Information processing apparatus, information processing method, and program

Abstract

To provide an information processing apparatus capable of reducing the data amount of image data to be stored in a storage unit of the information processing apparatus.SOLUTION: The information processing apparatus includes: an image acquisition unit 110 which acquires material discrimination image data based on detection signals related to X-ray photons transmitted through a subject in each of a plurality of energy bands; a region of interest acquisition unit 111 which acquires a region of interest in the material discrimination image data; a data processing unit 112 which generates partial image data of the material discrimination image data corresponding to the region of interest; and a storage unit 113 which stores the partial image data of the material discrimination image data.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an information processing apparatus, an information processing method, and a program for managing image data acquired from a medical imaging apparatus. [Background technology]

[0002] Dual-energy CT (Computed Tomography) devices irradiate X-rays with two different energies separately, and use the difference in brightness between the two images to generate material-decomposed image data with voxel values ​​corresponding to the densities of multiple materials assumed to be contained in the subject.

[0003] Furthermore, the X-ray CT apparatus generates material decomposition image data for each energy band of a plurality of materials by utilizing a detection signal based on the number of X-ray photons (number of photons) passing through the subject for each energy band. Patent Document 1 discloses a technique for generating composite image data in which a plurality of material densities are combined in one image from a plurality of material decomposition image data in an X-ray CT apparatus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-72082 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, for example, a plurality of material decomposition image data are necessary to generate composite image data, and a plurality of image data must be stored in a storage unit of an information processing device.

[0006] Therefore, the present invention aims to reduce the amount of image data stored in a storage unit of an information processing device. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0007] In order to achieve the object of the present invention, the present invention includes an image acquisition unit that acquires material decomposition image data based on detection signals related to X-ray photons in each of a plurality of energy bands that transmit through a subject, a region of interest acquisition unit that acquires a region of interest in the material decomposition image data, a data processing unit that generates partial image data of the material decomposition image data that corresponds to the region of interest, and a storage unit that stores the partial image data of the material decomposition image data. Effect of the Invention

[0008] According to the present invention, it is possible to reduce the amount of image data stored in the storage unit of the information processing device. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a medical imaging apparatus (X-ray CT apparatus) according to the present invention. [Diagram 2] FIG. 1 is a diagram showing an example of the configuration of an information processing device according to the present invention. [Diagram 3] FIG. 1 is a diagram showing an example of the configuration of an information processing device according to the present invention. [Figure 4] 4 is a flowchart showing an example of the operation of the information processing device of the present invention. [Diagram 5] FIG. 4 is a diagram showing obtaining a region of interest mask according to the present invention. [Figure 6] FIG. 13 illustrates obtaining a synthetic region of interest mask of the present invention. [Figure 7] FIG. 13 illustrates obtaining a synthetic region of interest mask of the present invention. [Figure 8] FIG. 4 is a diagram showing obtaining a region of interest mask according to the present invention. [Figure 9]FIG. 4 is a diagram showing an example of a data reduction process according to the present invention. [Figure 10] FIG. 4 is a diagram showing an example of a data reduction process according to the present invention. [Figure 11] FIG. 2 is a diagram showing storage objects to be stored in a storage unit of the present invention. [Figure 12] FIG. 2 is a diagram showing storage objects to be stored in a storage unit of the present invention. [Figure 13] 4 is a flowchart showing an example of the operation of the information processing device of the present invention. [Figure 14] FIG. 1 is a diagram showing one display mode of a display device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an information processing device, an information processing method, and a program according to an embodiment will be described with reference to the drawings. Note that parts with the same reference numerals perform the same operations, and redundant explanations will be omitted as appropriate. Hereinafter, an embodiment will be described with reference to the drawings.

[0011] [First embodiment] A first embodiment of the present invention will be described with reference to Figs. 1 to 10. An example of the configuration of a medical imaging apparatus (X-ray CT apparatus) according to the first embodiment will be described with reference to Fig. 1. The medical imaging apparatus 1 shown in Fig. 1 includes a gantry 10, a bed apparatus 30, and a console apparatus 40. In this embodiment, the rotation axis of the rotating frame 13 in a non-tilted state or the longitudinal direction of the top plate 33 of the bed apparatus 30 is defined as the Z-axis direction. Also, the axial direction perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction, and the axial direction perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction.

[0012] For example, the gantry device 10 and the bed device 30 are installed in a CT examination room, and the console device 40 is installed in a control room adjacent to the CT examination room. The console device 40 does not necessarily have to be installed in the control room. For example, the console device 40 may be installed in the same room as the gantry device 10 and the bed device 30. In any case, the gantry device 10, the bed device 30, and the console device 40 are connected to each other by wire or wirelessly so that they can communicate with each other.

[0013] The gantry device 10 is a scanning device having a configuration for performing X-ray CT imaging of a subject P. The gantry device 10 includes an X-ray tube 11, a detector 12, a rotating frame 13, an X-ray high voltage device 14, a control device 15, a wedge 16, a collimator 17, and a data acquisition device 18 (hereinafter also referred to as a DAS (Data Acquisition System)). For convenience of explanation, only a part of the configuration is shown here.

[0014] The X-ray tube 11 is a vacuum tube that generates X-rays by irradiating thermoelectrons from a cathode (filament) to an anode (target) by application of a high voltage from the X-ray high voltage device 14 and supply of a filament current. Specifically, X-rays are generated by the thermoelectrons colliding with the target. For example, the X-ray tube 11 includes a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons. The X-rays generated by the X-ray tube 11 are formed into a cone beam shape via a collimator 17, for example, and irradiated to the subject P. The X-ray tube 11 is an example of an X-ray generating unit.

[0015] The detector 12 detects X-rays irradiated from the X-ray tube 11 and transmitted through the subject P, and outputs a signal corresponding to the X-ray dose to the DAS 18. The detector 12 has, for example, a plurality of X-ray detection element rows in which a plurality of X-ray detection elements are arranged in the channel direction along one arc centered on the focal point of the X-ray tube 11. The detector 12 has, for example, a row structure in which a plurality of X-ray detection element rows in which a plurality of X-ray detection elements are arranged in the channel direction are arranged in the slice direction (row direction). The detector 12 is a photon-counting detector. The reconstruction processing unit can also reconstruct integral image data (CT image data) with a high S / N ratio by counting photons of the X-rays transmitted through the subject P using the photon-counting detector.

[0016] The detector 12 can be classified into an energy integration function and a photon counting function according to the measurement method performed by the DAS 18 on the converted signal. In the energy integration function, the energy of the X-rays transmitted through the subject P is integrated over a certain period of time to measure the total energy of the X-rays transmitted over a certain period of time. In the photon counting function, the number of X-ray photons contained in the X-rays transmitted through the subject P is measured by dividing them into multiple energy bands (also called energy bins or simply bins). This makes it possible to perform material fractionation based on the imaging data obtained for each energy band. Here, the imaging mode when material fractionation is performed is called the material fractionation mode (material decomposition image data mode), and the imaging mode when material fractionation is not performed is called the non-material decomposition mode (integrated image data mode).

[0017] The rotating frame 13 supports the X-ray generating unit and the X-ray detecting unit rotatably around a rotation axis Z. Specifically, the rotating frame 13 is an annular frame that supports the X-ray tube 11 and the detector 12 facing each other and rotates the X-ray tube 11 and the detector 12 by a control device 15. The rotating frame 13 is rotatably supported by a fixed frame (not shown) made of a metal such as aluminum. More specifically, the rotating frame 13 is connected to an edge of the fixed frame via a bearing. The rotating frame 13 receives power from a drive mechanism of the control device 15 and rotates around the rotation axis Z at a constant angular velocity.

[0018] The rotating frame 13 further includes and supports an X-ray high voltage device 14 and a DAS 18 in addition to the X-ray tube 11 and the detector 12. The rotating frame 13 is housed in a substantially cylindrical housing in which an opening (bore) 19 that forms an imaging space is formed. The opening substantially coincides with the FOV. The central axis of the opening coincides with the rotation axis Z of the rotating frame 13. The imaging data generated by the DAS 18 is transmitted from a transmitter having, for example, a light emitting diode (LED) to a receiver (not shown) having a photodiode. The transmission process is performed by optical communication with a photodiode provided in a non-rotating part (fixed frame) of the gantry device 10. The data is then transferred from the receiver to the console device 40.

[0019] The method of transmitting imaging data from the rotating frame 13 to the non-rotating portion of the gantry device 10 is not limited to optical communication, and any method of non-contact data transmission may be used.

[0020] The X-ray high voltage device 14 has electric circuits such as a transformer and a rectifier, and also has a high voltage generator having a function of generating a high voltage to be applied to the X-ray tube 11 and a filament current to be supplied to the X-ray tube 11. Furthermore, it has an X-ray control device that controls the output voltage according to the X-rays irradiated by the X-ray tube 11.

[0021] The control device 15 has a processing circuit having a CPU (Central Processing Unit) and the like, and a driving mechanism for a motor, an actuator, and the like. The processing circuit has a processor such as a CPU or an MPU (Micro Processing Unit) and a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory) as hardware resources. The control device 15 controls the X-ray high voltage device 14, the DAS 18, and the like according to commands from the console device 40. The processor realizes the above control by reading and executing a program stored in the memory.

[0022] 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 (wedge filter, bow-tie filter) is a filter made of processed aluminum so as to have a predetermined target angle and a predetermined thickness.

[0023] The collimator 17 is a lead plate or the like for narrowing down the irradiation range of the X-rays transmitted through the wedge 16, and a slit is formed by combining a plurality of lead plates or the like. The collimator 17 may also be called an X-ray aperture.

[0024] The DAS 18 generates digital data (also called imaging data) indicating the count value of X-ray photons detected by the detector 12 for each of a plurality of energy bands. The imaging data is a set of count value data identified by the channel number of the X-ray detection element that generated the data, the row number, the view number indicating the collected view (projection angle), and the energy bin number. The imaging data is transferred to the console device 40.

[0025] The bed device 30 is a device for placing and moving a subject P to be scanned, and includes a base 31, a bed driving device 32, a top board 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.

[0026] The bed driving device 32 is a motor or actuator that moves the top board 33, on which the subject P is placed, in the longitudinal direction of the top board 33. The top board 33, which is provided on the upper surface of a support frame 34, is a plate on which the subject P is placed. The bed driving device 32 may move the support frame 34 in the longitudinal direction of the top board 33 in addition to the top board 33.

[0027] The console device 40 has a memory 41, a display unit 42, an operation unit 43, and a processing circuit 44. Data communication between the memory 41, the display unit 42, the operation unit 43, and the processing circuit 44 is performed via a bus. Note that, although the console device 40 will be described as being separate from the gantry device 10, the gantry device 10 may include the console device 40 or some of the components of the console device 40.

[0028] The memory 41 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit storage device that stores various information. The memory 41 stores, for example, imaging data, integral image data, and material decomposition image data. In addition to an HDD or an SSD, the memory 41 may be a drive device that reads and writes various information between a portable storage medium such as a CD (Compact Disc), a DVD (Digital Versatile Disc), or a flash memory, or a semiconductor memory element such as a RAM (Random Access Memory). The memory 41 may be located within the medical image pickup apparatus 1 or may be located within an external storage device connected via a network. The memory 41 stores a control program according to the embodiment.

[0029] The display unit 42 displays various information. For example, the display unit 42 outputs image data (CT image data) generated by the processing circuit 44 and a GUI (Graphical User Interface) for receiving various operations from an operator. For example, a liquid crystal display (LCD), a cathode ray tube (CRT), an organic electroluminescence display (OELD), a plasma display, or any other display unit can be used as appropriate as the display unit 42. The display unit 42 may be provided on the gantry device 10. The display unit 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.

[0030] The operation unit 43 receives various input operations from the operator, converts the received input operations into electrical signals, and outputs the electrical signals to the processing circuitry 44. For example, the operation unit 43 receives from the operator collection conditions for collecting imaging data, reconstruction conditions for reconstructing CT image data, image processing conditions for generating post-processed images from CT image data, and the like. As the operation unit 43, for example, a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touchpad, a touch panel display unit, and the like can be used as appropriate. In the embodiment, the operation unit 43 is not limited to a device having physical operation parts such as a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touchpad, and a touch panel display unit. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs the electrical signal to the processing circuitry 44 is also included in the example of the operation unit 43. The operation unit 43 may be provided in the gantry device 10. The operation unit 43 may also be configured with a tablet terminal or the like capable of wireless communication with the console device 40 main body.

[0031] The processing circuitry 44 controls the operation of the entire medical imaging apparatus 1 in response to an electrical signal of an input operation output from the operation unit 43. For example, the processing circuitry 44 has a processor such as a CPU, MPU, or GPU (Graphics Processing Unit) and a memory such as a ROM or RAM as hardware resources. The processing circuitry 44 executes a control unit 441, a reconstruction processing unit 442, an image analysis unit 443, and a display control unit 443 by a processor that executes a program expanded in the memory. Note that each function (the control unit 441, the reconstruction processing unit 442, and the display control unit 443) is not limited to being realized by a single processing circuit. A processing circuit may be configured by combining multiple independent processors, and each processor may execute a program to realize each function.

[0032] The control unit 441 controls each function of the processing circuit 44 based on an input operation received from an operator via the operation unit 43. Specifically, the control unit 441 reads out a control program stored in the memory 41, expands it on the memory in the processing circuit 44, and controls each unit of the medical image pickup device 1 according to the expanded control program. In addition, the control unit 441 generates imaging data by performing pre-processing such as logarithmic conversion processing, offset correction processing, sensitivity correction processing between channels, and beam hardening correction on the imaging data output from the DAS 18.

[0033] The reconstruction processing unit 442 has a function of generating CT image data based on the imaging data output by the detector 12 (DAS 18). The reconstruction processing unit 442 reconstructs CT image data by, for example, backprojection processing of the imaging data stored in the memory circuitry 35. An example of the backprojection processing is backprojection processing by a Filtered Back Projection (FBP) method. The reconstruction processing unit 442 may perform the reconstruction processing by, for example, an iterative approximation method. The reconstruction processing unit 442 also generates CT image data by performing various image processing on the CT image data. The reconstruction processing unit 442 stores the reconstructed CT image data and the CT image data generated by various image processing in the memory 41.

[0034] The reconstruction processor 442 also calculates energy integral data by the sum of the counts (total value) of each energy bin, which is a signal obtained by the photon-counting detector 12, or the sum of the products of the representative values ​​of the energy bins and the counts. The reconstruction processor 442 can also reconstruct integral image data by using the energy integral data. The integral image data is treated as CT image data.

[0035] Furthermore, as an application of the photon-counting medical imaging apparatus 1, there is a technique for discriminating the type, abundance, density, etc. of the material contained in the subject P by utilizing the fact that each material has different X-ray absorption characteristics. This is called material decomposition. For example, the reconstruction processing unit 442 can perform material decomposition on the imaging data and obtain material decomposition information. Furthermore, the reconstruction processing unit 442 can reconstruct material decomposition image data indicating the material decomposition using the material decomposition information that is the result of the material decomposition.

[0036] For example, imaging data generated from counting results obtained by the photon-counting medical imaging device 1 contains information on the energy spectrum of X-rays attenuated by passing through the subject P. Therefore, the reconstruction processing unit 442 can reconstruct material decomposition image data in which, for example, a specific energy component is visualized.

[0037] The display control unit 443 causes the integral image data (CT image data) and the material decomposition image data to be displayed on the display unit 42. Either the integral image data (CT image data) or the material decomposition image data may be selected and displayed on the display unit 42.

[0038] Next, a first embodiment will be described with reference to Fig. 2. The present invention can be applied to an information processing device 100 connected to a medical imaging device 1, as well as to a workstation, an image interpretation terminal viewer, and the like. The medical imaging device 1 includes, for example, an X-ray CT device using a photon counting detector, and an X-ray CT device using a dual energy detector.

[0039] Here, when material decomposition image data (material density image data) obtained by imaging a subject with an X-ray CT device is stored in the memory unit 113 of the information processing device 100, a form of reducing the amount of image data stored in the memory unit 113 of the information processing device 100 is described.

[0040] The information processing device 100 acquires a plurality of material decomposition image data generated from a detection signal based on the number of detections of X-ray photons in each of a plurality of energy bands that transmit through a subject. Then, the information processing device 100 acquires a region of interest in each of the plurality of material decomposition image data, and stores in the storage unit 113 partial image data corresponding to the region of interest in each of the plurality of material decomposition image data.

[0041] The materials of the material decomposition image data are, for example, calcium, iodine, and water, but are not limited thereto and may be any material such as tungsten, titanium, etc. The energy bands are, for example, four energy bands of 20-40, 40-60, 60-80, and 80-100 (keV), which are set in advance in the medical imaging apparatus 1. Note that the number and range of energy bands are not limited to those described above.

[0042] 2 shows the configuration of an information processing device 100 according to the first embodiment. The information processing device 100 has an image acquisition unit 110, a region of interest acquisition unit 111, a data processing unit 112, a storage unit 113, and a display control unit 114. The information processing device 100 is connected to a medical imaging device 1 (X-ray CT device) via a network.

[0043] The information processing device 100 has an image acquisition unit 110 that acquires material decomposition image data from the medical imaging device 1, and a region of interest acquisition unit 111 that acquires a region of interest in the material decomposition image data. The information processing device 100 also has a data processing unit 112 that reduces the amount of data of the material decomposition image data based on the region of interest, and a storage unit 113 that stores the material decomposition image data with the reduced amount of data.

[0044] The image acquisition unit 110 acquires material decomposition image data from the medical imaging device 1. The image acquisition unit 110 can acquire data required to generate material decomposition image data of a plurality of energy bands from the medical imaging device 1, and can acquire imaging data indicating count values ​​of X-ray photons for each of a plurality of energy bands, for example. The image acquisition unit 110 may also acquire integral image data (CT image data), virtual monochromatic X-ray image data corresponding to virtual single energy imaging, X-ray image data for each energy band, and the like from the medical imaging device 1. The image acquisition unit 110 transmits the material decomposition image data, integral image data (CT image data), virtual monochromatic X-ray image data, X-ray image data for each energy band, and the like to the region of interest acquisition unit 111 and the data processing unit 112.

[0045] The region of interest acquisition unit 111 acquires a region of interest using the material decomposition image data transmitted from the image acquisition unit 110. The region of interest acquisition unit 111 acquires a region in which a predetermined material exists as a region of interest in the material decomposition image data. The region of interest acquisition unit 111 acquires a region in which each material exists as a region of interest in a plurality of material decomposition image data. The region of interest acquisition unit 111 acquires, for example, a region of interest mask (1 is set within the region of interest and 0 is set outside the region of interest) for the region of interest in the material decomposition image data, and transmits it to the data processing unit 112. Details of the processing will be described later. The region of interest acquisition unit 111 has a function of setting a region of interest mask.

[0046] The data processing unit 112 acquires partial image data corresponding to the region of interest in the material decomposition image data transmitted from the image acquisition unit 110, based on the region of interest mask acquired by the region of interest acquisition unit 111. The data processing unit 112 transmits the partial image data to the storage unit 113. The amount of data of the partial image data is smaller than the amount of data of the entire material decomposition image data. The data processing unit 112 may further acquire coordinate information of the partial image data in the material decomposition image data. Details of the processing will be described later.

[0047] The storage unit 113 stores partial image data corresponding to the region of interest of the material decomposition image data transmitted from the data processing unit 112. When coordinate information is transmitted from the data processing unit 112, the storage unit 113 stores the coordinate information in association with the partial image data. By storing the coordinate information together with the partial image data, it is possible to reduce the effort required for subsequent confirmation work. A display device 136 such as a display and an operation device 137 such as a mouse and a keyboard are connected to the information processing device 100. A display control unit 114 can control the display form of the display device 136.

[0048] The information processing device 100 is configured by a computer including a processor, a memory, a storage, and the like. In this case, a program stored in the storage is loaded into the memory, and the processor executes the program, thereby realizing the functions and processing of the image acquisition unit 110, the attention area acquisition unit 111, the data processing unit 112, the storage unit 113, and the like. However, this configuration is not limited to this, and for example, all or a part of the image acquisition unit 110, the attention area acquisition unit 111, the data processing unit 112, and the storage unit 113 may be realized by a dedicated processor (such as ASIC) or FPGA. Alternatively, a part of the arithmetic processing may be executed by a processor such as a GPU or DSP. In addition, the information processing device 100 may be configured by a single piece of hardware, or may be configured by multiple pieces of hardware. For example, the functions and processing of the information processing device 100 may be realized by multiple computers working together using cloud computing or distributed computing.

[0049] 3 shows an example of the configuration of the information processing device 100. In this example, the information processing device 100 has a CPU 130, a GPU 131, a RAM 132, a ROM 133, and a storage unit 113, which are connected by a system bus 135. In addition, a display device 136 such as a display and an operation device 137 such as a mouse and a keyboard are connected to the information processing device 100. The display device 136 has the same configuration as the display unit 42 described above. The operation device 137 has the same configuration as the operation unit 43 described above.

[0050] Next, the operation of the information processing device 100 will be described with reference to the flowchart of FIG.

[0051] (Step S40: Acquiring data) In step S40, the image acquisition unit 110 acquires material decomposition image data for each of a plurality of energy bands from the medical imaging device 1. The image acquisition unit 110 transmits the material decomposition image data to the region of interest acquisition unit 111 and the data processing unit 112. The image acquisition unit 110 may acquire integral image data (CT image data) or the like from the medical imaging device 1.

[0052] (Step S41: Obtaining an area of ​​interest) In step S41, the attention region acquisition unit 111 sets and acquires an attention region mask for the attention region in each of the material decomposition image data from the plurality of material decomposition image data. Then, the attention region acquisition unit 111 transmits the attention region mask corresponding to each material to the data processing unit 112.

[0053] The region-of-interest acquisition unit 111 will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining acquisition of a region-of-interest mask corresponding to a region of interest in material decomposition image data.

[0054] 5(a) shows multiple material decomposition image data for multiple energy bands. Here, material decomposition image data of calcium, iodine, and water will be used for explanation, but material decomposition image data of materials other than calcium, iodine, and water may be used.

[0055] The region of interest acquisition unit 111 acquires a region of interest for each material decomposition image data and sets a region of interest mask. The region of interest acquisition unit 111 sets a threshold value for a predetermined physical quantity for each material decomposition image data and acquires a region equal to or greater than the threshold as a region of interest. For example, the region of interest acquisition unit 111 sets a threshold value for a material density or a pixel value for each material decomposition image data and acquires a region equal to or greater than the threshold as a region of interest. The region of interest acquisition unit 111 sets a threshold value, for example, half of the maximum possible material density, for each material decomposition image data and acquires a region equal to or greater than the threshold as a region of interest. Then, the region of interest acquisition unit 111 sets a region of interest mask for a region equal to or greater than the threshold of each material decomposition image data.

[0056] The attention region acquiring unit 111 sets a threshold value for material density in the material decomposition image data of calcium, for example, and acquires a region equal to or greater than the threshold value as an attention region. Then, the attention region acquiring unit 111 sets an attention region mask for a region equal to or greater than the threshold value in the material decomposition image data of calcium. Also, the attention region acquiring unit 111 sets a threshold value for material density in the material decomposition image data of iodine, for example, and acquires a region equal to or greater than the threshold value as an attention region. Then, the attention region acquiring unit 111 sets an attention region mask for a region equal to or greater than the threshold value in the material decomposition image data of iodine. Note that the attention region mask for water is set in the same manner as above.

[0057] Furthermore, the attention region acquiring unit 111 can set, for example, a predetermined pixel value as a threshold in each material decomposition image data, and acquire a region having a pixel value equal to or greater than the predetermined pixel value as an attention region. Then, the attention region acquiring unit 111 sets an attention region mask for each material decomposition image data.

[0058] The attention region acquisition unit 111 sets a threshold corresponding to a predetermined pixel value in the material decomposition image data of calcium, for example, and acquires a region having a pixel value equal to or greater than the threshold as an attention region. Then, the attention region acquisition unit 111 sets an attention region mask for a region having a pixel value equal to or greater than the threshold in the material decomposition image data of calcium. Also, the attention region acquisition unit 111 sets a threshold corresponding to a predetermined pixel value in the material decomposition image data of iodine, for example, and acquires a region having a pixel value equal to or greater than the threshold as an attention region. Then, the attention region acquisition unit 111 sets an attention region mask for a region having a pixel value equal to or greater than the threshold in the material decomposition image data of iodine. Note that the attention region mask for water is set in the same manner as above.

[0059] Fig. 5(b) shows the region of interest mask in each material decomposition image data. The region of interest mask is indicated by hatching. The inside of the region of interest is set to 1, and the outside of the region of interest is set to 0.

[0060] Here, in the calcium material decomposition image data, a region where calcium is extracted at a predetermined value or more is set as a region of interest mask.In the iodine material decomposition image data, a region where iodine is extracted at a predetermined value or more is set as a region of interest mask.In the water material decomposition image data, a region where water is extracted at a predetermined value or more is set as a region of interest mask.

[0061] In addition to the above-mentioned method using a threshold value, any method for extracting a region of interest from material decomposition image data may be used for the region of interest mask. For example, a region extraction method based on deep learning may be used.

[0062] In the region extraction method based on deep learning, the attention region acquisition unit 111 uses, for example, a neural network (trained model) that performs a segmentation task. The attention region acquisition unit 111 acquires teacher data that pairs material decomposition image data with a correct answer label that is a label indicating a material target reflected in the material decomposition image data. Specifically, the attention region acquisition unit 111 acquires teacher data that pairs position information of a pixel of a material target reflected in the material decomposition image data with a correct answer image to which a correct answer label that is a label indicating a material target is added. The attention region acquisition unit 111 performs inference on each material decomposition image data using the trained model, and acquires the attention region.

[0063] The attention region acquisition unit 111 uses the trained model to acquire, as an attention region, a region inferred (segmented) as calcium from the material decomposition image data of calcium, and sets an attention region mask. The attention region acquisition unit 111 uses the trained model to acquire, as an attention region, a region inferred (segmented) as iodine from the material decomposition image data of iodine, and sets an attention region mask. The attention region acquisition unit 111 uses the trained model to acquire, as an attention region, a region inferred (segmented) as water from the material decomposition image data of water, and sets an attention region mask.

[0064] The attention area mask may be in a form other than an image. For example, it may be expressed by the coordinates of a group of points representing the boundary of the attention area. The information representing the attention area may be in a form other than the attention area mask, and may be, for example, image data (likelihood image data) in which the likelihood of the attention area is set for each pixel (for example, with a value of 0 to 1). The likelihood may be set to a value of 0 to 1 within the attention area, and 0 may be set outside the attention area. The attention area does not need to be an area that accurately represents the shape of the real object of interest, and may be a shape that represents the general shape of the real object. For example, it may be an area that has a shape that surrounds the real object, or a shape such as an ellipse or a rectangle.

[0065] Here, the region of interest obtaining section 111 obtains a region of interest in each of the material decomposition image data, and does not need to set a region of interest mask.

[0066] 6A and 6B are diagrams for explaining how to obtain a composite region-of-interest mask in composite image data obtained by combining a plurality of material decomposition image data. Fig. 6A shows a plurality of material decomposition image data for each of a plurality of energy bands, and composite image data obtained by combining the plurality of material decomposition image data.

[0067] The region of interest acquisition unit 111 generates composite image data from a plurality of material decomposition image data by a known method. The region of interest acquisition unit 111 aligns the plurality of material decomposition image data and synthesizes the plurality of material decomposition image data to generate composite image data. The region of interest acquisition unit 111 acquires a composite region of interest mask by performing threshold processing on the synthetic image data.

[0068] The region of interest acquisition unit 111 acquires a region of interest for composite image data obtained by combining a plurality of material decomposition image data, and sets a composite region of interest mask. The region of interest acquisition unit 111 sets a threshold value for a predetermined physical quantity (material density or pixel value) for the composite image data, and acquires a region equal to or greater than the threshold value as a composite region of interest. The region of interest acquisition unit 111 sets a threshold value, for example, half of the maximum possible material density, for the composite image data, and acquires a region equal to or greater than the threshold value as a composite region of interest. Then, the region of interest acquisition unit 111 sets a composite region of interest mask for the composite image data. The region of interest acquisition unit 111 can also set a threshold value corresponding to a predetermined pixel value for the composite image data, and acquire a region equal to or greater than the threshold value as a composite region of interest.

[0069] The data processing unit 112 generates partial image data of the composite image data based on the composite attention region mask, and the storage unit 113 stores the partial image data corresponding to the composite attention region in the composite image data.

[0070] Fig. 6(b) shows a composite attention area mask in the composite image data obtained by combining multiple material decomposition image data. The composite attention area mask is shown by hatching. The inside of the composite attention area is set to 1, and the outside of the composite attention area is set to 0.

[0071] Furthermore, the region of interest acquisition unit 111 may acquire region of interest masks from a plurality of material decomposition image data, and set a composite region of interest mask by combining the respective region of interest masks.

[0072] Acquisition of a composite region of interest mask will be described with reference to Fig. 7. Fig. 7(a) shows a plurality of material decomposition image data for each of a plurality of energy bands. Fig. 7(b) shows a region of interest mask for each material decomposition image data and a composite region of interest mask obtained by combining the plurality of region of interest masks.

[0073] 5, the attention region acquiring unit 111 acquires an attention region for each material decomposition image data. The attention region acquiring unit 111 sets a threshold value for a predetermined physical quantity (material density or pixel value) for each material decomposition image data, and acquires a region equal to or greater than the threshold value as an attention region. Then, the attention region acquiring unit 111 sets an attention region mask for each material decomposition image data.

[0074] The attention region acquisition unit 111 aligns the attention region masks in the material decomposition image data and synthesizes the attention region masks. Then, the attention region acquisition unit 111 sets a composite attention region mask by synthesizing the attention region masks. It is assumed that 1 is set within the composite attention region and 0 is set outside the composite attention region.

[0075] Fig. 8 is a diagram for explaining how to obtain a synthetic region of interest in synthetic image data obtained by synthesizing a plurality of material decomposition image data, and how to obtain a region of interest in a plurality of material decomposition image data. Fig. 8(a) shows a plurality of material decomposition image data for each of a plurality of energy bands, and synthetic image data obtained by synthesizing a plurality of material decomposition image data. Fig. 8(b) shows a synthetic region of interest mask and a region of interest mask for each material. Note that the process up to setting the synthetic region of interest mask is the same as Fig. 6, and therefore a description thereof will be omitted.

[0076] The region of interest acquisition unit 111 sets a region of interest mask for each material from the position information of the composite region of interest mask. For example, in the material decomposition image data of calcium, the region of interest acquisition unit 111 acquires the region of interest of calcium from position information of where calcium exists and position information of the composite region of interest mask. The region of interest acquisition unit 111 acquires a region where the position where calcium exists and the position of the composite region of interest mask overlap as the region of interest of calcium. Then, the region of interest acquisition unit 111 sets a region of interest mask for the region of interest of calcium.

[0077] For example, the attention region acquisition unit 111 acquires an attention region of iodine from position information of iodine existing in the material decomposition image data of iodine and position information of a composite attention region mask. The attention region acquisition unit 111 acquires an area where the position of iodine existing overlaps with the position of a composite attention region mask as an attention region of iodine. Then, the attention region acquisition unit 111 sets an attention region mask for the attention region of iodine. Note that the attention region mask of water is set in the same manner as above.

[0078] Fig. 8(b) shows the region of interest mask for each material decomposition image data. The inside of the region of interest is set to 1, and the outside of the region of interest is set to 0.

[0079] The attention region acquisition unit 111 may perform a smoothing process on the attention region mask, an opening process, a closing process, or other image processing.

[0080] The smoothing process is a process for reducing the difference between adjacent pixel values ​​of image data showing an attention area mask, thereby forming a collection of smoothly connected data, and can reduce singularities and noise. The opening process is a process for performing contraction processing multiple times on image data showing an attention area mask, followed by expansion processing, and can reduce noise, etc. The closing process is a process for performing contraction processing multiple times on image data showing an attention area mask, followed by expansion processing, and can reduce noise, etc.

[0081] (Step S42: Reducing the amount of data) In step S42, the data processing unit 112 reflects the region of interest mask acquired by the region of interest acquisition unit 111 in the material decomposition image data to reduce the amount of data. The data processing unit 112 acquires partial image data within the region of interest of the material decomposition image data, and deletes image data of regions outside the region of interest of the material decomposition image data. Since the regions outside the region of interest of the material decomposition image data are deleted, the amount of data is reduced.

[0082] The data processing unit 112, for example, sets a storage area including the region of interest represented by the region of interest mask, and generates partial image data by cutting out the storage area. Then, the data processing unit 112 transmits the partial image data (including coordinate information of the storage area) of the material decomposition image data to the storage unit 113. Note that the storage area may be an area circumscribing the region of interest, or an area with a predetermined offset added to the periphery of the region of interest. Here, when the region of interest is acquired as a likelihood image in step S41, the data processing unit 112 may set a storage area including an area where the likelihood exceeds a predetermined value, and generate partial image data by cutting out the storage area.

[0083] Fig. 9 is a diagram for explaining an example of the data reduction process in the data processing unit 112. Fig. 9(a) is a diagram showing an attention area mask 200. Fig. 9(b) is a diagram showing a storage area in the material decomposition image data. Fig. 9(c) is a diagram showing partial image data stored in the storage unit 113. Note that the data processing unit 112 may further acquire coordinate information of the partial image data.

[0084] 9(a), the attention region acquiring unit 111 acquires a region of interest in the material decomposition image data of calcium, and sets an attention region mask 200 in the material decomposition image data of calcium. The attention region acquiring unit 111 acquires a region of interest in the material decomposition image data of iodine, and sets an attention region mask 201 in the material decomposition image data of iodine. Similarly, the attention region acquiring unit 111 acquires a region of interest in the material decomposition image data of water, and sets an attention region mask 202 in the material decomposition image data of water.

[0085] As shown in FIG. 9(b), the data processing unit 112 sets a storage area including the attention area represented by the attention area mask, and generates partial image data by cutting out the storage area. The data processing unit 112 sets a storage area 210 including the attention area mask 200 set in the material decomposition image data of calcium. Here, the data processing unit 112 sets a rectangular storage area 210 including the attention area mask 200. The data processing unit 112 sets a storage area 211 including the attention area mask 201 set in the material decomposition image data of iodine. Here, the data processing unit 112 sets a rectangular storage area 211 including the attention area mask 201. Similarly, the data processing unit 112 sets a storage area 212 including the attention area mask 202 set in the material decomposition image data of water. Here, the data processing unit 112 sets a rectangular storage area 212 including the attention area mask 202. The storage area may include coordinate information.

[0086] As shown in FIG. 9(c), the data processing unit 112 generates partial image data 220 by cutting out the memory area 210 from the material decomposition image data of calcium. The data processing unit 112 transmits the partial image data 220 (including coordinate information in the material decomposition image data) in the material decomposition image data of calcium to the storage unit 113. The data processing unit 112 generates partial image data 221 by cutting out the memory area 211 from the material decomposition image data of iodine. The data processing unit 112 transmits the partial image data 221 (including coordinate information in the material decomposition image data) in the material decomposition image data of iodine to the storage unit 113. Similarly, the data processing unit 112 generates partial image data 222 by cutting out the memory area 212 from the material decomposition image data of water. The data processing unit 112 transmits the partial image data 222 (including coordinate information in the material decomposition image data) in the material decomposition image data of water to the storage unit 113.

[0087] In this embodiment, the region of interest specified in each of the plurality of material decomposition image data is stored. Note that the region of interest of the material decomposition image data may be different for each material decomposition image data.

[0088] When there are multiple regions of interest in the material decomposition image data, one storage area may be set to include (combine) all the regions of interest, or a storage area may be set for each region of interest that includes the region of interest.Also, adjacent regions of interest may be grouped together, and a storage area may be set for each group.

[0089] Fig. 10 is a diagram for explaining an example of the data reduction process in the data processing unit 112. Fig. 10(a) is a diagram showing a plurality of attention area masks 250, 251 in the combined image data of the material decomposition image data. Fig. 10(b) is a diagram showing a storage area 260 in the combined image data of the material decomposition image data. Fig. 10(c) is a diagram showing partial image data 270 stored in the storage unit 113.

[0090] As shown in FIG. 10A, the attention region acquisition unit 111 acquires an attention region in the combined image data of a plurality of material decomposition image data, and sets a plurality of attention region masks 250 and 251 in the combined image data.

[0091] 10(b), the data processing unit 112 sets a memory area 260 containing the region of interest represented by the multiple region of interest masks 250, 251. Then, the data processing unit 112 generates partial image data 270 by cutting out the memory area 260 from the composite image data of the multiple material decomposition image data. Here, the data processing unit 112 sets a rectangular memory area 260 containing the multiple region of interest masks 250, 251.

[0092] 10(c), the data processing unit 112 generates partial image data 270 by cutting out the memory area 260 from the composite image data of the plurality of material decomposition image data. The data processing unit 112 transmits the partial image data 270 (including coordinate information in the material decomposition image data) in the composite image data to the storage unit 113.

[0093] The storage area is not limited to a rectangle, but may be a predetermined shape such as a circle or ellipse that contains the area of ​​interest, or any other shape. In any case, the partial image data can be expressed by information representing the shape of the area and vector data that represents the pixel values ​​of each pixel in the shape as a one-dimensional array.

[0094] Here, when the storage area has a predetermined shape, parameters representing the shape, such as the center position and the radius, correspond to the information representing the shape of the area. Also, when the storage area has an indefinite shape, information such as a mask representing the shape corresponds to the information representing the shape of the area. In the latter case, the attention area mask can be used as it is as the information representing the shape of the storage area. That is, the data processing unit 112 can use the attention area as it is as the storage area.

[0095] (Step S43: Storing data) In step S43, the storage unit 113 stores (saves) the partial image data of the material decomposition image data acquired from the data processing unit 112.

[0096] The storage unit 113 stores partial image data of the material decomposition image data for each material. As shown in Fig. 9, the storage unit 113 stores partial image data 220 in the material decomposition image data of calcium. The storage unit 113 stores partial image data 221 in the material decomposition image data of iodine. The storage unit 113 stores partial image data 222 in the material decomposition image data of water.

[0097] Furthermore, as shown in FIG. 10, the storage unit 113 can also store partial image data 270 cut out from a storage area 260 of the combined image data of a plurality of material decomposition image data.

[0098] The information processing device 100 can read out partial image data of the material decomposition image data from the storage unit 113, and the display control unit 114 can display the partial image data of the material decomposition image data on the display device 136. When the user issues an instruction using the operation device 137 to display the material decomposition image data of the identified target material, the partial image data of the material decomposition image data of the identified target material is read out from the storage unit 113. The display control unit 114 can display the partial image data of the material decomposition image data of the identified target material on the display device 136.

[0099] For example, when a user issues an instruction using the operation device 137 to display the material decomposition image data of calcium, partial image data of the material decomposition image data of calcium is read from the storage unit 113. The display control unit 114 can display the partial image data of the material decomposition image data of calcium on the display device 136. When a user issues an instruction using the operation device 137 to display the material decomposition image data of iodine, partial image data of the material decomposition image data of iodine is read from the storage unit 113. The display control unit 114 can display the partial image data of the material decomposition image data of iodine on the display device 136. The partial image data of the material decomposition image data of water is displayed in the same manner as described above.

[0100] The information processing device 100 according to this embodiment includes an image acquisition unit 110 that acquires material decomposition image data based on detection signals related to X-ray photons in each of a plurality of energy bands that transmit through a subject. The information processing device 100 also includes a region-of-interest acquisition unit 111 that acquires a region of interest in the material decomposition image data. The information processing device 100 further includes a data processing unit 112 that generates partial image data of the material decomposition image data corresponding to the region of interest, and a storage unit 113 that stores the partial image data of the material decomposition image data. With this configuration, it is possible to reduce the amount of data required to store the material decomposition image data.

[0101] (Modification 1 of the first embodiment) In the embodiment described above, the region of interest of each of the multiple material decomposition image data is stored in the process of the storage unit 113 in step S43. However, the present invention is not limited to this embodiment, and the information processing device 100 may be configured to include a selection unit (operation device 137) that selects a material to be identified, and the storage unit 113 may store the region of interest of at least one or more material decomposition image data selected by the user. In other words, the storage unit 113 may be configured not to store the region of interest of the material decomposition image data of a material not selected by the user.

[0102] The selection method of the selection unit for at least one material decomposition image data may be material decomposition image data related to a material previously selected by the user. Furthermore, after analyzing a plurality of material decomposition image data, the selection unit may select the material decomposition image data that is most densely depicted. Furthermore, the storage unit 113 may store the respective attention areas of a plurality of material decomposition image data that satisfy a predetermined condition (for example, density is equal to or greater than a predetermined value).

[0103] For example, when the material to be identified selected by the user using the selection unit is iodine, the storage unit 113 stores partial image data 221 corresponding to the region of interest in the material decomposition image data of iodine, as shown in Fig. 9. When the X-ray CT device is used to check the effect of an iodine contrast agent (an iodine compound), the storage unit 113 stores the partial image data 221 corresponding to the region of interest in the material decomposition image data of iodine, and deletes the other material decomposition image data. Note that the storage unit 113 may store the partial image data 221 corresponding to the region of interest in the material decomposition image data of iodine and integral image data, which will be described later, and delete the material decomposition image data of materials other than iodine, calcium, and water.

[0104] Note that, for the material decomposition image data of the identified target material selected by the user in the selection unit, the entire material decomposition image data may be stored instead of partial image data. In this case, the process in which the attention area acquisition unit 111 acquires the attention area in step S41 may be omitted. For example, when the identified target material selected by the user in the selection unit is iodine, the storage unit 113 stores the material decomposition image data of iodine. When the identified target material selected by the user in the selection unit is calcium, the storage unit 113 stores the material decomposition image data of calcium. Since the material decomposition image data of the identified target material selected by the user in the selection unit is stored in the storage unit 113, the amount of data required for storing the material decomposition image data can be reduced.

[0105] 11 is a diagram showing a form in which material decomposition image data of a target substance selected by the user in the selection unit is stored in the storage unit 113. In accordance with the target substance selected by the user in the selection unit, the storage unit 113 stores material decomposition image data related to the target substance, and does not store material decomposition image data other than the target substance.

[0106] 11, when the material to be identified selected by the user in the selection unit is iodine, the storage unit 113 stores the material decomposition image data of iodine. Material decomposition image data other than iodine, i.e., material decomposition image data of calcium and water, is not stored in the storage unit 113. Since the storage unit 113 stores the material decomposition image data of iodine and does not store material decomposition image data other than iodine, it is possible to reduce the amount of data required to store the material decomposition image data.

[0107] When the material to be identified selected by the user in the selection unit is calcium and iodine, the storage unit 113 stores the material decomposition image data of calcium and the material decomposition image data of iodine. Material decomposition image data other than calcium and iodine, that is, the material decomposition image data of water, is not stored in the storage unit 113. Since the storage unit 113 stores the material decomposition image data of calcium and iodine and does not store the material decomposition image data other than calcium and iodine, it is possible to reduce the amount of data required for storing the material decomposition image data.

[0108] Here, even if the user selects a substance to be identified using the selection unit, if the area of ​​the substance to be identified in the material decomposition image data related to the substance to be identified is less than a predetermined range (area), it may be configured not to store it in the storage unit 113. If the area of ​​the substance to be identified in the material decomposition image data related to the substance to be identified is equal to or greater than a predetermined range (area), it is stored in the storage unit 113. Since the storage unit 113 does not store material decomposition image data including noise related to the substance to be identified, it is possible to reduce the amount of data required to store the material decomposition image data.

[0109] As described above, this embodiment includes the image acquisition unit 110 that acquires a plurality of material decomposition image data based on detection signals related to X-ray photons in each of a plurality of energy bands that transmit through a subject, and the selection unit (operation device 137) that selects a material to be identified. Furthermore, the device includes the storage unit 113 that stores at least one material decomposition image data from the plurality of material decomposition image data based on the selected material to be identified.

[0110] (Modification 2 of the first embodiment) In the embodiment described above, in step S43, the storage unit 113 stores partial image data corresponding to the region of interest of the material decomposition image data. However, the present invention is not limited to this embodiment, and the storage unit 113 may store spatial information such as the spatial position of each voxel in the region of interest of the material decomposition image data in association with a luminance value. In this way, even if there are no voxels outside the region of interest of the material decomposition image data, the spatial information and luminance value of each voxel in the region of interest are present, making it possible to display the region of interest at an appropriate position.

[0111] (Modification 3 of the first embodiment) In the above-described embodiment, in step S40, the image acquisition unit 110 acquires material decomposition image data from the detection signal. However, the present invention is not limited to this. For example, virtual monochromatic X-ray image data corresponding to virtual single energy imaging from the detection signal or integral image data obtained by reconstructing X-ray image data for each energy band may be acquired. Alternatively, integral image data may be acquired by reconstructing an energy integral signal obtained by adding up detection signals, which are the number of detected X-ray photons for each of a plurality of energy bands, for each detector.

[0112] Note that the region of interest that can be specified may differ depending on whether the image acquired by the image acquisition unit 110 is material decomposition image data, virtual monochromatic X-ray image data, X-ray image data by energy band, or integral image data. By specifying the region of interest even in image data other than material decomposition image data, the amount of data can be reduced.

[0113] Fig. 12 is a diagram showing a form in which X-ray image data for each energy band is stored, Fig. 12(a) shows the correspondence between material decomposition image data and X-ray image data, and Fig. 12(b) shows the X-ray image data to be stored.

[0114] The material decomposition image data is composed of X-ray image data for each energy band. When the material selected by the user through the selection unit (operation device 137) is iodine, the storage unit 113 stores X-ray image data for each energy band related to the material decomposition image data of iodine (e.g., most expressible).

[0115] The X-ray image data for each energy band is made up of a plurality of X-ray image data. For example, the first X-ray image data is high-energy imaging image data corresponding to a high tube voltage, and the second X-ray image data is low-energy imaging image data corresponding to a low tube voltage. For example, the information processing device 100 generates first material decomposition image data showing the distribution of a first material by material decomposition processing based on the first X-ray image data and the second X-ray image data. The information processing device 100 generates second material decomposition image data showing the distribution of a second material by material decomposition processing based on the second X-ray image data and the third X-ray image data.

[0116] Here, it is assumed that material decomposition image data showing the distribution of calcium is generated by material decomposition processing based on the first X-ray image data and the second X-ray image data, material decomposition image data showing the distribution of iodine is generated by material decomposition processing based on the first X-ray image data and the second X-ray image data, and material decomposition image data showing the distribution of water is generated by material decomposition processing based on the second X-ray image data and the third X-ray image data.

[0117] As shown in FIG. 12, when the material selected by the user in the selection unit is iodine, the storage unit 113 stores the first X-ray image data and the second X-ray image data related to the material decomposition image data of iodine.

[0118] When the material selected by the user in the selection unit is calcium, the storage unit 113 stores the first X-ray image data and the second X-ray image data related to the material decomposition image data of calcium. When the material selected by the user in the selection unit is water, the storage unit 113 stores the second X-ray image data and the third X-ray image data related to the material decomposition image data of water.

[0119] As described above, this embodiment includes an image acquisition unit 110 that acquires multiple material decomposition image data generated from X-ray image data in multiple energy bands based on detection signals related to X-ray photons in each of the multiple energy bands that transmit through a subject. Also, a selection unit (operation device 137) that selects a material to be identified is included. Furthermore, a storage unit 113 that stores X-ray image data in energy bands that are the source of material decomposition image data related to the selected material to be identified is included.

[0120] [Second embodiment] Next, a second embodiment will be described The second embodiment differs from the first embodiment in that the storage unit 113 stores partial image data corresponding to the region of interest in the material decomposition image data, and also stores integral image data.

[0121] In the second embodiment, material decomposition image data based on detection signals obtained by imaging the chest and abdomen of a subject using a medical imaging device 1 and integral image data reconstructed by converting the detection signals into energy integral signals are synthesized and displayed.

[0122] The materials and energy bands for generating material decomposition image data are the same as those in the first embodiment. That is, the materials for generating material decomposition image data are four materials, namely, calcium, iodine, water, and air, and the energy bands are five, namely, 20-40, 40-60, 60-80, 80-100, and 100-120 (keV).

[0123] Hereinafter, details of each component of the information processing device 100 according to this embodiment will be described with reference to FIG. 2. In this embodiment, the storage unit 113 stores material decomposition image data based on a region of interest mask, and stores integral image data regardless of the region of interest mask. Material decomposition image data within the region of interest is generated as partial image data, and the storage unit 113 stores the partial image data of the material decomposition image data, and stores integral image data inside and outside the region of interest (the entire image). In other words, the data processing unit 112 performs data amount reduction processing by deleting material decomposition image data outside the region of interest. Data amount reduction processing is not performed on the integral image data.

[0124] The display control unit 114 generates composite image data of the partial image data and the integral image data of the material decomposition image data, and displays the composite image data on the display device 136 .

[0125] (Image acquisition unit 110) The image acquisition unit 110 acquires material decomposition image data and integral image data for each of a plurality of energy bands from the medical image pickup device 1. Then, the image acquisition unit 110 transmits the data to the region of interest acquisition unit 111 and the data processing unit 112.

[0126] (Attention area acquisition unit 111) The region of interest identification unit 12 sets a threshold for each of the multiple material decomposition image data, and acquires a single region of interest mask by identifying a region equal to or greater than the threshold. Then, the single region of interest masks are synthesized to acquire a synthesized region of interest mask and transmitted to the data processing unit 112.

[0127] (Data processing unit 112) The data processing unit 112 acquires partial image data of each material decomposition image data corresponding to the synthetic region of interest using the synthetic region of interest mask acquired from the region of interest acquisition unit 111, and transmits the partial image data to the storage unit 113 and the display control unit 114. At this time, the integrated image data is not subjected to data reduction processing and is transmitted to the storage unit 113 and the display control unit 114.

[0128] (Storage unit 113) The storage unit 113 stores the partial image data and the integrated image data of each of the material decomposition image data.

[0129] (Display control unit 114) The display control unit 114 generates composite image data by synthesizing the partial image data and the integral image data of each of the material decomposition image data acquired from the data processing unit 112 for any cross sections, and displays the composite image data on the display device 136. Details of the process will be described later in the description of step S54.

[0130] Next, the operation of the information processing device 100 will be described with reference to the flowchart of FIG.

[0131] (Step S50: Acquiring data) In step S 50 , the image acquisition unit 110 acquires material decomposition image data and integral image data for each of a plurality of energy bands from the medical imaging device 1 , and transmits them to the region of interest acquisition unit 111 and the data processing unit 112 .

[0132] Instead of acquiring material decomposition image data and integral image data, data may be acquired or used by the following method. First, a detection signal based on the number of detections of X-ray photons for each of a plurality of energy bands that pass through the subject is acquired from the medical imaging device 1. Then, energy integral signals obtained by adding up the data for each detector may be acquired and reconstructed.

[0133] Here, the material decomposition image data and the integrated image data can be reconstructed (generated) by performing back projection processing on the detection signals using an image reconstruction algorithm. Any image reconstruction algorithm may be used, such as an analytical image reconstruction method based on the above-mentioned FBP method or UBP (Universal Back Projection) method, or a statistical image reconstruction method based on the ML-EM (Maximum Likelihood Expectation Maximization) method or OS-EM (Ordered Subset Expectation Maximization) method.

[0134] (Step S51: Acquire synthetic region of interest) In step S51, the region of interest acquisition unit 111 sets a region of interest mask for each of the plurality of material decomposition image data, as in the first embodiment. Then, a composite region of interest mask obtained by combining the plurality of region of interest masks is acquired and transmitted to the data processing unit 112. Note that, as a method for integrating the masks, for example, a logical sum, a majority vote, or a logical product can be used.

[0135] (Step S52: Reducing the amount of data) In step S52, the data processing unit 112, like the first embodiment, obtains partial image data of the region of interest of the material decomposition image data, and transmits it to the storage unit 113 and the display control unit 114. In this embodiment, a composite region of interest mask is used instead of the respective region of interest masks of the material decomposition image data. Here, the integrated image data is transmitted to the storage unit 113 and the display control unit 114 without undergoing data amount reduction processing.

[0136] (Step S53: Storing data) In step S53, the storage unit 113 stores the data with the reduced amount of data (that is, the partial image data and the integrated image data of each of the material decomposition image data).

[0137] (Step S54: Display of data) In step S54, the display control unit 114 generates composite image data of the partial image data and the integral image data of each of the material decomposition image data, and displays the composite image data on the display device 136.

[0138] The composite image data is generated by combining the integral image data and the plurality of material decomposition image data in a composite region of interest at a combination ratio of 0 to 1. In this embodiment, the combination ratio of the integral image data is 0.5, the combination ratio of the plurality of material decomposition image data is 0.5 in total, and 0.5 is distributed between the material decomposition image data by the material density ratio. The display control unit 114 may set the combination ratio of the plurality of material decomposition image data in the region of interest higher than a predetermined value. Thus, the material decomposition image data in the region of interest can be emphasized. The display control unit 114 may set the combination ratio outside the region of interest lower than a predetermined value. The display device 136 shown in FIG. 2 displays the integral image data in grayscale, and displays the plurality of material decomposition image data by applying different colors to each of them.

[0139] FIG. 14 is a diagram showing one display form of the display device 136. As shown in FIG.

[0140] The display device 136 displays a display screen 61, an image display window 62, a composite ratio setting bar 63, and a cursor 64. The display device 136 is a display attached to the information processing device 100, a mobile terminal of a hospital staff member via an external server, or the like.

[0141] The blending ratio may be set in advance by the user. The user may set it using a blending ratio setting bar 63 on the display device 136 in Fig. 14. In this case, the display device 136 may display an area in which a plurality of materials are mixed in the material decomposition image data by adding a different color. The display device 136 may display information for identifying the subject (patient information such as the patient's ID and name), information on the materials in the material decomposition image data, and blending parameters for creating the composite image data.

[0142] According to the information processing device 100 of this embodiment, it is possible to obtain a region of interest from material decomposition image data for each of a plurality of energy bands transmitted through a subject, and to obtain a composite region of interest of the material decomposition image data. Furthermore, it is possible to store partial image data and integral image data of the material decomposition image data corresponding to the composite region of interest. This makes it possible to store data with a reduced data amount compared to the case of storing material decomposition image data for each of a plurality of energy bands.

[0143] Although the display control unit 114 creates and displays the composite image data of the integral image data and the multiple material decomposition image data, it may also perform composition between material decomposition image data, or between energy band-specific X-ray image data and material decomposition image data. In this way, images based on detection signals can be composited and displayed.

[0144] (Modification 1 of the second embodiment) In the above-described embodiment, in step S52, the data processing unit 112 does not perform data amount reduction processing on the integral image data, and transmits the integral image data to the storage unit 113. However, the present invention is not limited to this embodiment, and the data amount reduction processing may also be performed on the integral image data. Specifically, for the integral image data, partial image data outside the region of interest may be generated instead of the entire image, and the partial image data may be transmitted to the storage unit 113. For the material decomposition image data, partial image data within the region of interest is generated, and the partial image data is transmitted to the storage unit 113. In this way, the data amounts of the integral image data and the material decomposition image data can be reduced and stored. That is, the storage unit 113 stores partial image data of the material decomposition image data within the region of interest, and stores partial image data of the integral image data outside the region of interest.

[0145] (Modification 2 of the second embodiment) In the above-described embodiment, in step S51, the region of interest acquisition unit 111 acquires a region of interest as a region of the material decomposition image data equal to or greater than a threshold value, but a specific disease region or biological structure may be set as the region of interest. In order to set a specific disease region or biological structure as the region of interest, a mask of the specific disease region or biological structure may be input separately, or a user may specify a region of interest using the operation device 137. Also, a mask of the specific disease region or biological structure may be automatically generated by image recognition processing of the material decomposition image data or integral image data.

[0146] Here, the region of interest may be, for example, a region derived from a biological structure such as a blood vessel, a bone, or an organ, or may be a specific region in a living body such as a primary cancer or a metastatic cancer. Here, the region derived from a biological structure or the specific region in a living body may be acquired by a user specifying it using the operation device 137, or may be acquired from a device or program different from the information processing device 100 via a network, or may be generated within the information processing device 100. In this way, it is possible to acquire the region of interest under conditions that are not dependent on the substance density.

[0147] In the above embodiment, the chest and abdomen of the subject are imaged by the X-ray CT device, but the subject may be the abdomen, head, or whole body. Also, the subject is not limited to the human body, and may be any other object such as animals such as pigs and mice, or objects such as cargo or airport baggage.

[0148] A computer program for realizing the functions of the above-mentioned embodiments can be supplied to a computer via a network or memory (not shown), and the computer program can be executed by a processor (not shown). This is a computer program for causing a computer to execute the above-mentioned information processing method. In other words, the computer program is a program for causing a computer to realize the functions of an information processing device. The memory stores the computer program.

Claims

1. an image acquisition unit that acquires material decomposition image data based on detection signals related to X-ray photons in each of a plurality of energy bands that pass through a subject; an attention region acquisition unit for acquiring an attention region in the material decomposition image data; a data processing unit that generates partial image data of the material decomposition image data corresponding to the region of interest; a storage unit that stores partial image data of the material decomposition image data.

2. 2 . The information processing apparatus according to claim 1 , wherein the region of interest acquisition unit acquires, as the region of interest, a region in which a predetermined material exists in the material decomposition image data.

3. the attention region acquisition unit sets an attention region mask for the attention region in the material decomposition image data; The information processing apparatus according to claim 1 , wherein the data processing unit generates partial image data of the material decomposition image data based on the region of interest mask.

4. 4. The information processing apparatus according to claim 3, wherein the data processing unit sets a storage area including the region of interest represented by the region of interest mask, and generates partial image data by cutting out the storage area.

5. 2 . The information processing apparatus according to claim 1 , wherein the data processing unit obtains partial image data within a region of interest of the material decomposition image data, and deletes image data of a region outside the region of interest of the material decomposition image data.

6. 2 . The information processing apparatus according to claim 1 , wherein the storage section stores partial image data corresponding to a region of interest in the material decomposition image data, and stores integral image data based on the detection signal.

7. 7. The information processing apparatus according to claim 6, wherein the storage section stores partial image data of the material decomposition image data within a region of interest, and stores partial image data of the integrated image data outside the region of interest.

8. the image acquisition unit acquires a plurality of material decomposition image data; the region of interest acquisition unit acquires a region of interest in each of the plurality of material decomposition image data; 2 . The information processing apparatus according to claim 1 , wherein the storage unit stores partial image data corresponding to a region of interest in each of a plurality of material decomposition image data.

9. 9. The information processing apparatus according to claim 8, wherein the region of interest acquisition section acquires, for a plurality of material decomposition image data, a region in which each material exists as the region of interest.

10. 10. The information processing apparatus according to claim 9, wherein the region of interest acquisition unit sets a threshold value for a predetermined physical quantity for each material decomposition image data, and acquires a region equal to or greater than the threshold value as a region of interest.

11. the region-of-interest acquisition unit sets a region-of-interest mask for each region of interest in the material decomposition image data; 9. The information processing apparatus according to claim 8, wherein the data processing unit generates partial image data of each of the material decomposition image data based on the region of interest mask.

12. the region of interest acquisition unit acquires a region of interest for composite image data obtained by combining a plurality of material decomposition image data, and sets a composite region of interest mask; The data processing unit generates partial image data of the composite image data based on the composite attention area mask, The information processing apparatus according to claim 1 , wherein the storage unit stores partial image data of the composite image data.

13. 13 . The information processing apparatus according to claim 12 , wherein the data processing unit sets a storage area containing the synthesis attention area mask, and generates partial image data of the synthesis image data based on the storage area.

14. The information processing apparatus according to claim 1 , wherein the storage unit stores partial image data of the material decomposition image data for each material.

15. an image acquisition unit that acquires a plurality of material decomposition image data based on detection signals related to X-ray photons in each of a plurality of energy bands that pass through a subject; A selection unit for selecting a substance to be identified; and a storage unit configured to store at least one material decomposition image data from among a plurality of material decomposition image data based on the selected material to be identified.

16. an image acquisition unit that acquires a plurality of material decomposition image data generated from X-ray image data of a plurality of energy bands based on detection signals related to X-ray photons for each of a plurality of energy bands that transmit through a subject; A selection unit for selecting a substance to be identified; and a storage unit that stores X-ray image data in an energy band that is a source of material decomposition image data related to the selected specific target material.

17. acquiring material decomposition image data based on detection signals relating to X-ray photons in each of a plurality of energy bands transmitted through a subject; obtaining a region of interest in the material decomposition image data; generating partial image data of the material decomposition image data corresponding to the region of interest; An information processing method comprising a step of storing partial image data of the material decomposition image data in a storage unit.

18. A program for causing a computer to execute the information processing method according to claim 17.

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