A multimodality imaging system allows for selective detection of the photoelectric effect and/or the Compton effect. The camera or detector is a module with a capture detector. Depending on the application or design, a scatter detector and/or a coded physical aperture are placed in front of the capture detector with respect to patient space. And, for low energies, the radiation passing through the scatter detector is subsequently passed through a coded aperture (hereinafter "coded aperture") to take advantage of the photoelectric effect to the capture detector. detected by Alternatively, it is possible not to provide a scatter detector. At high energies some radiation is scattered by the scattering detector and the resulting radiation passes through or by the coded aperture and is detected by the capture detector using the Compton effect. be done. Alternatively, no coded apertures may be provided . If both scatter detectors and coded apertures are provided with capture detectors, the same module can be used to detect both the photoelectric effect and the Compton effect. Multiple modules may be placed together to form a larger camera, or one module may be used alone. By utilizing modules , any number of modules can be used to accommodate a multimodality imaging system. One or more such modules may also be added to other imaging systems (eg CT or MR) to form a multimodality imaging system .

In a first aspect, a multimodality medical imaging system includes a first capture detector, a position of a first scatter detector spaced from the capture detector, and between patient space and the first capture detector. and a first physical opening location of . The image processor determines the angle of incidence of the Compton event if the first scatter detector is contained in the first module and the photoelectric event if the first physical aperture is contained in the first module. is configured to measure

In a second aspect, a medical imaging system comprises a plurality of Contains a solid state detector module. A plurality of solid-state detector modules are stacked on top of each other to form part of a geodesic dome, in cross-section perpendicular to a radial extending from the longitudinal patient axis. in a solid-state detector module having three , five , or six sides.

In a third aspect, a method is provided for forming a Compton camera and/or a single photon emission tomography camera. A capture detector is contained within the housing. The capture detector is arranged so that it can be used with the coded aperture for relatively low emission energies and with the scatter detector for relatively high emission energies. The housing is molded as part of a geodesic dome. The housing is attached to the patient bed along with selected one or both of the coded aperture and the scatter detector.

The invention is defined by the following claims and nothing in this section should be taken as limiting those claims. Further aspects and advantages of the invention are described below in connection with the preferred embodiments and may be claimed independently or in combination.

The components and drawings are not necessarily to scale , emphasis instead being placed upon explaining the principles of the invention. Furthermore, with respect to the drawings, the same reference numerals indicate corresponding parts throughout the different figures.

1 is a perspective view of multiple modules of a Compton camera according to one embodiment; FIG. 1 shows an example of a scatter detector. An example of a capture detector is shown. 1 is a side view of one embodiment of a Compton camera; FIG. 4B is an end view of the Compton camera of FIG. 4A; FIG. 4C is a detailed view of a portion of the Compton camera of FIG. 4B; FIG. 1 is a perspective view of one embodiment of a Compton camera in a medical imaging system; FIG. 1 is a perspective view of one embodiment of a full-ring Compton camera in a medical imaging system; FIG. 1 is a perspective view of one embodiment of a partial ring Compton camera in a medical imaging system; FIG. 1 is a perspective view of one embodiment of a full ring Compton camera with axially extending partial rings in a medical imaging system; FIG. 1 is a perspective view of one embodiment of a single module based Compton camera in a medical imaging system; FIG. 1 is a flow chart diagram of one embodiment of a method of forming a Compton camera; FIG. FIG. 3 shows a scatter detector and a capture detector with intervening coded apertures for imaging using both the photoelectric effect and the Compton effect. 1 is a perspective view of one embodiment of a full-ring multi-modality camera using modules shaped for geodesic dome-like structures; FIG. 1 is a perspective view of one embodiment of a dual-ring multi-modality camera using modules configured for geodesic dome-like structures; FIG. 1 is a perspective view of one embodiment of multiple axially stacked full rings in a multimodality camera using modules shaped for geodesic dome construction. FIG. 1 is a perspective view of one embodiment of a multimodality camera made from three modules shaped for a geodesic dome structure; FIG. 1 is a perspective view of one embodiment of a photoelectric effect camera made from three modules shaped for a geodesic dome structure; FIG.

Figures 1-9 show a multi-modality compatible Compton camera. Various modular designs are used to form Compton cameras for use with various other imaging modalities. Figures 11-16 show a modular design with a capture detector that can be used with either a scatter detector for Compton images or a coded aperture for SPECT images. The module provides the location of either or both the scatter detector and the coded aperture . After an overview of selectable SPECT-Compton embodiments, the Compton cameras of FIGS. 1-9 are described . Many of the features and components of the Compton camera of FIGS. 1-9 are used in the SPECT-Compton embodiment described in FIGS . 11-16.

As an optional SPECT-Compton embodiment , clinical multi-modality compatible and modular cameras are offered for medical imaging . For lower energy radiation, a coded aperture may be included in each module for SPECT operation . For higher energy radiation, a scatter detector can be included in each module for Compton operation. Modular design allows existing computed tomography (CT), magnetic resonance (MR), or positron emission tomography (PET) platforms to integrate selectable SPECT-Compton cameras as axially isolated systems or completely full flexibility to be added as a system integrated into the Modularity also allows for efficient manufacturing and serviceability . Improved sensitivity and image quality are desirable features of new SPECT imaging systems, with the added possibility of imaging higher photon energies. For hybrid imaging , both the scatter detector and the coded aperture are provided at their respective positions in the same module, with the Compton effect at higher energies and physical collimation at low energies of ~140.5 keV. Utilizes the photoelectric effect using

Referring to FIGS. 1-9, a medical imaging system includes a multimodality compatible Compton camera with a segmented detection module. Compton cameras, such as the Compton camera ring , are segmented into modules that house the detection units. Each module is independent and when assembled in a ring or partial ring, each module can communicate with each other. The modules are independent, but can be assembled into a multi-module unit that produces Compton scatter-based images. Cylindrically symmetric modules or spherical shell segment modules can be used.

The modular arrangement of the scatter-trap pair allows for efficient manufacturing, is field serviceable , high value and energy efficient . And multiple modules allow design flexibility to change the radius of each radiation detection unit, the angular span, and/or the axial span of a module. The scatter - capture pair module is multimodality compatible and /or forms a modular ring Compton camera for clinical radiographic imaging. This design provides flexibility so that the Compton camera can be used with existing computed tomography (CT), magnetic resonance (MR) and positron emission tomography systems as axially separate systems or as fully integrated systems. It can be added to an imaging (PET) or other medical imaging platform. Each module can handle heat dissipation, data collection, calibration, and/or enable efficient assembly and maintenance .

Each scatter - capture pair module is formed from commercially suitable solid-state detector modules (eg, Si, CZT, CdTe, HPGe or the like) and covers the energy range of 100-3000 keV. Compton imaging is offered in a wider range of isotope energies (>2 MeV) and allows new tracers/markers through the choice of scatter - capture detectors. Modularity allows individual modules to be removed and replaced, enabling time and cost efficient servicing. The modules may operate independently in isolation or in conjunction for crosstalk, using a scatter detector in one module and a capture detector in another module. allows for improved image quality and greater efficiency in detecting Compton events.

Modularization allows for flexible design shapes that are optimized for individual requirements . For example, using a partial ring for integration with a CT system (e.g. , connected between an X-ray source and a detector), a single photon emission tomography gamma camera, or other space - limited using a small number of modules (eg tiling) or using a full ring for integration with any imaging system. Functional imaging based on Compton-detected events can be added to other imaging systems (eg, CT, MR, or PET). Multiple full or partial rings can be placed adjacent to each other for greater axial coverage of the Compton camera. Dedicated or stand - alone Compton-based imaging systems may be formed. In one embodiment, the module includes a collimator for low energies (e.g. <300 keV) and high energies using multi-channel and multi-imaging (e.g. scatter-capture detectors for Compton events) using SPECT or PET Low energy imaging using one of the detectors for imaging ). The module may be stationary or rotating at high speed (0.1 rpm<<ω<<240 rpm) . Size , installation, service, and/or cost constraints are addressed by scatter -trap vs. modules.

FIG. 1 shows one embodiment of module 11 for a Compton camera. Although four modules 11 are shown, additional or fewer modules may be used. Compton cameras are formed from one or more modules, depending on the desired design of the Compton camera.

Compton cameras are for medical imaging . A patient space is provided for the module such that the module is positioned to detect photons emitted from the patient. The in-patient radiopharmaceutical contains a radioisotope. Photons are emitted from the patient by decay of the radioisotope. The energy from the radioisotope can be 100-3000 keV, depending on the detector material and construction. Any of a variety of radioisotopes can be used for patient imaging.

Each of the modules 11 contains the same or many of the same components. Scatter detector 12 , trap detector 13 , circuit board 14 and baffle 15 are provided within the same housing 21 . Additional, different, or fewer components may be provided. For example, scatter detector 12 and capture detector 13 are provided within housing 21 without other components. As another example, fiber optic data lines 16 are provided to all or a subset of modules 11 .

Modules 11 are shaped to be stacked together. The modules 11 fit together, such as having corresponding recesses and extensions , latches, rasps or clips. In other embodiments, flat surfaces or other surfaces are provided to rest against each other or against the partition . Latches, clips , bolts, rasps, 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 framework with or without direct connection to any adjacent module 11 .

The connection or connections to other modules 11 or gantry may be removable . Module 11 is connected and may be removed . The connection may be removable so that one module 11 or a group of modules 11 can be removed without removing all modules 11 .

In order to form a Compton camera from multiple modules 11, the housing 21 and/or the profile of the modules 11 are wedge-shaped. Due to their wedge shape, the modules 11 can be axially stacked to form rings or partial rings. The portion closer to the axis has a width dimension along the direction perpendicular to the axis that is narrower than the width dimension of the portion farther from the axis. In the module 11 of FIG. 1, the housing 21 is furthest from the axis at its widest part . In other embodiments, the widest portion is closer to the axis, but is located away from the narrowest portion closest to the axis. In the wedge shape , the scatter detector 12 is closer to the narrow portion of the wedge shape than the capture detector 13 is. This wedge shape in cross-section along a plane perpendicular to the axis successively overlaps and/or connects the modules 11 at adjacent positions so as to form at least part of a ring centered on the axis. make it possible.

The taper of the wedge provides N modules 11 to form a full ring around the axis . Any number N may be used , such as N=10-30 modules . The number N may be configurable to use different housings 21 for different numbers N. The number of modules 11 used in a given Compton camera may vary depending on the Compton camera design (eg, partial ring). The wedge shape may also be provided along other directions , such as having a wedge shape in a cross-section parallel to the axis.

The stacked modules 11 are of cylindrical symmetry in connection with the gantry of the medical imaging system. The narrowest end of the wedge-shaped cross- section may be closest to the patient space of the medical imaging system and the widest end of the wedge-shaped cross- section may be furthest from the patient space. In other embodiments, other shapes than wedges may be provided that stack together to allow stacking in a ring-like or generally curved shape.

Housing 21 is metal, plastic, fiberglass, carbon (eg, carbon fiber), and/or other materials. In one embodiment, different portions of housing 21 are of 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, housing 12 is the same material , such as aluminum.

The housing 21 is formed from various structures such as end plates having a wedge shape, a sheet of ground planes containing the circuit board 14, separate structures for the walls holding the scatter detector 12 and the capture detector 13 , and the like. where the separate structure is formed of a material (eg, aluminum or carbon fiber) through which photons of the desired energy from the Compton event can pass. In an alternative embodiment , the modules 11 are not walled between the endplates for the regions where the scatter detectors 12 and/or the capture detectors 13 are arranged , and one module 11 scatter It avoids interference of photons passing from detector 12 to capture detectors 13 of other modules 11 . The housing 21 beside the detectors 12, 13 and/or the housing 21 for holding the detectors 12, 13 is made of a low attenuation material such as aluminum or carbon fiber.

Housing 21 may enclose the module or may include openings. For example, an opening for air flow is provided, such as at the top of the widest portion of the wedge shape in the circuit board 14 . Housing 21 may include holes, grooves, tongues, latches, clips, standoffs, bumpers, or other structures for mounting, mating, and/or stacking .

Each solid-state detector module 11 includes both a scatter detector 12 and a capture detector 13 of a Compton sensor. Stacking each module increases the size of the Compton sensor . A given module 11 may itself be a Compton sensor, since both the scatter detector 12 and the capture detector 13 are included in the module.

Multiple modules 11 can be separately removed and/or added to the Compton sensor . For a given module 11 , scatter detector 12 and/or capture detector 13 may be removable from module 11 . For example, module 11 is removed for maintenance service. One or both of the failed detectors 12, 13 are removed from the module 11 for replacement . Once replaced , the repaired module 11 is returned to the medical imaging system. A bolt, clip, latch, rasp , or other removable connection member connects the detectors 12, 13 or a portion of the housing 21 for the detectors 12, 13 to the remainder of the module 11. can do.

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 wafer fabrication to an arbitrary thickness, eg , approximately 4 mm thick for CZT. Any size may be used, such as about 5 x 5 cm. FIG. 2 shows the square shape of the scatter detector 12 . Shapes other than squares , such as rectangles, may also be used. For module 11 of FIG. 1, scatter detector 12 may be rectangular extending between two wedge-shaped end plates .

In module 11, scatter detector 12 has an arbitrary range. For example, scatter detectors 12 extend from one wedge-shaped end wall to another wedge-shaped end wall. Smaller or larger extents may be provided, such as extending between mounts within module 11, or extending axially beyond one or both end walls. In one embodiment, the scatter detector 12 is located at , on, or by one end wall without extending to the other end wall . exist.

Scatter detector 12 forms an array of sensors. For example, the 5 × 5 cm scatter detector 12 of FIG. 2 is a 21 × 21 pixel array with a pixel pitch of approximately 2.2 mm. Other numbers of pixels, pixel pitches, and/or array sizes may be used.

Scatter detector 12 includes a semiconductor formatted for processing. For example, scatter detector 12 includes an application specific integrated circuit (ASIC) for sensing photon interactions with electrons within scatter detector 12 . The ASIC is co-located with the pixels of the scatter detector 12 . The thickness of the ASIC is arbitrary . Multiple ASICs may be provided, for example nine ASICS in a 3 × 3 grid of scatter detectors 12 .

Scatter detector 12 can operate at any count rate, such as >100 kcps/mm. Due to the interaction, electricity is generated for each pixel. This electricity is sensed by an application specific integrated circuit. Position, time and/or energy are sensed. The sensed signal may be conditioned, such as amplified, and sent to one or more of the circuit boards 14 . Flexible circuits, wires, or other communication paths carry signals from the ASIC to circuit board 14 .

Compton instrumentation works without collimation. Instead, a 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 determines the angle of the photons incident on the scatter detector 12. used to determine Compton processing is applied using a scatter detector 12 and a capture detector 13 .

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 made using wafer fabrication to an arbitrary thickness, eg , about 10 mm thick for CZT. Any size may be used, such as about 5 x 5 cm. Due to the wedge shape and the spaced apart placement of scatter detector 12 and capture detector 13 , capture detector 13 can be larger in size along at least one direction than scatter detector 12 . Although FIG. 3 shows a rectangular shape for capture detector 13, other shapes may be used. For the module 11 of FIG. 1, the capture detector 13 may be a rectangle extending between the two endplates and having the same length as the scatter detector 12 and a greater width than the scatter detector 12 .

Capture detectors 12 form a sensor array . For example, the 5 × 6 cm capture detector 13 of FIG. 3 is a 14 × 18 pixel array with a pixel pitch of approximately 3.4 mm. The pixel size is larger than the pixel size of scatter detector 12 . The number of pixels is less than the number of pixels of the scatter detector 12 . Other pixel counts, pixel pitches, and/or array sizes may be used. Other relative pixel sizes and/or numbers of pixels may be used.

In module 11 capture detector 13 has an arbitrary extent (range) . For example, the capture detector 13 extends from one wedge- shaped end wall to the other wedge- shaped end wall. A smaller or larger extent may be provided to extend between mounts within module 11 or extend axially beyond one or both end walls. In one embodiment, the capture detector 13 resides at, on, or by one end wall without extending to the other end wall. .

Capture detector 13 includes a semiconductor formatted for processing. For example, capture detector 13 includes an ASIC for sensing photon interactions with electrons within capture detector 13 . The ASIC is collocated with the capture detector 13 pixels. The thickness of the ASIC is arbitrary . A 2 × 3 grid of capture detectors 13 may be provided with a plurality of ASICS, eg 6 ASICS.

Capture detector 13 can operate at any count rate, such as >100 kcps/mm. Electricity is generated by the pixel due to the interaction. This electricity is sensed by the ASIC. Position, time and/or energy are sensed. The sensed signal may be conditioned, such as amplified, and sent to one or more of the circuit boards 14 . Flexible circuits, wires, or other communication paths carry signals from the ASIC to circuit board 14 .

Capture detector 13 is spaced any distance from scatter detector 12 along a radial line from the axis or along a normal to parallel scatter detector 12 and capture detector 13 . In one embodiment, the separation is about 20 cm, although larger or smaller separations may be provided . The space between capture detector 13 and scatter detector 12 is filled with air, other gases, and/or other materials that provide low attenuation for photons of the desired energy.

Circuit board 14 is a printed circuit board, although flexible circuits or other materials may be used. Any number of circuit boards 14 can be used for the circuit boards 14 of 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 .

Circuit board 14 is within housing 21 but may extend beyond housing 21 . Housing 21 may be grounded and may act as a ground plane for circuit board 14 . The circuit boards 14 may be mounted parallel to each other or may be non-parallel such as spaced apart depending on the shape of the wedge. The circuit board is positioned generally perpendicular to the capture detector 13 . Roughly is used to account for any extent due to the wedge shape. Brackets, bolts, screws, and/or standoffs from each other and/or from the housing 21 are used to hold the circuit board 14 in place .

Circuit board 14 is connected to the ASICS of scatter detector 12 and capture detector 13 via flexible circuits or wires. The ASIC outputs the detected signal. The circuit board 14 is the acquisition electronics and processes the detected signals to provide parameters to the Compton processor 19 . Any parameterization of the detected signal can be used. In one embodiment, energy, time of arrival, and position in three dimensions are output. Other acquisition processes may be provided.

Circuit boards 14 output to each other via galvanic connections within module 11 to data bridge 17 and/or to fiber optic data link 16 . Fiber data link 16 is a fiber optic interface for converting electrical signals to optical signals. A fiber optic cable or cables provide acquisition parameters of events detected by scatter detector 12 and capture detector 13 to Compton processor 19 .

Data bridge 17 is a circuit board, wire, flexible circuit, and/or other material for galvanic connections to enable communication between modules 11 . A housing or protective plate can cover the data bridge 17 . Data bridge 17 removably connects to one or more modules 11 . For example, plugs or mating connectors on data bridge 17 mate with corresponding plugs or mating connectors on housing 21 and/or circuit board 14 . Latches, clips, joints , screw and/or bolt connections can be used to removably hold data bridge 17 in place with module 11 .

A data bridge 17 allows communication between modules. For example, a fiber data link 16 is provided to one module 11 and not to another module 11 . This avoids the cost of providing a fiber data link 16 for each module 11 . Instead, parameters output by other modules 11 are provided to module 11 with fiber data link 16 via data bridge 17 . The circuit board or boards 14 of the module 11 with its fiber data links 16 route parameter outputs to the fiber data links 16 and report detected events from the modules 11 using the fiber data links 16. do. In alternative embodiments, each module 11 includes a fiber data link 16 so that no data bridge 17 is provided or conveys other information.

Data bridge 17 may connect other signals between modules 11 . For example, data bridge 17 includes conductors for power . Alternatively, a separate bridge provides power to module 11 or powers module 11 individually. As another example, data bridge 17 is used to communicate clock and/or synchronization signals between modules 11 .

In the embodiment of Figure 1, separate clock and/or synchronization bridges 18 are provided. Clock and/or synchronization bridge 18 is a circuit board, wire, flexible circuit, and/ or other material for galvanic connections to enable communication of clock and/or synchronization signals between modules 11 . A housing or protective plate may cover the clock and/or sync bridge 18 . A clock and/or synchronization bridge 18 removably connects to one or more modules 11 . For example, the plugs or mating connectors of clock and/or sync bridge 18 mate with corresponding plugs or mating connectors on housing 21 and/or circuit board 14 . Latches, clips, rasps , screw and/or bolt connections can be used to removably hold the clock and/or sync bridge 18 in place with the module 11 .

The clock and/or synchronization bridge 18 may connect with the same or multiple groups of modules 11 as the data bridge 17 . In the embodiment illustrated in FIG. 1, data bridges 17 connect between pairs of modules 11 and clock and/or synchronization bridges 18 connect across groups of four modules 11 .

Clock and/or sync bridge 18 provides a common clock and/or sync signal for synchronizing the clocks of modules 11 . One of the parameters defined by the circuit board 14 of each module 11 is when an event is detected. Compton detection is based on a pair of events : a scattering event and a capture event. Timing is used to pair events from multiple detectors 12,13 . When pairs of events are detected in multiple modules 11, a common clock and/or synchronization enables accurate pairing . In another embodiment, only scatter events and capture events detected by the same module 11 are used, so clock and/or synchronization bridge 18 may not be provided.

Other links or bridges between different modules 11 may be provided. Because the bridges 17, 18 are removable, individual modules 11 can be removed for servicing while leaving the remaining modules 11 in the gantry.

Each module 11 is air cooled. Module 11 may be provided with holes (ie, inlet and outlet holes) to force air through . One or more baffles 15 may be provided to guide air within the module 11 . Water, conductive transport , and/or other cooling may alternatively or additionally be provided.

In one embodiment, the top of the wedge -shaped module 11 or housing 21 is open (ie, there is no cover on the side furthest from the patient area). One or more baffles 15 are provided along the center of one or more circuit boards 14 and/or housing 21 . A fan and heat exchanger 20 forces cooled or ambient temperature air into each module 11 along one half of the module 11 at a location spaced from the capture detector 13 (e.g., at the top of the module 11). flow into Baffle 15 and/or circuit board 14 direct at least some air into the space between scatter detector 12 and capture detector 13 . The air then passes by baffles 15 and/or circuit boards 14 in another portion (eg, another half) of module 11 and exits heat exchanger 20 . Other paths of air may be provided.

Heat exchangers and fans 20 are provided for each individual module 11 and may reside wholly or partially within module 11 . In other embodiments, ducts, baffles, or other structures route air to multiple modules 11 . For example, a group of four modules 11 share a common heat exchanger and fan 20 mounted on the gantry or other framework to cool the module 11 group .

One or more modules 11 are used to form a Compton sensor. For example, two or more modules 11 are positioned relative to the patient 's bed or imaging space to detect photon emissions from the patient. By arranging a greater number of modules 11, more radiation can be detected. By using a wedge shape, the modules 11 can be arranged opposite , adjacent to, and/or connected to each other to form an arc around the patient space. The arc may have any extent (extent) . Modules 11 may be in direct contact with each other or may be in contact via spacers or a gantry with a small spacing (eg, 10 cm or less) between modules 11 .

In one embodiment, four modules 11 are placed together and 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 data links 16 are provided for groups of modules 11 . Such groups of modules 11 may be spaced apart from each other or adjacent to each other with respect to the same patient space.

The modular approach allows any number of modules 11 to be used. By constructing multiples of the same components , manufacturing is more efficient and more valuable than is used for others of modules 11 , even though any given module 11 is used in a different arrangement. .

A fiber data link 16 of a module 11 or group of modules 11 is connected to a Compton processor 19 . The Compton processor 19 receives values for parameters of a plurality of events. Scattering and capture events are paired using energy and timing parameters. For each pair, the spatial position and energy of the paired event are used to determine the angle of incidence of the photon on scatter detector 12 . Event pairs are limited to events in the same module 11 in one embodiment. In another embodiment, capture events from the same or different modules 11 can be paired with scatter events from a given module 11 . One or more Compton processors 19 may be used, such as to pair events from different parts of the partial ring 40 .

Once the paired events are linked , the Compton processor 19 or other processor can perform computed tomography to reconstruct the distribution of the detected radiation in two or three dimensions. The angle of incidence or line of incidence ( line of incidence) of each event is used in the reconstruction .

4A-6 show one exemplary arrangement of module 11. FIG . Modules 11 form a ring 40 that encloses the patient space. FIG. 4A shows four such rings 40 axially stacked. FIG. 4B shows scatter detectors 12 and corresponding capture detectors 13 of modules 11 in ring 40 . FIG. 4C shows a detail of a portion of ring 40 , with three modules 11 providing corresponding pairs of scatter detectors 12 and capture detectors 13 . Dimensions other than those shown may be used . Any number of modules 11 can be used to form ring 40 . Ring 40 completely encloses the patient space. Within the housing of the medical imaging system, the ring 40 is connected with a gantry 50 or other framework as shown in FIG. The ring 40 may be arranged such that the patient bed 60 can move the patient into and /or through the ring 40 . FIG. 6 shows an example of this configuration .

The ring can be used for Compton-based imaging of radiation from the patient. FIG. 7 shows an example of using the same type of module 11 in multiple configurations. A partial ring 40 is formed. One or more gaps 70 are provided in the ring 40 . This allows other components to be used in the interstices and/or a less expensive system by using fewer modules 11 .

FIG. 8 shows another configuration of module 11 . Ring 40 is a full ring. An additional partial ring 80 overlaps axially with respect to the bed 60 or patient space to extend the axial extent of the detected radiation . Partial ring 80 is not the partial ring 40 with two gaps 70 of FIG. Additional rings may be full rings. Full ring 40 may be a partial ring 80 . The different rings 40 and/or partial rings 80 are axially stacked with no or little separation (eg, less than 1/2 of the axial extent of one module 11) . Greater spacing may be provided , such as having a gap greater than the 11 axial extents of one module.

FIG. 9 shows yet another configuration of module 11 . A module 11 , or group of modules 11 , is located beside the patient space or bed 60 . A plurality of spaced apart single modules 11 or groups (eg, groups of four) may be provided at different positions relative to the bed 60 and/or patient space.

In either configuration, module 11 is held in place by mounting to a gantry, multiple gantrys, and/or other frameworks. The retention is removable , such as by using bolts or screws. A desired number of modules 11 are used to assemble a desired configuration for a given medical imaging system. The assembled modules 11 define a patient space or are mounted relative to the patient space in a medical imaging system . The result is a Compton sensor for imaging a patient.

The bed 60 can move the patient in order to scan different parts of the patient at different times . Alternatively or additionally, gantry 50 moves module 11 forming a Compton sensor. Gantry 50 translates axially along patient space and/or rotates the Compton sensor about patient space (ie, rotates about the longitudinal axis of bed 60 and/or the patient). Other rotations and/or translations may be provided, for example, module 11 may be rotated about an axis that is not parallel to the long axis of bed 60 or patient. Combinations of multiple translations and/or rotations may be provided.

Medical imaging systems with Compton sensors are used as stand-alone imaging systems. Compton sensing is used to measure the distribution of radiopharmaceuticals within a patient. For example, full ring 40, partial ring 40, and/ or axially stacked rings 40, 80 are used as a Compton-based imaging system.

In other embodiments, the medical imaging system is a multimodality imaging system. The Compton sensor formed by module 11 is one modality, other modalities are also provided. For example, other modalities are Single Photon Emission Tomography (SPECT), PET, CT, or MR imaging systems. Full rings 40, partial rings 40, axially stacked rings 40, 80 and/or single modules 11 or groups of modules 11 are combined with sensors for other types of medical imaging. Compton sensors can share bed 60 with other modalities, such as being positioned along the long axis of bed 60 . Here, the bed positions the patient in the Compton sensor in one direction and in the other modality in the other direction .

Compton sensors can share the outer housing with other modalities. For example, a full ring 40, a partial ring 40, axially stacked rings 40 , 80, and/or a single module 11 or group of modules 11 may be used in the same imaging system for a sensor or sensors of other modalities. Located within the housing . A bed 60 positions the patient within the imaging system housing relative to the desired sensors. The Compton sensor may be positioned axially adjacent to the other sensor and/or may be positioned within the gap at the same axial position. In one embodiment, 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 a sparse arrangement of modules 11 are coupled to the gantry of the SPECT system. The module 11 is placed adjacent to the gamma camera , where the gamma camera gantry moves the module 11 . Alternatively, a collimator is placed between module 11 and the patient, or between scatter detector 12 and capture detector 13, such that scatter detector 12 and/or capture detector 13 of module 11 are used for the detection of Compton events. Alternatively , or in addition , it may be used for detection of photoelectric events for SPECT imaging .

The module-based segmentation of the Compton sensor allows the same design of modules 11 to be used in any different configuration. Accordingly, different numbers of modules 11, module positions, and/or configurations of modules 11 may be used for different medical imaging systems. For example, one arrangement may be provided for use with one type of CT system, and a different arrangement (eg, number and/or positions of modules 11) may be used for different types of CT systems .

Module-based segmentation of Compton sensors enables more efficient and valuable service. That is, instead of replacing the entire Compton sensor, any module 11 can be detached and fixed or replaced. Modules 11 are individually connectable and disconnectable from each other and/or from gantry 50 . After removing any bridge, the module 11 is removed from the medical imaging system , leaving the other module 11 behind. Replacing individual modules 11 is cheaper . Also, the service time can be shortened. Furthermore, individual components of a defective module 11 can be easily replaced, such as replacing the scatter detector 12 or the capture detector 13 while leaving the other in place. The module 11 may be configured to operate with different radioisotopes (ie different energies) by using corresponding detectors 12,13.

11-15 illustrate embodiments in which module 11 optionally includes physical apertures for SPECT detection utilizing the photoelectric effect. The module can also optionally include a scatter detector for Compton detection. The module can be used for both Compton and photoelectric detection. A multimodality medical imaging system is formed from one or more modules . The module 11 arrangements and components discussed with respect to FIGS. 1-9 can be used for modules 11 having physical openings.

The segmented detection module 11 can be used to form a geodesic dome multilayer multimodal camera. The camera is divided into modules containing detection units. Each module 11 is independent and can communicate with each other when assembled in a ring, partial ring or other configuration. Each module 11 includes an inner shell -like layer, called the scattering layer, and an outer shell - like layer , called the trapping layer. If multiple modules 11 are used , the modules can at least partially surround the object to be imaged.

FIG. 16 shows an embodiment of a medical imaging system . In this system, the module 11 does not contain a scatter detector, allowing the modular construction of a SPECT camera with physical apertures and detectors. FIG. 15 shows an embodiment of a medical imaging system in which module 11 includes a scatter detector, thus providing a modular construction of Compton cameras using scatter detectors. Module 11 of FIG. 15 can include physical apertures so that it can operate as both a Compton camera and a SPECT camera. Depending on the desired energy to be imaged for any given system, the base module with capture detector may be a scatter detector (e.g., higher energy) or a physical aperture (e.g., lower energy). Either or both may be worn.

FIG. 11 shows the detector structure of one module 11, where both physical aperture 110 and scatter detector 12 are selected and included in the same module 11. FIG. Module 11 includes scatter detector 12 and capture detector 13 . Scatter detector 12 and/or capture detector 13 are solid state detectors , so module 11 is a solid state detector module. A bracket, frame, clip, or other mechanical structure is provided to position the scatter detector 12 within the module 11 in which it is selected . Its position may be a predetermined distance from the capture detector 13, or it may be adjustable during or after assembly. Within module 11 there are mechanisms for positioning additional capture and/or scatter detectors so that the designer of a given imaging system can select the number of capture and/or scatter layers to be included. A physical structure may be provided.

Additional capture detectors 13 or scatter detectors 12 , such as layered detectors 12, 13 perpendicular and parallel to the radiation from patient space (a radial) . A capture detector 13 or a scatter detector 12 may be provided (eg, along the axis of rotation in FIG. 11). Any radiation passing through one capture detector 13 may interact in other capture detectors 13 . Similarly, an intermediate detector can act as a scatter detector 12 with radiation passing through the initial scatter detector 12 . Such intermediate detectors can have the same structure as either scatter detector 12 or capture detector 13, but act as scatter detector 12 and/or capture detector 13. FIG. One of the scatter detectors 12 produces Compton scattered photons, which are captured by one of the subsequently disposed capture layers 13 .

A plurality of modules 11 can be independent but assembled into a unit that produces an imaging image on a multimodal basis. The modules 11 are allowed to vary the radial radius of each detection unit, the angular span in one module 11, and/or the axial span by design flexibility in its shape . The dimensions and position of the module 11 relative to the patient space can be redesigned as desired, such as by using different housings.

Any of the shapes described in FIGS. 1-9 may be used. For example, FIG. 1 shows module 11 having four sides in a cross-section orthogonal to the radiation (a radial) from patient space. In one embodiment, module 11 has 3 , 5 , 6, or more sides in a cross-section perpendicular to the radiation from patient space. FIG. 11 shows a module 11 with six sides . When multiple modules 11 are used together , all modules have the same number of sides. Alternatively, different modules 11 with different numbers of sides are used together, such as a combination of modules 11 with 5 sides and modules 11 with 6 sides.

Modules with 3, 5, or 6 sides are narrower in the orthogonal cross- section closer to the patient space than farther from the patient space, and can realize a geodesic dome. Modules 11 may be arranged to form a spherical or geodesic dome. No full dome is used in any given imaging system. Two or more modules 11 can be arranged to form part of a geodesic dome. In alternative embodiments, module 11 is not shaped to form a sphere or geodesic dome, such as module 11 of FIG. 1 is shaped to form a ring or cylinder.

Module 11 is cylindrically symmetrical. The narrowest end of each of the plurality of modules 11 is closest to the patient space of the medical imaging system. The widest end of each of the plurality of modules 11 is further or furthest from the patient space. The scatter detector 12 is narrower and smaller in area than the capture detector 13 .

If module 11 includes both scatter detector 12 and capture detector 13, Compton-based imaging can be provided. A physical aperture 110 is included in module 11 to detect events using the photoelectric effect for SPECT. Physical aperture 110 is a plate or sheet of material . Physical aperture 110 is any material that is opaque to lower energies (eg, about 140.5 keV or less), such as lead or tungsten. Any thickness may be employed, for example 0.5-5 mm ( eg 1-3 mm) . The thickness is chosen to allow all or part of the higher energy (eg >>140.5 keV) radiation or photons to pass for Compton detection .

A physical aperture 110 is located between the locations of the scatter detector 12 and the capture detector 13 . The physical opening 110 may be between either detector layer if intermediate detectors are provided. The coded aperture may be adjacent to the capture detector 13, eg, within 1 cm (eg, within 5 mm), or further away from the capture detector 13. In an alternative embodiment, the physical aperture 110 is placed in front of the position for the scatter detector 12 (ie closer to patient space).

Brackets, frames, clips, or other mechanical structures are provided to position the physical opening 110 within the module 11 selected for the physical opening 110 to be contained within the module 11 . be. Its position may be at a predetermined distance from the capture detector 13 or adjustable during or after assembly.

The physical aperture 110 is orthogonal to the radiation (radial direction) from the patient space and thus parallel to the detectors 12,13. Alternatively , the physical aperture 110 is not parallel to one or both detectors 12, 13 and/or not orthogonal to the radiation (radial direction) from the patient space. The radial direction is shown as the axis of rotation in FIG.

The physical aperture 110 has the same shape as the detectors 12,13. For example, as shown in FIG. 11, physical aperture 110 and detectors 12, 13 have six sides. The physical aperture 110 may have a different perimeter shape than one or both detectors 12,13.

Physical aperture 110 is a coded aperture . A regular or varying (different) pattern of holes is provided to project a shadow onto the capture detector 13 . The shape and/or size of the holes may be the same or different. The holes are large enough to allow radiation from different angles (eg, angles 0-40 degrees away from the direction perpendicular to the physical opening 11) to pass through the holes. The aperture hole encoding results in an overlapping shadow on the capture detector 13 when illuminated from the source (eg, patient). The shadow coding can be used as a mask in reconstruction to deconvolve the image. In an alternative embodiment, physical aperture 110 is a parallel aperture collimator (eg, only radiation between 0 and 1 degrees from orthogonal passes through the aperture) .

The coded aperture may be a time-encoded aperture to reduce noise, source size, and/or scatter issues. Physical opening 110 rotates about a central axis (eg, radially from patient space). The shadow coding is shifted or changed for detection at different times. Detection from different placements of the coded apertures 110 relative to the capture detector 13 is used to reduce noise and/or distinguish background radiation from patient radiation . A time-encoded coded aperture near the capture detector 13 rotates about the axis of rotation to improve image quality and expand the field of view. In other embodiments, physical opening 110 translates instead of or in addition to rotation . Translation shifts the position of physical aperture 110 relative to capture detector 13 within module 11 . Other time encodings may be used.

In one embodiment, physical aperture 110 is positioned relative to capture detector 13 such that it casts a shadow on central region 112 of capture detector 13 and not on outer region 114 of capture detector 13 . . For example, physical aperture 110 has the same or similar area (eg, within 10%) as scatter detector 12 and has a smaller area than capture detector 13 . Due to scattering in Compton detection, photons detected by the capture layer using the Compton effect tend to be away from the center of the capture detector 13 . Conversely , photons detected using the photoelectric effect are more likely to reside in the central region 112 because the photoelectric effect does not utilize scattering . The central region 112 records Compton scattered photons as well as photoelectric events that do not interact with the internal detector. The outer region 114 records only or most Compton scatter events from the inner scatter detector 12 or other scatter detectors 12 .

The actual structure of the capture detector 13 may be uniform or the same for both the central region 112 and the outer region 114, but different pixel sizes for the different regions 112, 114, It may have a thickness and/or other properties. Reading from capture detector 13 may be limited to one or both regions 112, 114 based on the type of imaging being performed. Alternatively, a different structure is used, or detection over the capture detector 13 is used regardless of image type. A Compton event from one module 11 may be detected in any of the regions 112, 114 of another module 11 when the modules 11 are arranged to communicate.

Image processor 19 uses physical aperture 110 and trapping detector 13 to detect photoelectric effect radiation and scatter detector 12 and trapping detector 13 to detect Compton effect radiation . Configured . Detected events output by circuit board 14 are used by image processor 19 for SPECT or Compton imaging . For SPECT , instead of using events from the scatter detector 12, coded apertures or time-coded apertures are used. Photons of energy below about 140.5 keV are detected using the photoelectric effect. For Compton scattering , scatter detector 12 and capture detector 13 are used without shadowing from physical aperture 110 . Photons with energies an order of magnitude higher (eg, 1450 keV or higher) are detected using the Compton effect. The same module 11 and image processor 19 are used for both photoelectric and Compton imaging .

For Compton detection, events from scatter detector 12 and capture detector 13 are paired and used to determine the angle of incidence of the Compton event at one or more modules 11 . Photons interact first in the scattering layer by Compton scattering and then in the trapping layer by the photoelectric effect . These photons rain down their full energy on all layers (multi-layer event), triggering both the scattering and trapping layers. Due to scattering, more than half or most of the events detected at capture detector 13 are in outer region 114 . Photon interaction events are detected primarily (more than half or mostly) in the outer region 114 . To determine the correct source direction by knowing (estimating) the Compton kinematics based on the measured positions (x,y,z) and energies (E) for paired events: Compton reconstruction is used .

For photoelectric detection (ie, SPECT imaging ), photoelectric events from capture detector 13 are counted . Physical aperture 110 of module 11 and capture detector 13 are used. Photons can only interact in the trapping layer due to the photoelectric effect. Low-energy photons may not trigger the scattering layer and instead deposit their full energy onto the trapping layer (monolayer event). Photo-electric events are counted from the central region 112 rather than the outer region 114 of the capture detector 13 because scattering is not utilized . Events from the outer region 114 can be used as a measure of background.

A time-coded, coded aperture can be rotated about the axis of module 11 and is used to determine the correct source direction. A time-encoded aperture may reduce background (eg, scattering, higher energy photons emitted by the source , etc.).

The image processor 19 is arranged to generate SPECT images. The counts and positions on the capture detector 13 (ie, the positions indicating the response line ) are used to reconstruct a two-dimensional or three-dimensional representation of the patient. Radiation positions are represented . Image processor 19 is configured to generate Compton images from Compton events. A two-dimensional or three-dimensional representation is reconstructed from the Compton scattering events and the corresponding estimated angles . For a three-dimensional representation of object or image space, a two-dimensional image can be rendered three-dimensionally from the representation .

Display 22 is a CRT, LCD, projector, printer, or other display. Display 22 is configured to display SPECT and/or Compton images. One image or multiple images are stored in the display plane buffer and read out to the display unit 22 . The images may be displayed separately or may be combined, such as displaying the Compton image overlaid with the SPECT image, or displaying the Compton image next to the SPECT image .

12-16 show a medical imaging system formed from two or more modules 11. FIG. Depending on the shape of the solid-state detector modules 11, the modules 11 can be stacked together with or without direct contact to form part of a geodesic dome. Multiple modules 11 can be combined to form a 3D geodesic dome SPECT-Compton camera. Figures 12-16 show different implementations of the same concept with 18, 34 , 54 , 3 and 3 modules respectively.

FIG. 12 shows modules 11 used to form full ring 120 . Eighteen modules 11 form a full ring 120 based on the radius of the ring and the size of the modules 11 . More or less modules 11 may be used to form full ring 120 . Alternatively , one or more partial rings may be formed.

FIG. 13 shows the module 11 used to form two full rings 130,132. The two rings 130 , 132 intersect and thus share two modules 134 . One of the rings 130 is at 90 degrees to the other ring 132 . Other angles may be set depending on the number and/or shape of the sides of module 134 . In the example of FIG. 13, 34 modules 11 form two rings 130,132 . Other numbers of modules 11 may be used. One or both of rings 130 , 132 may be partial rings. In that case, the rings 130, 132 are separate but intersecting. In other embodiments, the rings 130, 132 do not intersect and are spaced apart in parallel or non-parallel planes . Additional rings may be included .

Rings 130, 132 are held or fixed in place. In other embodiments, rings 130, 132 connect with a hinge or pivot. Rings 130 , 132 pivot about a common axis , such as the axis through two shared modules 134 . Translation and/or rotation of both rings 130, 132 or each ring 130, 132 can be provided independently.

FIG. 14 shows module 11 used to shape the three rings into a larger portion of geodesic dome 140 compared to FIGS. Part of the spherical shell is formed from segmented modules 11 . The three rings are axially adjacent to each other with little (eg, less than 1/2 the width of the module 11) or no separation . The rings may be in direct contact with each other and/or attached to the same gantry or framework. Although three full rings are shown, one or more rings may be partial rings. Also, two, four, or more rings may be used. In the example of FIG. 14, fifty-four modules 11 are used for three rings, but additional or fewer modules 11 may be used.

FIG. 15 shows three modules 11 arranged relative to patient bed 60 . One, two, four or more modules 11 may be used. Modules 11 are spaced from each other by more than one module width, although smaller spacing or adjacent placement may be employed . The module 11 may be connected with other modalities such as dedicated SPECT cameras. Module 11 interfaces with the gantry to allow rotation around and/or movement (translation ) along the patient (eg, transaxially ) . Alternatively or additionally, bed 60 moves the patient relative to module 11 .

FIG. 16 shows the three module arrangement of FIG. 15 using different types of modules 160. FIG. The scatter detector 12 is removed , allowing the module 160 to be of a lower height or have a smaller range along the radiation from patient space . The same height may be employed , such as using the same housing but without the scatter detector 12 . Since Compton imaging is not provided, module 160 uses physical aperture 110 with one or more capture detectors 13 . The capture detector 13 works with a time-encoded coded aperture 110 for SPECT or photoelectric effect based imaging . The capture detector 13 absorbs photons by the photoelectric effect. A time-encoded coded aperture 110 near the trapping layer can be rotated about an axis of rotation to improve image quality. The coded aperture may also be moved (laterally) in the XY detector plane to increase the field of view. Other arrangements of module 160 for SPECT imaging , such as those of FIGS. 12-14, may be used. A single module 160 may be used. Fewer or more modules in any of the different configurations may be used.

FIG. 10 illustrates one embodiment of a flowchart of a method for making, using , and repairing a camera selectable to be a Compton camera, a SPECT camera, or both. Cameras are formed with a segmented approach. Rather than assembling the entire camera in place, one or more capture detectors are positioned relative to each other to form the desired configuration of the camera. A capture detector is arranged with a coded aperture for use with relatively low radiant energies and a scatter detector with scatter detectors for use with relatively high radiant energies. This selectable and segmented approach may allow different configurations using the same components, ease of assembly , ease of repair, and/or integration with other imaging modalities.

Another embodiment forms a combination of Compton and SPECT cameras, where both the scatter detector and the coded aperture are chosen to be used in the same camera as the capture detector. Here the segmented module 11 of FIG. 11 is used. Module 160 of FIG. 16 may be used to form a SPECT camera that does not include a scatter detector. Module 11 of FIG. 11 may also be used to form a Compton camera without a coded aperture .

The method may be performed by the system of FIG. 1 to assemble a Compton sensor as shown in any of FIGS . 4-9. The method may be performed by the system of FIG. 11 to assemble a Compton sensor as shown in any of FIGS. 12-16. Other systems, modules, and/or configurations of Compton sensors may be used .

Operations (steps) may be performed in the order shown ( ie, from top to bottom , or numerically ) or in some other order . For example, operation 108 may be performed as part of operation 104 .

Additional, different, or fewer acts may be provided. For example, operations 102 and 104 are provided for assembling a Compton camera without performing operations 106 and 108. FIG. As another example, operation 106 is performed without performing other operations.

At operation 102, the capture detector is contained within a separate housing. The modules are assembled such that each module contains a capture detector. Machines and / or humans manufacture the housing. Only one housing and corresponding modules may be used.

The plurality of modules are shaped to abut where respective scatter detector and capture detector pairs in different ones of the plurality of housings are non-planar. For example , as shown in FIG. 4C, a wedge shape and/or positioning is provided such that the detector pairs are formed from circular arcs . This shape allows and/or enforces an arcuate shape when the modules are positioned relative to each other .

In the case of a Compton-SPECT camera (eg, FIG. 11) , the scatter detector, coded aperture , and capture detector are contained within a housing. The housing and corresponding modules have any shape, such as a shape that is or forms part of a geodesic dome. The housing selectively includes one or both of the scatter detector and the coded aperture . for both scatter detectors and coded apertures , even if only one of the scatter detectors or coded apertures is positioned or installed, depending on design and/or radiant energy requirements The same housing with positions may be used. Alternatively, different housings are used depending on whether scatter detectors and/or coded apertures are to be included.

In operation 104 the housings are abutted . A human or machine assembles the Compton sensor from the housing. The abutted housings form an arc by stacking the housings adjacent to each other in direct contact or in contact through spacers, gantry, or frameworks. A full or partial ring is formed around the patient space to at least partially define the patient space. Based on the design of a Compton camera, SPECT camera, or Compton-SPECT camera, any number of housings with corresponding scatter detector and capture detector pairs are placed together to form a camera. A single housing may be used.

The housings can be adjacent as part of a multimodality system or to create a single imaging system. For multimodality systems , the housing is located within the same external housing and/or relative to the same bed as sensors for other modalities such as SPECT, PET, CT, or MR imaging systems. The same or different gantry or support framework may be used for the Compton camera housing and sensors for other modalities. For the embodiments of Figures 11-15, the module provides multimodality by providing both a Compton camera and a SPECT imaging system.

The configuration or design of the Compton camera dictates the number and/or locations of the housings. Once abutted , the housings can be connected for communication , such as via one or more bridges. The housing can connect with other components such as an air cooling system and/or a Compton processor.

At operation 106 , the assembled Compton camera detects radiation . A given emitted photon interacts with a scatter detector. The result is the scattering of another photon at a particular angle from the line of incidence of the emitted photon. This secondary photon has less energy . This secondary photon is detected at the capture detector. and pair the events based on the energy and timing of both the detected scattering and capture events. The position and energy of the paired events can be obtained for line and scattering angles between detectors. As a result, the line of incidence of the emitted photons is determined.

Capture events from one housing can be paired with scattering events from another housing to increase the likelihood of detecting secondary photons. Depending on the angle, scatter from one scatter detector can be incident on a paired capture detector in the same housing or a capture detector in another housing. More Compton events can be detected by having the housing open in the detector area and/or by using materials with low photon attenuation.

Detected events are counted or collected . Reconstruction uses response lines or lines where different Compton events occur. The three-dimensional distribution of radiation from the patient can be reconstructed based on Compton sensing . No collimator is required for reconstruction, as Compton sensing describes or provides the angle of incidence of the emitted photons.

Using the Compton-SPECT module 11 of FIG. 11, the module can also be used to detect radiation as photoelectric events. Low energy radiation passes through a scatter detector. These rays either pass through the holes of the coded apertures or are blocked by the coded apertures . A capture detector detects at least a portion of the radiation passing through the apertures of the coded aperture . Depending on the choice of including either or both of the scatter detector and the coded aperture , radiation at relatively low and/or high energies is detected.

The detected events are used to reconstruct the position of the radioisotope. Compton and/or photoelectric imaging are generated from detected events and corresponding line information from the events.

At operation 108, a person or machine (eg, robot) removes one of the housings. If one of the housing's detectors or associated electronics fails or is replaced to detect at a different energy, the housing can be removed . The other housing is then left in the medical imaging system. This allows for easier repair and/or replacement of the housing and/or detector without the expense of greater disassembly and/or replacement of the entire Compton camera.

Although the invention has been described above with reference to various embodiments, it should be understood that many variations and modifications can be made without departing from the scope of the invention. Accordingly, the foregoing detailed description is to be taken as illustrative rather than limiting of the invention, and it is the following claims, including all equivalents, which define the spirit of the invention and the scope of the claims. It should be understood that it is based on the description of.

Claims (20)

A first capture detector (13), a position for a first scatter detector (12) spaced from said capture detector (13), patient space and said first capture detector (13). a first module (11) having a location for a first physical opening (110) between
Determines the angle of incidence of a Compton event when said first scatter detector (12) is included in said first module (11) and said first physical aperture (110) is in said first module an image processor (19) configured to count photoelectric events when included in (11);
A multimodality medical imaging system comprising: said first physical opening (110) being in a position for said first physical opening (110), said first physical opening (110) being coded of lead or tungsten; 10. The multimodality medical imaging system of claim 1, comprising an aperture . Said coded aperture comprises a time coded aperture , said time coded aperture for projecting shadows at different positions on said first capture detector (13) . 3. The multimodality medical imaging system of claim 2 , rotatable about and/or translatable in a plane perpendicular to said axis. Said first physical aperture (110) is in a position for said first physical aperture (110), said first capture detector (13) and said first physical aperture. (110) are parallel and said first physical opening (110) is not in the outer area of said first capture detector (13) but in the central area of said first capture detector (13). has a shadow on
The image processor (19) is configured to count photoelectric events from the central region rather than the outer region and to determine angles of incidence of the Compton events with photon interaction events predominantly from the outer region. 2. The multimodality medical imaging system of claim 1, wherein further a second module (11) comprising a second capture detector (13) with a position for a second scatter detector (12) and a position for a second physical aperture (110) prepared ,
2. A multimodality medical image according to claim 1, wherein said first and second modules (11) have 3 , 5 or 6 sides in a cross-section orthogonal to the radiation from patient space. system. The first and second modules (11) are of cylindrical symmetry, the narrowest end of each of the first and second modules (11) being closest to the patient space of the medical imaging system, the 6. The multimodality medical imaging system of claim 5, wherein the widest ends of each of the first and second modules (11) are furthest from the patient space. said first module (11) comprises a circuit board orthogonal to said first capture detector (13), an application specific integrated circuit with said first capture detector (13), said application specific integrated circuit to said circuit board, and locations for one or more additional trapping and/or scattering layers between said first trapping layer and said first scattering layer. A multimodality medical imaging system as described. The multimodality medical imaging system of claim 1, wherein the first module (11) is part of a ring (120) or partial ring around the patient space of the medical imaging system. further comprising an additional group of modules (11) for said ring (130) or partial ring and another ring (132) or partial ring ;
9. The multimodality medical imaging system of claim 8 , wherein said further ring (132) or partial ring intersects said ring or partial ring in two of said additional groups of modules (134) . 10. The multi-modality medical imaging system of claim 9, wherein said ring (130) or partial ring and said another ring (132) or partial ring are separated by 90 degrees. further comprising an additional ring or partial ring axially adjacent to said ring or partial ring comprising said first modules (11) and consisting of said first modules (11);
9. The multimodality medical imaging system of claim 8, wherein said additional ring or partial ring and said ring or partial ring form a portion (140) of a geodesic dome . The first scatter detector (12) is in the position for the first scatter detector (12) in the first module (11) and the first physical opening (110). is in position for said first physical opening (110) in said first module (11),
said image processor (19) is configured to generate a single photon emission tomography image from said counts and a Compton image from said Compton event;
2. The multimodality medical imaging system of claim 1, further comprising a display configured to display the single photon emission tomography image and the Compton image. said first scatter detector (12) is provided in said first module (11) at a location for said first scatter detector (12) where relatively higher energies are to be detected;
Said first physical aperture (110) is included in said first module (11) at a location for said first physical aperture (110) where relatively lower energy is to be detected. 2. The multimodality medical imaging system of claim 1. a plurality of solid state detector modules ( 11 ),
Said solid-state detector modules (11) are stacked on top of each other to form part of a geodesic dome, so that in a cross-section perpendicular to a radial direction from the longitudinal patient axis, said solid-state detector modules (11): A medical imaging system with three , five , or six sides. each of said solid-state detector modules (11) further comprising said scatter detector (12) and said plate (110);
said plate (110) is between said scatter detector (12) and said first detector (13) ;
The plate (110) and the first detector (13) are used to detect radiation using the photoelectric effect and the scatter detector (12) and the first detector (13) are used to detect the Copton effect . 15. The medical imaging system of claim 14, further comprising an image processor (19) configured to utilize and detect radiation . each of the solid state detector modules (11) comprises said plate (110);
15. The medical imaging system of claim 14, wherein said plate is rotatable and /or translatable with respect to said first detector (13) in each solid state detector module (11). 15. Said stack for forming said part of said geodesic dome comprises two separate rings (130, 132) sharing two of said plurality of solid state detector modules (11). The medical imaging system according to . A method for forming a Compton camera and/or a single photon emission tomography camera, comprising:
housing a capture detector (13) in a housing (21) , wherein said capture detector (13) is usable for relatively low radiant energies using a coded aperture (110); and arranged to be usable for relatively high radiant energies using a scatter detector (12), said housing (21) being molded as part of a geodesic dome, and
mounting the housing (21) to a patient bed (60) with selected one or both of the coded aperture (110) and the scatter detector (12);
method including. Wearing
said Compton camera using said scatter detector (12) in said housing (21) and a single photon emission tomography imaging system using said coded aperture (110) in said housing (21) forming a ring (120) or partial ring comprising said housing (21) and forming an additional ring or partial ring consisting of said housing (21) as part of a multimodality system comprising 19. The method of claim 18, comprising: detecting the first radiation as a Compton event using the scatter detector (12) and the capture detector (13);
detecting second radiation as photoelectric events passing through the coded aperture (110) with the capture detector (13);
19. The method of claim 18, further comprising:

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