JP7505899B2 - Radiation detector and radiation diagnostic device - Google Patents

Description

The embodiments disclosed in this specification and the drawings relate to a radiation detector and a radiation diagnostic device.

Conventionally, radiological diagnostic devices such as X-ray CT (Computed Tomography) devices and PET (Positron Emission Tomography) devices are equipped with radiation detectors for detecting radiation. Some of these radiological diagnostic devices are equipped with wide-coverage radiation detectors, such as detectors called area detectors.

JP 2016-25187 A JP 2009-118943 A JP 2019-502284 A

One of the problems that the embodiments disclosed in this specification and the drawings attempt to solve is to realize a wide-coverage radiation detector at low cost. However, the problems that the embodiments disclosed in this specification and the drawings attempt to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems.

The radiation detector according to the embodiment includes a chip and a radiation protection shield. The chip has a plurality of photodiodes arranged in two dimensions, and an element that needs to be protected from radiation is provided in a portion of the same plane as the plane on which the photodiodes are arranged. The radiation protection shield is provided on the radiation incident side of the element.

FIG. 1 is a diagram showing an example of the configuration of an X-ray CT apparatus according to this embodiment. FIG. 2 is a diagram showing an example of the configuration of the X-ray detector according to this embodiment. FIG. 3 is a diagram showing an example of the configuration of the X-ray detector module according to the present embodiment. FIG. 4 is a diagram showing an example in which a 4-sided tallyable detector and a 3-sided tallyable detector are used as chips as comparative examples according to this embodiment. FIG. 5 is a diagram showing an example in which a 4-sided tallyable detector and a 3-sided tallyable detector are used as chips as comparative examples according to this embodiment. FIG. 6 is a diagram showing an example in which a 4-sided tallyable detector and a 3-sided tallyable detector are used as chips as comparative examples according to this embodiment. FIG. 7 is a diagram showing an example in which a 4-sided tallyable detector and a 3-sided tallyable detector are used as chips as comparative examples according to this embodiment. FIG. 8 is a diagram showing an example of a scintillator array and a photodiode array included in the X-ray detector module according to this embodiment. FIG. 9 is a diagram for explaining an example of the X-ray protection shield according to this embodiment. FIG. 10 is a diagram for explaining an example of the X-ray protection shield according to this embodiment. FIG. 11 is a diagram for explaining an example of an X-ray protection shield according to a modified example of this embodiment. FIG. 12 is a diagram for explaining an example of an X-ray protection shield according to a modified example of this embodiment. FIG. 13 is a diagram showing an example of an element according to a modified example of this embodiment.

(Embodiment)
Hereinafter, embodiments of a radiation detector and a radiation diagnostic device disclosed in the present application will be described with reference to the drawings. The configurations shown in the drawings are schematic, and the dimensions of each component and the dimensional ratios between the components shown may differ from the actual ones. Furthermore, the dimensions of the same component and the dimensional ratios between the components may be different between the drawings.

In the embodiment described below, an example is described in which the configuration of the radiation detector and radiation diagnostic device disclosed in this application is applied to an X-ray detector and an X-ray CT device.

Figure 1 is a diagram showing an example of the configuration of an X-ray CT device according to this embodiment.

For example, as shown in FIG. 1, the X-ray CT apparatus 1 according to this embodiment includes a gantry device 10, a bed device 30, and a console device 40. For ease of explanation, FIG. 1 shows multiple gantry devices 10.

In this embodiment, the rotation axis of the rotating frame 13 in a non-tilted state or the longitudinal direction of the tabletop 33 of the bed device 30 is defined as the "Z-axis direction." The axis direction that is perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the "X-axis direction." The axis direction that is perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the "Y-axis direction."

The gantry device 10 is a device that irradiates X-rays onto a subject P (such as a patient), detects the X-rays that have passed through the subject P, and outputs them to a console device 40. The gantry device 10 has an X-ray tube 11, an X-ray detector 12, a rotating frame 13, a control device 15, a wedge 16, an X-ray aperture 17, and an X-ray high voltage device 14.

The X-ray tube 11 is a vacuum tube that generates X-rays by irradiating thermoelectrons from a cathode (filament) to an anode (target) when a high voltage is applied from the X-ray high voltage device 14. For example, the X-ray tube 11 is a rotating anode type X-ray tube that generates X-rays by irradiating thermoelectrons to a rotating anode.

The wedge 16 is a filter for adjusting the amount of X-rays irradiated from the X-ray tube 11. Specifically, the wedge 16 is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 11 so that the X-rays irradiated from the X-ray tube 11 to the subject P have a predetermined distribution. For example, the wedge 16 is a filter made of processed aluminum to have a predetermined target angle and a predetermined thickness. The wedge 16 is also called a wedge filter or a bow-tie filter.

The X-ray aperture 17 includes a lead plate or the like for narrowing the irradiation range of the X-rays that have passed through the wedge 16, and a slit is formed by combining multiple lead plates or the like.

The X-ray detector 12 detects X-rays emitted from the X-ray tube 11 and passing through the subject P. Specifically, the X-ray detector 12 has multiple detection element rows in which multiple detection elements are arranged in the channel direction along a single arc centered on the focal point of the X-ray tube 11. For example, the X-ray detector 12 has a structure in which multiple detection element rows in which multiple detection elements are arranged in the channel direction are arranged in the row direction (also called the slice direction or row direction).

The X-ray detector 12 also has a Data Acquisition System (DAS) that processes the electrical signals output from each detection element. The DAS generates detection data based on the electrical signals output from each detection element of the X-ray detector 12. The detection data generated by the DAS is transferred to the console device 40.

The X-ray high voltage device 14 has electrical circuits such as a transformer and a rectifier, and includes a high voltage generator that generates a high voltage to be applied to the X-ray tube 11, and an X-ray control device that controls the output voltage according to the X-ray output emitted by the X-ray tube 11. The high voltage generator may be of a transformer type or an inverter type. The X-ray high voltage device 14 may be provided on the rotating frame 13 described later, or on a support frame (not shown) in the gantry device 10 that rotatably supports the rotating frame 13.

The rotating frame 13 is an annular frame that supports the X-ray tube 11 and the X-ray detector 12 facing each other and rotates the X-ray tube 11 and the X-ray detector 12 by a control device 15 described later. In addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 further supports an X-ray high voltage device 14. Here, the detection data generated by the DAS of the X-ray detector 12 is transmitted by optical communication from a transmitter having a light emitting diode (LED) provided on the rotating frame 13 to a receiver having a photodiode provided on a non-rotating part of the gantry 10 (e.g., a support frame, etc.), and transferred to the console device 40. The method of transmitting the detection data from the rotating frame 13 to the non-rotating part of the gantry 10 is not limited to the optical communication described above, and any method of non-contact data transmission may be used.

The control device 15 has a processing circuit having a CPU (Central Processing Unit) and the like, and a driving mechanism such as a motor and an actuator. The control device 15 has a function of receiving an input signal from the console device 40 or the input interface 43 attached to the gantry device 10 and controlling the operation of the gantry device 10 and the bed device 30. For example, the control device 15 receives an input signal and controls the rotation of the rotating frame 13, the tilt of the gantry device 10, and the operation of the bed device 30 and the tabletop 33. The control of tilting the gantry device 10 is realized by the control device 15 rotating the rotating frame 13 around an axis parallel to the X-axis direction based on the inclination angle (tilt angle) information input by the input interface 43 attached to the gantry device 10. The control device 15 may be provided in the gantry device 10 or in the console device 40.

The bed device 30 is a device on which the subject P, who is the subject of the scan, is placed and moved, and has a base 31, a bed driving device 32, a top plate 33, and a support frame 34. The base 31 is a housing that supports the support frame 34 so that it can move in the vertical direction. The bed driving device 32 is a motor or actuator that moves the top plate 33, on which the subject P is placed, in the longitudinal direction of the top plate 33. The top plate 33, which is provided on the upper surface of the support frame 34, is a plate on which the subject P is placed. Note that the bed driving device 32 may move the support frame 34 in the longitudinal direction of the top plate 33 in addition to the top plate 33.

The console device 40 is a device that accepts operations of the X-ray CT device 1 by an operator, and reconstructs CT image data using detection data collected by the gantry device 10. The console device 40 has a memory 41, a display 42, an input interface 43, and a processing circuit 44. Note that, although an example in which the console device 40 and the gantry device 10 are separate is described here, the gantry device 10 may include the console device 40 or some of the components of the console device 40.

The memory 41 is realized, for example, by a semiconductor memory element such as a random access memory (RAM), a flash memory, a hard disk, an optical disk, etc. The memory 41 stores, for example, projection data and CT image data.

The display 42 displays various information. For example, the display 42 outputs medical images (CT images) generated by the processing circuit 44, a GUI (Graphical User Interface) for receiving various operations from the operator, and the like. For example, the display 42 is a liquid crystal display or a CRT (Cathode Ray Tube) display. Note that, for example, the display 42 may be provided on the pedestal device 10. Also, for example, the display 42 may be a desktop type, or may be configured as a tablet terminal capable of wireless communication with the console device 40 main body.

The input interface 43 accepts various input operations from the operator, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing circuit 44. For example, the input interface 43 accepts from the operator the collection conditions for collecting projection data, the reconstruction conditions for reconstructing CT image data, and the image processing conditions for generating post-processed images from CT images. For example, the input interface 43 is realized by a mouse, a keyboard, a trackball, a switch, a button, a joystick, or the like. Note that, for example, the input interface 43 may be provided in the gantry device 10. Also, for example, the input interface 43 may be configured by a tablet terminal or the like capable of wireless communication with the console device 40 main body.

The processing circuitry 44 controls the operation of the entire X-ray CT device 1. For example, the processing circuitry 44 executes a system control function 441, a pre-processing function 442, a reconstruction processing function 443, and an image processing function 444.

The system control function 441 controls various functions of the processing circuit 44 based on input operations received from an operator via the input interface 43. For example, the system control function 441 controls the CT scan performed in the X-ray CT device 1. The system control function 441 also controls the generation and display of CT image data in the console device 40 by controlling the pre-processing function 442, the reconstruction processing function 443, and the image processing function 444.

The pre-processing function 442 generates projection data by performing pre-processing such as logarithmic conversion, offset correction, inter-channel sensitivity correction, and beam hardening correction on the detection data output from the DAS of the X-ray detector 12. Note that the data before pre-processing (detection data) and the data after pre-processing may be collectively referred to as projection data.

The reconstruction processing function 443 performs reconstruction processing using a filtered backprojection method, an iterative reconstruction method, or the like on the projection data generated by the preprocessing function 442 to generate CT image data (reconstructed image data).

The image processing function 444 converts the CT image data generated by the reconstruction processing function 443 into tomographic image data of an arbitrary cross section or three-dimensional image data by a known method based on the input operation received from the operator via the input interface 43. Note that the generation of the three-dimensional image data may be performed directly by the reconstruction processing function 443.

Here, for example, the processing circuitry 44 is realized by a processor. In this case, each processing function possessed by the processing circuitry 44 is stored in the memory 41 in the form of a program executable by a computer. Then, the processing circuitry 44 realizes the function corresponding to each program by reading each program from the memory 41 and executing it. In other words, the processing circuitry 44 in a state in which each program has been read has each processing function shown in the processing circuitry 44 in FIG. 1.

Here, it has been described that each of the above-mentioned processing functions is realized by a single processing circuit 44, but for example, it is also possible to configure the processing circuit 44 by combining multiple independent processors, and each processor executes a program to realize each processing function. Also, each processing function possessed by the processing circuit 44 may be appropriately distributed or integrated and realized in a single or multiple processing circuits. Also, each processing function possessed by the processing circuit 44 may be realized by a mixture of hardware and software such as circuits. Also, here, an example has been described in which a single memory 41 stores a program corresponding to each processing function, but the embodiment is not limited to this. For example, it is also possible to configure a configuration in which multiple storage circuits are distributed and the processing circuit 44 reads out and executes the corresponding program from each storage circuit.

Figure 2 is a diagram showing an example of the configuration of the X-ray detector 12 according to this embodiment.

For example, as shown in FIG. 2, the X-ray detector 12 is formed in a generally arc-like shape and is fixed to the rotating frame 13 described above so that the center of the arc coincides with the position of the X-ray tube 11.

Here, the circumferential direction of the arc in the X-ray detector 12 coincides with the channel direction. The axial direction of the arc in the X-ray detector 12 coincides with the row direction. The radial direction of the arc in the X-ray detector 12 coincides with the X-ray irradiation direction. Note that in each drawing referenced in the following description, the channel direction is indicated by arrow C, the row direction is indicated by arrow R, and the X-ray irradiation direction is indicated by arrow I.

For example, the X-ray detector 12 has a plurality of X-ray detector modules 121, a collimator 122, a first fixed frame 123, a second fixed frame 124, a first support frame 125, a second support frame 126, and a light shielding plate 127.

Each X-ray detector module 121 has an X-ray detection array 1211, a support member 1212, and a DAS 1213.

The X-ray detection array 1211 has a scintillator array and a photodiode array. The scintillator array has multiple scintillators arranged in the channel direction and column direction, and each scintillator has a scintillator crystal that outputs light with a photon amount corresponding to the amount of incident X-rays. The photodiode array has multiple photodiodes arranged in the channel direction and column direction as detection elements. Here, the photodiodes included in the photodiode array are each arranged so as to correspond one-to-one with the scintillators included in the scintillator array, and output an electrical signal corresponding to the amount of light output from the corresponding scintillator to the DAS 1213.

The support member 1212 is formed in a substantially rectangular parallelepiped shape, and the X-ray detection array 1211 is fixed to the surface arranged opposite the X-ray tube 11, thereby supporting the X-ray detection array 1211.

The DAS 1213 is attached to the surface of the support member 1212 opposite the X-ray detection array 1211 so as to extend along the X-ray irradiation direction, and generates detection data based on the electrical signals output from each photodiode of the X-ray detection array 1211.

The collimator 122 has a plurality of X-ray shielding plates arranged in a grid pattern along the channel direction and the row direction, and the X-ray shielding plates prevent the incidence of scattered X-rays on the X-ray detection array 1211 of each X-ray detector module 121. Specifically, the collimator 122 is formed in a substantially arc shape along the channel direction and is arranged to cover each X-ray detector module 121, and each X-ray shielding plate removes scattered rays from the X-rays incident on the X-ray detection array 1211 of each X-ray detector module 121.

In this embodiment, the collimator 122 is configured such that each of the multiple slits (rectangular through holes) formed by the X-ray shielding plates arranged in a lattice pattern is arranged in a row along the channel direction of the scintillators and photodiodes included in one X-ray detection array 1211.

The first and second fixed frames 123 and 124 are fixed to both ends of the collimator 122 in the column direction, and multiple X-ray detector modules 121 are attached in a line in the channel direction on the side opposite to the side where X-rays are incident. Here, the first and second fixed frames 123 and 124 are configured so that each X-ray detector module 121 can be attached and detached independently.

The first support frame 125 and the second support frame 126 support the collimator 122 and the fixed frame. Specifically, the first support frame 125 and the second support frame 126 support the first fixed frame 123, the second fixed frame 124, and the collimator 122 by sandwiching them from both sides in the column direction, and in this state are fixed to the support frame (not shown) of the gantry device 10.

The light shielding plate 127 suppresses light incident on the X-ray detection array 1211 of each X-ray detector module 121. For example, the light shielding plate 127 is a member formed in a thin plate shape using a material capable of suppressing light, and is attached to the first support frame 125 and the second support frame 126 so as to cover the entire collimator 122.

Figure 3 is a diagram showing an example of the configuration of the X-ray detector module 121 according to this embodiment.

For example, as shown in FIG. 3, the X-ray detection array 1211 included in the X-ray detector module 121 has a scintillator array 12111 and a photodiode array 12112.

The scintillator array 12111 is disposed on the X-ray incidence side of the multiple photodiodes included in the photodiode array 12112, and has multiple scintillators arranged in the channel direction and column direction. Here, the scintillator array 12111 includes multiple scintillators arranged with partitions between them to prevent optical crosstalk between the scintillators.

The photodiode array 12112 has a plurality of photodiodes arranged in the channel direction and the column direction as detection elements. Here, as described above, the photodiodes included in the photodiode array 12112 are arranged so as to correspond one-to-one with the scintillators included in the scintillator array.

The above describes the configuration of the X-ray CT device 1 and the X-ray detector 12. Based on this configuration, in this embodiment, in order to realize an X-ray detector 12 with wide coverage, the photodiode array 12112 of each X-ray detector module 121 is configured by arranging multiple chips 50, each having multiple photodiodes, in a row.

Here, the chip 50 has multiple photodiodes arranged in a two-dimensional direction and an ADC (Analog to Digital Converter) that converts the electrical signal output from each photodiode into a digital signal.

As such, one technique for constructing a photodiode array by arranging multiple chips each having multiple photodiodes side by side is to use, for example, a 4-sided tallyable detector or a 3-sided tallyable detector as the chips.

Figures 4 to 7 are diagrams showing examples of using a 4-sided tallyable detector and a 3-sided tallyable detector as chips, which are comparative examples of this embodiment.

For example, as shown in FIG. 4, a 4-sided tallyable detector 50a has a configuration in which multiple photodiodes 51a are arranged in a two-dimensional direction across the entire incident surface on which X-rays are incident, and an ADC (not shown) is provided on the back side of the substrate on which the photodiodes are arranged.

For example, when using a 4-side tileable detector 50a as shown on the left side of Fig. 5, a photodiode array of an X-ray detector is realized by arranging multiple 4-side tileable detectors 50a in a row direction. In this case, for example, as shown on the right side of Fig. 5, a scintillator array 60a is used in which multiple scintillators are arranged with partitions (shown by thick solid lines) between them over the entire range on the photodiode array.

Here, the 4-side tallyable detector 50a has photodiodes 51a arranged across the entire incident surface, so by lining up multiple 4-side tallyable detectors 50a in succession, the photodiodes 51a can be arranged seamlessly over a wide range. For this reason, the 4-side tallyable detector 50a is effective in realizing a wide-coverage X-ray detector 12.

However, when the 4-side tallyable detector 50a is used, the cost of the X-ray detector 12 generally increases. For example, in the 4-side tallyable detector 50a, the ADC is provided on the back side of the substrate on which the photodiodes 51a are arranged, so the photodiodes 51a and the ADC must be connected vertically via TSVs (Through Silicon Vias) or the like, which increases the manufacturing cost. There is also a method of connecting the ADC to the back side using a ceramic substrate as an interposer, but this is difficult to implement due to the long analog wiring, which reduces performance, and the constraint of having to connect the photodiodes 51a via BIP (Backside Illuminated Photodiode), which increases the manufacturing cost.

On the other hand, as shown in FIG. 6, for example, a 3-side tileable detector 50b has a configuration in which a plurality of photodiodes 51b are arranged in a two-dimensional direction, and an ADC 52b is provided on one side of the same inner plane as the substrate on which the plurality of photodiodes 51b are arranged. As a result, the 3-side tileable detector 50b has a configuration in which a plurality of photodiodes 51b are arranged on three of the four sides of a rectangle, and an ADC 52b is arranged on one side.

For example, when using a 3-side tileable detector 50b as shown on the left side of Figure 7, a photodiode array of an X-ray detector is realized by arranging two 3-side tileable detectors 50b side by side in the column direction. In this case, for example, as shown on the right side of Figure 7, a scintillator array 60b is used in which multiple scintillators are arranged via partitions (shown by thick solid lines) only in the range where they are placed on the photodiode array.

The 3-side tallyable detector 50b can realize a high-performance X-ray detector at low cost because the photodiode 51b and ADC 52b can be formed on the same silicon surface by a CMOS (Complementary Metal Oxide Semiconductor) process, compared to the case where the 4-side tallyable detector 50a is used.

However, in the 3-side tileable detector 50b, the photodiodes 51b and the ADCs 52b are arranged on the same plane, so in order to arrange the photodiodes 51b without gaps, they are arranged so that the opposite sides of the side on which the ADCs 52b are provided are adjacent to each other. Therefore, when using the 3-side tileable detector 50b, the photodiode array of the X-ray detector is realized with only two 3-side tileable detectors 50b, making it difficult to realize an X-ray detector 12 with wide coverage.

For these reasons, this embodiment makes it possible to realize a wide-coverage X-ray detector 12 at low cost.

Specifically, in this embodiment, the X-ray detector 12 includes a chip 50 in which a plurality of photodiodes are arranged in a two-dimensional direction and an ADC is provided in a portion of the same plane as the plane on which the photodiodes are arranged.

In this embodiment, the chip 50 is a three-sided tileable detector in which multiple photodiodes are arranged in a two-dimensional direction and an ADC is provided on one side on the same plane as the substrate on which the photodiodes are arranged.

Figure 8 is a diagram showing an example of a scintillator array 12111 and a photodiode array 12112 included in an X-ray detector module 121 according to this embodiment.

For example, as shown on the left side of FIG. 8, in this embodiment, the photodiode array 12112 included in the X-ray detector module 121 is configured by arranging multiple chips 50, which are 3-sided tileable detectors, in a column direction. Specifically, the chip 50 has multiple photodiodes 51 arranged in a two-dimensional direction, and an ADC 52 is provided on one side on the same inner plane as the substrate on which the multiple photodiodes 51 are arranged.

For example, the photodiode array 12112 is formed by arranging four chips 50 in the column direction. Here, the two chips 50 arranged on the inside in the column direction are arranged side by side so that the opposite sides of the sides on which the ADC 52 is provided are adjacent to each other. The two chips 50 arranged on the outside in the column direction are arranged side by side so that the opposite sides of the sides on which the ADC 52 is provided are adjacent to the side on which the ADC 52 is provided of the chip 50 arranged on the inside.

In this way, when multiple chips 50, which are 3-sided tileable detectors, are arranged in a column direction, multiple photodiodes 51 and ADCs 52 are arranged alternately in the column direction. As a result, the X-ray detector 12 has a surface detector structure in which sensitive and insensitive areas appear periodically.

Here, the ADC 52 is an element that needs to be protected from X-rays because there is concern that it may deteriorate if X-rays are incident on it. Therefore, in this embodiment, the X-ray detector 12 is provided with an X-ray protection shield provided on the X-ray incident side of the ADC 52.

For example, as shown on the right side of FIG. 8, the scintillator array 12111 included in the X-ray detector module 121 further includes multiple scintillators arranged without any partitions between them, and the multiple scintillators form the X-ray protective shield 70.

Figures 9 and 10 are diagrams illustrating an example of an X-ray protective shield 70 according to this embodiment.

Here, in this embodiment, the ADC 52 is larger than the spacing between the partitions included in the scintillator array 12111 and is larger than the thickness of the X-ray shielding plate included in the collimator 122. As described above, in this embodiment, the collimator 122 is configured so that each of the multiple slits formed by the X-ray shielding plates arranged in a lattice pattern is arranged in a row along the channel direction of the scintillators and photodiodes included in one X-ray detection array 1211.

In such a case, for example, as shown in FIG. 9, if multiple scintillators arranged on the X-ray entrance side of the ADC 52 are arranged with partitions (shown by thick solid lines) between them, the X-rays (shown by arrows) that pass through the slits in the collimator 122 will pass through the partitions between the scintillators and enter the ADC 52 arranged on the substrate 53.

In contrast, as shown in FIG. 10, for example, in this embodiment, multiple scintillators are arranged without a partition on the X-ray entrance side of the ADC 52, and the multiple scintillators form the X-ray protection shield 70. That is, in this embodiment, multiple scintillators are arranged in close contact with each other on the X-ray entrance side of the ADC 52. As a result, X-rays (indicated by the arrows) that pass through the slits of the collimator 122 are attenuated by the multiple scintillators arranged on the X-ray entrance side of the ADC 52, and do not enter the ADC 52.

Furthermore, in this embodiment, the pre-processing function 442 generates data corresponding to the positions where the ADCs 52 are arranged. Here, the pre-processing function 442 is an example of a generating unit.

For example, the pre-processing function 442 generates projection data in which the data corresponding to the positions where the ADCs 52 are arranged is interpolated by performing interpolation processing such as linear interpolation or weighted interpolation based on the detection data output from the DAS 1213 of each X-ray detector module 121, thereby generating data corresponding to the positions where the ADCs 52 are arranged.

Alternatively, for example, the pre-processing function 442 may use a trained model created by machine learning such as deep learning to generate projection data in which data corresponding to the positions at which the ADCs 52 are arranged is interpolated. In this case, for example, the trained model is created in advance by machine learning using detection data collected from a subject using the X-ray detector 12 according to this embodiment, projection data collected from the same subject using an X-ray detector in which multiple photodiodes are arranged without interruption, and learning data, and is stored in the memory 41. Here, for example, the trained model is a model that inputs detection data output from the DAS 1213 of each X-ray detector module 121 and outputs projection data in which data corresponding to the positions at which the ADCs 52 are arranged is interpolated.

As described above, in this embodiment, the X-ray detector 12 includes a chip 50 on which a plurality of photodiodes are arranged in a two-dimensional direction, and on which an ADC 52 that requires protection from X-rays is provided in a portion of the same plane as the plane on which the photodiodes are arranged. The X-ray detector 12 also includes an X-ray protection shield 70 provided on the X-ray entrance side of the ADC 52. The X-ray CT device 1 also includes a pre-processing function 442 that generates data corresponding to the positions at which the ADC 52 are arranged.

With this configuration, the X-ray detector 12 can be constructed using a low-cost detector such as a 3-side tallyable detector as the chip 50. Therefore, according to this embodiment, a wide-coverage X-ray detector 12 can be realized at low cost.

(Modification)
The above-described embodiment can be modified as appropriate.

For example, in the above embodiment, an example was described in which a three-sided tallyable detector is used as the chip 50, but the embodiment is not limited to this. For example, a detector may be used that is on the same plane as the substrate on which the photodiodes are arranged and has an ADC provided between the photodiodes.

In other words, various detectors can be used as chip 50 as long as they have multiple photodiodes arranged in two dimensions and an ADC provided in a portion of the same plane as the plane on which the photodiodes are arranged. In such detectors, the photodiodes and ADC can be formed on the same silicon surface by a CMOS process, so that an X-ray detector with better performance can be realized at a lower cost than a detector in which an ADC is provided on the back side of a substrate on which photodiodes are arranged, such as a 4-side tallyable detector.

In addition, in the above-described embodiment, an example has been described in which the photodiode array 12112 of the X-ray detector module 121 is configured by arranging multiple chips 50 in a row direction, but the embodiment is not limited to this. For example, multiple rows of chips 50 arranged in the row direction may be further arranged in the channel direction. This allows the coverage of the X-ray detector 12 to be expanded not only in the row direction but also in the channel direction.

In the above-described embodiment, an example has been described in which multiple chips 50 are arranged so that multiple photodiodes 51 and ADCs 52 are arranged alternately in the column direction, but the embodiment is not limited to this. For example, multiple chips 50 may be arranged so that the ADCs 52 are continuously arranged in a row in the channel direction at one end side of the channel direction. Alternatively, multiple chips 50 may be arranged so that ADCs 52 arranged along the channel direction and ADCs 52 arranged along the column direction are arranged alternately.

In addition, for example, in the above-described embodiment, an example was described in which the X-ray protective shield 70 is composed of multiple scintillators arranged without partitions between them, but the embodiment is not limited to this.

For example, the X-ray protection shield 70 may be composed of a shielding material provided on a portion of the scintillator array 12111.

Figure 11 is a diagram illustrating an example of an X-ray protective shield 70 according to a modified example of this embodiment.

For example, as shown in FIG. 11, in the scintillator array 12111, a part of the scintillator located on the X-ray entrance side of the ADC 52 is cut out, and a shielding material such as lead is placed in that part to form the X-ray protection shield 70.

Alternatively, for example, rather than cutting away a portion of the scintillator located on the X-ray entrance side of the ADC 52, the X-ray protection shield 70 may be constructed by removing the entire scintillator and placing a shielding material in its place.

Alternatively, for example, the X-ray protection shield 70 may be constructed by leaving the scintillator arranged on the X-ray entrance side of the ADC 52 in place and arranging a shielding material on the surface of the scintillator on the X-ray entrance side of the scintillator or between the scintillator and the ADC 52.

Also, for example, the X-ray protection shield 70 may be composed of a shielding material provided on a part of the collimator 122.

Figure 12 is a diagram illustrating an example of an X-ray protective shield 70 according to a modified example of this embodiment.

For example, as shown in FIG. 12, the X-ray protection shield 70 is formed by placing a shielding material such as lead in the slit located on the X-ray entrance side of the ADC 52 in the collimator 122.

In the above embodiment, an example has been described in which the element provided on the chip 50 is the ADC 52, but the embodiment is not limited to this. For example, the element provided on the chip 50 may be an AFE (Analog Front End), an amplifier circuit, an integration circuit, a switch array chip, etc.

Furthermore, for example, the elements provided on chip 50 may be bonding pads.

Figure 13 shows an example of an element according to a modified example of this embodiment.

13, for example, in chip 50, bonding pads 54 are provided on the same plane as the plane on which multiple photodiodes 51 are arranged. In this case, for example, ADC 52 is provided on the back side of substrate 53 of chip 50, and is connected to photodiode 51 by wire bonding via bonding pad 54. Alternatively, ADC 52 may be provided in DAS1213, and connected to photodiode 51 via a connector and bonding pad 54 provided between substrate 53 of chip 50 and DAS1213.

Note that if the elements provided on the chip 50 are bonding pads, these elements do not require protection from X-rays, and therefore the X-ray protective shield 70 does not need to be provided.

In addition, in the above-described embodiment, an example has been described in which the pre-processing function 442 generates data corresponding to the position where the ADC 52 is arranged, but the embodiment is not limited to this. For example, the control device 15 included in the gantry device 10 or the reconstruction processing function 443 of the processing circuit 44 included in the console device 40 may generate data corresponding to the position where the ADC 52 is arranged. In this case, the control device 15 or the reconstruction processing function 443 is an example of a generating unit.

In the above-described embodiment, the preprocessing function 442 uses a trained model created by machine learning to generate projection data in which data corresponding to the position where the ADC 52 is arranged is interpolated, but the embodiment is not limited to this. For example, when the reconstruction processing function 443 generates data corresponding to the position where the ADC 52 is arranged, the trained model created by machine learning may be used to generate CT image data in which data corresponding to the position where the ADC 52 is arranged is interpolated. In this case, for example, the trained model is created by machine learning in advance using CT image data collected using the X-ray detector 12 according to this embodiment and CT image data collected from the same subject using an X-ray detector in which multiple photodiodes are arranged without interruption as learning data, and is stored in the memory 41. Here, for example, the trained model is a model that inputs a CT image reconstructed from projection data collected using the X-ray detector 12 according to this embodiment and outputs CT image data in which data corresponding to the position where the ADC 52 is arranged is interpolated.

In the above-described embodiment, an example was described in which the configuration of the radiation detector and radiation diagnostic device disclosed in the present application is applied to an X-ray detector and an X-ray CT device, but the embodiment is not limited to this. For example, the configuration of the radiation detector and radiation diagnostic device disclosed in the present application can be similarly applied to other radiation detectors and radiation diagnostic devices, such as a gamma ray detector and a PET device.

The term "processor" used in the above description means, for example, a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an Application Specific Integrated Circuit (ASIC), or a programmable logic device (for example, a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA)). When the processor is, for example, a CPU, the processor realizes a function by reading and executing a program stored in a memory circuit. On the other hand, when the processor is, for example, an ASIC, instead of storing a program in a memory circuit, the function is directly incorporated as a logic circuit in the circuit of the processor. Note that each processor in this embodiment is not limited to being configured as a single circuit for each processor, but may be configured as a single processor by combining multiple independent circuits to realize its function. Furthermore, the multiple components in FIG. 1 may be integrated into a single processor to realize its function.

In addition, in the above-mentioned embodiment and modified examples, each component of each device shown in the figures is functionally conceptual, and does not necessarily have to be physically configured as shown. In other words, the specific form of distribution or integration of each device is not limited to that shown in the figures, and all or part of it can be functionally or physically distributed or integrated in any unit depending on various loads, usage conditions, etc. Furthermore, each processing function performed by each device can be realized in whole or in any part by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware using wired logic.

Furthermore, among the processes described in the above-mentioned embodiments and variations, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using known methods. In addition, the information including the processing procedures, control procedures, specific names, various data, and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified.

According to at least one of the embodiments described above, a wide-coverage radiation detector can be realized at low cost.

Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and spirit of the invention.

REFERENCE SIGNS LIST 1 X-ray CT device 12 X-ray detector 12111 Scintillator array 122 Collimator 44 Processing circuit 442 Pre-processing function 50 Chip 51 Photodiode 52 ADC
70 X-ray protection shield

Claims (9)

a chip on which a plurality of photodiodes are arranged in a two-dimensional direction and on which an element that needs to be protected from radiation is provided in a part of the same plane as the plane on which the photodiodes are arranged;
a scintillator array arranged on radiation incident sides of the plurality of photodiodes, the scintillator array including a plurality of scintillators arranged in the two-dimensional direction;
a radiation protection shield provided on the radiation incident side of the element,
The radiation protection shield is composed of a shielding material disposed in a portion obtained by cutting out a part of a scintillator disposed on the radiation incidence side of the element in the scintillator array, or a shielding material disposed on a surface of the radiation incidence side of a scintillator disposed on the radiation incidence side of the element in the scintillator array.
Radiation detector. a chip on which a plurality of photodiodes are arranged in a two-dimensional direction and on which an element that needs to be protected from radiation is provided in a part of the same plane as the plane on which the photodiodes are arranged;
a scintillator array arranged on radiation incident sides of the plurality of photodiodes, the scintillator array including a plurality of scintillators arranged in the two-dimensional direction;
a radiation protection shield provided on the radiation incident side of the element,
the scintillator array includes a plurality of scintillators arranged with partitions interposed therebetween to prevent optical crosstalk between the scintillators, and a plurality of scintillators arranged without the partitions interposed therebetween;
The radiation protection shield is composed of a plurality of scintillators arranged without the partition wall.
Radiation detector. a chip on which a plurality of photodiodes are arranged in a two-dimensional direction and on which an element that needs to be protected from radiation is provided in a part of the same plane as the plane on which the photodiodes are arranged;
a collimator having a plurality of radiation shielding plates arranged in a grid pattern along the two-dimensional direction, the collimator preventing scattered radiation from being incident on the tip;
a radiation protection shield provided on the radiation incident side of the element,
The radiation protection shield is constituted by a shielding material provided on a part of the collimator.
Radiation detector. a scintillator array disposed on a radiation incident side of the plurality of photodiodes and including a plurality of scintillators arranged in the two-dimensional direction;
The scintillator array includes a plurality of scintillators arranged with partitions interposed therebetween to prevent optical crosstalk between the scintillators.
The radiation detector according to claim 3 . The elements are greater than the spacing between the partitions included in the scintillator array.
The radiation detector according to claim 2 or 4. a collimator having a plurality of radiation shielding plates arranged in a grid pattern along the two-dimensional direction to protect the chip from scattered radiation;
The radiation detector according to claim 1 or 2 . The element is greater than the thickness of the radiation shielding plate included in the collimator.
The radiation detector according to claim 3 or 6. The element is an ADC (Analog to Digital Converter), an AFE (Analog Front End), an amplifier circuit, or an integrator circuit.
The radiation detector according to any one of claims 1 to 7. A radiation detector according to any one of claims 1 to 8,
and a generating unit that generates data corresponding to positions at which the elements are arranged.

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