Control device, control method, and control processing program

Abstract

A control device, a control method, and a control processing program are provided that can facilitate the setting of imaging parameters in photon-counting CT even when the number of protocols increases according to the number of measurement modes. [Solution] At least one processor provided in a control device used for CT imaging, which captures multiple projection data of a subject using a photon-counting radiation detector, identifies the imaging area and examination purpose of the subject, obtains imaging parameters based on the identified imaging area and examination purpose, and presents the obtained imaging parameters as part of the imaging conditions.

Description

[Technical Field]

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

[0002] BACKGROUND ART Energy-integrated CT (photon-counting CT) devices using photon-counting radiation detectors are known as CT (Computed Tomography) devices for capturing medical images (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-57301 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, photon-counting CT is equivalent to being able to switch between CT devices with different characteristics, and simply put, the number of examination protocols doubles by the number of measurement modes. Therefore, it is no longer practical to set parameters for each protocol considered necessary for an examination and register them in association with the body part to be imaged, as was done in the past.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a control device, control method, and control processing program that can easily set imaging parameters in photon-counting CT, even if the number of protocols increases according to the number of measurement modes. [Means for solving the problem]

[0006] In order to achieve the above object, a control device of a first aspect of the present disclosure is configured such that at least one processor included in a control device used for CT imaging that captures multiple projection data of a subject using a photon-counting radiation detector identifies the imaging region of the subject and the examination purpose, obtains imaging parameters based on the identified imaging region and examination purpose, and presents the obtained imaging parameters as part of the imaging conditions.

[0007] The control device of the second aspect is the control device of the first aspect, wherein the imaging parameters are associated with each other based on a rule according to at least one of the imaging region and the purpose of the examination.

[0008] The control device of the third aspect is the control device of the second aspect, in which there are multiple types of shooting parameters, and the processor acquires first shooting parameters to which parameter values ​​are associated based on a first rule corresponding to the shooting area, and second shooting parameters to which parameter values ​​are associated based on a second rule corresponding to the purpose of the examination.

[0009] A fourth aspect of the control device is the control device of the third aspect, wherein when the type of the first shooting parameter and the type of the second shooting parameter are the same, the processor presents the second shooting parameter as part of the shooting conditions.

[0010] A control device according to a fifth aspect is the control device according to the third aspect, wherein the second imaging parameter includes at least one of a measurement mode and a focal spot size.

[0011] A sixth aspect of the control device is the control device of the first aspect, wherein the processor identifies a system state for CT imaging, and acquires imaging parameters based on the identified system state.

[0012] In order to achieve the above object, a control method of a seventh aspect of the present disclosure includes at least one processor provided in a control device used for CT imaging that captures multiple projection data of a subject using a photon-counting radiation detector, identifying the imaging region of the subject and the examination purpose, obtaining imaging parameters based on the identified imaging region and examination purpose, and presenting the obtained imaging parameters as part of the imaging conditions.

[0013] In order to achieve the above object, the eighth type of control processing program disclosed herein causes at least one processor provided in a control device used for CT imaging, which captures multiple projection data of a subject using a photon-counting radiation detector, to execute a process of identifying the imaging region and examination purpose of the subject, obtaining imaging parameters based on the identified imaging region and examination purpose, and presenting the obtained imaging parameters as part of the imaging conditions. [Effects of the Invention]

[0014] According to the present disclosure, even if the number of protocols increases according to the number of measurement modes in photon-counting CT, it is possible to easily set imaging parameters. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a configuration diagram illustrating an example of the configuration of a radiation CT imaging 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 4] 10 is a flowchart illustrating an example of the flow of a control process according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] First, an example of the configuration of a radiation CT (Computed Tomography) imaging device of this embodiment will be described. Fig. 1 shows a configuration diagram illustrating an example of the configuration of a radiation CT imaging device 10 of this embodiment. The radiation CT imaging device 10 of this embodiment is an apparatus that performs CT imaging by capturing a plurality of projection data using a photon-counting detector 28, the details of which will be described later. In this embodiment, this CT that captures a plurality of projection data using a photon-counting detector 28 is referred to as a "photon-counting CT."

[0018] As shown in FIG. 1, the radiation CT imaging apparatus 10 of this embodiment includes a gantry 20, a bed 27, and a console 30.

[0019] The gantry 20 has an opening 26, and a 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. The subject S in this embodiment is an example of a subject of the present disclosure.

[0020] Inside the gantry 20, a radiation generator 23 having a radiation tube (not shown), a bowtie filter 24, a collimator 25, and a detector 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 suitable for the size of the subject S, and is irradiated onto the subject S. The detector 28 detects the radiation that has passed through the subject S and generates projection data corresponding to the dose of the detected radiation. The detector 28 in 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 28, which is a photon-counting detector, outputs projection data corresponding to the photon energy.

[0021] The radiation generator 23 and the detector 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 28 are repeated as they rotate, thereby obtaining projection data at various projection angles. The multiple projection data obtained by the detector 28 are reconstructed by an image reconstruction unit (not shown) of the console 30 and output as an image.

[0022] The console 30 of this embodiment performs various controls related to imaging, generates medical images, etc. The console 30 of this embodiment is an example of a control 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 memory unit 34, an I / F (Interface) unit 35, an operation unit 36, and a display unit 38. The control unit 32, the memory 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.

[0023] 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 a control processing program 33 (described later), which are executed by the CPU 32A. The RAM 32C temporarily stores various data.

[0024] The storage unit 34 stores the projection data output from the detector 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), and a flash memory.

[0025] 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 28 via wired or wireless communication. The console 30 of this embodiment receives projection data from the detector 28 via the I / F unit 35. The received projection data is stored in the memory unit 34.

[0026] The operation unit 36 ​​is used by the user to input various information such as scan conditions for acquiring projection data, 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.

[0027] 3 is a functional block diagram showing an example of the functions of the console 30. The console 30 includes an identification unit 40, an acquisition unit 42, and a presentation unit 44. As an example, the console 30 of this embodiment executes a control processing program 33, whereby the CPU 32A of the control unit 32 functions as the identification unit 40, the acquisition unit 42, and the presentation unit 44.

[0028] The identification unit 40 identifies the imaging region and the examination purpose of the subject S. The identification unit 40 outputs the identified imaging region and examination purpose of the subject S to the acquisition unit 42. Note that the method by which the identification unit 40 identifies the imaging region and the examination purpose of the subject S is not limited. For example, the identification unit 40 may identify the imaging region and the examination purpose of the subject S from information input by the user via the operation unit 36. Furthermore, for example, the identification unit 40 may identify the imaging region and the examination purpose of the subject S from the imaging order, medical record information of the subject S, etc.

[0029] The acquisition unit 42 acquires imaging parameters based on the imaging region and examination purpose identified by the identification unit 40. Here, an example of a method for acquiring imaging parameters in the acquisition unit 42 of this embodiment will be described in detail as "Example 1." Note that the imaging parameters of this example include a measurement mode and a focal spot size.

[0030] Example 1 In this embodiment, the protocol of an energy-integrated radiation CT apparatus is used as a base, and general imaging parameters such as scan type, tube voltage, and tube current are associated with the imaging region, and measurement modes, which are imaging parameters specific to photon-counting CT, and focal spot sizes, which are closely related to the measurement modes in terms of spatial resolution, are grouped and assigned rules, and then associated with the examination purpose.

[0031] Table 1-1 shows an example of the characteristics of the measurement mode, which is one of the imaging parameters of this embodiment. The measurement mode is prepared by the system based on a combination of the spatial resolution in the XY plane, the minimum slice thickness of the tomographic image to be reconstructed (slice thickness: Z direction in FIG. 1), and energy information (specifically, energy resolution), and corresponds to determining the contents of the projection data, i.e., RawData, which is transmitted from the detector 28 to the console 30 when imaging the subject S and is used to reconstruct the image.

[0032] In this embodiment, the combination of spatial resolution in the XY plane, minimum slice thickness, and energy information is set to fit within a certain data size, taking into account the relationship between data transmission volume and storage capacity. Measurement mode A has standard spatial resolution in the XY plane and minimum slice thickness, but provides a large amount of energy information and is a mode in which calibration is performed using a reference material suitable for quantitative value measurement. Measurement mode B has the same spatial resolution in the XY plane as measurement mode A, but is characterized by the ability to set a thinner slice thickness than measurement mode A. Measurement mode B provides less energy information than measurement mode A due to the amount of data. Measurement modes C and D are characterized by the ability to obtain data with higher spatial resolution in the XY plane than measurement mode A by setting an appropriate focal spot size. Measurement mode C can be used with the same minimum slice thickness as measurement mode A and can also use energy information. On the other hand, measurement mode D can set a thinner slice thickness than measurement mode A, but does not provide energy information. Measurement mode E has even higher spatial resolution in the XY plane than measurement modes C and D and can set a thinner minimum slice thickness. Measurement mode E is similar to measurement mode D in that it does not provide energy information, but the spatial resolution in the XY plane is higher and the minimum slice thickness is thinner, which increases the amount of data, thereby limiting the coverage of data that can be acquired at one time.

[0033] [Table 1-1]

[0034] Table 1-2 also shows an example of the characteristics of the focal spot size, which is one of the imaging parameters of this embodiment. The focal spot size is a parameter that determines the spatial resolution in the XY plane, and there is a focal spot size that is appropriate for the spatial resolution of each measurement mode. For example, in measurement mode A, which has standard spatial resolution, setting the focal spot size to "small" does not achieve a spatial resolution higher than that achieved when the focal spot size is set to "medium." Furthermore, the smaller the focal spot size, the more limited the tube current that can be applied. Therefore, in measurement mode A, there is no benefit to setting the focal spot size to "small" or "extremely small." Furthermore, in measurement mode E, which has ultra-high resolution, setting the focal spot size to "medium" does not achieve a spatial resolution higher than that achieved in measurement mode D. Therefore, rules are established to ensure that a focal spot size appropriate for each measurement mode is set. Table 1-3 shows an example of the rules for the optimal focal spot size for each measurement mode. Note that when the focal spot size in the imaging parameters is set to "optimal," the optimal focal spot size (see Table 1-3) is set for that measurement mode. Note that the optimal focal spot size is a focal spot size that is expected to provide higher spatial resolution than other focal spot sizes.

[0035] [Table 1-2]

[0036] [Table 1-3]

[0037] The measurement modes and focal spot sizes shown in Tables 1-1 to 1-3 above are associated with the inspection purposes. Table 1-4 shows an example of the correspondence between the inspection purposes, measurement modes, and focal spot sizes.

[0038] [Table 1-4]

[0039] Any word can be set as the examination purpose, and the examination purpose set here will be selected when the protocol is read. It is also possible to set multiple combinations of measurement modes and focal spot sizes by assigning priorities to a single examination purpose, such as "routine." When reading a protocol, the one with a priority of "1" is normally read. If a combination different from the combination with a priority of "1" is to be used, it is possible to change to another combination, for example, without changing the examination purpose when planning the scan, by checking the purpose described in the identification information, such as "normal," "examination (energy)," or "high definition."

[0040] For example, if the purpose of the test is to measure "quantitative values," measurement mode A, which has a lot of energy information and is calibrated using a reference material suitable for measuring quantitative values, and the focal size that is optimal for measurement mode A, "large" are suitable.

[0041] Furthermore, if the purpose of the examination is a general "routine" examination to check for abnormalities, standard spatial resolution is sufficient, and measurement mode B, which can reconstruct images with thin slice thicknesses for MPR (Multi Planar Reconstruction) and 3D (3 dimensions), and can obtain virtual monochromatic radiographic images that can improve contrast and reduce metal artifacts when necessary, and the focal size, which is the optimal focal size for measurement mode B, are appropriate. If the doctor's opinion emphasizes detailed examination even in routine examinations, measurement mode C, which has higher spatial resolution than thin slice thicknesses and allows the use of energy information, and a focal size of "medium" are appropriate. Furthermore, if it is desired to obtain high-resolution images with thin slice thicknesses even if energy information is not available, measurement mode D and a focal size of "medium" are appropriate.

[0042] Furthermore, in the "Blood Vessels (Ca Processing)" examination, where the purpose is to suppress calcium (Ca) or perform calcium scoring in the blood vessels (coronary arteries) of the heart, calcium can be identified using energy information, and measurement mode C, which has high spatial resolution, and a focus size of "medium" are suitable. However, if the subject S is large, the focus size must be set to "large" in measurement mode C to increase the dose (tube current), which reduces the spatial resolution. This makes selecting measurement mode C less meaningful. Therefore, if the subject S is large, measurement mode B, which can obtain a thin slice thickness, and a focus size of "large," which is the optimal focus size for measurement mode B, are suitable.

[0043] Furthermore, when the inspection objective is "stent lumen" to evaluate the lumen inside a stent, measurement mode D, which has high spatial resolution and can reconstruct images with thin slice thickness for MPR and 3D, and a "small" focal spot size are suitable. The same applies when the inspection objective is "blood vessels" to observe the running state of blood vessels.

[0044] Furthermore, since acute fractures can be diagnosed by observing the presence or absence of bone marrow edema in calcium-suppressed water density images, when the examination objective is "fracture (large area)," measurement mode C, which allows the use of energy information and has high spatial resolution, and a focus size of "medium" are suitable. On the other hand, when the examination objective is "fracture (small area)," when more precise observation is required in a small area such as the hand, measurement mode E, which can obtain ultra-high resolution images, and a focus size of "extremely small," which is suitable for measurement mode E, are suitable.

[0045] The optimal focus size for measurement modes C and D is "small" for "Detailed Examination (Energy)" and "High Resolution" for the examination purpose of "Routine," and for "Detailed Examination," "Fracture (Large Area)," and "Blood Vessel (Ca Treatment)" for "Normal" and "Large Build." However, in the example shown in Table 1-4 above, taking into consideration the dose (tube current) related to the S / N (Signal / Noise), the focus size is set to "medium," which is expected to provide higher spatial resolution than measurement modes A and B, although the resolution will be slightly reduced.

[0046] In addition to the imaging required to obtain diagnostic images, the protocol also includes a combination of auxiliary scan types, such as scanograms for planning the imaging and monitoring scans for monitoring the contrast agent staining. The measurement modes and focal spot sizes for these scan types are set separately, as shown in Table 1-5.

[0047] [Table 1-5]

[0048] For the scan type "Scanogram," the same measurement mode and focal spot size as the diagnostic scan type are set. For "Monitoring Positioning" and "Monitoring," measurement mode B and the focal spot size optimal for measurement mode B are set to "Large."

[0049] In this embodiment, the parameters of the reconstructed image (tomographic image) used for diagnosis are associated with the imaging site. When the configurable imaging parameters, such as the type of image that can be reconstructed and spatial resolution, are changed depending on the examination purpose, i.e., the measurement mode and focal spot size, the image type and parameters set in the protocol are adjusted to maintain the same as possible. For example, if the protocol associated with the imaging site is set to a calcium-suppressed image that requires energy information, but the examination purpose is selected as "routine" and the priority is changed to "high resolution" (3) (see Tables 1-4), the measurement mode becomes measurement mode D, which does not contain energy information, and a calcium-suppressed image cannot be obtained. However, if the spatial resolution of the CT image is set to "highest," a high-resolution image of measurement mode D is obtained, rather than the standard resolution of measurement mode B.

[0050] In this embodiment, since the imaging parameters are associated with the imaging region and the examination purpose, the console 30 can obtain information representing the correspondence. The acquisition unit 42 acquires imaging parameters corresponding to the imaging region of the subject S and the examination purpose based on the information representing the correspondence. The acquisition unit 42 outputs the acquired imaging parameters to the presentation unit 44.

[0051] The presentation unit 44 presents the imaging parameters acquired by the acquisition unit 42 as imaging conditions. Note that the presentation method and presentation destination of the acquired imaging parameters by the presentation unit 44 as imaging conditions are not limited. For example, the presentation unit 44 may present the imaging parameters on a device mounted on the gantry 20, such as a touchpad. Furthermore, imaging parameters related to the reconstruction of a tomographic image, i.e., the generation of an image, may be presented to an image reconstruction unit (not shown) in the console 30. For example, the presentation unit 44 may present the imaging conditions to the user by displaying the imaging conditions on the display unit 38 of the console 30. Note that the presentation destination to which the presentation unit 44 presents the imaging conditions may be one location or multiple locations. Furthermore, for example, the presented imaging conditions may include items other than the imaging parameters. The presentation unit 44 may present the imaging parameters acquired by the acquisition unit 42 as imaging conditions together with other information.

[0052] Next, the operation of the console 30 of this embodiment will be described.

[0053] In the console 30 of this embodiment, the CPU 32A of the control unit 32 executes the control processing program 33 stored in the ROM 32B, thereby performing the control processing, an example of which is shown in Fig. 4. Fig. 4 shows a flowchart illustrating an example of the flow of the control processing in the console 30 of this embodiment.

[0054] First, in step S100 of FIG. 4, the identifying unit 40 identifies the imaging region of the subject S and the examination purpose, as described above.

[0055] In the next step S102, the acquisition unit 42 acquires imaging parameters based on the imaging region of the subject S and the examination purpose identified in step S100, as described above.

[0056] In the next step S104, the presentation unit 44 presents the shooting parameters acquired in step S102 as shooting conditions, as described above. When the process of step S104 ends, the control process shown in FIG.

[0057] The present disclosure is not limited to the above embodiment, and various modifications are possible. Below, an example that is a modification of the first example will be described.

[0058] Example 2 In this embodiment, a method for forming a protocol by grouping and assigning rules to each imaging parameter based on its role and meaning, and associating it with the imaging region or the purpose of the examination will be described. Table 2-1 shows an example of a set of imaging parameters (hereinafter referred to as a parameter set) associated with the imaging region. In the example shown in Table 2-1, information indicating the characteristics of the imaging region is set, for example, the size (width, length, and height) covering the imaging region, the presence or absence of influence due to movement of the subject S or the imaging region, and the influence due to bones. In addition, the tube voltage, tube current, scan time, and compensation object size are grouped together as a "dose group."

[0059] [Table 2-1]

[0060] Table 2-2 shows an example of setting feature information assuming that the imaging region is the "head."

[0061] [Table 2-2]

[0062] Furthermore, Table 2-3 shows an example of settable values ​​for each imaging parameter belonging to the above dose group, and Table 2-4 shows an example of setting the optimum rule for tube voltage, which is one of the imaging parameters.

[0063] [Table 2-3]

[0064] [Table 2-4]

[0065] The standard tube voltage is 120 kV, taking into account the window level (WL) and window width (WW) during interpretation. If the subject S is large, a higher value of 140 kV is recommended to reduce beam hardening artifacts. For children, a lower value than the standard is preferable, with 70 kV being recommended to ensure contrast even with a reduced dose. Taking into account this recommended tube voltage, the optimal tube voltage (kV) is automatically set based on the weight and age information of the subject S.

[0066] The tube current, which is one of the imaging parameters, is set optimally by AEC (Auto Exposure Control) using a scanogram, taking into consideration the setting of SD (Standard Deviation), which is the standard deviation of CT values.

[0067] Table 2-5 shows an example of setting the automatic setting rule for scan time, which is one of the imaging parameters.

[0068] [Table 2-5]

[0069] The scan time is set to a fast scan time of 0.5 seconds for imaging areas that move due to breathing, pulsation, etc., or imaging areas that are affected by these, and a slower scan time of 1.0 seconds for imaging areas that are stationary and have high absorption such as bones, or imaging areas surrounded by such bodies, in order to increase the dose. When the imaging area is the heart, the scan time is set based on the heart rate.

[0070] Table 2-6 shows an example of setting the automatic setting rule for the compensation object size, which is one of the imaging parameters.

[0071] [Table 2-6]

[0072] The size of the compensation object is determined based on the size (width) of the imaging region.

[0073] The above-mentioned dose group parameters are set for each combination of scan type, measurement mode, and focal spot size.

[0074] Table 2-7 shows a specific example of setting a dose group that is assumed to be associated with the imaging region when the imaging region is "head."

[0075] [Table 2-7]

[0076] When the scan type is scanogram, the tube voltage, tube current, and compensator are fixed values ​​for any combination of measurement mode and focal spot size. Also, when the scan type is conventional scan, helical scan, or dynamic scan, the tube voltage is set to "optimum," the tube current to "AEC," and the scan time and compensator size to "automatic" when the measurement mode is A, B, C, or D and the focal spot size is "large" or "medium." When the scan type is monitoring scan, the settings are made for the measurement mode A and the focal spot size is "large." Note that if an attempt is made to set a combination not defined here in the protocol, the user is prompted to either register the combination in a dose group or set it as an individual parameter.

[0077] Table 2-8 shows the parameter sets associated with the examination objectives defined for each imaging region.

[0078] [Table 2-8]

[0079] The imaging sequence frame is a set of parameters related to the imaging flow determined by the examination purpose for each imaging region. The image set is a set of parameters related to the diagnostic images to be obtained by imaging. Note that the parameters belonging to the image set are also treated as imaging parameters because they are parameters for reconstructing the projection data obtained by imaging.

[0080] Table 2-9 shows the possible values ​​of the parameters belonging to the above-mentioned shooting sequence frames.

[0081] [Table 2-9]

[0082] Table 2-10 shows an example of the automatic setting rule for the scanogram imaging length.

[0083] [Table 2-10]

[0084] The scanogram can image coronal and sagittal sections, and the imaging length is set to the width or height of the imaging region based on the pixel size when imaging. If the length (length in the body axis direction of the subject S) of the imaging region is greater than the width or height, the imaging length is adjusted to the length direction.

[0085] The imaging sequence frame here refers to a parameter for specifying how to combine and control each imaging method, and also includes the measurement mode specific to photon-counting CT and the focal spot size, which is closely related to it.

[0086] Table 2-11 shows specific examples of setting the imaging sequence frames for each examination purpose when the imaging area is "head." Note that "Purpose" in Table 2-11 indicates the examination purpose for which correspondence is assumed. Note that the actual correspondence is shown in Table 2-15, which will be described later.

[0087] [Table 2-11]

[0088] The sequence frame "SF-0001" in Table 2-11 corresponds to a general routine and consists of two scan types: "scanogram" and "conventional." The scanogram measurement mode and focal spot size are set to be the same as those for diagnostic scans. Furthermore, the conventional measurement mode and focal spot size are set to "purpose-specific settings" that are tailored to the examination purpose. When this "purpose-specific setting" is specified, multiple "examination purposes" can be configured, and detailed settings can be made using the "Sub-****" sequence frame for each examination purpose. In the example settings shown in Table 2-11, "Sub-0001" is associated with the "routine" examination purpose, and measurement mode B and focal spot size are set to "optimal," i.e., "large." Furthermore, "Sub-0002" is associated with the "detailed" examination purpose, and measurement mode C and focal spot size are set to "medium." In addition, other parameters (blank spaces in Table 2-11) in "Sub-0001" and "Sub-0002" will inherit the settings of "SF-0001".

[0089] Although not shown in the above setting example, it is also possible to add "Sub-0003" to be associated with the examination purpose "Detailed examination (contrast)" and set the contrast to "ON," thereby overwriting the parameters inherited from "SF-0001." Note that "SF-0001," which is the base for the purpose-specific settings, can be associated with the imaging region rather than the examination purpose, with common parameters inherited from the imaging region, and parameters that need to be changed according to the examination purpose can be set for each purpose.

[0090] In addition, for "Sub-0001": "Routine" and "Sub-0002": "Detailed Examination" in "SF-0001", "SF-0002": "Cerebral Blood Vessels", and "SF-0003": "Blood Flow", the scanogram imaging length is set to "automatic" and is determined based on the imaging area information, i.e., the "size (width, length, height)" information in the set of imaging parameters associated with the imaging area shown in Table 2-1 above.

[0091] Here, it may be necessary to adjust some or all of the parameters (dose information group) associated with the imaging region according to the purpose of the examination. In this case, the parameters can be set in the imaging sequence frame, and the setting is given priority. For example, if the tube voltage is set in the imaging sequence frame, the setting is given priority.

[0092] Table 2-12 shows examples of configurable values ​​of the imaging parameters belonging to the image sets described above.

[0093] [Table 2-12]

[0094] The shooting parameters belonging to an image set are parameters for specifying what kind of diagnostic image (tomographic image) will be created, and also include specifications for processing the generated image (automatic analysis such as 3D, MPR, etc., and image transfer destination).

[0095] Table 2-13 shows specific examples of image set settings for each examination purpose when the imaging area is "head." Table 2-14 also shows examples of settings for the automatic setting table for matrix size, which is the size of the entire set of pixels that make up a tomographic image.

[0096] [Table 2-13]

[0097] [Table 2-14]

[0098] The image set "IM-0001" in Table 2-13 has parameters set for reconstructing CT images, with the matrix size set to "automatic" and the spatial resolution set to "highest." In the case of measurement mode A, a CT image with "standard resolution," the highest resolution in measurement mode A, is reconstructed with a matrix size of "512" (specifically, 512 x 512), which is the setting when the FOV (Field of View) is "240," by referring to the matrix size automatic setting table in Table 2-14. Similarly, in the case of measurement mode C, a CT image with "high resolution," the highest resolution in measurement mode C, is reconstructed with a matrix size of "1024" (specifically, 1024 x 1024), which is the setting when the FOV is "240."

[0099] On the other hand, for the image set "IM-0002" in Table 2-13, a "standard resolution" virtual monochromatic radiation image (70 keV) is reconstructed with a matrix size of "512" in any of the available energy measurement modes A, B, and C.

[0100] Table 2-15 shows the protocolized content in which the parameter sets grouped into the dose groups, imaging sequence frames, and image sets are associated with the imaging region and examination purpose.

[0101] [Table 2-15]

[0102] In this way, also in this embodiment, the parameter set of imaging parameters is associated with the imaging region and the examination purpose, so that the console 30 can obtain information representing the correspondence. The acquisition unit 42 of the console 30 acquires imaging parameters corresponding to the imaging region of the subject S and the examination purpose based on the information representing the correspondence. The acquisition unit 42 outputs the acquired imaging parameters to the presentation unit 44.

[0103] Example 3 In this embodiment, an example of the flow of an examination using the protocol shown in the first embodiment will be described.

[0104] First, the subject information (such as name, sex, and age), imaging position (head first / feet first, and supine / prone / right lateral / left lateral), imaging area, and examination purpose are set. The imaging position can also be set by obtaining information from the 3D camera. Table 3-1 shows an example of setting subject information, imaging position, imaging area, and examination purpose.

[0105] [Table 3-1]

[0106] When the identifying unit 40 identifies "heart" as the imaging region and "blood vessel (Ca processing)" as the examination purpose, the acquiring unit 42 acquires the protocols shown in Tables 3-2 to 3-4 as imaging parameters. Then, the presenting unit 44 presents the protocols. As an example, in this embodiment, the protocols are displayed on the display unit 38. Tables 3-2 to 3-4 show examples of protocols associated with the combination of "heart" as the imaging region and "blood vessel (Ca processing)" as the examination purpose.

[0107] [Table 3-2]

[0108] [Table 3-3]

[0109] [Table 3-4]

[0110] In the example of Table 3-4, the scanogram measurement mode is set to "same as diagnostic scan type," and the focal spot size is also set to "same as diagnostic scan type." Therefore, measurement mode C, which is a measurement mode in which the scan type is set to "ECG (Electrocardiogram)-helical," and the focal spot size are set to "medium."

[0111] After the start position of the scanogram is set, a scanogram of the subject S is taken.

[0112] After the scanogram is taken, a monitoring positioning scan is performed to determine the scan position for monitoring the contrast agent. The measurement mode and focal spot size are set to measurement mode B and "optimal," i.e., "large," as previously set.

[0113] After the monitoring positioning scan, contrast setting is performed. Here, the plan is to perform a monitoring scan with measurement mode B and a focus size set to "optimal," i.e., "large," and an ECG-helical scan with measurement mode C and a focus size set to "medium." However, if the current value reaches the upper limit when the focus size is set to "medium" in the automatic tube current control (AEC) setting for the ECG-helical scan, the imaging parameters (imaging conditions) are switched to perform imaging. For example, the user clicks the right button of the mouse (an example of the operation unit 36) on the examination objective "Blood vessels (Ca processing)" displayed on the display unit 38 and selects "large physique," which has a priority of "2," from the displayed menu. As a result, measurement mode B and the focus size associated with "large physique" are switched to "optimal," as shown in Table 3-3. This changes the focus size to "large," allowing imaging to be performed under imaging conditions with a higher upper limit for tube current.

[0114] After ECG (Electrocardiogram)-helical scanning, the diagnostic images set in the protocol are registered as queue jobs, and reconstructed tomographic images are obtained as diagnostic images.

[0115] Thus, according to this embodiment, CT imaging of the subject S is performed using the imaging conditions presented by the console 30 of the present disclosure, and diagnostic images can be obtained, allowing examination of the subject S to be performed.

[0116] Example 4 In this embodiment, an example of the flow of an examination using the protocol shown in the second embodiment will be described.

[0117] First, the subject information (such as name, sex, and age), imaging position (head first / feet first, and supine / prone / right lateral / left lateral), imaging area, and examination purpose are set. The imaging position can also be set by obtaining information from the 3D camera. Table 4-1 shows an example of setting subject information, imaging position, imaging area, and examination purpose.

[0118] [Table 4-1]

[0119] When the identifying unit 40 identifies "head" as the imaging region and "routine" as the examination purpose, the acquiring unit 42 acquires the protocols shown in Tables 4-2 to 4-10 as imaging parameters. Then, the presenting unit 44 presents the protocols. As an example, in this embodiment, the protocols are displayed on the display unit 38. Tables 4-2 to 4-10 show examples of protocols associated with the combination of "head" as the imaging region and "routine" as the examination purpose.

[0120] [Table 4-2]

[0121] [Table 4-3]

[0122] [Table 4-4]

[0123] [Table 4-5]

[0124] [Table 4-6]

[0125] [Table 4-7]

[0126] [Table 4-8]

[0127] [Table 4-9]

[0128] [Table 4-10]

[0129] The scanogram imaging parameters for planning the imaging position and imaging range are determined based on pre-set rules or set values, with the same measurement mode B as for the diagnostic scan (conventional scan), the focus size set to "optimal" (i.e., the focus size is set to "large"), the tube voltage set to 120 kV, the tube current set to 50 mA, and the imaging length set to 250 mm based on the size information associated with the imaging area.

[0130] The imaging direction is set to head first, and the bed 27 is controlled in a direction away from the scanner so that imaging is performed from the lower side (legs) of the body to the upper side (head).

[0131] The start position of the scanogram is adjusted by adjusting the position of the bed 27 with the projector as a reference while checking the subject S. Alternatively, the start position of the scanogram may be automatically set using camera information.

[0132] After setting the scanogram start position, a scanogram is taken. The scanogram is imaged in real time to confirm that the intended imaging has been achieved and to stop imaging once the required area has been imaged, so the spatial resolution of measurement mode B is downsampled to create an image with a data volume.

[0133] After the scanogram is taken, depending on the scanogram measurement mode, the image is refined (high definition) to the spatial resolution of measurement mode B, or a virtual monochromatic radiographic image is generated using the energy information, recreating an image useful for scan planning with improved contrast or reduced artifacts, allowing additional information to be confirmed.

[0134] The scan conditions are adjusted based on information obtained from the images obtained by scanogram capture. For example, the "examination objective" can be changed by setting the scan start position or by reviewing the scanogram image generated in post-processing. In this example, if the scan start position is set on the scanogram and the scan is performed according to the displayed protocol, the conventional scan will be performed using measurement mode B, a "large" focal spot size, a tube voltage of 120 kV, an AEC tube current value, a scan voltage of 1.0 s, and a "standard" compensation device, with a scan length of 120 mm from the lower part of the body (legs) to the upper part of the body (head).

[0135] When the user confirms the imaging parameters (starts imaging preparation), the scanner system operates according to the imaging parameters. Once imaging preparation is complete, imaging begins with an imaging start operation. During imaging, a preview image is displayed on the display unit 38 of the console 30, allowing the user to confirm that the scan is being performed at the intended position.

[0136] Once the imaging is complete, a queue job reconstructs a CT image with a matrix size of 512 x 512, using the pre-set parameters, i.e., a standard resolution CT image with a 240 mm FOV, which is the highest resolution for measurement mode A. The reconstructed CT image is then transferred to the PACS (Picture Archiving and Communication System), which is the set destination.

[0137] Thus, according to this embodiment, CT imaging of the subject S is performed according to the imaging conditions presented by the console 30 of the present disclosure, and a CT image can be obtained, thereby enabling an examination of the subject S to be performed.

[0138] Example 5 In principle, photon-counting CT requires calibration for each measurement mode. Therefore, for devices with many measurement modes, maintenance work takes time, and it is conceivable that the device will be used with only some of the measurement modes calibrated. There are various types of calibration. For example, a calibration method uses energy information to identify a substance by varying the size of the basis material, measuring photon count values ​​under various measurement conditions, such as tube voltage and tube current, and creating a table. Another example is a calibration method that measures circular phantoms of different sizes under various measurement conditions to achieve CT value uniformity regardless of the size of the substance and determines correction parameters. Because multiple types of calibration exist, this embodiment first establishes a correspondence between the measurement mode and the system status (usable calibration status table and detector element status table) as shown in Table 5-1. Furthermore, for each calibration status table, information on whether each of the multiple types of calibration has been performed or not is obtained. As an example, Table 5-2 indicates whether each of calibrations 1 to n in the calibration status table (A) has been performed or not. Table 5-3 also shows whether each of calibrations 1 to n in the calibration status table (B) has been performed or not. In Tables 5-2 and 5-3, "Completed" indicates that the calibration has been performed, "Not yet" indicates that the calibration has not been performed, and "-" indicates that the calibration does not need to be performed.

[0139] Based on the correspondence shown in Table 5-1, unavailable measurement modes are determined from the calibration status table corresponding to the measurement mode used for imaging, and if a measurement mode is unavailable when the protocol is read out, the system controls to use a measurement mode closest to it. For example, according to Tables 5-2 and 5-3, if calibration 2 required for measurement mode A has not been performed, the system controls to use the next measurement mode B instead of measurement mode A. However, if a reconstructed image that cannot be performed in measurement mode B is set, the user is notified of this.

[0140] Furthermore, there may be cases where a pixel of a detector element of the detector 28 is defective. Therefore, the measurement mode may be controlled depending on the state of the detector element. In this embodiment, a detector element status table is prepared to store information indicating whether each pixel of the detector element of the detector 28 is defective, and whether it can be used. As an example, Table 5-4 shows whether each pixel, represented by column x channel (CH), in the detector element status table (D) can be used. Table 5-5 also shows whether each pixel, represented by column x channel (CH), can be used in the detector element status table (E). In Tables 5-4 and 5-5, "○" indicates that the pixel is not defective and can be used; "△" indicates that the pixel is usable but may be degraded; and "×" indicates that the pixel cannot be used.

[0141] For example, it may be impossible to use the ultra-high resolution measurement mode E, but there may be no problem if the high resolution measurement mode D, which bundles pixels, is used. Therefore, the detector element status is determined from the detector element status table, and control is exercised to use a measurement mode that is closest to the purpose of the inspection.

[0142] [Table 5-1]

[0143] [Table 5-2]

[0144] [Table 5-3]

[0145] [Table 5-4]

[0146] [Table 5-5]

[0147] Furthermore, the radiation generator 23 may have limited usable focal spot sizes due to incomplete calibration using the focal spot size, misalignment of the focal spot size itself, etc. Therefore, a correspondence between the focal spot size and the system status (radiation tube usability status table) as shown in Table 5-6 is set, and the usability of the focal spot size is obtained for each usability status table (Table 5-7). In Table 5-7, "○" indicates usable, and "×" indicates unusable.

[0148] If it is determined that an appropriate focal size cannot be used to utilize the measurement mode based on the usability status corresponding to each focal size as shown in Table 5-6, control is exercised to use a set of measurement mode and focal size that is closest to the spatial resolution required for the inspection.If the usability status in the usability status table (reduced) as shown in Table 5-7 is "x", i.e., the focal size (reduced) is unavailable, and measurement mode E and focal size are set to extremely small, the closest available focal size, with a usability status of "○", i.e., usable "(small)", is selected, and measurement mode D, which is most suitable for that focal size, is set.

[0149] [Table 5-6]

[0150] [Table 5-7]

[0151] In this way, the console 30 of this modified example can identify the system state for CT imaging, and acquire imaging parameters based on the identified state.

[0152] As described above, the console 30 is a control device used for CT imaging that captures multiple projection data of the subject S using a photon-counting radiation detector, and the identification unit 40 identifies the imaging region and examination purpose of the subject S. The acquisition unit 42 also acquires imaging parameters based on the identified imaging region and examination purpose. The presentation unit 44 then presents the acquired imaging parameters as imaging conditions.

[0153] In conventional energy-integrated CT systems, examination protocols are registered in association with the imaging region, read out according to the imaging region, and then used by adjusting the necessary conditions, imaging length, etc. Because the detectors of photon-counting CT systems can bundle the basic element size and number of energy bins, the system typically provides multiple combinations of spatial resolution in the XY plane (number of channels), slice thickness and rows in the Z direction, and number of energy bins (measurement modes) that the user can select. Therefore, photon-counting CT is equivalent to being able to switch between CT systems with different characteristics. Simply put, the number of examination protocols doubles by the number of measurement modes. Therefore, it is no longer practical to individually set parameters for each protocol considered necessary for an examination and register them in association with the imaging region, as was done in the past.

[0154] In contrast, as shown in the above examples, the console 30 of this embodiment structures (groups) parameters, assigns rules to them, and associates them with those determined by the "portion to be imaged" and those determined by the "purpose of examination," thereby facilitating protocol management. For example, an examination protocol is determined based on the "portion to be imaged," which corresponds to the position (location) of the human body, and the "purpose of examination," which is what is desired to be viewed at that portion to be imaged (e.g., checking the overall status of the portion to be imaged, checking the state of stenosis of blood vessels, checking the state of blood flow, etc.).

[0155] Therefore, according to the console 30 of this embodiment, even if the number of protocols increases according to the number of measurement modes in photon-counting CT, it is possible to easily set imaging parameters.

[0156] In each of the above embodiments, the following various processors can be used as the hardware structure of the processing units that execute various processes, such as the identification unit 40, the acquisition unit 42, and the presentation unit 44. 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 designed specifically for executing 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).

[0157] 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.

[0158] 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.

[0159] Furthermore, more specifically, the hardware structure of these various processors can be an electric circuit that combines circuit elements such as semiconductor elements.

[0160] In the above embodiment, the control 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 control 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 control processing program 33 may also be downloaded from an external device via a network.

[0161] Furthermore, the configurations and operations of the radiation CT imaging apparatus 10 and the console 30, etc., 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.

[0162] The present invention is also applicable to programs and program products.

[0163] The following additional notes are provided regarding the above-described embodiment. (Appendix 1) At least one processor included in a control device used in CT imaging that captures multiple projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. Control device.

[0164] (Appendix 2) The imaging parameters are associated based on rules according to at least one of the imaging region and the purpose of the examination. 10. The control device of claim 1.

[0165] (Appendix 3) There are multiple types of imaging parameters, The processor: A first imaging parameter to which a parameter value is associated based on a first rule corresponding to an imaging region and a second imaging parameter to which a parameter value is associated based on a second rule corresponding to an examination purpose are acquired. 3. The control device according to claim 2.

[0166] (Appendix 4) The processor: When the type of the first imaging parameter and the type of the second imaging parameter are the same, the second imaging parameter is included in the imaging conditions and presented. 4. The control device according to claim 3.

[0167] (Appendix 5) The second imaging parameter includes at least one of a measurement mode and a focal spot size. 4. The control device according to claim 3.

[0168] (Appendix 6) The processor: identifying a system state for the CT scan; acquiring imaging parameters further based on the determined system state; 6. The control device according to any one of claims 1 to 5.

[0169] (Appendix 7) At least one processor included in a control device used in CT imaging that captures multiple projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. Control method.

[0170] (Appendix 8) At least one processor of a control device used in CT imaging that captures a plurality of projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. A control processing program for executing processing.

[0171] (Appendix 9) At least one processor of a control device used in CT imaging that captures a plurality of projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. A computer program product including a control processing program for causing a process to be performed.

[0172] (Appendix 10) At least one processor of a control device used in CT imaging that captures a plurality of projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. A computer-readable storage medium that stores a control processing program for executing processing. [Explanation of symbols]

[0173] 10. Radiation CT imaging device 20 Gantry 23 Radiation Generator 24 Bowtie Filter 25 Collimator 26 Opening 27 berths 28 detectors 30 Console 32 control unit, 32A CPU, 32B ROM, 32C RAM 33 Control Processing Program 34 Storage section 35 I / F section 36 Operation section 38 Display section 39 Bus 40 Specific section 42 Acquisition Department 44 Presentation part R Radiation S subject

Claims

1. At least one processor included in a control device used in CT imaging that captures a plurality of projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. Control device.

2. The imaging parameters are associated based on rules according to at least one of the imaging region and the purpose of the examination. The control device according to claim 1 .

3. There are multiple types of imaging parameters, The processor: A first imaging parameter to which a parameter value is associated based on a first rule corresponding to an imaging region and a second imaging parameter to which a parameter value is associated based on a second rule corresponding to an examination purpose are acquired. The control device according to claim 2 .

4. The processor: When the type of the first photographing parameter and the type of the second photographing parameter are the same, the second photographing parameter is included in the photographing conditions and presented. The control device according to claim 3 .

5. The second imaging parameter includes at least one of a measurement mode and a focal spot size. The control device according to claim 3 .

6. The processor: Identifying a system state for the CT scan; acquiring imaging parameters further based on the determined system state; The control device according to claim 1 .

7. At least one processor included in a control device used in CT imaging that captures a plurality of projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. Control method.

8. At least one processor included in a control device used for CT imaging that captures a plurality of projection data of a subject using a photon-counting radiation detector, Identifying the imaging region and the examination purpose of the subject; acquiring imaging parameters based on the identified imaging region and the examination purpose; The acquired imaging parameters are included in the imaging conditions and presented. A control processing program for executing processing.

Images