JP2017217137A - X-ray CT apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus which allows an operator to easily execute setting for imaging.SOLUTION: The X-ray CT apparatus has a collection part, an image reconstruction part, an acquisition part, a storage part and a setting part. The collection part collects projection data by detecting X-rays passing through a subject. The image reconstruction part reconstructs image data from the projection data. The acquisition part acquires location information regarding a plurality of sections of the subject in the image data. The storage part stores virtual patient figure information having location information of each of a plurality of sections of the virtual patient. The setting part sets an imaging range not including an imaging range of the image data on the basis of location information regarding the plurality of sections in the image data and the virtual patient figure information.SELECTED DRAWING: Figure 2

Description

  Embodiments described herein relate generally to an X-ray CT apparatus.

  Conventionally, in imaging using an X-ray CT apparatus (CT; Computed Tomography), before performing actual imaging (main scanning) for collecting data used for diagnosis, an imaging range for actual imaging is set. A positioning image (scano image) is taken.

Japanese Patent Laid-Open No. 2014-238751 JP2015-119768A Special table 2012-008296 JP 2010-017215 A

  The problem to be solved by the present invention is to provide an X-ray CT apparatus that allows an operator to easily perform settings when performing imaging.

  The X-ray CT apparatus of the embodiment includes an acquisition unit, an image reconstruction unit, an acquisition unit, a storage unit, and a setting unit. The collection unit collects projection data by detecting X-rays transmitted through the subject. The image reconstruction unit reconstructs image data from the projection data. The acquisition unit acquires position information relating to a plurality of parts of the subject in the image data. A memory | storage part memorize | stores the virtual patient body type information which has each positional information on the several site | part of a virtual patient. The setting unit sets an imaging range that does not include the imaging range of the image data, based on position information relating to the plurality of parts in the image data and the virtual patient body type information.

FIG. 1 is a diagram illustrating an example of a configuration of a medical information processing system according to the first embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the X-ray CT apparatus according to the first embodiment. FIG. 3 is a diagram for explaining the three-dimensional positioning image shooting by the scan control circuit according to the first embodiment. FIG. 4A is a diagram for explaining an example of acquisition processing by the acquisition function according to the first embodiment. FIG. 4B is a diagram for explaining an example of acquisition processing by the acquisition function according to the first embodiment. FIG. 5 is a diagram for explaining an example of acquisition processing by the acquisition function according to the first embodiment. FIG. 6 is a diagram for explaining an example of acquisition processing by the acquisition function according to the first embodiment. FIG. 7 is a diagram illustrating an example of virtual patient figure information. FIG. 8 is a diagram for explaining an example of collation processing by the setting function according to the first embodiment. FIG. 9 is a diagram illustrating a scan range conversion example by coordinate conversion according to the first embodiment. FIG. 10 is a flowchart illustrating an example of a processing procedure performed by the X-ray CT apparatus according to the first embodiment. FIG. 11 is a diagram illustrating an example of a positioning image. FIG. 12 is a diagram illustrating an example of an MPR image that is a coronal cross-sectional image reconstructed from the deformed region by the image reconstruction circuit. FIG. 13 is a diagram illustrating an example of the estimated shooting range. FIG. 14 is a diagram illustrating an example of the composite image data. FIG. 15 is a flowchart illustrating an example of a processing procedure performed by the X-ray CT apparatus according to the second embodiment. FIG. 16 is a diagram for explaining a modification. FIG. 17 is a diagram for explaining a modification.

  Embodiments of an X-ray CT (Computed Tomography) apparatus will be described below in detail with reference to the accompanying drawings. Hereinafter, a medical information processing system including an X-ray CT apparatus will be described as an example. In the medical information processing system 100 shown in FIG. 1, only one server device and one terminal device are shown, but the medical information processing system 100 may include a plurality of server devices and terminal devices. . The medical information processing system 100 may include a medical image diagnostic apparatus other than the X-ray CT apparatus, for example, a medical image diagnostic apparatus such as an X-ray diagnostic apparatus, an MRI (Magnetic Resonance Imaging) apparatus, and an ultrasonic diagnostic apparatus.

(First embodiment)
FIG. 1 is a diagram illustrating an example of a configuration of a medical information processing system 100 according to the first embodiment. As illustrated in FIG. 1, the medical information processing system 100 according to the first embodiment includes an X-ray CT apparatus 1, a server apparatus 2, and a terminal apparatus 3. The X-ray CT apparatus 1, the server apparatus 2, and the terminal apparatus 3 are in a state in which they can communicate with each other directly or indirectly through, for example, a hospital LAN (Local Area Network) 4 installed in a hospital. It has become. For example, when a PACS (Picture Archiving and Communication System) is introduced in the medical information processing system 100, each device transmits and receives medical images and the like according to the DICOM (Digital Imaging and Communications in Medicine) standard.

  Further, in the medical information processing system 100, for example, HIS (Hospital Information System), RIS (Radiology Information System), etc. are introduced to manage various information. For example, the terminal device 3 transmits the created inspection order to the X-ray CT apparatus 1 or the server apparatus 2. The X-ray CT apparatus 1 acquires patient information from an examination order received directly from the terminal apparatus 3 or a patient list (modality work list) for each modality created by the server apparatus 2 that has received the examination order. X-ray CT image data is collected every time. Then, the X-ray CT apparatus 1 transmits the collected X-ray CT image data and image data generated by performing various image processing on the X-ray CT image data to the server apparatus 2. The server apparatus 2 stores the X-ray CT image data and image data received from the X-ray CT apparatus 1, generates image data from the X-ray CT image data, and responds to an acquisition request from the terminal apparatus 3. Data is transmitted to the terminal device 3. The terminal device 3 displays the image data received from the server device 2 on a monitor or the like. Hereinafter, each device will be described.

  The terminal device 3 is a device that is arranged in each department in the hospital and is operated by a doctor who works in each department, such as a PC (Personal Computer), a tablet PC, a PDA (Personal Digital Assistant), a mobile phone, etc. It is. For example, in the terminal device 3, medical record information such as a patient's symptom and a doctor's findings is input by a doctor. Further, the terminal device 3 receives an inspection order for ordering an inspection by the X-ray CT apparatus 1, and transmits the input inspection order to the X-ray CT apparatus 1 and the server apparatus 2. That is, the doctor in the medical department operates the terminal device 3 to read the reception information of the patient who has visited the hospital and information on the electronic medical record, examines the corresponding patient, and inputs the medical record information to the read electronic medical record. Then, the doctor in the medical department operates the terminal operation 3 according to the necessity of the examination by the X-ray CT apparatus 1 and transmits the examination order.

  The server apparatus 2 stores medical images (for example, X-ray CT image data and image data collected by the X-ray CT apparatus 1) collected by the medical image diagnostic apparatus, and performs various image processing on the medical images. For example, a PACS server or the like. For example, the server device 2 receives a plurality of examination orders from the terminal device 3 arranged in each medical department, creates a patient list for each medical image diagnostic device, and transmits the created patient list to each medical image diagnostic device. To do. For example, the server apparatus 2 receives an examination order for performing an examination by the X-ray CT apparatus 1 from the terminal device 3 of each clinical department, creates a patient list, and creates the created patient list as an X-ray CT. Transmit to device 1. And the server apparatus 2 memorize | stores the X-ray CT image data and image data which were collected by the X-ray CT apparatus 1, and according to the acquisition request from the terminal device 3, X-ray CT image data and image data are stored in the terminal apparatus. 3 to send.

  The X-ray CT apparatus 1 collects X-ray CT image data for each patient and uses the collected X-ray CT image data and image data generated by performing various image processing on the X-ray CT image data as a server. Transmit to device 2. FIG. 2 is a diagram illustrating an example of the configuration of the X-ray CT apparatus 1 according to the first embodiment. As shown in FIG. 2, the X-ray CT apparatus 1 according to the first embodiment includes a gantry 10, a bed apparatus 20, and a console 30.

  The gantry 10 is a device that irradiates a subject (patient) P with X-rays, detects X-rays transmitted through the subject P, and outputs the X-rays to the console 30. The gantry 10 generates X-rays. The apparatus 12 includes a detector 13, a data acquisition circuit (DAS) 14, a rotating frame 15, and a gantry drive circuit 16.

  The rotating frame 15 supports the X-ray generator 12 and the detector 13 so as to face each other with the subject P interposed therebetween, and is rotated at a high speed in a circular orbit around the subject P by a gantry driving circuit 16 described later. An annular frame.

  The X-ray irradiation control circuit 11 is a device that supplies a high voltage to the X-ray tube 12a as a high voltage generator. The X-ray irradiation control circuit 11 irradiates the subject P from the X-ray tube 12a by adjusting the tube voltage and tube current supplied to the X-ray tube 12a under the control of the scan control circuit 33 described later. Adjust the X-ray dose.

  The X-ray irradiation control circuit 11 switches the wedge 12b. The X-ray irradiation control circuit 11 adjusts the X-ray irradiation range (fan angle and cone angle) by adjusting the aperture of the collimator 12c. In addition, this embodiment may be a case where an operator manually switches a plurality of types of wedges.

  The X-ray generator 12 is an apparatus that generates X-rays and irradiates the subject P with the generated X-rays, and includes an X-ray tube 12a, a wedge 12b, and a collimator 12c.

  The X-ray tube 12 a is a vacuum tube that irradiates the subject P with the X-ray beam by the high voltage supplied by the X-ray irradiation control circuit 11. The X-ray beam is applied to the subject P as the rotating frame 15 rotates. Irradiate. The X-ray tube 12a generates an X-ray beam that spreads with a fan angle and a cone angle. For example, under the control of the X-ray irradiation control circuit 11, the X-ray tube 12 a continuously exposes X-rays around the subject P for full reconstruction or exposure that can be reconfigured for half reconstruction. It is possible to continuously expose X-rays in the irradiation range (180 degrees + fan angle). Further, the X-ray irradiation control circuit 11 can control the X-ray tube 12a to intermittently emit X-rays (pulse X-rays) at a preset position (tube position). The X-ray irradiation control circuit 11 can also modulate the intensity of the X-rays emitted from the X-ray tube 12a. For example, the X-ray irradiation control circuit 11 increases the intensity of X-rays emitted from the X-ray tube 12a at a specific tube position, and exposes from the X-ray tube 12a at a range other than the specific tube position. Reduce the intensity of the emitted X-rays.

  The wedge 12b is an X-ray filter for adjusting the X-ray dose of X-rays emitted from the X-ray tube 12a. Specifically, the wedge 12b transmits the X-rays exposed from the X-ray tube 12a so that the X-rays irradiated from the X-ray tube 12a to the subject P have a predetermined distribution. Attenuating filter. For example, the wedge 12b is a filter obtained by processing aluminum so as to have a predetermined target angle or a predetermined thickness. The wedge is also called a wedge filter or a bow-tie filter.

  The collimator 12 c is a slit for narrowing the X-ray irradiation range in which the X-ray dose is adjusted by the wedge 12 b under the control of the X-ray irradiation control circuit 11.

  The gantry driving circuit 16 rotates the rotary frame 15 to rotate the X-ray generator 12 and the detector 13 on a circular orbit around the subject P.

  The detector 13 is a two-dimensional array type detector (surface detector) that detects X-rays transmitted through the subject P, and a detection element array formed by arranging X-ray detection elements for a plurality of channels is the subject P. A plurality of rows are arranged along the body axis direction (Z-axis direction shown in FIG. 2). Specifically, the detector 13 in the first embodiment includes X-ray detection elements arranged in multiple rows such as 320 rows along the body axis direction of the subject P. For example, the lungs of the subject P It is possible to detect X-rays transmitted through the subject P over a wide range, such as a range including the heart and the heart.

  The data collection circuit 14 is a DAS, and collects projection data from the X-ray detection data detected by the detector 13. For example, the data collection circuit 14 generates projection data by performing amplification processing, A / D conversion processing, inter-channel sensitivity correction processing, and the like on the X-ray intensity distribution data detected by the detector 13. The projected data is transmitted to the console 30 described later. For example, when X-rays are continuously emitted from the X-ray tube 12a while the rotary frame 15 is rotating, the data acquisition circuit 14 collects projection data groups for the entire circumference (for 360 degrees). Further, the data collection circuit 14 associates the tube position with each collected projection data and transmits it to the console 30 described later. The tube position is information indicating the projection direction of the projection data. Note that the sensitivity correction processing between channels may be performed by the preprocessing circuit 34 described later.

  The couch device 20 is a device on which the subject P is placed, and includes a couch driving device 21 and a top plate 22 as shown in FIG. The couch driving device 21 moves the subject P into the rotary frame 15 by moving the couchtop 22 in the Z-axis direction. The top plate 22 is a plate on which the subject P is placed.

  For example, the gantry 10 executes a helical scan that rotates the rotating frame 15 while moving the top plate 22 to scan the subject P in a spiral shape. Alternatively, the gantry device 10 performs a conventional scan in which the subject P is scanned in a circular orbit by rotating the rotating frame 15 while the position of the subject P is fixed after the top plate 22 is moved. Alternatively, the gantry device 10 executes a step-and-shoot method in which a conventional scan is performed in a plurality of scan areas by moving the position of the top plate 22 at regular intervals.

  The console 30 is a device that accepts an operation of the X-ray CT apparatus 1 by an operator and reconstructs X-ray CT image data using projection data collected by the gantry 10. As shown in FIG. 2, the console 30 includes an input circuit 31, a display 32, a scan control circuit 33, a preprocessing circuit 34, a storage circuit 35, an image reconstruction circuit 36, and a processing circuit 37. .

  The input circuit 31 includes a mouse, a keyboard, a trackball, a switch, a button, a joystick, and the like that are used by the operator of the X-ray CT apparatus 1 to input various instructions and settings, and instructions and settings information received from the operator. Is transferred to the processing circuit 37. For example, the input circuit 31 receives imaging conditions for X-ray CT image data, reconstruction conditions for reconstructing X-ray CT image data, image processing conditions for X-ray CT image data, and the like from the operator. Further, the input circuit 31 receives an operation for selecting an examination for the subject P. Further, the input circuit 31 accepts a designation operation for designating a part on the image.

  The display 32 is a monitor that is referred to by the operator, and displays image data generated from the X-ray CT image data to the operator under the control of the processing circuit 37, or the operator via the input circuit 31. A GUI (Graphical User Interface) for accepting various instructions, various settings, and the like is displayed. The display 32 displays a plan screen for a scan plan, a screen being scanned, and the like. The display 32 displays virtual patient body type information including exposure information, image data, and the like. The virtual patient form information displayed on the display 32 will be described in detail later.

  The scan control circuit 33 controls the operations of the X-ray irradiation control circuit 11, the gantry driving circuit 16, the data acquisition circuit 14, and the bed driving device 21 under the control of the processing circuit 37, thereby Control the collection process. Specifically, the scan control circuit 33 controls projection data collection processing in photographing for collecting positioning images (scano images). Further, the scan control circuit 33 controls the projection data collection process in the main photographing (scan) for collecting images used for diagnosis. Here, in the X-ray CT apparatus 1 according to the first embodiment, a two-dimensional positioning image and a three-dimensional positioning image can be taken.

  For example, the scan control circuit 33 fixes the X-ray tube 12a at a position of 0 degree (a position in the front direction with respect to the subject P) and continuously performs imaging while moving the top plate 22 at a constant speed. Then, a two-dimensional positioning image is taken. Alternatively, the scan control circuit 33 fixes the X-ray tube 12a at a position of 0 degree and moves the top plate 22 intermittently, while repeating the imaging intermittently in synchronization with the top plate movement. Take a positioning image. Here, the scan control circuit 33 can capture a positioning image with respect to the subject P not only from the front direction but also from an arbitrary direction (for example, a side surface direction).

  The scan control circuit 33 captures a three-dimensional positioning image by collecting projection data for the entire circumference of the subject P in capturing the positioning image. FIG. 3 is a view for explaining three-dimensional positioning image shooting by the scan control circuit 33 according to the first embodiment. For example, as shown in FIG. 3, the scan control circuit 33 collects projection data for the entire circumference of the subject P by a helical scan or a non-helical scan. Here, the scan control circuit 33 performs a helical scan or a non-helical scan on a wide range of the subject P such as the entire chest, abdomen, the entire upper body, and the whole body at a lower dose than the main imaging. As the non-helical scan, for example, the above-described step-and-shoot scan is executed.

  In this way, the scan control circuit 33 collects projection data for the entire circumference of the subject P, so that an image reconstruction circuit 36 described later reconstructs three-dimensional X-ray CT image data (volume data). As shown in FIG. 3, it is possible to generate a positioning image from an arbitrary direction using the reconstructed volume data. Since a positioning image is generated from this volume data, this volume data is also called a three-dimensional positioning image. Here, whether the positioning image is photographed two-dimensionally or three-dimensionally may be set arbitrarily by the operator, or may be preset according to the examination contents. The scan control circuit 33 is an example of a collection unit.

  Returning to FIG. 2, the preprocessing circuit 34 performs logarithmic conversion processing and correction processing such as offset correction, sensitivity correction, and beam hardening correction on the projection data generated by the data acquisition circuit 14. Generate corrected projection data. Specifically, the preprocessing circuit 34 generates corrected projection data for the projection data of the positioning image generated by the data collection circuit 14 and stores it in the storage circuit 35. Further, the preprocessing circuit 34 generates corrected projection data for the diagnostic projection data collected by the main imaging, which is generated by the data collection circuit 14, and stores it in the storage circuit 35.

  The storage circuit 35 stores the corrected projection data generated by the preprocessing circuit 34. Specifically, the storage circuit 35 stores the corrected positioning image projection data and the corrected diagnostic projection data generated by the preprocessing circuit 34. Further, the storage circuit 35 stores image data and virtual patient body type information generated by an image reconstruction circuit 36 described later. Further, the storage circuit 35 appropriately stores a processing result by a processing circuit 37 described later. The virtual patient form information will be described later.

  The image reconstruction circuit 36 reconstructs X-ray CT image data using the projection data stored in the storage circuit 35. Specifically, the image reconstruction circuit 36 reconstructs X-ray CT image data from the projection data of the positioning image. The image reconstruction circuit 36 reconstructs X-ray CT image data from projection data of an image used for diagnosis. Here, as the reconstruction method, there are various methods, for example, back projection processing. Further, as the back projection process, for example, a back projection process by an FBP (Filtered Back Projection) method can be cited. Alternatively, the image reconstruction circuit 36 can reconstruct the X-ray CT image data using a successive approximation method.

  Further, the image reconstruction circuit 36 generates image data by performing various image processing on the X-ray CT image data. Then, the image reconstruction circuit 36 stores the reconstructed X-ray CT image data and image data generated by various image processes in the storage circuit 35.

  The processing circuit 37 performs overall control of the X-ray CT apparatus 1 by controlling operations of the gantry 10, the couch device 20, and the console 30. Specifically, the processing circuit 37 controls the CT scan performed on the gantry 10 by controlling the scan control circuit 33. The processing circuit 37 controls the image reconstruction circuit 36 and the image generation process in the console 30 by controlling the image reconstruction circuit 36. In addition, the processing circuit 37 controls the display 32 to display various image data stored in the storage circuit 35. The image reconstruction circuit 37 is an example of an image reconstruction unit.

  Further, as shown in FIG. 2, the processing circuit 37 executes an acquisition function 37a, a selection function 37b, a setting function 37c, a generation function 37d, a display control function 37e, and a control function 37f. Here, for example, each processing function executed by the acquisition function 37a, selection function 37b, setting function 37c, generation function 37d, display control function 37e, and control function 37f, which are components of the processing circuit 37 shown in FIG. Is stored in the storage circuit 35 in the form of a program that can be executed. The processing circuit 37 is a processor that implements a function corresponding to each program by reading each program from the storage circuit 35 and executing each read program. In other words, the processing circuit 37 in a state where each program is read has each function shown in the processing circuit 37 of FIG. The acquisition function 37a described in the present embodiment is an example of a special acquisition unit. The selection function 37b is an example of a selection unit. The setting function 37c is an example of a setting unit. The generation function 37d is an example of a generation unit. The display control function 37e is an example of a display control unit.

  The term “processor” used in the above description is, for example, a central processing unit (CPU), a graphics processing unit (GPU), or an application specific integrated circuit (ASIC)), a programmable logic device. (For example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)) are meant. The processor implements a function by reading and executing a program stored in the storage circuit. Instead of storing the program in the storage circuit, the program may be directly incorporated in the processor circuit. In this case, the processor implements the function by reading the program incorporated in the circuit and executing the read program. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, but may be configured as a single processor by combining a plurality of independent circuits to realize the function. Good.

  The acquisition function 37a acquires position information relating to a plurality of parts of the subject P in the image data. Specifically, the acquisition function 37a detects the position of a plurality of parts such as an organ included in the three-dimensional X-ray CT image data (volume data) reconstructed by the image reconstruction circuit 36, thereby The positions of a plurality of parts of the specimen P are acquired. For example, the acquisition function 37a detects a site such as an organ based on anatomical feature points (Anatomical Landmark) in the volume data of the positioning image. In addition, the acquisition function 37a detects a site such as an organ based on anatomical feature points of image volume data used for diagnosis. Here, the anatomical feature point is a point indicating a feature of a part such as a specific bone, organ, blood vessel, nerve, or lumen. That is, the acquisition function 37a detects bones, organs, blood vessels, nerves, lumens, and the like included in the volume data by detecting anatomical feature points such as specific organs and bones. The acquisition function 37a can also detect positions of the head, neck, chest, abdomen, feet, etc. included in the volume data by detecting characteristic feature points of the human body. In addition, the site | part demonstrated by this embodiment means what included these positions in bones, organs, blood vessels, nerves, lumens, and the like. Hereinafter, an example of detection of a part by the acquisition function 37a will be described.

  For example, the acquisition function 37a extracts anatomical feature points from the voxel values included in the volume data in the volume data of the positioning image or the volume data of the image used for diagnosis. Then, the acquisition function 37a compares the three-dimensional position of the anatomical feature point in the information such as the textbook with the position of the feature point extracted from the volume data, thereby obtaining the feature point extracted from the volume data. The inaccurate feature points are removed from the inside, and the positions of the feature points extracted from the volume data are optimized. Thereby, the acquisition function 37a acquires position information relating to each part of the subject included in the volume data. For example, the acquisition function 37a first extracts anatomical feature points included in the volume data using a supervised machine learning algorithm. Here, the machine learning algorithm is constructed using a plurality of teacher images in which correct anatomical feature points are manually arranged. For example, a decision forest is used as a machine learning algorithm. Is done.

  Then, the acquisition function 37a optimizes the extracted feature points by comparing a model indicating the three-dimensional positional relationship of anatomical feature points in the body with the extracted feature points. Here, the model indicating the three-dimensional positional relationship of anatomical feature points in the body is constructed using the above-described teacher image, and for example, a point distribution model is used. That is, the acquisition function 37a includes a model in which the shape and positional relationship of the part, points unique to the part, and the like are defined based on a plurality of teacher images in which correct anatomical feature points are manually arranged, and the extracted features. By comparing the points, the inaccurate feature points are removed and the feature points are optimized.

  Hereinafter, an example of an acquisition process for acquiring position information related to a part by the acquisition function 37a will be described with reference to FIGS. 4A, 4B, 5, and 6. FIG. 4A, 4B, 5, and 6 are diagrams for explaining an example of acquisition processing by the acquisition function 37a according to the first embodiment. In FIGS. 4A and 4B, black points indicate feature points, and feature points are arranged three-dimensionally. For example, the acquisition function 37a extracts voxels regarded as anatomical feature points by applying a supervised machine learning algorithm to volume data, as shown in FIG. 4A. Then, the acquisition function 37a fits the position of the extracted voxel to a model in which the shape and positional relationship of the part, a point unique to the part, etc. are defined, as shown in FIG. 4B, among the extracted voxels Incorrect feature points are removed, and only voxels corresponding to more accurate feature points are extracted.

  Here, the acquisition function 37a gives an identification code for identifying the feature point indicating the feature of each part to the extracted feature point (voxel), and the identification code and position (coordinate) information of each feature point Is associated with the image data and stored in the storage circuit 35. For example, as shown in FIG. 4B, the acquisition function 37a gives identification codes such as C1, C2, and C3 to the extracted feature points (voxels). Here, the acquisition function 37a adds an identification code to each piece of data for which acquisition processing has been performed, and stores the identification code in the storage circuit 35. Specifically, the acquisition function 37a includes at least one projection data among the projection data of the positioning image, the projection data collected under non-contrast, and the projection data collected in a state of being imaged by the contrast agent. The position information related to the part of the subject P included in the volume data reconstructed from is acquired.

  For example, as shown in FIG. 5, the acquisition function 37a attaches to the volume data information in which the identification code is associated with the coordinates of each voxel detected from the volume data (positioning in the figure) of the positioning image. To store. For example, the acquisition function 37a extracts the coordinates of the feature points from the volume data of the positioning image, and, as shown in FIG. 5, “identification code: C1, coordinates (x1, y1, z1)”, “identification” Code: C2, coordinates (x2, y2, z2) "and the like are stored in association with the volume data. Thereby, the acquisition function 37a can identify which feature point is in which position in the volume data of the positioning image, and can detect each part such as an organ based on the information. .

  Further, for example, as shown in FIG. 5, the acquisition function 37a attaches to the volume data information in which the identification code is associated with the coordinates of each voxel detected from the volume data (scan in the figure) of the diagnostic image. And stored in the memory circuit 35. Here, the acquisition function 37a includes, for example, volume data contrasted with a contrast medium (contrast phase in the figure) and volume data not contrasted with a contrast medium (non-contrast Phase in the figure) in a scan. Each feature point coordinate can be extracted, and an identification code can be associated with the extracted coordinate.

  For example, the acquisition function 37a extracts the feature point coordinates from the volume data of the non-contrast phase from the volume data of the diagnostic image, and, as shown in FIG. (X′1, y′1, z′1) ”,“ identification code: C2, coordinates (x′2, y′2, z′2) ”and the like are stored in association with the volume data. Further, the acquisition function 37a extracts the coordinates of the feature points from the volume data of the contrast phase out of the volume data of the diagnostic image, and, as shown in FIG. 5, “identification code: C1, coordinates (x′1 , Y′1, z′1) ”,“ identification code: C2, coordinates (x′2, y′2, z′2) ”and the like are stored in association with the volume data. Here, when feature points are extracted from volume data of contrast phase, feature points that can be extracted by being contrasted are included. For example, the acquisition function 37a can extract a blood vessel or the like contrasted with a contrast agent when extracting feature points from volume data of contrast phase. Accordingly, in the case of volume data of contrast phase, the acquisition function 37a performs coordinate (x′31, y′31, z′31) to the coordinates of feature points such as blood vessels extracted by contrasting as shown in FIG. The coordinates (x′34, y′34, z′34) and the like are associated with identification codes C31, C32, C33 and C34 for identifying each blood vessel.

  As described above, the acquisition function 37a can identify which feature point is in which position in the volume data of the positioning image or the diagnostic image, and based on such information, an organ or the like It is possible to acquire the position information related to each part. For example, the acquisition function 37a detects the position of the target part using information on the anatomical positional relationship between the part to be detected (target part) and the part around the target part. For example, when the target region is “lung”, the acquisition function 37a acquires coordinate information associated with an identification code indicating the characteristics of the lung, and “rib”, “clavicle”, “heart” , Coordinate information associated with an identification code indicating a region around the “lung”, such as “diaphragm”. Then, the acquisition function 37a uses the information on the anatomical positional relationship between the “lung” and surrounding parts and the acquired coordinate information to extract the “lung” region in the volume data.

  For example, the acquisition function 37a uses the positional relationship information such as “pulmonary apex: 2 to 3 cm above the clavicle”, “lower end of the lung: height of the seventh rib”, and coordinate information of each part, as shown in FIG. As shown, a three-dimensional region R1 corresponding to “lung” is extracted from the volume data. That is, the acquisition function 37a extracts the coordinate information of the voxel of the region R1 in the volume data. The acquisition function 37a associates the extracted coordinate information with the part information, attaches it to the volume data, and stores it in the storage circuit 35. Similarly, as shown in FIG. 6, the acquisition function 37a can extract a three-dimensional region R2 or the like corresponding to “heart” in the volume data.

  In addition, the acquisition function 37a detects the position of a part included in the volume data based on feature points that define parts such as the head and chest in the human body. Here, parts such as the head and chest in the human body can be arbitrarily defined. For example, if the seventh cervical vertebra to the lower end of the lung is defined as the chest, the acquisition function 37a detects from the feature point corresponding to the seventh cervical vertebra to the feature point corresponding to the lower end of the lung as the chest. In addition, the acquisition function 37a can detect a site | part by various methods besides the method using the anatomical feature point mentioned above. For example, the acquisition function 37a can detect a part included in the volume data by a region expansion method based on a voxel value.

  The selection function 37b receives and accepts, from the operator via the input circuit 31, a part different from the part corresponding to the plurality of parts of the subject P among the plurality of parts of the virtual patient included in the virtual patient body type information. Select the site. Details of the selection function 37b will be described later.

  The setting function 37c sets an imaging range that does not include the imaging range of the image data based on the position information related to the plurality of parts in the image data and the virtual patient body type information. The setting function 37c has a collation function for collating the positions of the plurality of parts in the subject P included in the image data with the positions of the plurality of parts in the virtual patient included in the virtual patient body type information. The virtual patient is a standard and virtual patient. Hereinafter, the verification function will be described. The setting function 37c collates the position of the part of the subject P with the position of the standard part in the virtual patient, and stores the collation result in the storage circuit 35. For example, the selection function 37b matches virtual patient body type information in which a human body part is arranged at a standard position with volume data of the subject P.

  Here, first, virtual patient form information will be described. The virtual patient form information is information representing the standard position of each of a plurality of parts in the human body. Virtual patient form information is taken with X-rays of a human body (virtual patient) having a standard physique corresponding to multiple combinations of parameters related to physique such as age, adult / child, male / female, weight, height, etc. The generated image is stored in the storage circuit 35 in advance. That is, the storage circuit 35 stores in advance a plurality of virtual patient body type information corresponding to the combination of parameters described above. Here, the anatomical feature points (feature points) are stored in association with the virtual patient body type information stored by the storage circuit 35. For example, the human body has many anatomical feature points that can be extracted from an image based on morphological features and the like relatively easily by image processing such as pattern recognition. The positions and arrangements of these many anatomical feature points in the body are roughly determined according to age, adult / child, male / female, physique such as weight and height.

  A large number of these anatomical feature points are detected in advance, and the positional information of the detected feature points is stored in the storage circuit 35 along with or associated with the virtual patient body type information together with the identification code of each feature point. FIG. 7 is a diagram illustrating an example of virtual patient figure information. For example, as shown in FIG. 7, the storage unit 35 has identification codes “V1”, “V2”, and the like for identifying anatomical feature points and feature points on a three-dimensional human body including a part such as an organ. The virtual patient body type information associated with “V3” or the like is stored.

  That is, the storage circuit 35 stores the coordinates of the feature points in the coordinate space of the three-dimensional human body image and the corresponding identification code in association with each other. For example, the storage circuit 35 stores the coordinates of the corresponding feature points in association with the identification code “V1” shown in FIG. The storage circuit 35 stores the coordinates of the corresponding feature points in association with the identification code “V2”. Further, the storage circuit 35 stores the coordinates of the corresponding feature points in association with the identification code “V3”. In FIG. 7, only the lung, heart, liver, stomach, kidney, and the like are shown as organs, but the virtual patient body type information includes a larger number of organs, bones, blood vessels, nerves, and the like. In FIG. 7, only the feature points corresponding to the identification codes “V1”, “V2”, and “V3” are shown, but actually more feature points are included.

  The setting function 37c matches the feature points in the volume data of the subject P acquired by the acquisition function 37a with the feature points in the virtual patient body information described above using an identification code, and coordinates space of the volume data Is associated with the coordinate space of the virtual patient body type information. FIG. 8 is a diagram for explaining an example of collation processing by the setting function 37c according to the first embodiment. Here, in FIG. 8, matching is performed using three sets of feature points to which identification codes indicating the same feature points are assigned between the feature points detected from the positioning image and the feature points detected from the virtual patient body type information. However, the embodiment is not limited to this, and matching can be performed using an arbitrary set of feature points.

  For example, as illustrated in FIG. 8, the setting function 37c includes feature points indicated by identification codes “V1”, “V2”, and “V3” in the virtual patient body information, and identification codes “C1”, “C2” in the positioning image. When matching the feature points indicated by “C3” and “C3”, the coordinate space between the images is associated by performing coordinate transformation so that the positional deviation between the same feature points is minimized. For example, as shown in FIG. 8, the setting function 37c has the same anatomically characteristic points “V1 (x1, y1, z1), C1 (X1, Y1, Z1)”, “V2 (x2, y2, z2). , C2 (X2, Y2, Z2) "," V3 (x3, y3, z3) ", C3 (X3, Y3, Z3), the following coordinates to minimize the total" LS " A transformation matrix “H” is obtained.

LS = ((X1, Y1, Z1) -H (x1, y1, z1))
+ ((X2, Y2, Z2) -H (x2, y2, z2))
+ ((X3, Y3, Z3) -H (x3, y3, z3))

  The setting function 37c can convert the scan range specified on the virtual patient body type information into the scan range on the positioning image by the obtained coordinate conversion matrix “H”. For example, the setting function 37c uses the coordinate transformation matrix “H” to change the scan range “SRV” designated on the virtual patient body type information to the scan range “SRC” on the positioning image as shown in FIG. Can be converted. FIG. 9 is a diagram illustrating a scan range conversion example by coordinate conversion according to the first embodiment. For example, as shown on the virtual patient type information in FIG. 9, when the operator sets the scan range “SRV” on the virtual patient type information, the setting function 37c is set using the coordinate transformation matrix described above. The scan range “SRV” is converted into a scan range “SRC” on the positioning image.

  Thereby, for example, the scan range “SRV” set so as to include the feature point corresponding to the identification code “Vn” on the virtual patient body type information has the identification code “Cn” corresponding to the same feature point on the positioning image. "Is included in the scan range" SRC ". Note that the coordinate transformation matrix “H” described above may be stored in the storage circuit 35 for each subject and appropriately read and used, or calculated every time a positioning image is collected. It may be the case. As described above, according to the first embodiment, the virtual patient body information is displayed for the range designation at the preset time, and the position / range is planned on the virtual patient body shape information. It is possible to automatically set numerical values for the position / range on the positioning image corresponding to the determined position / range.

  Returning to FIG. 2, the generation function 37 d generates estimated image data corresponding to the extension region of the image data so that the part selected by the selection function 37 b is included. The generation function 37d will be described later.

  The display control function 37e controls to display various display information on the display 32. For example, the display control function 37e controls the display 32 to display various image data stored in the storage circuit 35. In addition, the display control function 37e controls the display 32 to display information according to the acquisition result obtained by the acquisition function 37a. Details of information displayed by the control of the display control function 37e will be described later.

  The control function 37f performs overall control of the X-ray CT apparatus 1 by controlling the operations of the gantry 10, the couch device 20, and the console 30. Specifically, the control function 37 f controls the CT scan performed on the gantry 10 by controlling the scan control circuit 33. The control function 37f controls the image reconstruction process and the image generation process in the console 30 by controlling the image reconstruction circuit 36. The control by the control function 37f will be described in detail later.

  The overall configuration of the X-ray CT apparatus 1 according to the first embodiment has been described above.

  Here, in imaging using an X-ray CT apparatus, imaging of a positioning image for setting an imaging range of actual imaging is performed before performing actual imaging for collecting data used for diagnosis. Then, the X-ray CT apparatus displays the captured positioning image on the display, and accepts the imaging range of the main imaging from the operator. Then, the X-ray CT apparatus sets the accepted imaging range and performs main imaging within the set imaging range. Here, when the X-ray CT apparatus accepts the imaging range of the main imaging, the operator may want to set a range including a part existing outside the range of the positioning image as the imaging range of the main imaging. In this case, for example, the operator first estimates the position of a part that is not included in the positioning image, that is, a part that is not displayed. Then, the operator inputs an instruction for main imaging of a range including the estimated part to the X-ray CT apparatus via the input circuit. As a result, the X-ray CT apparatus performs main imaging within a range instructed by the operator. In this way, when an operator inputs a range including a part that exists outside the range of the positioning image as an imaging range of the main imaging, the operator is not easy to estimate the position of the part. In this case, the shooting range cannot be set, and as a result, shooting cannot be performed easily. In view of this, the X-ray CT apparatus 1 according to the first embodiment allows the operator to easily perform settings when performing imaging, as described below, based on the above-described configuration. Various processes are executed.

  An example of a processing procedure of the X-ray CT apparatus 1 according to the first embodiment will be described with reference to FIG. FIG. 10 is a flowchart illustrating an example of a processing procedure performed by the X-ray CT apparatus 1 according to the first embodiment. As shown in FIG. 10, the control function 37f determines whether or not the inspection is started (step S101). If the inspection has not been started (step S101: No), the control function 37f determines again whether or not the inspection has been started in step S101. On the other hand, when the inspection is started (step S101: Yes), the control function 37f controls the scan control circuit 33, the image reconstruction circuit 36, and the like to collect a three-dimensional positioning image (volume data). (Step S102).

  The display control function 37e displays an MPR (multi-planar reconstruction) image, which is a coronal cross-sectional image reconstructed by the image reconstruction circuit 37, from the collected three-dimensional positioning image on the display 32 as a two-dimensional positioning image. (Step S103). FIG. 11 is a diagram illustrating an example of a positioning image. For example, in step S103, the display control function 37e causes the display 32 to display a positioning image 50 that is a coronal cross-sectional image illustrated in the example of FIG. In step S103, the display control function 37e may superimpose the virtual patient body type information as reference information on the positioning image and display the positioning image on which the virtual patient body type information is superimposed on the display 32. In step S103, the image displayed on the display 32 as the two-dimensional positioning image is not limited to the MPR image. For example, the display control function 37e generates various types of two-dimensional images other than MPR images that can be generated (reconstructed) from a three-dimensional positioning image that is volume data on the display 32 as a two-dimensional positioning image. It may be displayed. Then, the control function 37f determines whether or not the photographing range of the main photographing has been received from the operator via the input circuit 31 (Step S104). When the photographing range of the main photographing is accepted (step S104: Yes), the control function 37f proceeds to step S113 described later.

  On the other hand, when the photographing range of the main photographing is not received (step S104: No), the selection function 37b exists outside the range of the currently displayed positioning image from the operator via the input circuit 31. It is determined whether or not an instruction to perform main imaging in a range including the part has been input (step S105). If such an instruction has not been input (step S105: No), the selection function 37b returns to step S104.

  On the other hand, when such an instruction is input (step S105: Yes), the selection function 37b determines whether designation of a part that exists outside the range of the positioning image has been received (step S106). For example, in step S106, the selection function 37b causes the virtual patient body type information to be displayed on the display 32, and determines whether or not a part designated by the operator among a plurality of parts of the human body has been received. In step S106, the selection function 37b may display a list of parts on the display 32 and determine whether or not a part specified by the operator from the displayed list of parts has been received. When the part is not received (step S106: No), the selection function 37b determines again whether the part is received in step S106.

  On the other hand, when a part is received (step S106: Yes), the selection function 37b selects the received part (step S107). The setting function 37c corresponds to each of a plurality of parts of the subject P among a plurality of parts of the subject P in the three-dimensional positioning image and a plurality of parts of the virtual patient included in the virtual patient body type information. The coordinate transformation matrix as described above is calculated so as to minimize the total positional deviation between the parts (step S108). That is, in step S108, the setting function 37c positions each part corresponding to the plurality of parts of the subject P among the plurality of parts of the virtual patient at each position indicated by the position information of the plurality of parts of the subject P. As described above, a coordinate transformation matrix for transforming the virtual patient body type information is calculated.

  Then, the generation function 37d extracts a three-dimensional region including the selected part from the human body indicated by the virtual patient body type information, and deforms the extracted region using the calculated coordinate transformation matrix, thereby generating the coordinates. A region after deformation using the transformation matrix is calculated (step S109). Here, the deformed area is a three-dimensional image indicated by the three-dimensional image data including the part designated by the operator. Further, the range indicated by the deformed area is a range that includes a part that is designated by the operator and that exists outside the range of the positioning image that is currently displayed. Further, the MPR image area which is a coronal cross-sectional image reconstructed from the three-dimensional image by the image reconstruction circuit 37 corresponds to an area (extended area) obtained by extending the two-dimensional positioning image. The image data of the MPR image, which is a coronal cross-sectional image reconstructed by the image reconstruction circuit 37 from the three-dimensional image generated in step S109, is an example of estimated image data.

  The process of step S109 will be described with a specific example. FIG. 12 is a diagram illustrating an example of an MPR image that is a coronal cross-sectional image reconstructed by the image reconstruction circuit 37 from the region after deformation. For example, a case where the pelvis is designated by the operator will be described. In this case, in step S109, the generation function 37d extracts a three-dimensional region including the designated pelvis 51a from the human body indicated by the virtual patient body type information, and uses the coordinate transformation matrix to extract the extracted region. Is deformed to generate image data of a three-dimensional image including the designated pelvis 51a. In step S109, the image reconstruction circuit 37 reconstructs (generates) image data of the MPR image 51, which is a coronal cross-sectional image shown in the example of FIG. 12, from the generated image data of the three-dimensional image. Note that the area of the MPR image 51 corresponds to an extended area of the two-dimensional positioning image 50 shown in FIG.

  Returning to the description of FIG. 10, the setting function 37c estimates the imaging range including the designated part, and sets the estimated imaging range (step S110). That is, in step S110, an imaging range that does not include the imaging range of the image data is set using the deformed virtual patient body type information. FIG. 13 is a diagram illustrating an example of the estimated shooting range. For example, in step S110, the setting function 37c estimates the range 52 including the pelvis 51a shown in the previous example of FIG. 12 as shown in the example of FIG. In addition, a frame 53 indicating the range 52 is displayed on the display 32. Here, the operator can change the shooting range in the main shooting indicated by the frame 53 by changing the size of the frame 53 via the input circuit 31. As described above, the setting function 37c sets the imaging range in the main imaging so as to include the pelvis designated by the operator without allowing the operator to estimate the position of the pelvis. Therefore, according to the X-ray CT apparatus 1 according to the present embodiment, the operator can easily make settings for performing imaging.

  The display control function 37e then uses the two-dimensional positioning image (MPR image) reconstructed from the collected three-dimensional positioning image by the image reconstruction circuit 37 and the image data of the three-dimensional image generated in step S109. The image data of the MPR image generated by the image reconstruction circuit 37 is synthesized, and the synthesized image data (synthesized image data) is displayed on the display 32 (step S111). FIG. 14 is a diagram illustrating an example of the composite image data. For example, in step S111, as shown in the example of FIG. 14, the display control function 37e combines the positioning image data indicating the two-dimensional positioning image 50 and the image data of the MPR image 51 including the pelvis 51a. Image data 54 is generated. Then, the display control function 37e displays the composite image data 54 on the display 32. Thus, the composite image data displayed on the display 32 includes a part designated by the operator. For this reason, when changing the imaging range in the main imaging, the operator can set the imaging range including the designated part simply by changing the imaging range to include the displayed part. Therefore, by displaying the composite image data, it is possible to make it easier for the operator to make settings for shooting.

  Returning to the description of FIG. 10, the control function 37f determines whether or not the photographing range of the main photographing input by the operator is received via the input circuit 31 (step S112). For example, when the operator sets the shooting range set in step 110 as the shooting range for main shooting as it is, the operator uses the input circuit 31 to set the shooting range set in step 110 as the shooting range for main shooting. input. In addition, when the operator changes the shooting range set in step 110 and sets the changed shooting range as the shooting range of the main shooting, the shooting range set in step 110 is set using the input circuit 31. , And input the changed shooting range as the shooting range for actual shooting. If the photographing range for main photographing has not been received (step S112; No), the control function 37f determines again whether or not the photographing range for main photographing has been accepted in step S112.

  On the other hand, when the photographing range of the main photographing is accepted (step S112; Yes), the control function 37f controls the scan control circuit 33 so that the main photographing of the photographing range accepted in step S104 or step S112 is performed. (Step S113). Then, the control function 37f controls the image reconstruction circuit 36 so as to reconstruct the X-ray CT image data from the projection data of the image used for diagnosis collected in the main imaging (step S114), and the process is terminated. To do. Note that the X-ray CT image reconstructed in step S114 is displayed on the display 32 by the display control function 37e, for example. At this time, the display control function 37e may superimpose virtual patient body type information as reference information on the X-ray CT image and display the X-ray CT image on which the virtual patient body type information is superimposed on the display 32.

  Note that Step S101, Step S102, Step S104, Step S112, Step S113, and Step S114 are steps in which the processing circuit 37 reads a program corresponding to the control function 37f from the storage circuit 35 and is executed. Steps S103 and S111 are steps in which the processing circuit 37 reads a program corresponding to the display control function 37e from the storage circuit 35 and executes it. Steps S105, S106, and S107 are steps in which the processing circuit 37 reads a program corresponding to the selection function 37b from the storage circuit 35 and executes it. Steps S108 and S110 are steps in which the processing circuit 37 reads a program corresponding to the setting function 37c from the storage circuit 35 and executes it. In step S109, the processing circuit 37 reads a program corresponding to the generation function 37d from the storage circuit 35 and is executed.

  In step S102, the control function 37f controls the scan control circuit 33, the image reconstruction circuit 36, and the like to collect a three-dimensional positioning image. In a step after step S102, the three-dimensional positioning image is collected. It illustrated about the case where it processes using. However, in step S102, the control function 37f controls the scan control circuit 33, the image reconstruction circuit 36, and the like to collect a two-dimensional positioning image, and in a step after step S102, the two-dimensional positioning image. You may process using. By collecting a two-dimensional positioning image, the processing amount is reduced and processing can be performed in a shorter time than when collecting a three-dimensional positioning image.

  The first embodiment has been described above. According to the X-ray CT apparatus 1 according to the first embodiment, as described above, the operator can easily make settings for performing imaging.

(Second Embodiment)
Here, as described above, in the imaging using the X-ray CT apparatus, the positioning image for setting the imaging range of the main imaging is acquired before the main imaging for collecting data used for diagnosis is performed. Done. As described above, the X-ray CT apparatus displays the captured positioning image on the display and accepts the imaging range of the main imaging from the operator. Then, the X-ray CT apparatus sets the accepted imaging range and performs main imaging within the set imaging range. Here, after the X-ray CT apparatus performs the main imaging, the operator may want to additionally perform the main imaging including an imaging range including a part that exists outside the range of the positioning image. When performing such additional main imaging, for example, the operator first estimates the position of a part that is not included in the positioning image, that is, a part that is not displayed. Then, the operator inputs an instruction to additionally perform the main imaging in the imaging range including the estimated part to the X-ray CT apparatus via the input circuit. Thereby, the X-ray CT apparatus additionally performs the main imaging within the imaging range designated by the operator. Thus, when an operator inputs a range including a part that exists outside the range of the positioning image as an imaging range for additional main imaging, the operator is not easy to estimate the position of the part. Therefore, it is not possible to easily set the shooting range, and as a result, additional shooting cannot be easily performed. Therefore, the X-ray CT apparatus 1 according to the second embodiment can make the operator easily perform settings when performing additional imaging, as described below, based on the above-described configuration. As described above, various processes are executed.

  An example of a processing procedure of the X-ray CT apparatus 1 according to the second embodiment will be described with reference to FIG. FIG. 15 is a flowchart illustrating an example of a processing procedure performed by the X-ray CT apparatus 1 according to the second embodiment. The processing in steps S201 to S203 is the same as the processing in steps S101 to S103 shown in FIG.

  As illustrated in FIG. 15, the control function 37 f determines whether or not the photographing range of the main photographing has been received from the operator via the input circuit 31 (Step S <b> 204). When the photographing range for main photographing has not been received (step S204: No), the control function 37f determines again whether or not the photographing range for main photographing has been accepted in step S204.

  On the other hand, when the photographing range of the main photographing is received (step S204: Yes), the control function 37f controls the scan control circuit 33 so that the main photographing within the photographing range accepted in step S204 is performed (step S204). S205). Then, the control function 37f controls the image reconstruction circuit 36 so as to reconstruct the X-ray CT image data from the projection data of the image used for diagnosis collected in the main imaging in step S205 (step S206). Note that the X-ray CT image reconstructed in step S206 is displayed on the display 32 by the display control function 37e, for example. At this time, the display control function 37e may superimpose virtual patient body type information as reference information on the X-ray CT image and display the X-ray CT image on which the virtual patient body type information is superimposed on the display 32.

  Then, the display control function 37e displays a message on the display 32 for confirming whether or not an additional shooting range other than the shooting range of the main shooting performed in step S205 is to be performed, and then by the operator. Then, it is determined whether or not an instruction indicating whether or not to additionally perform the main shooting has been input (step S207). If an instruction not to perform the main shooting is additionally input (step S207: No), the control function 37f ends the process.

  On the other hand, when an instruction to additionally perform main imaging is input (step S207: Yes), the selection function 37b determines whether designation of a part that exists outside the range of the positioning image has been received (step S207). S208). For example, in step S208, the selection function 37b performs a process similar to the process in step S106 shown in FIG. For example, the selection function 37b displays virtual patient body type information on the display 32, and determines whether or not a part designated by the operator among a plurality of parts of the human body has been received. When the part is not received (step S208: No), the selection function 37b determines again whether the part is received in step S208.

  On the other hand, when a part is received (step S208: Yes), the selection function 37b selects the received part (step S209).

  Then, the setting function 37c performs positioning for the feature points included only in the positioning image data out of the three-dimensional positioning image data collected in step S202 and the X-ray CT image data reconstructed in step S206. Using feature points included in image data, for feature points included only in X-ray CT image data, use feature points included in X-ray CT image data, and for feature points included in both image data, position The following processing is performed using feature points included in X-ray CT image data with high accuracy. That is, the setting function 37c includes a plurality of parts of the subject P in the three-dimensional positioning image or the X-ray CT image, and a plurality of parts of the virtual patient included in the virtual patient body type information. The coordinate transformation matrix as described above is calculated so as to minimize the total positional deviation between each part corresponding to the part (step S210). That is, in step S210, the setting function 37c basically uses X-ray CT image data with high accuracy of the position of the feature point when calculating the coordinate transformation matrix, but the feature point included only in the positioning image. Is used for positioning image data. For example, when the imaging range of the positioning image is wider than the imaging range of the X-ray CT image, an event that a certain feature point is not included in the X-ray CT image but only included in the positioning image may occur. Thus, the setting function 37c does not simply use only the X-ray CT image data with high accuracy of the position of the feature point when calculating the coordinate transformation matrix, but the X-ray CT image data and the positioning image data. By using, the coordinate transformation matrix can be calculated with high accuracy. In addition, as a result of being able to calculate the coordinate transformation matrix with high accuracy, the shooting range can be set with high accuracy.

  In step S210, the setting function 37c calculates the coordinate transformation matrix by using the position in the positioning image data and the X-ray CT for the feature points included in both the positioning image data and the X-ray CT image data. When the difference from the position in the image data is within a predetermined value, feature points included in the positioning image data may be used.

  Then, the generation function 37d extracts a three-dimensional region including the selected part from the human body indicated by the virtual patient body type information, and uses the calculated coordinate transformation matrix, as in the process of step S109. By deforming the extracted region, a region after deformation using the coordinate transformation matrix is calculated (step S211). Here, the deformed area is a three-dimensional image indicated by the three-dimensional image data including the part designated by the operator. Further, the range indicated by the deformed area is a range that includes a part that is designated by the operator and that exists outside the range of the positioning image that is currently displayed. Further, the MPR image area which is a coronal cross-sectional image reconstructed from the three-dimensional image by the image reconstruction circuit 37 corresponds to an area (extended area) obtained by extending the two-dimensional positioning image. Note that the image data of the MPR image, which is a coronal cross-sectional image reconstructed by the image reconstruction circuit 37 from the three-dimensional image generated in step S211, is an example of estimated image data.

  Then, the setting function 37c estimates the imaging range including the designated part and sets the estimated imaging range in the same manner as in the previous step S110 (step S212). As described above, the setting function 37c sets the imaging range in the main imaging so as to include the region designated by the operator without causing the operator to estimate the position of the region to be actually captured. Therefore, according to the X-ray CT apparatus 1 according to the present embodiment, the operator can easily make settings for performing imaging.

  Then, the display control function 37e, like the processing in the previous step S111, the two-dimensional positioning image reconstructed by the image reconstruction circuit 37 from the collected three-dimensional positioning image, and the 3D generated in step S211. The image data of the MPR image generated by the image reconstruction circuit 37 is synthesized from the image data of the three-dimensional image, and the synthesized image data is displayed on the display 32 (step S213). Here, the composite image data displayed on the display 32 includes a part designated by the operator. For this reason, when changing the imaging range in the main imaging, the operator can set the imaging range including the designated part simply by changing the imaging range to include the displayed part. Therefore, by displaying the composite image data, it is possible to make it easier for the operator to make settings for shooting.

  Then, the control function 37f determines whether or not the photographing range of the main photographing input from the operator is received via the input circuit 31, similarly to the processing of the previous step S112 (step S214). When the photographing range for main photographing has not been received (step S214; No), the control function 37f determines again whether or not the photographing range for main photographing has been accepted in step S214.

  On the other hand, when the photographing range of the main photographing is received (step S214; Yes), the control function 37f controls the scan control circuit 33 so that the main photographing within the photographing range accepted in step S214 is performed (step S214). S215). Here, an example of a method for setting the imaging conditions including the collection column, the tube voltage, and the tube current in the additional main imaging in step S215 will be described. For example, the control function 37f may set the collection column and tube voltage in the main photographing performed in the previous step S205 as the additional collection column and tube voltage in the main photographing in step S215. In this way, the quality of the X-ray CT image obtained by the main imaging performed in step S205 can be obtained by taking over the collection column and the tube voltage in the main imaging performed in step S205 in the additional main imaging. Thus, it is possible to suppress the image quality of the X-ray CT image obtained by the additional main imaging from being greatly different. Further, the control function 37f is based on the collected information (adjacent positioning image, X-ray CT image collected by the main imaging performed in step S205, and virtual patient body type information). The thickness is estimated, and the tube current is calculated by AEC (Automatic Exposure Control). Then, the control function 37f may set the calculated tube current as the tube current in the additional actual photographing in step S215.

  Note that the method of setting shooting conditions in additional actual shooting in step S215 is not limited to the method described above. For example, the control function 37f may set the imaging condition of the part specified by the operator or the imaging condition selected by the operator from the expert plan for each part set in the virtual patient body type information. . In addition, the control function 37f may take over the shooting conditions of the expert plan set immediately before, or if there is an additional shooting protocol for which shooting conditions are set, the protocol may be selected. Good. Note that the control function 37f may estimate the tube current by AEC from the set image quality.

  Then, the control function 37f controls the image reconstruction circuit 36 so as to reconstruct the X-ray CT image data from the projection data of the image used for diagnosis collected in the main imaging (Step S216), and ends the processing. To do. Note that the X-ray CT image reconstructed in step S216 is displayed on the display 32 by the display control function 37e, for example. At this time, the display control function 37e may superimpose virtual patient body type information as reference information on the X-ray CT image and display the X-ray CT image on which the virtual patient body type information is superimposed on the display 32.

  Note that step S201, step S202, step S204, step S205, step S206, step S214, step S215, and step S216 are steps in which the processing circuit 37 reads a program corresponding to the control function 37f from the storage circuit 35 and executes it. is there. Steps S203, S207, and S213 are steps in which the processing circuit 37 reads a program corresponding to the display control function 37e from the storage circuit 35 and executes it. Steps S208 and S209 are steps in which the processing circuit 37 reads a program corresponding to the selection function 37b from the storage circuit 35 and executes it. Steps S210 and S212 are steps in which the processing circuit 37 reads a program corresponding to the setting function 37c from the storage circuit 35 and executes it. In step S211, the processing circuit 37 reads a program corresponding to the generation function 37d from the storage circuit 35 and executes the program.

  The second embodiment has been described above. According to the X-ray CT apparatus 1 according to the second embodiment, as described above, the operator can easily make settings for performing imaging.

(Modification)
Here, among a plurality of X-ray CT images obtained by reconstructing the projection data collected by the main imaging, the subject P moves during imaging of some X-ray CT images, and other X-ray CTs. In some cases, the direction or position of the subject P is deviated from the image. Therefore, the X-ray CT apparatus 1 specifies a X-ray CT image in which a deviation in the direction or position of the subject P has occurred, and issues a message that prompts the operator to take the specified X-ray CT image again. It may be displayed. Such an embodiment will be described as a modification according to the first embodiment or the second embodiment.

  FIG.16 and FIG.17 is a figure for demonstrating a modification. In the example of FIG. 16, a plurality of diagnostic slice images 70a,... 70b,. The diagnostic slice image 70a is the first image, and the diagnostic slice image 70b is the Nth image. Further, in the example of FIG. 16, positioning slice images which are a plurality of axial cross-sectional images obtained as a result of the MPR processing performed by the image reconstruction circuit 36 on the three-dimensional positioning image collected in step S <b> 102. 71a, ... 71b, ... are shown. The positioning slice image 71a is the first image, and the positioning slice image 71b is the Nth image.

  The control function 37f according to the modified example compares the position of the feature point included in the diagnostic slice image with the position of the corresponding feature point included in the positioning slice image corresponding to the diagnostic slice image. It is determined whether or not the position is a predetermined value or more. For example, the control function 37f compares the position of the feature point included in the diagnostic slice image 70a illustrated in the example of FIG. 16 with the position of the corresponding feature point included in the positioning slice image 71a, and determines the position of both. It is determined whether or not is more than a predetermined value. In addition, the control function 37f compares the position of the feature point included in the diagnostic slice image 70b with the position of the corresponding feature point included in the positioning slice image 71b, and the positions of both are separated by a predetermined value or more. It is determined whether or not.

  Then, the control function 37f specifies the diagnostic slice image determined to be separated by a predetermined value or more as a diagnostic slice image in which a deviation in the direction or position of the subject P has occurred. In addition, the control function 37f causes the display 32 to display a message that prompts the operator to perform imaging again for the specified diagnostic slice image, and prompts the operator to perform imaging again. For example, when the position of the feature point included in the diagnostic slice image 70b is away from the position of the corresponding feature point included in the positioning slice image 71b by a predetermined value or more, the control function 37f For the image 70b, the display 32 displays a message that prompts the user to take another image “The Nth slice image for diagnosis is misaligned locally, so please take another image”.

  Then, when a re-shooting instruction is input by the operator via the input circuit 31, the control function 37f controls the scan control circuit 33 so that re-shooting is performed based on the instruction. For example, the control function 37f controls the scan control circuit 33 so as to perform imaging again for the N-th diagnostic slice image 70b. Thus, as shown in FIG. 17, a case where a diagnostic slice image 72b is obtained as the Nth diagnostic slice image will be described. In this case, the control function 37f treats a plurality of diagnostic slice images 70a... Other than the diagnostic slice image 70b and the diagnostic slice image 72b as the same series as the same series. As a result, the diagnostic slice image collected by the main photographing and the diagnostic slice image collected by the additional main photographing can be handled as the same series, so that the image can be easily managed.

  The modification has been described above. According to the X-ray CT apparatus 1 according to the modified example, as in the first embodiment and the second embodiment, it is possible to make the operator easily perform settings when performing imaging.

  According to the X-ray CT apparatus 1 of at least one embodiment and the modification described above, the operator can easily perform the setting when performing shadowing.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

1 X-ray CT apparatus 37a Acquisition function 37b Selection function 37c Setting function 37d Generation function 37e Display control function 37f Control function

Claims (7)

A collection unit that detects X-rays transmitted through the subject and collects projection data;
An image reconstruction unit for reconstructing image data from the projection data;
An acquisition unit for acquiring position information relating to a plurality of parts of the subject in the image data;
A storage unit for storing virtual patient body type information having position information of a plurality of parts of the virtual patient;
A setting unit configured to set an imaging range that does not include the imaging range of the image data based on the positional information on the plurality of parts in the image data and the virtual patient body type information;
An X-ray CT apparatus comprising:   The setting unit is configured to position each part corresponding to the plurality of parts of the subject among the plurality of parts of the virtual patient at each position indicated by the position information of the plurality of parts of the subject. The X-ray CT apparatus according to claim 1, wherein the virtual patient body type information is deformed and an imaging range that does not include the imaging range of the image data is set using the virtual patient body type information after the deformation. A selection unit that selects a part different from a part corresponding to the plurality of parts of the subject among the plurality of parts of the virtual patient;
A generating unit that generates estimated image data corresponding to an extension region of the image data so that the selected portion is included;
The X-ray CT apparatus according to claim 1, further comprising:   The X-ray CT apparatus according to claim 3, further comprising a display control unit configured to display combined image data obtained by combining the image data and the estimated image data on a display unit. The collection unit collects projection data of positioning images and projection data of images used for diagnosis,
The image reconstruction unit reconstructs a plurality of the positioning images from the projection data of the positioning images, and reconstructs a plurality of images used for the diagnosis from the projection data of the images used for the diagnosis,
Comparison with other images used for the diagnosis based on position information related to the part included in each of the plurality of positioning images and position information related to the part included in each of the plurality of images used for the diagnosis And further comprising a control unit that identifies an image to be used for diagnosis in which the position or orientation of the subject is deviated, and informs that the identified image is imaged again. The X-ray CT apparatus described.   The X-ray CT apparatus according to claim 5, wherein the control unit treats an image obtained by imaging again for the identified image and the other image as the same series.   The X-ray CT apparatus according to claim 1, wherein the image data is positioning image data, data used for diagnosis, or positioning image data and data used for diagnosis.