JP6925786B2 - X-ray CT device - Google Patents

Description

Embodiments of the present invention relate to an X-ray CT apparatus.

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

Japanese Unexamined Patent Publication No. 2014-238751 Japanese Unexamined Patent Publication No. 2015-119768 Special Table 2012-008296 Japanese Unexamined Patent Publication No. 2010-017215

An object to be solved by the present invention is to provide an X-ray CT apparatus capable of easily causing an operator to make settings when performing imaging.

The X-ray CT apparatus of the embodiment includes a collecting unit, an image reconstruction unit, an acquisition unit, a storage unit, and a setting unit. The collecting unit detects the X-rays that have passed through the subject and collects the projection data. The image reconstruction unit reconstructs the 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. The storage unit stores virtual patient body shape information having each position information of a plurality of parts of the virtual patient. The setting unit 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 shape information.

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

Hereinafter, embodiments of an X-ray CT (Computed Tomography) apparatus will be described 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. .. Further, the medical information processing system 100 may include a medical image diagnostic device other than the X-ray CT device, for example, a medical image diagnostic device such as an X-ray diagnostic device, an MRI (Magnetic Resonance Imaging) device, and an ultrasonic diagnostic device.

(First Embodiment)
FIG. 1 is a diagram showing an example of the configuration of the medical information processing system 100 according to the first embodiment. As shown in FIG. 1, the medical information processing system 100 according to the first embodiment includes an X-ray CT device 1, a server device 2, and a terminal device 3. The X-ray CT device 1, the server device 2, and the terminal device 3 can communicate with each other directly or indirectly by, for example, an in-hospital LAN (Local Area Network) 4 installed in the 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 to and from each other in accordance with the DICOM (Digital Imaging and Communications in Medicine) standard.

Further, in the medical information processing system 100, for example, HIS (Hospital Information System) and RIS (Radiology Information System) are introduced to manage various information. For example, the terminal device 3 transmits the created inspection order to the X-ray CT device 1 and the server device 2. The X-ray CT device 1 acquires patient information from a patient list (modality work list) for each modality created by a test order received directly from the terminal device 3 or a server device 2 that receives the test order, and the patient. Collect X-ray CT image data for each. Then, the X-ray CT apparatus 1 transmits the collected X-ray CT image data and the image data generated by performing various image processing on the X-ray CT image data to the server apparatus 2. The server device 2 stores the X-ray CT image data and the image data received from the X-ray CT device 1, generates the image data from the X-ray CT image data, and responds to the acquisition request from the terminal device 3. The 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 clinical department in the hospital and operated by a doctor working in each clinical department, and is a PC (Personal Computer), a tablet PC, a PDA (Personal Digital Assistant), a mobile phone, or the like. 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 is input with an inspection order for ordering the inspection by the X-ray CT device 1, and transmits the input inspection order to the X-ray CT device 1 and the server device 2. That is, the doctor in the clinical department operates the terminal device 3 to read the reception information of the patient who visited the hospital and the information of the electronic medical record, examine the corresponding patient, and input the medical record information into the read electronic medical record. Then, the doctor in the clinical department operates the terminal operation 3 to transmit the examination order according to the necessity of the examination by the X-ray CT apparatus 1.

The server device 2 stores medical images (for example, X-ray CT image data and image data collected by the X-ray CT device 1) collected by the medical image diagnostic device, and performs various image processing on the medical image. It is a device for performing, for example, a PACS server. For example, the server device 2 receives a plurality of examination orders from the terminal devices 3 arranged in each clinical department, creates a patient list for each medical diagnostic imaging device, and transmits the created patient list to each medical diagnostic imaging device. do. As an example, the server device 2 receives an examination order for performing an examination by the X-ray CT device 1 from the terminal device 3 of each clinical department, creates a patient list, and uses the created patient list as an X-ray CT. Send to device 1. Then, the server device 2 stores the X-ray CT image data and the image data collected by the X-ray CT device 1, and in response to the acquisition request from the terminal device 3, the X-ray CT image data and the image data are stored in the terminal device. Send to 3.

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. It is transmitted to the device 2. FIG. 2 is a diagram showing 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 sleeper apparatus 20, and a console 30.

The gantry 10 is a device that irradiates the subject (patient) P with X-rays, detects the X-rays transmitted through the subject P, and outputs the X-rays to the console 30. The X-ray irradiation control circuit 11 and the X-ray generator are generated. It has a device 12, a detector 13, a data acquisition circuit (DAS: Data Acquisition System) 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 in between, and rotates at high speed in a circular orbit centered on the subject P by a gantry drive circuit 16 described later. It is 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 generating unit. The X-ray irradiation control circuit 11 irradiates the subject P from the X-ray tube 12a by adjusting the tube voltage and the 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.

Further, the X-ray irradiation control circuit 11 switches the wedge 12b. Further, the X-ray irradiation control circuit 11 adjusts the X-ray irradiation range (fan angle and cone angle) by adjusting the opening degree of the collimator 12c. In this embodiment, the operator may manually switch between a plurality of types of wedges.

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

The X-ray tube 12a is a vacuum tube that irradiates the subject P with an X-ray beam by a high voltage supplied by the X-ray irradiation control circuit 11, and causes the X-ray beam to the subject P as the rotating frame 15 rotates. Irradiate against. 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 12a is continuously exposed to X-rays all around the subject P for full reconstruction, or half-reconstructable for half-reconstruction. It is possible to continuously expose X-rays within the range (180 degrees + fan angle). Further, under the control of the X-ray irradiation control circuit 11, the X-ray tube 12a can 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 X-rays exposed 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 the X-ray tube 12a to a range other than the specific tube position. Decreases the intensity of the emitted X-rays.

The wedge 12b is an X-ray filter for adjusting the X-ray dose of X-rays exposed 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 radiated from the X-ray tube 12a to the subject P have a predetermined distribution. It is a filter that attenuates. For example, the wedge 12b is a filter made of aluminum so as to have a predetermined target angle and a predetermined thickness. The wedge is also called a wedge filter or a bow-tie filter.

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

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

The detector 13 is a two-dimensional array type detector (surface detector) that detects X-rays that have passed through the subject P, and the detection element sequence 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 has 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 that have passed through the subject P over a wide range, such as in the 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, sensitivity correction processing between channels, and the like on the X-ray intensity distribution data detected by the detector 13. The projected projection data is transmitted to the console 30 described later. For example, when X-rays are continuously exposed from the X-ray tube 12a during the rotation of the rotating frame 15, the data collection circuit 14 collects the projected data group for the entire circumference (360 degrees). Further, the data collection circuit 14 associates the tube position with each of the collected projection data and transmits the data to the console 30 described later. The tube position is information indicating the projection direction of the projection data. The sensitivity correction processing between channels may be performed by the preprocessing circuit 34, which will be described later.

The sleeper device 20 is a device on which the subject P is placed, and has a sleeper drive device 21 and a top plate 22 as shown in FIG. The sleeper drive device 21 moves the top plate 22 in the Z-axis direction to move the subject P into the rotating frame 15. The top plate 22 is a plate on which the subject P is placed.

The gantry 10 executes, for example, a helical scan in which the rotating frame 15 is rotated while the top plate 22 is moved to scan the subject P in a spiral shape. Alternatively, the gantry device 10 executes a conventional scan in which the rotating frame 15 is rotated while the position of the subject P is fixed after the top plate 22 is moved to scan the subject P in a circular orbit. Alternatively, the gantry device 10 executes a step-and-shoot method in which the position of the top plate 22 is moved at regular intervals to perform a conventional scan in a plurality of scan areas.

The console 30 is a device that accepts the operation of the X-ray CT device 1 by the operator and reconstructs the X-ray CT image data using the 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 has a mouse, keyboard, trackball, switch, button, joystick, etc. used by the operator of the X-ray CT device 1 to input various instructions and various settings, and information on the instructions and settings received from the operator. Is transferred to the processing circuit 37. For example, the input circuit 31 receives from the operator the imaging conditions for the X-ray CT image data, the reconstruction conditions for reconstructing the X-ray CT image data, the image processing conditions for the X-ray CT image data, and the like. Further, the input circuit 31 accepts an operation for selecting a test for the subject P. Further, the input circuit 31 accepts a designation operation for designating a portion on the image.

The display 32 is a monitor referred to by the operator, and under the control of the processing circuit 37, displays the image data generated from the X-ray CT image data to the operator, or displays the image data to the operator via the input circuit 31. Displays a GUI (Graphical User Interface) for receiving various instructions and various settings from. In addition, the display 32 displays a plan screen for a scan plan, a screen during scanning, and the like. In addition, the display 32 displays virtual patient body shape information including exposure information, image data, and the like. The virtual patient body shape information displayed by 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 drive circuit 16, the data collection circuit 14, and the sleeper drive device 21 under the control of the processing circuit 37, thereby displaying the projected data on the gantry 10. Control the collection process. Specifically, the scan control circuit 33 controls the collection process of projection data in the photographing in which the positioning image (scano image) is collected. In addition, the scan control circuit 33 controls the collection process of projection data in the main shooting (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 captured.

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

In addition, the scan control circuit 33 captures a three-dimensional positioning image by collecting projection data for the entire circumference of the subject P when capturing the positioning image. FIG. 3 is a diagram for explaining three-dimensional positioning image capture 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 helical scan or non-helical scan. Here, the scan control circuit 33 executes a helical scan or a non-helical scan on a wide area such as the entire chest, abdomen, upper body, and whole body of the subject P at a lower dose than the main imaging. As the non-helical scan, for example, the above-mentioned step-and-shoot method scan is executed.

In this way, the scan control circuit 33 collects the projection data for the entire circumference of the subject P, and the image reconstruction circuit 36 described later reconstructs the 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 the positioning image is generated from this volume data, this volume data is also called a three-dimensional positioning image. Here, whether to capture the positioning image in two dimensions or in three dimensions may be arbitrarily set by the operator, or may be preset according to the inspection content. The scan control circuit 33 is an example of a collecting 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 collection 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 the corrected projection data 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 the corrected projection data 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 projection data of the positioning image and the corrected projection data for diagnosis generated by the preprocessing circuit 34. In addition, the storage circuit 35 stores image data and virtual patient body shape information generated by the image reconstruction circuit 36, which will be described later. Further, the storage circuit 35 appropriately stores the processing result by the processing circuit 37 described later. The virtual patient body shape information will be described later.

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

The processing circuit 37 controls the operation of the gantry 10, the sleeper device 20, and the console 30 to control the entire X-ray CT device 1. Specifically, the processing circuit 37 controls the CT scan performed on the gantry 10 by controlling the scan control circuit 33. Further, the processing circuit 37 controls the image reconstruction processing and the image generation processing in the console 30 by controlling the image reconstruction circuit 36. Further, 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 the acquisition function 37a, the selection function 37b, the setting function 37c, the generation function 37d, the display control function 37e, and the control function 37f. Here, for example, each processing function executed by the acquisition function 37a, the selection function 37b, the setting function 37c, the generation function 37d, the display control function 37e, and the control function 37f, which are the components of the processing circuit 37 shown in FIG. 2, is a computer. It is recorded in the storage circuit 35 in the form of a program that can be executed by. The processing circuit 37 is a processor that realizes 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 the 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 the 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 word "processor" used in the above description means, for example, a CPU (central processing unit), a GPU (Graphics Processing Unit), an integrated circuit for a specific application (Application Specific Integrated Circuit (ASIC)), or a programmable logic device. (For example, it means a circuit such as a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). The processor realizes the function by reading and executing the program stored in the storage circuit. Instead of storing the program in the storage circuit, the program may be directly embedded in the circuit of the processor. In this case, the processor reads the program embedded in the circuit and executes the read program to realize the function. It should be noted that each processor of the present embodiment is not limited to the case where each processor is configured as a single circuit, and a plurality of independent circuits may be combined to form one processor to realize its 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 positions of a plurality of parts such as organs included in the three-dimensional X-ray CT image data (volume data) reconstructed by the image reconstruction circuit 36, thereby being covered. The positions of a plurality of parts of the sample P are acquired. For example, the acquisition function 37a detects a part such as an organ based on an anatomical landmark on 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 in the volume data of the image used for diagnosis. Here, the anatomical feature point is a point showing the feature of a specific part such as a bone, an organ, a blood vessel, a nerve, or a lumen. That is, the acquisition function 37a detects bones, organs, blood vessels, nerves, lumens, etc. included in the volume data by detecting anatomical feature points such as specific organs and bones. In addition, the acquisition function 37a can also detect the positions of the head, neck, chest, abdomen, legs, etc. included in the volume data by detecting the characteristic feature points of the human body. The site described in the present embodiment means a bone, an organ, a blood vessel, a nerve, a lumen, or the like including these positions. Hereinafter, an example of detecting a portion 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 a textbook with the position of the feature point extracted from the volume data to obtain the feature point extracted from the volume data. Inaccurate feature points are removed from the inside to optimize the position of the feature points extracted from the volume data. As a result, the acquisition function 37a acquires the position information related to each part of the subject included in the volume data. As an example, the acquisition function 37a first extracts anatomical feature points included in the volume data by using a supervised machine learning algorithm. Here, the machine learning algorithm is constructed by 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. Will be done.

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

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

Here, the acquisition function 37a assigns an identification code for identifying the feature points indicating the features of each part to the extracted feature points (voxels), and the identification code and the position (coordinate) information of each feature point. The information associated with and is attached to the image data and stored in the storage circuit 35. For example, as shown in FIG. 4B, the acquisition function 37a assigns identification codes such as C1, C2, and C3 to the extracted feature points (voxels). Here, the acquisition function 37a attaches an identification code to each of the acquired data and stores the data in the storage circuit 35. Specifically, the acquisition function 37a is the projection data of at least one of the projection data of the positioning image, the projection data collected under non-contrast, and the projection data collected in the state of being imaged by the contrast medium. The position information related to the site 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 information associated with the coordinates of each voxel detected from the volume data (positioning in the figure) of the positioning image to the volume data to the storage circuit 35. Store in. As an 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 what kind of 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 this information. ..

Further, as shown in FIG. 5, for example, the acquisition function 37a attaches information in which an identification code is associated with the coordinates of each voxel detected from the volume data (scan in the figure) of the image for diagnosis to the volume data. Is stored in the storage circuit 35. Here, the acquisition function 37a is, for example, from the volume data (contrast-enhanced Phase in the figure) imaged by the contrast medium and the volume data (non-contrast-enhanced Phase in the figure) not imaged by the contrast medium in the scan. The coordinates of each feature point can be extracted, and the identification code can be associated with the extracted coordinates.

As an example, the acquisition function 37a extracts the coordinates of the feature points from the volume data of the non-contrast phase from the volume data of the image for diagnosis, 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. Further, the acquisition function 37a extracts the coordinates of the feature points from the volume data of the contrast Phase from the volume data of the image for diagnosis, 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 the feature points are extracted from the volume data of the contrast-enhanced Phase, the feature points that can be extracted by being contrast-enhanced are included. For example, the acquisition function 37a can extract blood vessels and the like imaged by a contrast agent when extracting feature points from the volume data of the contrast-enhanced Phase. Therefore, in the case of the volume data of the contrast-enhanced Phase, the acquisition function 37a has the coordinates (x'31, y'31, z'31) of the feature points such as blood vessels extracted by the contrast as shown in FIG. Identification codes C31, C32, C33, C34, etc. for identifying each blood vessel are associated with the coordinates (x'34, y'34, z'34) and the like.

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

For example, the acquisition function 37a is based on the positional relationship information such as "lung apex: 2-3 cm above the clavicle" and "lower end of the lung: height of the 7th rib" and the coordinate information of each part. As shown in, the three-dimensional region R1 corresponding to the “lung” is extracted from the volume data. That is, the acquisition function 37a extracts the coordinate information of the voxels 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 the “heart” in the volume data.

Further, the acquisition function 37a detects the position of the part included in the volume data based on the feature points that define the parts such as the head and the 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 area from the 7th cervical spine to the lower end of the lung is defined as the chest, the acquisition function 37a detects from the feature point corresponding to the 7th cervical spine to the feature point corresponding to the lower end of the lung as the chest. The acquisition function 37a can detect the site by various methods other than the method using the above-mentioned anatomical feature points. For example, the acquisition function 37a can detect a portion included in the volume data by a region expansion method based on a voxel value or the like.

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

The setting function 37c sets the 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 shape information. The setting function 37c has a collation function for collating the positions of the plurality of sites in the subject P included in the image data with the positions of the plurality of sites in the virtual patient included in the virtual patient body shape information. The virtual patient is a standard and virtual patient. The collation function will be described below. The setting function 37c collates the position of the site of the subject P with the position of a standard site in the virtual patient, and stores the collation result in the storage circuit 35. For example, the selection function 37b matches the virtual patient body shape information in which a part of the human body is arranged at a standard position with the volume data of the subject P.

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

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

That is, the storage circuit 35 stores the coordinates of the feature points in the coordinate space of the three-dimensional human body image in association with the corresponding identification code. As an example, the storage circuit 35 stores the coordinates of the corresponding feature points in association with the identification code “V1” shown in FIG. Further, 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 lungs, hearts, livers, stomachs, kidneys and the like are shown as organs, but the virtual patient body shape information includes a larger number of organs, bones, vasculars, nerves and the like. Further, in FIG. 7, only the feature points corresponding to the identification codes “V1”, “V2” and “V3” are shown, but in reality, a larger number of 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 shape information described above by using the identification code, and the coordinate space of the volume data. Is associated with the coordinate space of the virtual patient body shape 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 shape information. However, the embodiment is not limited to this, and matching can be performed using any set of feature points.

For example, as shown in FIG. 8, the setting function 37c has the feature points indicated by the identification codes “V1”, “V2” and “V3” in the virtual patient body shape information, and the identification codes “C1” and “C2” in the positioning image. When matching with the feature points indicated by "" 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 the same feature 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) ” Find the conversion matrix "H".

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

As a result, for example, the scan range "SRV" set to include the feature points corresponding to the identification code "Vn" on the virtual patient body shape information has the identification code "Cn" corresponding to the same feature points on the positioning image. Is converted to the scan range "SRC" including "" and set. The coordinate transformation matrix "H" described above may be stored in the storage circuit 35 for each subject and appropriately read out and used, or calculated each time a positioning image is collected. It may be the case. As described above, according to the first embodiment, the virtual patient body shape information is displayed for specifying the range at the time of presetting, and the position / range is planned on the virtual patient body shape information, so that the position / range is planned after the positioning image is taken. It is possible to automatically set the numerical value of the position / range on the positioning image corresponding to the position / range.

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

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

The control function 37f controls the operation of the gantry 10, the sleeper device 20, and the console 30 to control the entire X-ray CT device 1. Specifically, the control function 37f controls the CT scan performed on the gantry 10 by controlling the scan control circuit 33. Further, 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 the imaging using the X-ray CT apparatus, the positioning image for setting the imaging range of the main imaging is captured before the main imaging for collecting the data used for the diagnosis. Then, the X-ray CT apparatus displays the captured positioning image on the display and receives the imaging range of the main imaging from the operator. Then, the X-ray CT apparatus sets the received imaging range and performs the 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 the imaging range of the main imaging to a range including a portion existing outside the range of the positioning image. In this case, for example, the operator first estimates the position of a portion not included in the positioning image, that is, a portion not displayed. Then, the operator inputs an instruction for main imaging of a range including the estimated portion to the X-ray CT apparatus via the input circuit. As a result, the X-ray CT apparatus performs the main imaging within the range instructed by the operator. As described above, when the operator inputs a range including a part existing outside the range of the positioning image as the shooting range of the main shooting, it is easy because the operation of estimating the position of the part is involved. The shooting range cannot be set, and as a result, shooting cannot be easily performed. Therefore, the X-ray CT apparatus 1 according to the first embodiment has the above-described configuration so that the operator can easily make settings for performing imaging as described below. , Perform various processes.

An example of the 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 showing an example of a processing procedure 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 has been started (step S101). If the inspection has not been started (step S101: No), the control function 37f again determines in step S101 whether or not the inspection has been started. On the other hand, when the inspection is started (step S101: Yes), the control function 37f collects a three-dimensional positioning image (volume data) by controlling the scan control circuit 33, the image reconstruction circuit 36, and the like. (Step S102).

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

On the other hand, when the shooting range of the main shooting is not accepted (step S104: No), the selection function 37b exists outside the range of the positioning image currently displayed by the operator via the input circuit 31. It is determined whether or not an instruction to perform the main imaging of the range including the portion is input (step S105). If such an instruction is not 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 or not the designation of a portion existing outside the range of the positioning image has been accepted (step S106). For example, in step S106, the selection function 37b displays the virtual patient body shape information on the display 32, and determines whether or not the portion designated by the operator among the plurality of portions of the human body has been accepted. In step S106, the selection function 37b may display a list of parts on the display 32 and determine whether or not a part designated by the operator has been accepted from the list of displayed parts. When the part is not accepted (step S106: No), the selection function 37b again determines in step S106 whether or not the part has been accepted.

On the other hand, when a part is accepted (step S106: Yes), the selection function 37b selects the accepted part (step S107). Then, the setting function 37c corresponds to a plurality of parts of the subject P in the three-dimensional positioning image and a plurality of parts of the previous subject P among the plurality of parts of the virtual patient included in the virtual patient body shape 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, in the setting function 37c, each part corresponding to the plurality of parts of the subject P among the plurality of parts of the virtual patient is positioned at each position indicated by the position information of the plurality of parts of the subject P. The coordinate transformation matrix for transforming the virtual patient body shape information is calculated so as to be performed.

Then, the generation function 37d extracts a three-dimensional region including the selected part from the human body indicated by the virtual patient body shape information, and uses the calculated coordinate transformation matrix to deform the extracted region to obtain coordinates. The transformed region using the transformation matrix is calculated (step S109). Here, the deformed region is a three-dimensional image indicated by three-dimensional image data including a portion designated by the operator. Further, the range indicated by the deformed area is a range including a part designated by the operator and existing outside the range of the currently displayed positioning image. Further, from this three-dimensional image, the region of the MPR image, which is the coronal cross-sectional image reconstructed by the image reconstruction circuit 37, corresponds to the region (extended region) 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 the estimated image data.

The process of step S109 will be described with reference to specific examples. FIG. 12 is a diagram showing an example of an MPR image which is a coronal cross-sectional image reconstructed by the image reconstruction circuit 37 from the deformed region. 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 shape information, and uses the coordinate transformation matrix to extract the extracted region. Is transformed to generate image data of a three-dimensional image including the designated pelvis 51a. Then, in step S109, the image data of the MPR image 51, which is the coronal cross-sectional image shown in the example of FIG. 12, is reconstructed (generated) from the image data of the generated three-dimensional image by the image reconstruction circuit 37. The region of the MPR image 51 corresponds to an extension region of the two-dimensional positioning image 50 shown in FIG. 11 above.

Returning to the description of FIG. 10, the setting function 37c estimates the imaging range including the designated portion and sets the estimated imaging range (step S110). That is, in step S110, the imaging range that does not include the imaging range of the image data is set by using the deformed virtual patient body shape information. FIG. 13 is a diagram showing 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, and sets the estimated range 52 as the imaging range in the main imaging, as shown in the example of FIG. At the same time, the frame 53 showing 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. In this way, the setting function 37c sets the imaging range in the main imaging so as to include the pelvis designated by the operator without having the operator 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.

Then, the display control function 37e is based on the two-dimensional positioning image (MPR image) reconstructed by the image reconstruction circuit 37 from the collected three-dimensional positioning image 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 combined, and the combined image data (composited image data) is displayed on the display 32 (step S111). FIG. 14 is a diagram showing an example of composite image data. For example, in step S111, as shown in the example of FIG. 14, the display control function 37e synthesizes the positioning image data showing the two-dimensional positioning image 50 and the image data of the MPR image 51 including the pelvis 51a, and synthesizes them. Image data 54 is generated. Then, the display control function 37e causes the composite image data 54 to be displayed on the display 32. As described above, the composite image data displayed on the display 32 includes a portion designated by the operator. Therefore, when changing the shooting range in the main shooting, the operator can set the shooting range including the designated part only by changing the shooting range so as to include the displayed part. Therefore, by displaying the composite image data, it is possible to make the operator more easily perform the setting at the time of shooting.

Returning to the description of FIG. 10, the control function 37f determines whether or not the shooting range of the main shooting input from the operator has been accepted via the input circuit 31 (step S112). For example, when the operator uses 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. Further, when the operator changes the shooting range set in step 110 and sets the changed shooting range as the shooting range for the main shooting, the operator uses the input circuit 31 to set the shooting range set in step 110. And enter the changed shooting range as the shooting range for the main shooting. When the shooting range of the main shooting is not accepted (step S112; No), the control function 37f again determines in step S112 whether or not the shooting range of the main shooting is accepted.

On the other hand, when the shooting range of the main shooting is accepted (step S112; Yes), the control function 37f controls the scan control circuit 33 so that the main shooting of the shooting range received 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 the diagnosis collected in the main imaging (step S114), and ends the process. do. The X-ray CT image reconstructed in step S114 is displayed on the display 32 by, for example, the display control function 37e. At this time, the display control function 37e may superimpose the virtual patient body shape information on the X-ray CT image as reference information and display the X-ray CT image on which the virtual patient body shape information is superposed 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 executes the program. Further, step S103 and step 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 the program. Further, 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 the program. Further, step S108 and step 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 the program. Further, step S109 is a step in which the processing circuit 37 reads a program corresponding to the generation function 37d from the storage circuit 35 and executes the program.

Further, in step S102, the control function 37f collects a three-dimensional positioning image by controlling the scan control circuit 33, the image reconstruction circuit 36, and the like, and the three-dimensional positioning image is taken in a step after step S102. The case where the processing is performed using is illustrated. However, in step S102, the control function 37f collects a two-dimensional positioning image by controlling the scan control circuit 33, the image reconstruction circuit 36, and the like, and the two-dimensional positioning image is taken in a step after step S102. May be used for processing. By collecting the two-dimensional positioning image, the processing amount is smaller than in the case of collecting the three-dimensional positioning image, and the processing can be performed in a short time.

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 captured before the main imaging for collecting the data used for the diagnosis. Will be done. Then, as described above, the X-ray CT apparatus displays the captured positioning image on the display and receives the imaging range of the main imaging from the operator. Then, the X-ray CT apparatus sets the received imaging range and performs the main imaging within the set imaging range. Here, after the X-ray CT apparatus performs the main shooting, the operator may want to additionally perform the main shooting in a shooting range including a portion existing outside the range of the positioning image. When performing such additional main imaging, for example, the operator first estimates the position of a portion not included in the positioning image, that is, a portion not displayed. Then, the operator inputs an instruction for additional main imaging to include the estimated portion to the X-ray CT apparatus via the input circuit. As a result, the X-ray CT apparatus additionally performs the main imaging in the imaging range instructed by the operator. As described above, when the operator inputs a range including a part existing outside the range of the positioning image as the shooting range of the additional main shooting, the operator involves an uneasy task of estimating the position of the part. , The shooting range cannot be easily set, and as a result, additional shooting cannot be easily performed. Therefore, the X-ray CT apparatus 1 according to the second embodiment can easily allow the operator to make settings for performing additional imaging based on the above-described configuration, as described below. As such, various processes are executed.

An example of the 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 showing an example of the processing procedure by the X-ray CT apparatus 1 according to the second embodiment. The processing of steps S201 to S203 is the same as the processing of steps S101 to S103 shown in FIG. 10, and thus the description thereof will be omitted.

As shown in FIG. 15, the control function 37f determines whether or not the shooting range of the main shooting is received from the operator via the input circuit 31 (step S204). When the shooting range of the main shooting is not accepted (step S204: No), the control function 37f again determines in step S204 whether or not the shooting range of the main shooting is accepted.

On the other hand, when the shooting range of the main shooting is accepted (step S204: Yes), the control function 37f controls the scan control circuit 33 so that the main shooting of the shooting range received in step S204 is performed (step S204: Yes). 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 the diagnosis collected in the main imaging in step S205 (step S206). The X-ray CT image reconstructed in step S206 is displayed on the display 32 by, for example, the display control function 37e. At this time, the display control function 37e may superimpose the virtual patient body shape information on the X-ray CT image as reference information and display the X-ray CT image on which the virtual patient body shape information is superposed on the display 32.

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

On the other hand, when an additional instruction to perform main shooting is input (step S207: Yes), the selection function 37b determines whether or not the designation of a portion existing outside the range of the positioning image has been accepted (step). S208). For example, in step S208, the selection function 37b performs the same processing as the processing of step S106 shown in FIG. For example, the selection function 37b displays the virtual patient body shape information on the display 32, and determines whether or not the portion designated by the operator among the plurality of portions of the human body has been accepted. When the part is not accepted (step S208: No), the selection function 37b again determines in step S208 whether or not the part has been accepted.

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

Then, the setting function 37c positions the feature points included only in the positioning image data among the three-dimensional positioning image data collected in step S202 and the X-ray CT image data reconstructed in step S206. The feature points included in the image data are used, the feature points included only in the X-ray CT image data are used, the feature points included in the X-ray CT image data are used, and the feature points included in both image data are the positions. The following processing is performed using the feature points included in the X-ray CT image data having high accuracy. That is, the setting function 37c has 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 previous subject P among the plurality of parts of the virtual patient included in the virtual patient body shape information. The coordinate transformation matrix as described above is calculated so as to minimize the total of the positional deviations with each part corresponding to the parts (step S210). That is, in step S210, the setting function 37c basically uses the 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. For, the positioning image data is used. For example, when the imaging range of the positioning image is wider than the imaging range of the X-ray CT image, an event may occur in which a certain feature point is not included in the X-ray CT image but is included only in the positioning image. As described above, 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. Further, as a result of being able to calculate the coordinate transformation matrix with high accuracy, it is possible to set the shooting range with high accuracy.

In step S210, when the setting function 37c calculates the coordinate conversion matrix, the position in the positioning image data and the X-ray CT are related to 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, the 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 shape information, and uses the calculated coordinate transformation matrix, as in the process of the previous step S109. By transforming the extracted region, the transformed region using the coordinate transformation matrix is calculated (step S211). Here, the deformed region is a three-dimensional image indicated by three-dimensional image data including a portion designated by the operator. Further, the range indicated by the deformed area is a range including a part designated by the operator and existing outside the range of the currently displayed positioning image. Further, from this three-dimensional image, the region of the MPR image, which is the coronal cross-sectional image reconstructed by the image reconstruction circuit 37, corresponds to the region (extended region) 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 S211 is an example of the estimated image data.

Then, the setting function 37c estimates the shooting range including the designated portion and sets the estimated shooting range (step S212), as in the process of step S110. In this way, the setting function 37c sets the shooting range in the main shooting so as to include the part designated by the operator without having the operator estimate the position of the part to be additionally photographed. 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 has the same as the process of step S111, the two-dimensional positioning image reconstructed by the image reconstruction circuit 37 from the collected three-dimensional positioning image, and the 3 generated in step S211. The image data of the dimensional image is combined with the image data of the MPR image generated by the image reconstruction circuit 37, and the combined combined image data is displayed on the display 32 (step S213). Here, the composite image data displayed on the display 32 includes a portion designated by the operator. Therefore, when changing the shooting range in the main shooting, the operator can set the shooting range including the designated part only by changing the shooting range so as to include the displayed part. Therefore, by displaying the composite image data, it is possible to make the operator more easily perform the setting at the time of shooting.

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

On the other hand, when the shooting range of the main shooting is accepted (step S214; Yes), the control function 37f controls the scan control circuit 33 so that the main shooting of the shooting range received in step S214 is performed (step S214). S215). Here, an example of a method of setting imaging conditions including a collection row, a tube voltage, and a tube current in the additional main imaging in step S215 will be described. For example, the control function 37f may set the collection line and tube voltage in the main shooting performed in the previous step S205 as the additional collection line and tube voltage in the main shooting in step S215. In this way, the collection line and tube voltage in the main shooting performed in step S205 are inherited in the additional main shooting, so that the image quality of the X-ray CT image obtained in the main shooting performed in step S205 can be obtained. , It is possible to suppress a large difference in the image quality of the X-ray CT image obtained by the additional main shooting. 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 shape information) of the subject P. 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 additional tube current in the main imaging in step S215.

The method of setting the shooting conditions in the additional main shooting in step S215 is not limited to the above-mentioned method. For example, the control function 37f may set the imaging condition of the region specified by the operator or the imaging condition selected by the operator from the expert plan for each region set in the virtual patient body shape information. .. Further, the control function 37f may inherit the shooting conditions of the expert plan set immediately before, or if there is an additional shooting protocol in which the shooting conditions are set, the protocol may be selected. good. 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 the diagnosis collected in the main imaging (step S216), and ends the process. do. The X-ray CT image reconstructed in step S216 is displayed on the display 32 by, for example, the display control function 37e. At this time, the display control function 37e may superimpose the virtual patient body shape information on the X-ray CT image as reference information and display the X-ray CT image on which the virtual patient body shape information is superposed 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 is executed. be. Further, 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 the program. Further, step S208 and step 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 the program. Further, step S210 and step 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 the program. Further, step S211 is a step in which 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 the setting at the time of photographing.

(Modification example)
Here, among the plurality of X-ray CT images in which the projection data collected by the main imaging is reconstructed, the subject P moves in the imaging of a part of the X-ray CT images, and the other X-ray CT The orientation and position of the subject P may be misaligned with the image. Therefore, the X-ray CT apparatus 1 identifies an X-ray CT image in which the orientation and position of the subject P are deviated, and sends a message to the operator to urge the operator to take the identified 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.

16 and 17 are diagrams for explaining a modified example. In the example of FIG. 16, a plurality of diagnostic slice images 70a, ... 70b, ... In which the projection data collected by the main imaging are reconstructed are shown. 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, a positioning slice image which is a plurality of axial cross-sectional images obtained as a result of performing MPR processing on the three-dimensional positioning image collected in step S102 by the image reconstruction circuit 36 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, and both of them. It is determined whether or not the positions are separated by 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 shown in the example of FIG. 16 with the position of the corresponding feature point included in the positioning slice image 71a, and positions both of them. Is determined whether or not is separated by a predetermined value or more. Further, 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. Judge whether or not.

Then, the control function 37f identifies the diagnostic slice image determined to be separated by a predetermined value or more as the diagnostic slice image in which the orientation, position, and the like of the subject P are deviated. In addition, the control function 37f displays a message on the display 32 prompting the user to take another picture of the specified diagnostic slice image, and prompts the operator to take another picture. For example, when the position of the feature point included in the diagnostic slice image 70b and the position of the corresponding feature point included in the positioning slice image 71b are separated by a predetermined value or more, the control function 37f performs the diagnostic slice. Regarding the image 70b, the message "The Nth diagnostic slice image is locally displaced, so please take a picture again." Is displayed on the display 32.

Then, when the operator inputs an instruction for re-imaging via the input circuit 31, the control function 37f controls the scan control circuit 33 so as to perform re-imaging based on the instruction. For example, the control function 37f controls the scan control circuit 33 so that the Nth diagnostic slice image 70b is photographed again. As a result, as shown in FIG. 17, a case where the 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 imaging and the diagnostic slice image collected by the additional main imaging can be treated as the same series, so that the images can be easily managed.

The modified example has been described above. According to the X-ray CT apparatus 1 according to the modified example, the operator can easily make the setting at the time of performing the imaging as in the first embodiment and the second embodiment.

According to the X-ray CT apparatus 1 of at least one embodiment and the modified example described above, the operator can easily make the setting when performing the shadow.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

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

Claims (6)

A collection unit that detects X-rays that have passed through the subject and collects projection data,
An image reconstruction unit that reconstructs image data from the projection data,
An acquisition unit that acquires position information related to a plurality of parts of the subject in the image data, and an acquisition unit.
A storage unit that stores virtual patient body shape information that has position information of each of a plurality of parts of the virtual patient,
Among the plurality of parts of the virtual patient, a selection part that selects a part that is different from the part corresponding to the plurality of parts included in the image data and is designated by the operator, and a selection part.
A generation unit that generates estimated image data corresponding to an extension region of the image data so that the selected portion is included, and a generation unit.
Using the estimated image data, a setting unit that sets a shooting range that does not include the shooting range of the image data, and a setting unit.
Equipped with a,
In the generation unit, each part corresponding to the plurality of parts of the subject among the plurality of parts of the virtual patient is located at each position indicated by the position information of the plurality of parts of the subject. , The virtual patient body shape information is deformed, and a portion of the deformed virtual patient body shape information including the different parts is generated as the estimated image data.
X-ray CT device. The setting unit uses a virtual patient type information after the modification, and sets the imaging range not contain shooting range of the image data, X-rays CT apparatus according to claim 1. The X-ray CT apparatus according to claim 1 or 2, further comprising a display control unit for displaying a composite image data obtained by combining the image data and the estimated image data on the display unit. The collecting unit collects the projection data of the positioning image and the projection data of the image used for diagnosis.
The image reconstructing 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 the position information relating to the site included in each of the plurality of positioning images and the position information relating to the site included in each of the plurality of images used for the diagnosis. In any one of claims 1 to 3, further comprising a control unit for identifying an image used for diagnosis in which the position or orientation of the subject is misaligned and notifying the identified image to be photographed again. The X-ray CT apparatus described. The X-ray CT apparatus according to claim 4, wherein the control unit treats the image obtained by re-shooting the specified image and the other image as the same series. The X-ray CT apparatus according to any one of claims 1 to 3, wherein the image data is positioning image data, data used for diagnosis, or positioning image data and data used for diagnosis.

Images