Image processing apparatus, image processing method, and image processing program

Abstract

To provide an image processor, an image processing method, and an image processing program capable of improving the throughput of the whole inspection.SOLUTION: An image processing device used for CT imaging in which multi-reconstruction for acquiring a plurality of projection images using a photon counting-type radiation detector and generating a tomographic image reconstructed from the plurality of projection images on the basis of a predetermined parameter is performed as a series of processes, the image processing device comprising at least one processor, wherein the processor acquires the projection images and adjusts the parameter on the basis of the acquired projection images.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an image processing device, an image processing method, and an image processing program. [Background technology]

[0002] Energy-integrated CT (photo-counting CT) using a photon-counting radiation detector is known as a CT (Computed Tomography) device for capturing medical images (see, for example, Patent Document 1). In an examination using photo-counting CT, the basic operations generally involve a series of processes, including scanning, multi-recon, and automatic analysis, under conditions set in advance in a protocol. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-011181 Summary of the Invention [Problem to be solved by the invention]

[0004] Although photocounting CT allows for the reconstruction of various types of images, it can take longer than conventional methods to reconstruct images, which can result in a decrease in the overall throughput of the examination.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide an image processing device, an image processing method, and an image processing program that can improve the throughput of the entire inspection. [Means for solving the problem]

[0006] In order to achieve the above object, the image processing device of a first aspect of the present disclosure is an image processing device used for CT imaging in which a series of processes, namely, acquisition of multiple projection images using a photon-counting radiation detector and multi-reconstruction of multiple projection images based on predetermined parameters to generate a tomographic image, is performed, and the image processing device includes at least one processor, which acquires projection images and adjusts parameters based on the acquired projection images.

[0007] The image processing device of the second aspect is the image processing device of the first aspect, in which the multi-reconstructor sequentially reconstructs multiple types of tomographic images based on parameters that differ at least in part for each type, and the processor sequentially reconstructs the multiple types of tomographic images using the adjusted parameters.

[0008] In the image processing device of the third aspect, in the image processing device of the second aspect, the parameters are at least one of the number of tomographic images, the range of the field of view, the thickness of the tomographic image, the matrix size, the type of tomographic image, whether or not to perform correction processing, the strength of the correction processing, energy, and window conditions.

[0009] In a fourth aspect of the image processing device, in the image processing device of the third aspect, when the projection image includes an image of a contrast agent or an image of a metal, the processor sets the type of tomographic image to a virtual monochromatic X-ray image and the energy to an energy corresponding to the contrast agent or metal.

[0010] In the image processing device of the fifth aspect, in the image processing device of the fourth aspect, when the processor determines that the projection image contains a calcium component, the type of the tomographic image is a calcium-suppressed image in which the calcium component is suppressed.

[0011] An image processing device of a sixth aspect is the image processing device of the second aspect, wherein the processor determines the order of reconstruction depending on the type of tomographic image.

[0012] In the image processing device of a seventh aspect, in the image processing device of the second aspect, the processor adjusts the range of the slice for generating the tomographic image based on an image of the object of interest included in the projection image as a parameter.

[0013] In the image processing device of an eighth aspect, in the image processing device of the second aspect, the processor outputs the generated tomographic image to an output destination according to the type of the tomographic image.

[0014] An image processing device of a ninth aspect is the image processing device of the second aspect, wherein, when a user's designation of a parameter is accepted, the processor adjusts the parameter based on the designation.

[0015] An image processing device according to a tenth aspect is the image processing device according to the ninth aspect, wherein the processor displays a projected image and accepts a designation made to the projected image.

[0016] In order to achieve the above object, an image processing method according to an eleventh aspect of the present disclosure comprises at least one processor included in an image processing device used for CT imaging, in which a series of processes are performed, including acquiring multiple projection images using a photon-counting radiation detector and generating a tomographic image by reconstructing the multiple projection images based on predetermined parameters, acquiring projection images and adjusting parameters based on the acquired projection images.

[0017] In order to achieve the above object, the image processing program of the twelfth aspect of the present disclosure is for causing at least one processor provided in an image processing device used for CT imaging, in which a series of processes are performed, including acquiring multiple projection images using a photon-counting radiation detector and generating a tomographic image by reconstructing the multiple projection images based on predetermined parameters, to acquire projection images and adjust parameters based on the acquired projection images. [Effects of the Invention]

[0018] According to the present disclosure, the overall throughput of the examination can be improved. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a configuration diagram illustrating an example of the configuration of a CT apparatus according to an embodiment. [Figure 2] FIG. 2 is a configuration diagram illustrating an example of a configuration of a console according to an embodiment. [Figure 3] FIG. 2 is a functional block diagram illustrating an example of functions of a console according to an embodiment. [Figure 4A] FIG. 10 is a diagram illustrating an example of a display of a preview image. [Figure 4B] 10A and 10B are diagrams for explaining an example of display of types of parameters that can be adjusted by an adjustment unit. [Figure 5] 10 is a flowchart illustrating an example of the flow of image processing according to an embodiment. [Figure 6A] 10 is a flowchart illustrating an example of the flow of a parameter adjustment process related to parameter adjustment of image type and energy. [Figure 6B] 10 is a flowchart illustrating an example of the flow of a parameter adjustment process related to parameter adjustment of the field of view (FOV). [Figure 6C] 10 is a flowchart showing an example of the flow of a parameter adjustment process related to parameter adjustment of an image type in imaging using a contrast agent. [Figure 6D] 10 is a flowchart illustrating an example of the flow of a parameter adjustment process related to parameter adjustment of window conditions (WW / WL). [Figure 7] 10A and 10B are diagrams for explaining adjustment of the order of generating tomographic images. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the embodiment.

[0021] First, an example of the configuration of a CT (Computed Tomography) device of this embodiment will be described. Fig. 1 shows a configuration diagram illustrating an example of the configuration of a CT device 10 of this embodiment. In CT imaging using the CT device 10 of this embodiment, a series of processes are performed: acquisition of multiple projection images using a photon-counting detector panel 28; and multi-reconstruction, which generates a tomographic image by reconstructing the multiple projection images based on predetermined parameters. When the series of processes of irradiating the subject S with radiation R, acquiring projection images using the detector panel 28, and performing multi-reconstruction is completed, the examination of the subject S is completed.

[0022] As shown in FIG. 1, the CT apparatus 10 of this embodiment includes a gantry 20, a bed 27, and a console 30.

[0023] The gantry 20 has an opening 26, and the subject S to be imaged is placed on a bed 27 and placed in the opening 26. The gantry 20 and the bed 27 are capable of moving relatively in a direction passing through the opening 26.

[0024] Inside the gantry 20, a radiation generator 23 having a radiation tube (not shown), a bowtie filter 24, a collimator 25, and a detector panel 28 are arranged facing each other with the subject S in between. The radiation R irradiated from the radiation generator 23 is shaped by the bowtie filter 24 and the collimator 25 into a beam shape appropriate for the size of the subject S, and is then irradiated onto the subject S. The detector panel 28 detects the radiation that has passed through the subject S and generates a projection image corresponding to the dose of the detected radiation. The detector panel 28 of this embodiment is a photon-counting type photon-counting detector in which a plurality of detection elements (not shown) that detect photon energy, which is the energy of photons of incident radiation, are arranged in an arc shape centered on the focus of the radiation tube of the radiation generator 23. The detector panel 28, which is a photon-counting detector, outputs a projection image corresponding to the photon energy.

[0025] The radiation generator 23 and the detector panel 28 are rotated around the subject S by a rotation drive unit (not shown) of the gantry 20. The irradiation of radiation from the radiation generator 23 and the detection of radiation by the detector panel 28 are repeated as they rotate, thereby obtaining projection images at various projection angles. The multiple projection images obtained by the detector panel 28 are output to the console 30.

[0026] The console 30 of this embodiment performs various controls related to imaging, generates medical images, etc. The medical images generated by the console 30 are output to an image management system 12, such as a PACS (Picture Archiving and Communication System), and a workstation 14 via a network N. Although FIG. 1 illustrates one image management system 12 and one workstation 14, the number of image management systems 12 and workstations 14 connected to the console 30 via the network N is not limited to one. For example, at least one of the image management systems 12 and workstations 14 may be arranged according to a medical department such as radiology or cardiac surgery, or at least one of the image management systems 12 and workstations 14 may be arranged according to a radiologist.

[0027] The console 30 of this embodiment is an example of an image processing device of the present disclosure. As an example, the console 30 of this embodiment is a server computer. As shown in Fig. 2, the console 30 includes a control unit 32, a storage unit 34, an I / F (Interface) unit 35, an operation unit 36, and a display unit 38. The control unit 32, the storage unit 34, the I / F unit 35, the operation unit 36, and the display unit 38 are connected via a bus 39 such as a system bus or a control bus so that various information can be exchanged between them.

[0028] The control unit 32 of this embodiment controls the overall operation of the console 30. The control unit 32 includes a CPU (Central Processing Unit) 32A, a ROM (Read Only Memory) 32B, and a RAM (Random Access Memory) 32C. The ROM 32B stores in advance various programs, including an image processing program 33 (described later), which are executed by the CPU 32A. The RAM 32C temporarily stores various data.

[0029] The storage unit 34 stores the projection image output from the detector panel 28 and various other information. Specific examples of the storage unit 34 include a storage medium such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a flash memory.

[0030] The I / F unit 35 communicates various types of information with a rotation drive unit (not shown) of the gantry 20, the radiation generation device 23, and the detector panel 28 via wired or wireless communication. The console 30 of this embodiment receives a projection image from the detector panel 28 via the I / F unit 35. The received projection image is stored in the memory unit 34.

[0031] The console 30 acquires a plurality of projection images from the detector panel 28 via the I / F unit 35. The control unit 32 performs reconstruction processing on the acquired plurality of projection images to generate a tomographic image of the subject S.

[0032] The I / F unit 35 also outputs the generated tomographic images to the image management system 12 and the workstation 14 via the network N by wired or wireless communication.

[0033] The operation unit 36 ​​is used by the user to input various information such as scan conditions for acquiring a projection image, instructions related to image generation such as parameter instructions, and instructions related to image display. The operation unit 36 ​​is not particularly limited, and examples thereof include various switches, buttons, a touch panel, a touch pen, a keyboard, and a mouse. The display unit 38 displays various information, medical images, and the like. The operation unit 36 ​​and the display unit 38 may be integrated into a touch panel display. Alternatively, for example, the operation unit 36 ​​may receive voice input from the user.

[0034] 3 is a functional block diagram showing an example of the functions of the console 30. The console 30 includes an acquisition unit 40, a display control unit 42, a reception unit 44, a generation unit 46, and an output unit 48. As an example, the console 30 of this embodiment executes an image processing program 33, whereby the CPU 32A of the control unit 32 functions as the acquisition unit 40, the display control unit 42, the reception unit 44, the generation unit 46, and the output unit 48.

[0035] The acquisition unit 40 has a function of acquiring a plurality of projection images from the detector panel 28. Specifically, as described above, the acquisition unit 40 acquires projection images captured by radiation sequentially irradiated from a plurality of directions from the detector panel 28 via the I / F unit 35. Note that the acquisition unit 40 may also be configured to acquire, from the storage unit 34, projection images that have been acquired from the detector panel 28 and temporarily stored in the storage unit 34. The acquisition unit 40 outputs the acquired projection images to the display control unit 42 and the generation unit 46.

[0036] The display control unit 42 controls the display unit 38 to display the projection image acquired from the acquisition unit 40 as a preview image. FIG. 4A shows an example of a state in which the preview image PV is displayed on the display unit 38. In this embodiment, a projection image acquired from the detector panel 28 is used as the preview image PV, and is a real-time image during CT imaging. The user can change various parameters of the preview image PV using the operation unit 36 ​​to make the preview image PV easier to view. Here, the parameters that can be changed by the user for the preview image PV may be the same as or different from the parameters that can be adjusted by the adjustment unit 47, for example.

[0037] The display control unit 42 also controls the display unit 38 to display information about parameters used to generate tomographic images that can be adjusted by the adjustment unit 47 of the generation unit 46. FIG. 4B shows an example of a state in which types of adjustable parameters are displayed on the display unit 38. In the example shown in FIG. 4B, eight types of buttons are displayed corresponding to the types of parameters that can be adjusted by the adjustment unit 47: "Number of Images," "FOV," "Image Slice Thickness," "Matrix Size," "Image Type," "Correction Process," "keV," and "WW / WL." Details of these buttons will be described later.

[0038] Furthermore, the display control unit 42 of this embodiment controls the display unit 38 to display the tomographic image generated by the generation unit 46.

[0039] The receiving unit 44 receives parameter designations made by the user through the operation unit 36 ​​for the preview image PV, which is the projection image displayed on the display unit 38, based on the display shown in FIG. 4B. The parameter designations received by the receiving unit 44 are output to the generation unit 46.

[0040] The generation unit 46 generates a tomographic image by reconstructing a plurality of projection images. The generation unit 46 of this embodiment includes an adjustment unit 47 that adjusts parameters based on the projection images. As an example, parameters that can be adjusted by the adjustment unit 47 of this embodiment include the number of tomographic images, the range of the field of view, the thickness of the tomographic image, the matrix size, the type of tomographic image, whether or not to perform correction processing, the strength of the correction processing, energy, and window conditions.

[0041] The "number of tomographic images" is the number of tomographic images generated by the generating unit 46, and corresponds to the "number of images" displayed on the display unit 38 (see FIG. 4B).

[0042] The "range of the field of view" is the range of the effective field of view in the image, and corresponds to the "FOV" (Field of View) displayed on the display unit 38 (see FIG. 4B).

[0043] The "thickness of the tomographic image" is the thickness of the tomographic image generated by the generating unit 46 (so-called slice thickness), and corresponds to the "image slice thickness" (see FIG. 4B) displayed on the display unit 38. The number of images and the image slice thickness are related to each other.

[0044] The "matrix size" is the size of the entire set of pixels that make up the tomographic image generated by the generation unit 46, and is represented by the number of rows and columns of the tomographic image. It corresponds to the "matrix size" displayed on the display unit 38 (see FIG. 4B).

[0045] The "type of tomographic image" is the type of tomographic image generated by the generation unit 46, and examples thereof include a virtual monochromatic X-ray image and a calcium-suppressed image. Note that the type of tomographic image may be a type of commonly known tomographic image (CT image) or a unique type of tomographic image registered by the user by specifying parameter values, etc. This corresponds to the "type of image" (see FIG. 4B) displayed on the display unit 38.

[0046] "Whether or not to perform correction processing" and "strength of correction processing" refer to whether or not to perform correction processing on the tomographic image generated by the generation unit 46, and the strength of the correction processing. These correspond to the "correction processing" (see FIG. 4B) displayed on the display unit 38. Note that there may be multiple types of correction processing.

[0047] "Energy" is the energy spectrum of the tomographic image generated by the generation unit 46. In a low-energy image, the contrast is improved, so for example, the CT value of the contrast agent is enhanced. Conversely, in a high-energy image, the CT value of the contrast agent is weakened, but metal artifacts and the like can be reduced. This corresponds to "keV" displayed on the display unit 38 (see FIG. 4B). In this embodiment, the type of tomographic image and the energy are set in conjunction with each other. In other words, when one is adjusted, the other is automatically set accordingly.

[0048] The "window conditions" are the conditions for the gradation you want to see, and the window conditions have appropriate values ​​determined depending on the part you want to see, for example. They correspond to "WW / WL" (see FIG. 4B) displayed on the display unit 38. Note that "WW" (WW: Window Width) is the window width, and "WL" (WL: Window Level) is the level (gradation).

[0049] These parameters can be adjusted by the adjustment unit 47 based on the projected image. As described above, the user can specify parameters by operating the buttons corresponding to the types of parameters shown in FIG. 4B using the operation unit 36. When a parameter is specified, the specification is accepted by the acceptance unit 44. In this case, the adjustment unit 47 adjusts the parameter based on the specification accepted by the acceptance unit 44.

[0050] On the other hand, if no user specification has been received, the adjustment unit 47 adjusts the parameters based on the projection image. Specifically, the adjustment unit 47 adjusts the parameters based on the analysis result of the projection image using a predetermined adjustment method, an adjustment method based on known standards, or the like.

[0051] The generating unit 46 reconstructs a tomographic image using the parameters adjusted by the adjusting unit 47. Note that default values ​​for the above parameter values ​​are set in advance in the protocol, and the default values ​​are used for reconstruction for parameters that have not been adjusted by the adjusting unit 47. The tomographic image generated by the generating unit 46 is output to the display control unit 42 and the output unit 48.

[0052] The output unit 48 outputs the generated tomographic image to at least one of the designated destinations, the image management system 12 and the workstation 14. The output destination may be one or more. The designated output destination may be predetermined depending on the type of tomographic image, or may be designated by the user.

[0053] Next, the operation of the console 30 of this embodiment will be described.

[0054] In the console 30 of this embodiment, as an example, in the implementation of multi-recon used for CT imaging by the CT device 10, the CPU 32A of the control unit 32 executes the image processing program 33 stored in the ROM 32B, thereby performing image processing, an example of which is shown in Fig. 5. Fig. 5 shows a flowchart illustrating an example of the flow of image processing in the console 30 of this embodiment.

[0055] First, in step S100 of FIG. 5, the acquisition unit 40 acquires a plurality of projection images obtained by imaging the subject S with the CT apparatus 10, as described above.

[0056] In the next step S102, the display control unit 42 controls the display unit 38 to display the projection image acquired in step S100 as a preview image, as described above.

[0057] In the next step S104, the adjustment unit 47 of the generation unit 46 executes the parameter adjustment process for adjusting the parameters for reconstruction, as described above. The parameter adjustment process will be described in detail later.

[0058] In the next step S106, the generating unit 46 reconstructs a plurality of projection images based on the parameters adjusted in step S104 to generate a tomographic image.

[0059] In the next step S108, the display control unit 42 controls the display unit 38 to display the tomographic image generated in step S106.

[0060] In the next step S110, the output unit 48 outputs the tomographic image generated in step S106 to a specified output destination, as described above. For example, the image may be output to the image management system 12 of each medical department via the workstation 14 of the radiology department. Alternatively, for example, if the image interpreter wishes to perform the analysis himself, the image may be output to the workstation 14 of the medical department to which the image interpreter belongs. Alternatively, for example, if the image interpreter wishes to obtain confirmation of the radiological technologist's analysis results, the image may be output to the image management system 12 of the medical department to which the image interpreter belongs. In this way, by quickly outputting the tomographic image to a specified output destination, the time required for diagnosis can be shortened.

[0061] In the next step S112, it is determined whether or not to terminate generation of the tomographic images. For example, if another type of tomographic image is to be generated, the determination in step S112 is negative, and the process returns to step S104, and the processing in steps S104 to S110 is repeated. On the other hand, if generation of the predetermined tomographic image has been terminated, the determination in step S112 is positive, and the image processing shown in FIG. 5 terminates.

[0062] Next, details of the parameter adjustment process in step S104 of the image processing shown in Fig. 5 will be described. In this embodiment, a plurality of parameter adjustment processes are provided in advance to adjust various parameters, and adjustment processes are executed appropriately according to the parameters to be adjusted. The plurality of parameter adjustment processes are set in advance for each type of parameter, based on settings by the user or a combination of known parameter values.

[0063] In this embodiment, specific examples of the parameter adjustment process will be described with reference to Figures 6A to 6D. It goes without saying that the parameter adjustment process is not limited to the specific examples shown in Figures 6A to 6D.

[0064] Fig. 6A shows a flowchart illustrating an example of the flow of a parameter adjustment process related to parameter adjustment of the image type and energy. In this embodiment, the type of tomographic image and the energy (keV) are adjusted in conjunction with each other, as in the example shown in Fig. 6A.

[0065] 6A, the adjustment unit 47 determines whether the projection image includes an image of a contrast agent or an image of a metal. The method by which the adjustment unit 47 determines whether the projection image includes an image of a contrast agent or an image of a metal is not limited, and any known method may be applied, such as determining based on the CT value of the projection image.

[0066] If the projection image does not include an image of a contrast agent or an image of a metal, the determination in step S200 is negative, and the process proceeds to step S202. In step S202, the adjustment unit 47 adjusts the type of tomographic image to a preset value in the protocol (here, the default value described above), or, if a user designation has been accepted, to the designated value.

[0067] In the next step S204, the adjustment unit 47 adjusts the energy (keV) of the tomographic image to a set value (here, the above-mentioned default value) predetermined in the protocol, or to a specified value if specified by the user. When the process of step S204 ends, the parameter adjustment process shown in FIG. 6A ends.

[0068] On the other hand, if the projection image includes an image of a contrast agent or an image of a metal, the determination in step S200 is affirmative, and the process proceeds to step S206. In step S206, the adjustment unit 47 adjusts the type of tomographic image to "virtual monochromatic X-ray image."

[0069] In the next step S208, the adjustment unit 47 adjusts the energy (keV) of the tomographic image to a value corresponding to the "virtual monochromatic X-ray image." Note that the value corresponding to the "virtual monochromatic X-ray image" for the energy of the tomographic image may be a known value or a preset value. When the processing of step S208 is completed, the parameter adjustment processing shown in FIG. 6A is terminated.

[0070] 6B shows a flowchart illustrating an example of the flow of a parameter adjustment process related to parameter adjustment of the field of view (FOV). In this embodiment, as in the example shown in FIG. 6B, the range of the field of view (FOV) changed by the user for the preview image PV is used as a parameter for multi-recon.

[0071] In step S220 of FIG. 6B, the adjustment unit 47 determines whether the field of view (FOV) of the preview image PV has been changed by the user.

[0072] If the field of view (FOV) has not been changed, the determination in step S220 is negative, and the process proceeds to step S222. In step S222, adjustment unit 47 adjusts the field of view (FOV) to a preset value in the protocol (here, the default value described above), or to a specified value if a user specification has been accepted. When the process in step S222 ends, the parameter adjustment process shown in FIG. 6B ends.

[0073] On the other hand, if the field of view (FOV) has been changed, the determination in step S220 is affirmative, and the process proceeds to step S224. In step S224, adjustment unit 47 adjusts the field of view (FOV) in the multi-reconfiguration to the same value as the value changed for preview image PV. When the process of step S224 ends, the parameter adjustment process shown in FIG. 6B ends.

[0074] 6C shows a flowchart illustrating an example of the flow of a parameter adjustment process related to parameter adjustment of an image type in imaging using a contrast agent. In this embodiment, as in the example shown in FIG. 6C, parameters of the image type are adjusted depending on the presence or absence of a calcium component. The type of tomographic image and the energy (keV) are adjusted in conjunction with each other.

[0075] 6C, the adjustment unit 47 determines whether or not the preview image PV contains a calcium component. Note that the method by which the adjustment unit 47 determines whether or not the preview image PV contains a calcium component is not limited, and any known method may be applied, such as determining based on the CT value of the preview image PV.

[0076] If the preview image PV image does not contain calcium components, the determination in step S240 is negative, and the process proceeds to step S242. In step S242, the adjustment unit 47 determines whether conditions for generating a calcium-suppressed image are set in the multi-recon. If conditions for generating a calcium-suppressed image are not set, the determination in step S242 is negative, and the parameter adjustment process shown in FIG. 6C is terminated. In this case, the generation unit 46 generates a calcium-suppressed image as set in the multi-recon.

[0077] On the other hand, if the conditions for generating a calcium-suppressed image are set in the multi-recon, the determination in step S242 is affirmative, and the process proceeds to step S244. In step S244, the adjustment unit 47 determines whether or not it has been specified that the setting of the conditions for generating the calcium-suppressed image be kept unchanged. If the user has specified that the setting of the conditions for generating the calcium-suppressed image be kept unchanged, the determination in step S244 is affirmative, and the parameter adjustment process shown in FIG. 6C is terminated. In this case, the generation unit 46 generates a calcium-suppressed image, even though the preview image PV does not contain calcium components.

[0078] On the other hand, if the user has not specified that the setting of the condition for generating a calcium-suppressed image should not be turned off, the determination in step S244 is negative, and the process proceeds to step S246. In step S246, the adjustment unit 47 turns off the setting of the condition for generating a calcium-suppressed image set in the multi-recon. That is, the adjustment unit 47 adjusts the multi-recon so that a calcium-suppressed image is not generated. When the process in step S246 ends, the parameter adjustment process shown in FIG. 6C ends.

[0079] Furthermore, if the preview image PV image contains calcium components, the determination in step S240 is affirmative, and the process proceeds to step S248. In step S248, the adjustment unit 47 adjusts the type of tomographic image to a "calcium-suppressed image." When the process in step S248 ends, the parameter adjustment process shown in FIG. 6C ends. In this case, as described with reference to FIG. 6A, the adjustment unit 47 adjusts the energy (keV) to a value appropriate for a calcium-suppressed image.

[0080] 6D shows a flowchart illustrating an example of the flow of a parameter adjustment process for adjusting the parameters of the window conditions (WW / WL). In this embodiment, as in the example shown in FIG. 6D, the window conditions (WW / WL) changed by the user for the preview image PV are used as parameters for multi-recon.

[0081] In step S260 of Fig. 6D, adjustment unit 47 determines whether the window conditions (WW / WL) of preview image PV have been changed by the user. If the window conditions (WW / WL) have not been changed, the determination in step S260 is negative, and the parameter adjustment process shown in Fig. 6D ends.

[0082] On the other hand, if the window conditions (WW / WL) have been changed, the determination in step S260 is affirmative, and the process proceeds to step S262. In step S262, the adjustment unit 47 adjusts the window conditions (WW / WL) applied to the virtual monochromatic X-ray image set in the multi-controller to values ​​similar to the window conditions (WW / WL) changed for the preview image PV. Note that instead of adjusting to exactly the same values, adjusted values ​​may be used taking into account the energy characteristics (keV) corresponding to the virtual monochromatic X-ray image. When the process in step S262 ends, the parameter adjustment process shown in FIG. 6D ends.

[0083] The technology of the present disclosure is not limited to the above embodiment, and various modifications are possible. For example, the following modifications 1 and 2 may be applied.

[0084] (Variation 1) In the above embodiment, the generating unit 46 generates a tomographic image of the entire area using all acquired projection images. In contrast, the adjusting unit 47 of this modified example may adjust the range of the tomographic image generated by the generating unit 46. For example, the range in which the tomographic image is generated may be adjusted based on an image of the object of interest included in the projection image (preview image PV). Specifically, the adjusting unit 47 may adjust the range so that a tomographic image is generated only for a cross section including the image of the object of interest or only for a section immediately before or after the cross section. In other words, the adjusting unit 47 may adjust the range so that a tomographic image is not generated for a range that does not include the object of interest. The range in which a tomographic image is generated (or not generated) refers to at least one of the range in the depth direction, i.e., the range in the direction of the slice thickness, and the range of the cross section of the tomographic image.

[0085] In this way, by adjusting the range of the tomographic images to be generated, the range of the tomographic images generated by the generating unit 46 can be reduced, thereby reducing the time required for reconstruction.

[0086] (Variation 2) In the multi-reconstruction of each of the above embodiments, a configuration has been described in which multiple types of tomographic images are sequentially reconstructed using parameters adjusted by the adjustment unit 47 based on an order predetermined in the protocol. In contrast, in this modified example, a configuration will be described in which the order in which tomographic images are generated can be changed. That is, in this modified example, the order of multi-reconstruction may be changed.

[0087] For example, a tomographic image that is important for image interpretation may be generated with priority, that is, a tomographic image that the image interpreter wants to see may be generated with priority.

[0088] As a specific example, when the generation of a virtual monochromatic X-ray image is registered in the multi-recon, the generation of the virtual monochromatic X-ray image is given the highest priority, and when the generation of a calcium-suppressed image is registered in the multi-recon, the generation of the calcium-suppressed image is given the highest priority. Note that when the user specifies the order, it is preferable to give the order specified by the user a higher priority. It is also preferable to present to the user the order in which the tomographic images will be generated, i.e., the order in which the multi-recon will be executed.

[0089] 7 shows an example of the order of multi-recon images displayed on the display unit 38 by the display control unit 42. In FIG. 7, the multi-recon protocol is set to generate three types of tomographic images in the order of "virtual monochromatic X-ray image," "□□□ (representing any type of image)," and "calcium-suppressed image." In addition, FIG. 7 shows a state in which the user has designated "virtual monochromatic X-ray image" as having the highest priority by checking the checkbox corresponding to "virtual monochromatic X-ray image."

[0090] If it is determined that the calcium-suppressed image should be generated first, the adjustment unit 47 adjusts the order so that the user-specified "virtual monochromatic X-ray image" is generated first (No. 1) and the "calcium-suppressed image" is generated next (No. 2), as shown in FIG. 7A. That is, the adjustment unit 47 swaps the second (No. 2) and third (No. 3) images in the order. The display control unit 42 also updates the display as shown in FIG. 7B so that the user can recognize that the order has been swapped.

[0091] In this way, by adjusting the order in which tomographic images are generated, it is possible to check the image of interest at an early stage. This makes it possible to immediately retake images or redo reconstruction under changed conditions, if necessary. Therefore, according to this modification, the time required to complete the examination can be further shortened.

[0092] As described above, the console 30 of each of the above embodiments is used in the CT apparatus 10, which performs a series of processes: acquiring multiple projection images using the photon-counting detector panel 28; and generating a tomographic image by reconstructing the multiple projection images based on predetermined parameters. In the console 30, the CPU 32A functions as the acquisition unit 40 to acquire projection images, and also functions as the adjustment unit 47 to adjust the parameters of the multi-reconstruction based on the acquired projection images.

[0093] In this way, the console 30 of each of the above embodiments can optimize the parameters of the multi-recon using the projected images. This allows for better optimization than the parameters set in the protocol. Therefore, the console 30 of each of the above embodiments can improve the throughput of the entire examination.

[0094] In each of the above embodiments, the following various processors can be used as the hardware structure of processing units that perform various processes, such as the acquisition unit 40, the display control unit 42, the reception unit 44, the generation unit 46, and the output unit 48. As described above, the various processors include a CPU, which is a general-purpose processor that executes software (programs) and functions as various processing units, as well as dedicated electrical circuits that are processors having a circuit configuration specifically designed to perform specific processes, such as a programmable logic device (PLD), which is a processor whose circuit configuration can be changed after manufacture, such as an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit).

[0095] A single processing unit may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs, or a combination of a CPU and an FPGA). Also, multiple processing units may be configured with a single processor.

[0096] Examples of configuring multiple processing units with a single processor include, first, a form in which one processor is configured with a combination of one or more CPUs and software, and this processor functions as multiple processing units, as typified by computers such as client and server. Second, a form in which a processor is used to realize the functions of an entire system including multiple processing units with a single IC (Integrated Circuit) chip, as typified by systems on chips (SoCs). In this way, various processing units are configured using one or more of the above-mentioned various processors as a hardware structure.

[0097] Furthermore, more specifically, the hardware structure of these various processors can be an electric circuit that combines circuit elements such as semiconductor elements.

[0098] In the above embodiment, the image processing program 33 is pre-stored (installed) in the storage unit 34 of the console 30, but the present invention is not limited to this. The image processing program 33 may be provided in a form recorded on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a USB (Universal Serial Bus) memory. The image processing program 33 may also be downloaded from an external device via a network.

[0099] Furthermore, the configurations and operations of the CT device 10 and console 30 described in the above embodiments are merely examples, and it goes without saying that they can be modified according to the circumstances without departing from the spirit of the present invention. It also goes without saying that the above embodiments can be combined as appropriate.

[0100] The present invention is also applicable to programs and program products.

[0101] The following additional notes are provided regarding the above-described embodiment. (Appendix 1) An image processing device used for CT imaging, in which a series of processes are performed, including acquisition of a plurality of projection images using a photon-counting radiation detector, and multi-reconstruction of a tomographic image by reconstructing the plurality of projection images based on predetermined parameters, at least one processor; The processor: acquiring the projection image; The parameters are adjusted based on the acquired projection image. Image processing device.

[0102] (Appendix 2) The multi-reconstruction sequentially reconstructs a plurality of types of tomographic images based on the parameters, at least some of which differ for each type; The processor: The plurality of types of tomographic images are sequentially reconstructed using the adjusted parameters. 2. The image processing device according to claim 1.

[0103] (Appendix 3) The parameter is at least one of the number of tomographic images, the range of the field of view, the thickness of the tomographic image, the matrix size, the type of tomographic image, whether or not correction processing is performed, the strength of the correction processing, energy, and window conditions. 3. The image processing device according to claim 2.

[0104] (Appendix 4) The processor: When the projection image includes an image of a contrast agent or an image of a metal, the type of the tomographic image is set to a virtual monochromatic X-ray image, and the energy is set to an energy corresponding to the contrast agent or the metal. 4. The image processing device according to claim 3.

[0105] (Appendix 5) The processor: If it is determined that the projection image contains a calcium component, The type of the tomographic image is a calcium-suppressed image in which the calcium component is suppressed. 5. The image processing device according to claim 3 or 4.

[0106] (Appendix 6) The processor: The order of reconstruction is determined according to the type of the tomographic image. 6. An image processing device according to any one of Supplementary Note 2 to Supplementary Note 5.

[0107] (Appendix 7) The processor: The range of the tomography for generating the tomographic image is adjusted based on an image of the object of interest included in the projection image as the parameter. 7. An image processing device according to any one of Supplementary Note 2 to Supplementary Note 6.

[0108] (Appendix 8) The processor: The generated tomographic image is output to an output destination according to the type of the tomographic image. 8. An image processing device according to any one of claims 2 to 7.

[0109] (Appendix 9) The processor: When a user's designation of the parameter is accepted, the parameter is adjusted based on the designation. 9. An image processing device according to any one of Supplementary Note 2 to Supplementary Note 8.

[0110] (Appendix 10) The processor: Displaying the projected image; Accepting the designation made to the projected image 10. The image processing device according to claim 9.

[0111] (Appendix 11) At least one processor included in an image processing device used for CT imaging, in which a series of processes, including acquisition of a plurality of projection images using a photon-counting radiation detector and generation of a tomographic image by reconstructing the plurality of projection images based on predetermined parameters, is performed, acquiring the projection image; The parameters are adjusted based on the acquired projection image. Image processing methods.

[0112] (Appendix 12) At least one processor of an image processing device used for CT imaging, in which a series of processes are performed, including acquisition of a plurality of projection images using a photon-counting radiation detector and generation of a tomographic image by reconstructing the plurality of projection images based on predetermined parameters, acquiring the projection image; The parameters are adjusted based on the acquired projection image. Image processing program to execute the process.

[0113] (Appendix 13) At least one processor of an image processing device used for CT imaging, in which a series of processes are performed, including acquisition of a plurality of projection images using a photon-counting radiation detector and generation of a tomographic image by reconstructing the plurality of projection images based on predetermined parameters, acquiring the projection image; The parameters are adjusted based on the acquired projection image. A computer program product including an image processing program for causing the processing to be performed.

[0114] (Appendix 14) At least one processor of an image processing device used for CT imaging, in which a series of processes are performed, including acquisition of a plurality of projection images using a photon-counting radiation detector and generation of a tomographic image by reconstructing the plurality of projection images based on predetermined parameters, acquiring the projection image; The parameters are adjusted based on the acquired projection image. A computer-readable storage medium that stores an image processing program for executing the process. [Explanation of symbols]

[0115] 10 CT device 12 Image Management System 14 workstations 20 Gantry 23 Radiation Generator 24 Bowtie Filter 25 Collimator 26 Opening 27 berths 28 Detector Panel 30 Console 32 control unit, 32A CPU, 32B ROM, 32C RAM 33 Image Processing Program 34 Storage section 35 I / F section 36 Control section 38 Display section 39 Bus 40 Acquisition Department 42 Display control unit 44 Reception Department 46 Generation part 47 Adjustment section 48 Output section PV preview image R Radiation S subject

Claims

1. An image processing device used for CT imaging, in which a series of processes are performed, including acquisition of a plurality of projection images using a photon-counting radiation detector, and multi-reconstruction of the plurality of projection images to generate a tomographic image based on predetermined parameters, at least one processor; The processor: acquiring the projection image; The parameters are adjusted based on the acquired projection image. Image processing device.

2. The multi-reconstruction sequentially reconstructs a plurality of types of tomographic images based on the parameters, at least some of which differ for each type; The processor: The plurality of types of tomographic images are sequentially reconstructed using the adjusted parameters. The image processing device according to claim 1 .

3. The parameter is at least one of the number of tomographic images, the range of the field of view, the thickness of the tomographic image, the matrix size, the type of tomographic image, whether or not correction processing is performed, the strength of the correction processing, energy, and window conditions. The image processing device according to claim 2 .

4. The processor: When the projection image includes an image of a contrast agent or an image of a metal, the type of the tomographic image is set to a virtual monochromatic X-ray image, and the energy is set to an energy corresponding to the contrast agent or the metal. The image processing device according to claim 3 .

5. The processor: If it is determined that the projection image contains a calcium component, The type of the tomographic image is a calcium-suppressed image in which the calcium component is suppressed. The image processing device according to claim 4 .

6. The processor: The order of reconstruction is determined according to the type of the tomographic image. The image processing device according to claim 2 .

7. The processor: The range of the tomography for generating the tomographic image is adjusted based on an image of the object of interest included in the projection image as the parameter. The image processing device according to claim 2 .

8. The processor: The generated tomographic image is output to an output destination according to the type of the tomographic image. The image processing device according to claim 2 .

9. The processor: When a user's designation of the parameter is accepted, the parameter is adjusted based on the designation. The image processing device according to claim 2 .

10. The processor: Displaying the projected image; Accepting the designation made to the projected image The image processing device according to claim 9 .

11. At least one processor included in an image processing device used for CT imaging, in which a series of processes, including acquisition of a plurality of projection images using a photon-counting radiation detector and generation of a tomographic image by reconstructing the plurality of projection images based on predetermined parameters, is performed, acquiring the projection image; The parameters are adjusted based on the acquired projection image. Image processing methods.

12. At least one processor of an image processing device used for CT imaging, in which a series of processes are performed, including acquisition of a plurality of projection images using a photon-counting radiation detector and multi-reconstruction of the plurality of projection images to generate a tomographic image based on predetermined parameters, acquiring the projection image; The parameters are adjusted based on the acquired projection image. Image processing program to execute the process.

Images