JP6985047B2 - X-ray CT device - Google Patents

Description

Embodiments of the present invention relate to an X-ray CT (Computed Tomography) apparatus.

Conventionally, an X-ray CT apparatus has been used for lung cancer screening of the chest and the like. Here, when an examination is performed on a patient whose lesion site has been detected in the past examination, a plurality of times of imaging may be performed depending on the lesion site. For example, an X-ray CT device images the entire chest, followed by imaging the lesion site.

Japanese Patent No. 5072526

An object to be solved by the present invention is to provide an X-ray CT apparatus capable of improving the efficiency of inspection and reducing radiation exposure.

The X-ray CT apparatus of the embodiment includes a setting unit. The setting unit integrates the first plan for the subject and the second plan for the subject to set the third plan for the subject.

FIG. 1 is a diagram showing an example of the configuration of the X-ray CT apparatus 1 according to the first embodiment. FIG. 2A is a diagram (1) for explaining the prior art. FIG. 2B is a diagram (2) for explaining the prior art. FIG. 2C is a diagram (3) for explaining the prior art. FIG. 2D is a diagram (4) for explaining the prior art. FIG. 3 is a flowchart showing a processing procedure by the X-ray CT apparatus according to the first embodiment. FIG. 4A is a diagram (1) for explaining a processing operation by the acquisition function according to the first embodiment. FIG. 4B is a diagram (2) for explaining a processing operation by the acquisition function according to the first embodiment. FIG. 4C is a diagram (3) for explaining a processing operation by the acquisition function according to the first embodiment. FIG. 5 is a flowchart showing a processing procedure by the setting function according to the first embodiment. FIG. 6A is a diagram (1) for explaining a processing operation by the setting function according to the first embodiment. FIG. 6B is a diagram (2) for explaining a processing operation by the setting function according to the first embodiment. FIG. 6C is a diagram (1) for explaining a processing operation by the processing circuit according to the first embodiment. FIG. 6D is a diagram (2) for explaining a processing operation by the processing circuit according to the first embodiment. FIG. 6E is a diagram (3) for explaining a processing operation by the processing circuit according to the first embodiment. FIG. 6F is a diagram (4) for explaining a processing operation by the processing circuit according to the first embodiment. FIG. 7A is a diagram (1) for explaining a modification of the first embodiment. FIG. 7B is a diagram (2) for explaining a modification of the first embodiment. FIG. 7C is a diagram (3) for explaining a modified example of the first embodiment. FIG. 7D is a diagram (4) for explaining a modification of the first embodiment. FIG. 7E is a diagram (5) for explaining a modification of the first embodiment. FIG. 8A is a diagram for explaining a second modification of the first embodiment. FIG. 8B is a diagram for explaining a second modification of the first embodiment. FIG. 9A is a diagram (1) for explaining a third modification of the first embodiment. FIG. 9B is a diagram (2) for explaining a third modification of the first embodiment. FIG. 9C is a diagram (3) for explaining a third modification of the first embodiment. FIG. 10 is a flowchart showing a processing procedure by the setting function according to the second embodiment. FIG. 11A is a diagram (1) for explaining a processing operation by the setting function according to the second embodiment. FIG. 11B is a diagram (2) for explaining a processing operation by the setting function according to the second embodiment. FIG. 11C is a diagram (3) for explaining a processing operation by the setting function according to the second embodiment. FIG. 11D is a diagram (4) for explaining a processing operation by the setting function according to the second embodiment. FIG. 11E is a diagram (5) for explaining a processing operation by the setting function according to the second embodiment. FIG. 11F is a diagram (6) for explaining a processing operation by the setting function according to the second embodiment. FIG. 12 is a diagram for explaining other embodiments.

Hereinafter, the X-ray CT apparatus according to the embodiment will be described with reference to the drawings. The embodiment is not limited to the following embodiments. Further, in principle, the contents described in one embodiment are similarly applied to other embodiments.

(First Embodiment)
FIG. 1 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. 1, the X-ray CT apparatus 1 according to the first embodiment has a gantry 10, a sleeper 20, and a console 30.

The gantry 10 is a device that irradiates the subject P (patient) 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 generation. 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. Further, in the gantry 10, as shown in FIG. 1, an orthogonal coordinate system including an X-axis, a Y-axis, and a Z-axis is defined. That is, the X-axis indicates the horizontal direction, the Y-axis indicates the vertical direction, and the Z-axis indicates the rotation center axis direction of the rotating frame 15 when the gantry 10 is not tilted.

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 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, and the X-ray tube 12a uses the high voltage supplied from the X-ray irradiation control circuit 11 to X-ray. Generate a line. The X-ray irradiation control circuit 11 adjusts the X-ray dose irradiated to the subject P 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. ..

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 a high voltage generator (not shown), and the X-ray beam is sent 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 around the entire circumference of the subject P for full reconstruction, or is exposed to half reconstruction 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 in 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 obtained by processing 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 irradiation range of X-rays whose X-ray dose is adjusted by the wedge 12b under the control of the X-ray irradiation control circuit 11 described later.

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 transmitted 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. 1). 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 the area including the heart and the heart.

In the detector 13, a detection element having a pixel pitch (0.25 mm) of 1/2 of the conventional one is arranged in order to enable reconstruction of a high-definition image. As a result, for example, the detector 13 is arranged with 160 rows and 1792 channel detection elements, whereas 80 rows and 896 channel detection elements are conventionally arranged in the detector 13. That is, the detector 13 has a high-definition resolution.

The data acquisition circuit 14 is a DAS and collects projection data from the X-ray detection data detected by the detector 13. For example, the data acquisition circuit 14 generates projection data by performing amplification processing, A / D conversion processing, sensitivity correction processing between channels, etc. 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 acquisition circuit 14 collects the projection data group for the entire circumference (360 degrees). Further, the data acquisition 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 process between channels may be performed by the preprocessing circuit 34, which will be described later.

The sleeper 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 sleeper drive device 21 can move the top plate 22 in the X-axis direction as well. 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 spirally scan the subject P. Alternatively, the gantry 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 10 executes a step-and-shoot method in which the position of the top plate 22 is moved at regular intervals to perform conventional scanning 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. 1, the console 30 has 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 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 shooting 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 referenced 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 settings from. In addition, the display 32 displays a plan screen for a scan plan, a screen during scanning, and the like. Further, the display 32 displays a virtual patient image including exposure information, image data, and the like. The virtual patient image 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 acquisition circuit 14, and the sleeper drive device 21 under the control of the processing circuit 37, thereby displaying the projection data on the gantry 10. Control the collection process. Specifically, the scan control circuit 33 controls the collection process of projection data in the imaging for collecting the positioning image (scano image) and the main imaging (scan) for collecting the image used for diagnosis. Here, in the X-ray CT apparatus 1 according to the first embodiment, a two-dimensional scanno image and a three-dimensional scanno image can be taken.

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 scano image with. Alternatively, the scan control circuit 33 fixes the X-ray tube 12a at a position of 0 degrees, and while moving the top plate 22 intermittently, the scan control circuit 33 intermittently repeats shooting in synchronization with the movement of the top plate in two dimensions. Take a scanno 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.

Further, the scan control circuit 33 captures a three-dimensional scanno image by collecting projection data for the entire circumference of the subject P in capturing the scanno image. For example, 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 range 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). It is possible to generate a positioning image from any direction using the reconstructed volume data. Here, whether to shoot the positioning image in two dimensions or three dimensions may be arbitrarily set by the operator, or may be set in advance according to the inspection content.

The preprocessing circuit 34 performs logarithmic transformation 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, and obtains the corrected projection data. Generate. Specifically, the preprocessing circuit 34 generates corrected projection data for each of the projection data of the positioning image generated by the data acquisition circuit 14 and the projection data collected by the main shooting, and the storage circuit 35. Store in.

The storage circuit 35 stores the projection data generated by the preprocessing circuit 34. Specifically, the storage circuit 35 stores the projection data of the positioning image generated by the preprocessing circuit 34 and the projection data for diagnosis collected by the main imaging. Further, the storage circuit 35 stores image data and a virtual patient image generated by the image reconstruction circuit 36 described later. Further, the storage circuit 35 appropriately stores the processing result by the processing circuit 37 described later. The virtual patient image and the processing result by the processing circuit 37 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 and the projection data of the image used for 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 20, and the console 30 to control the entire X-ray CT apparatus 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.

Further, as shown in FIG. 1, the processing circuit 37 executes the acquisition function 37a, the setting function 37b, and the reconstruction function 37c. Here, for example, each processing function executed by the acquisition function 37a, the setting function 37b, and the reconstruction function 37c, which are the components of the processing circuit 37 shown in FIG. 1, is stored in the storage circuit 35 in the form of a program that can be executed by a computer. It has been recorded. 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 the program. In other words, the processing circuit 37 in the state where each program is read out has each function shown in the processing circuit 37 of FIG. The acquisition function 37a is also referred to as an acquisition unit, the setting function 37b is also referred to as a setting unit, and the reconstruction function 37c is also referred to as a reconstruction unit.

The configuration of the X-ray CT apparatus 1 according to the first embodiment has been described above. Under such a configuration, the X-ray CT apparatus 1 according to the first embodiment is used for an examination for a healthy person or a follow-up person whose lesion site is already known and undergoes regular follow-up.

By the way, in the X-ray CT apparatus 1, a plurality of inspections may be performed on the inspection site. Here, the X-ray CT apparatus according to the prior art accepts a plan for each inspection, executes a scan, and reconstructs an image for each plan. 2A to 2D are diagrams for explaining the prior art.

FIG. 2A shows an example of a chest lung cancer CT examination for a follow-up person whose lesion site was detected in a past examination. In the example of FIG. 2A, the case where the entire chest, the lesion site 904, and the lesion site 905 are photographed is shown. The lesion site 904 and the lesion site 905 are examples of regions of interest. In such a case, for example, the imaging range is set based on the CT image related to the past examination of the subject P. More specifically, the region 901 is set as the imaging range of the entire chest, the region 902 is set as the imaging range including the lesion site 904, and the region 903 is set as the imaging range including the lesion site 905.

The left figure of FIG. 2B shows the area 901, and the right figure of FIG. 2B shows the data collection conditions for the area 901. As shown in the right figure of FIG. 2B, the data acquisition condition 906 for photographing the entire chest at an ultra-low dose is set as Plan A. For example, in Plan A, CTDI (Computed tomography dose index) is 3 mGy or less. Further, the left figure of FIG. 2C shows the region 902, and the right figure of FIG. 2C shows the data collection conditions for the region 902. As shown in the right figure of FIG. 2C, the data acquisition condition 907 for photographing the lesion site 904 at a normal dose is set as Plan B. For example, in Plan B, CTDI is about 15 mGy. Further, the left figure of FIG. 2D shows the region 903, and the right figure of FIG. 2D shows the data collection conditions for the region 903. As shown in the right figure of FIG. 2D, the data acquisition condition 908 for photographing the lesion site 905 at a normal dose is set as Plan C. For example, in Plan C, CTDI is about 15 mGy.

Then, the scan is executed in Plan A to reconstruct the image of the entire chest, and the scan is executed in Plan B to reconstruct the high-definition image including the lesion site 904, and the scan is performed in Plan C. Is executed to reconstruct a high-definition image including the lesion site 905. As described above, in the X-ray CT apparatus according to the prior art, the exposure dose of the subject P increases because the image is reconstructed by using the data collected by executing the scan for each examination. The total dose of Plan A, Plan B, and Plan C: CTDI is about 33 mGy.

Therefore, the X-ray CT apparatus 1 according to the first embodiment integrates the first plan for the subject and the second plan for the subject P to form a third plan for the subject P. To set. For example, the X-ray CT apparatus 1 according to the first embodiment includes a first scan condition including a data collection condition for a test site of a subject P, and a data collection condition for a region of interest included in the test site. Based on the second scan condition, the data collection condition of this scan is set for the inspection site of the subject P including the region of interest. Then, the X-ray CT apparatus 1 according to the first embodiment uses the data collected under the set data acquisition conditions to obtain an image under the image reconstruction conditions included in the first scan condition and a second image. Each image is reconstructed according to the image reconstruction conditions included in the scan conditions. Such a function is realized by the setting function 37b and the reconstruction function 37c. Hereinafter, the setting function 37b and the reconstruction function 37c will be described.

FIG. 3 is a flowchart showing a processing procedure by the X-ray CT apparatus 1 according to the first embodiment. FIG. 3 shows a flowchart illustrating the operation of the entire X-ray CT apparatus 1, and describes which step of the flowchart each component corresponds to. The process by the X-ray CT apparatus 1 according to the first embodiment shown in FIG. 3 is executed as the main scan after the positioning scan is completed, for example, in the follow-up based on the CT image related to the past inspection. To.

Step S101 is a step realized by the input circuit 31. In step S101, the input circuit 31 accepts the scan conditions of each plan. For example, the input circuit 31 accepts a scan condition for photographing the entire chest as Plan A. Further, the input circuit 31 accepts a scan condition for photographing the lesion site of the chest as Plan B. The scan conditions include a data acquisition condition and an image reconstruction condition.

Step S102 is a step corresponding to the acquisition function 37a. The acquisition function 37a is realized by the processing circuit 37 calling and executing a predetermined program corresponding to the acquisition function 37a from the storage circuit 35. In step S102, the acquisition function 37a acquires the scan conditions of each plan. For example, the acquisition function 37a acquires the scan conditions of the plan A and the plan B received in step S101.

The processing operation by the acquisition function 37a will be described with reference to FIGS. 4A to 4C. 4A to 4C are diagrams for explaining the processing operation by the acquisition function 37a according to the first embodiment. FIG. 4A shows the shooting range 51 of the plan A and the shooting range 52 of the plan B. As shown in FIG. 4A, the imaging range 51 of Plan A is the entire chest, and the imaging range 52 of Plan B includes the lesion site 53, which is the region of interest.

The left figure of FIG. 4B shows the shooting range 51 of the plan A, and the right figure of FIG. 4B shows the scan conditions of the plan A. The acquisition function 37a acquires the data acquisition condition 54 and the image reconstruction condition shown in the right figure of FIG. 4B as scan conditions. As shown in the right figure of FIG. 4B, in Plan A, a data acquisition condition 54 for photographing the entire chest at an ultra-low dose is set. Here, the data collection condition 54 of the plan A includes "HP (Helical Pitch): early", and the image reconstruction condition of the plan A includes, for example, "DFOV (Display Field Of View): 512 matrix," Reconstruction mode: Normal reconstruction "etc. are included. The term "normal reconstruction" as used herein means that an image is reconstructed using, for example, a detection signal detected by a conventional detector in which detection elements of 80 rows and 896 channels are arranged. In the example shown in FIG. 4B, a case where the tube current is modulated is shown, but the embodiment is not limited to this. For example, the data acquisition condition may be set so that the tube current is constant as in the right figure of FIG. 2B. The helical pitch is adjusted by, for example, the moving speed of the top plate 22.

The left figure of FIG. 4C shows the shooting range 52 of the plan B, and the right figure of FIG. 4C shows the scan conditions of the plan B. The acquisition function 37a acquires the data acquisition condition 55 and the image reconstruction condition shown in the right figure of FIG. 4C as scan conditions. As shown in the right figure of FIG. 4C, in the plan B, the data acquisition condition 55 for photographing with a normal dose is set at a position corresponding to the region of interest. Here, the data collection condition 55 of the plan B includes "HP: slow", and the image reconstruction condition of the plan B includes, for example, "DFOV: 1024" for reconstructing the image with higher definition than the plan A. Matrix, reconstruction mode: high-definition reconstruction "and so on. The term "high-definition reconstruction" as used herein means that an image is reconstructed using, for example, a detection signal detected by a detector 13 in which detection elements of 160 rows and 1792 channels are arranged.

Return to FIG. Step S103 is a step corresponding to the setting function 37b. The setting function 37b is realized by the processing circuit 37 calling and executing a predetermined program corresponding to the setting function 37b from the storage circuit 35. In step S103, the setting function 37b acquires the position information of the region of interest based on the positioning image or the CT image related to the past examination of the subject P, and sets the data collection condition of this scan.

The details of the process of step S103 by the setting function 37b will be described with reference to FIGS. 5, 6A and 6B. FIG. 5 is a flowchart showing a processing procedure by the setting function 37b according to the first embodiment, and FIGS. 6A and 6B are diagrams for explaining a processing operation by the setting function 37b according to the first embodiment. be.

The processing procedure shown in FIG. 5 corresponds to the processing of step S103 shown in FIG. Steps S201 to S203 shown in FIG. 5 are steps corresponding to the setting function 37b. The setting function 37b is realized by the processing circuit 37 calling and executing a predetermined program corresponding to the setting function 37b from the storage circuit 35.

In step S201, the setting function 37b acquires the position information of the region of interest. For example, the setting function 37b acquires the position information of the region of interest based on the positioning image or the CT image related to the past examination of the subject P. As an example, as shown in the left figure of FIG. 6A, the setting function 37b acquires the position information of the lesion site 53 detected in the CT image related to the past examination of the subject P. In other words, the region of interest is the region including the lesion site in the positioning image of the subject P or the CT image related to the past examination of the subject P.

In step S202, the setting function 37b modulates the tube current or tube voltage in the region of interest. Here, for example, the setting function 37b combines the data collection condition 54 of the plan A acquired in step S102 and the data collection condition 55 of the plan B as one data collection condition 56. The data collection condition 56 shown on the right side of FIG. 6A is a data collection condition executed by the helical scan. More specifically, as shown in the right figure of FIG. 6A, the setting function 37b is to take a picture at the position of the lesion site 53 acquired in step S201 at a normal dose, and the tube current of the data acquisition condition 54 of the plan A is taken. To modulate. In such a case, the tube current at the position of the lesion site 53 becomes the tube current shown in the data collection condition 55 of Plan B. In this way, the setting function 37b sets the data collection condition of this scan that modulates the tube current or tube voltage in the region of interest with respect to the region other than the region of interest.

In step S203, the setting function 37b sets the helical pitch in the region of interest. For example, as shown in the right figure of FIG. 6A, the setting function 37b sets the data collection condition 56 so that the helical pitch becomes slow at the position of the lesion site 53 in order to increase the spatial resolution of the lesion site 53 acquired in step S201. To set. That is, the setting function 37b sets the data collection condition of the main scan that makes the helical pitch in the region of interest slower than that in the region of interest. As a result, the helical pitch at the position of the lesion site 53 is slower than the helical pitch at the position other than the lesion site 53. In this way, the setting function 37b sets the data collection conditions of the plan that integrates the plan A and the plan B. In the following, Plan A will also be referred to as the first plan, and Plan B will also be referred to as the second plan. A plan that integrates Plan A and Plan B is referred to as a third plan.

As shown in FIG. 6B, the setting function 37b sets a data acquisition condition 57 that further increases the tube current without changing the helical pitch at the position of the lesion site 53 in order to enhance the spatial resolution of the lesion site 53. You may try to do it. In this way, the setting function 37b integrates the first plan for the subject P and the second plan for the subject P to set the third plan for the subject P. For example, the setting function 37b is based on the first scan condition including the data collection condition for the test site of the subject P and the second scan condition including the data collection condition for the region of interest included in the test site. , Set the data collection conditions for this scan for the test site of the subject P including the region of interest. In other words, the setting function 37b integrates the first plan for the imaging target region of the subject P and the second plan for the region of interest included in the imaging target region, and the setting function 37b of the subject P including the region of interest. Set a third plan for the part to be imaged.

Return to FIG. Step S104 is a step realized by the processing circuit 37. In step S105, the processing circuit 37 causes the display 32 to display the data acquisition conditions set in step S103.

Step S105 is a step realized by the processing circuit 37. In step S105, the processing circuit 37 determines whether or not the execution of this scan has been accepted. Here, when the processing circuit 37 determines that the execution of this scan has been accepted (step S105, Yes), the process proceeds to step S106.

Step S106 is a step realized by the scan control circuit 33. In step S106, the scan control circuit 33 executes the scan. For example, the scan control circuit 33 is set in step S103 by controlling the operations of the X-ray irradiation control circuit 11, the gantry drive circuit 16, the data acquisition circuit 14, and the sleeper drive device 21 under the control of the processing circuit 37. The data collection conditions are controlled to control the collection process of projection data on the gantry 10. As a result, the detector 13 detects high-definition detection data from the detection element of 160 rows and 1792 channels in the third plan.

Step S107 is a step corresponding to the reconstruction function 37c. The reconstruction function 37c is realized by the processing circuit 37 calling and executing a predetermined program corresponding to the reconstruction function 37c from the storage circuit 35. In step S107, the reconstruction function 37c reconstructs the image based on the scan conditions of each plan. That is, the reconstruction function 37c uses the data collected under the set data acquisition conditions to reconstruct the image according to the image reconstruction condition included in the first scan condition and the image reconstruction included in the second scan condition. Reconstruct the images according to the conditions. For example, the reconstruction function 37c reconstructs an image under the image reconstruction conditions of Plan A using the data collected in step S106. Further, the reconstruction function 37c reconstructs an image under the image reconstruction conditions of Plan B using the data collected in step S106.

Here, the reconstruction function 37c reconstructs the first image and the second image having different resolutions. For example, the reconstruction function 37c has a first image and a second image from the data corresponding to the first resolution, which is the high-definition resolution collected in the plan third plan that integrates the plan A and the plan B. It produces an image in which one resolution of the image is the first resolution and the other resolution is the second resolution, which is lower than the first resolution. More specifically, the reconstruction function 37c reconstructs an image having the first resolution when the reconstruction mode is high-definition reconstruction, and when the reconstruction mode is normal reconstruction, the first reconstruction function 37c. Reconstruct an image with a resolution of 2.

For example, the reconstruction function 37c reconstructs an image having the first resolution from the data collected in the third plan, and bundles the data collected in the third plan into the second resolution. , Reconstruct the image with the second resolution. As an example, the reconstruction function 37c reconstructs an image having a second resolution because the reconstruction mode of the image reconstruction condition of Plan A is normal reconstruction. Here, the projection data collected in the third plan is projection data based on the high-definition detection data detected by the detection element of 160 columns and 1792 channels. Therefore, the reconstruction function 37c usually bundles high-definition projection data for reconstruction. For example, the high-definition projection data corresponding to the four detection elements summarized as one unit for each of the four detection elements are added together. Then, the reconstruction function 37c reconstructs the image corresponding to the shooting range of the plan A from the added projection data.

Further, the reconstruction function 37c reconstructs the image having the first resolution because the reconstruction mode of the image reconstruction condition of the plan B is high-definition reconstruction. The reconstruction function 37c reconstructs an image corresponding to the shooting range of the plan B from the high-definition projection data collected in the third plan.

The reconstruction function 37c does not generate a low-resolution image by bundling high-definition projection data when generating images having different resolutions, but generates a low-resolution image by image processing. You may. For example, the reconstruction function 37c reconstructs the first image and the second image having the first resolution from the high-definition projection data collected in the third plan, and reconstructs the first image and the second image. Image processing is performed so that the resolution of one of the second images becomes the second resolution. More specifically, the reconstruction function 37c corresponds to the image (image A) corresponding to the shooting range of the plan A and the shooting range of the plan B from the high-definition projection data collected in the third plan. Reconstruct the image (image B). Then, the reconstruction function 37c collects the pixels in the image A as one unit for every four pixels to generate a low-resolution image.

Step S108 is a step realized by the processing circuit 37. In step S108, the processing circuit 37 causes the display 32 to display an image of each plan reconstructed in step S107. For example, the processing circuit 37 displays the image of the plan A and the image of the plan B on the display 32, respectively. Alternatively, the processing circuit 37 causes the display 32 to display a composite image obtained by combining the image of the plan A and the image of the plan B. Further, the processing circuit 37 displays the image of the plan A, the image of the plan B, and the composite image obtained by synthesizing the image of the plan A and the image of the plan B on the display 32, respectively.

If the processing circuit 37 does not determine in step S105 that the execution of this scan has been accepted (steps S105, No), the process proceeds to step S109. Steps S109 to S111 are steps realized by the processing circuit 37. In step S109, the processing circuit 37 determines whether or not the plan edit request has been accepted. Here, when the processing circuit 37 determines that the plan edit request has been accepted (step S109, Yes), the process proceeds to step S110.

In step S110, the processing circuit 37 accepts the editing of the plan. For example, the processing circuit 37 accepts the editing of the plan by the operator performing an operation of editing the shooting range on the GUI. Here, the processing circuit 37 may accept editing for each plan received in step S101, or may accept editing of the plan after the data collection conditions are set in step S103. The details of the processing of step S110 by the processing circuit 37 will be described with reference to FIGS. 6C to 6F. 6C to 6F are diagrams for explaining the processing operation by the processing circuit 37 according to the first embodiment.

In FIGS. 6C and 6D, a first editing mode for accepting editing for each plan will be described. FIG. 6C shows a case where the editing of the shooting range 52 of the plan B is accepted without accepting the editing of the shooting range 51 of the plan A. In other words, the processing circuit 37 temporarily disassembles the integrated shooting range and changes only the shooting range 52. For example, as shown in FIG. 6C, the display 32 displays an image showing the shooting range 52 of the plan B. Here, the operator assumes that the shooting range 52 is expanded in the direction of the double-headed arrow by, for example, operating the finger-shaped icon 59. As a result, the processing circuit 37 determines that the operation of expanding the shooting range 52 of the plan B has been accepted, and changes the shooting range 52 as shown in the left figure of FIG. 6D. In the left figure of FIG. 6D, the shooting range 52 before the change is shown by a broken line, and the shooting range 52 after the change is shown by a solid line. Although it has been described that the shooting range 52 is expanded in the direction of the double-headed arrow by operating the finger-shaped icon 59, the embodiment is not limited to this, and the shooting range 52 is operated by the finger-shaped icon 59. You may want to spread it in only one direction.

Further, in FIGS. 6E and 6F, a second editing mode for accepting editing of a plan in which plan A and plan B are integrated will be described. For example, as shown in FIG. 6E, the display 32 displays an image showing the shooting range 51 and the shooting range 52 of the plan in which the plan A and the plan B are integrated. Here, the operator assumes that the shooting range 51 is expanded in the direction of the arrow by, for example, operating the finger-shaped icon 59. In such a case, the processing circuit 37 determines that the operation of expanding both the shooting range 51 and the shooting range 52 of the integrated plan has been accepted, and changes the shooting range 51 and the shooting range 52 as shown in the left figure of FIG. 6F. In other words, the processing circuit 37 integrally changes the shooting range 51 and the shooting range 52 without disassembling the integrated shooting range. In the left figure of FIG. 6F, the shooting range 51 and the shooting range 52 before the change are shown by broken lines, and the shooting range 51 and the shooting range 52 after the change are shown by the solid line. That is, when the processing circuit 37 accepts an operation to edit one of the shooting ranges of the integrated plan, the processing circuit 37 simultaneously changes all the shooting ranges included in the integrated plan.

Return to FIG. In step S111, the processing circuit 37 modifies the scan conditions of the plan for which editing has been accepted. For example, when the processing circuit 37 accepts editing for each plan, the processing circuit 37 modifies the scanning conditions for each plan for which editing is accepted. As an example, when the processing circuit 37 accepts editing for each plan, the processing circuit 37 changes the scanning conditions as shown in the right figure of FIG. 6D. More specifically, in the right figure of FIG. 6D, the processing circuit 37 shows the scan condition 55 of the plan B before the change with a broken line, and the scan condition 55 of the plan B after the change with a solid line.

Further, for example, when the processing circuit 37 accepts the editing of the integrated plan, the processing circuit 37 modifies the scan conditions for each plan included in the integrated plan. As an example, when the processing circuit 37 accepts the editing of the integrated plan, the scanning conditions are changed as shown in the middle figure and the right figure of FIG. 6F. More specifically, in the middle diagram of FIG. 6F, the processing circuit 37 shows the scan condition 54 of the plan A before the change by a broken line, and the scan condition 54 of the plan A after the change by a solid line. Further, in the right figure of FIG. 6F, the scan condition 55 of the plan B before the change is shown by a broken line, and the scan condition 55 of the plan B after the change is shown by a solid line. After the end of step S111, in step S102, the acquisition function 37a acquires the scan conditions of each plan. Further, when the processing circuit 37 accepts the editing of the plan by manipulating the data collection conditions of the integrated plan in step S110, after modifying the scan conditions in step S111, steps S102 and S103 are omitted. Move to S104.

Return to FIG. If the processing circuit 37 does not determine in step S109 that the plan edit request has been accepted (steps S109, No), the process proceeds to step S112. In step S112, the processing circuit 37 determines whether or not the cancellation has been accepted. Here, when the processing circuit 37 determines that the cancellation has been accepted (step S112, Yes), the processing circuit 37 ends the processing. On the other hand, if it is not determined that the cancellation has been accepted (step S112, No), the processing circuit 37 continues the determination process of step S105.

It should be noted that in FIGS. 6C to 6F, the processing circuit 37 has been described as accepting the editing of the plan by, for example, accepting the operation of editing the shooting range on the GUI, but the embodiment is not limited to this. .. For example, the processing circuit 37 may accept the editing of the plan by accepting the operation of editing the data acquisition condition. In such a case, the processing circuit 37 may accept editing of the data collection condition on the graph shown on the right side of FIG. 6D, or edit the data collection condition set as a numerical value such as a tube current value or a tube voltage value. May be accepted. Further, when the processing circuit 37 accepts the editing of the data collection condition on the graph, the data collection condition set as a numerical value may be changed, or the processing circuit 37 accepts the editing of the data collection condition set as a numerical value. In that case, the shape of the graph may be changed. Further, the processing circuit 37 may change the shooting range on the GUI in synchronization with the editing of the data acquisition condition.

Further, the processing circuit 37 may be able to switch between the above-mentioned first editing mode and the second editing mode. Further, the processing circuit 37 displays only the editable shooting range and hides or edits the non-editable shooting range according to the switching between the first editing mode and the second editing mode. You may want to display the shooting range that is not, but do not accept editing. Further, the processing circuit 37 can similarly edit the data collection conditions set as numerical values and the data collection conditions shown in the graph according to the switching between the first edit mode and the second edit mode. You may want to display only the data collection conditions, or display the non-editable data collection conditions but not accept editing.

As described above, in the first embodiment, the X-ray CT apparatus 1 sets the first scan condition including the data collection condition for the examination site of the subject and the data collection condition for the region of interest included in the examination site. Based on the included second scan conditions, the data collection conditions for this scan are set for the test site of the subject including the region of interest. As described above, in the X-ray CT apparatus 1 according to the first embodiment, for example, when executing two independently set plans, the X-ray CT apparatus 1 is photographed as one plan based on the data collection conditions of the two plans. Set the data collection conditions. As a result, the operator of the X-ray CT apparatus 1 only needs to press the shooting start button once. As a result, the operator of the X-ray CT apparatus 1 can improve the efficiency of the inspection.

Further, when the region of interest included in the inspection site is photographed after the inspection site of the subject is photographed, the area of interest is irradiated with X-rays twice. In the X-ray CT apparatus 1 according to the first embodiment, it is possible to reduce the number of X-ray irradiations to the region of interest by setting the data acquisition conditions for shooting as one plan. Thus, according to the first embodiment, the exposure can be reduced.

Further, in the X-ray CT apparatus according to the prior art, since a plurality of times of imaging are required, the restraint time of the subject becomes long. On the other hand, in the X-ray CT apparatus according to the first embodiment, the number of times of imaging can be reduced, so that the restraint time of the subject can be shortened. This makes it possible to reduce the load on the subject according to the first embodiment.

(First modification of the first embodiment)
In the above-described embodiment, the case where there is only one lesion site in the examination site has been described, but the embodiment is not limited to this. For example, there may be a plurality of lesion sites at the examination site. The X-ray CT apparatus 1 executes the processing procedure shown in FIG. 3 even when a plurality of lesion sites are placed at the examination site. Hereinafter, the operation of the acquisition function 37a and the setting function 37b according to the modified example of the first embodiment will be described with reference to FIGS. 7A to 7E. 7A to 7E are diagrams for explaining a first modification of the first embodiment.

In the example of FIG. 7A, the case where the entire chest, the lesion site 64, and the lesion site 65 are photographed is shown. More specifically, the region 61 is set as the plan A as the imaging range of the entire chest, the region 62 is set as the plan B as the imaging range including the lesion site 64, and the region 63 is set as the imaging range including the lesion site 65. Is set as plan C. In the example shown in FIG. 7A, the acquisition function 37a acquires the scan conditions of Plan A, Plan B, and Plan C.

The left figure of FIG. 7B shows the shooting range 61 of the plan A, and the right figure of FIG. 7B shows the scan conditions of the plan A. The acquisition function 37a acquires the data acquisition condition 66 and the image reconstruction condition shown in the right figure of FIG. 7B as scan conditions. As shown in the right figure of FIG. 7B, in Plan A, a data acquisition condition 66 for photographing the entire chest at an ultra-low dose is set. Here, the data collection condition 66 of the plan A includes "HP: early", and the image reconstruction condition of the plan A includes, for example, "DFOV: 512 matrix, reconstruction mode: normal reconstruction". included. In the example shown in FIG. 7B, a case where the tube current is modulated is shown, but the embodiment is not limited to this. For example, the data acquisition condition may be set so that the tube current is constant as in the right figure of FIG. 2B.

The left figure of FIG. 7C shows the shooting range 62 of the plan B, and the right figure of FIG. 7C shows the scan conditions of the plan B. The acquisition function 37a acquires the data acquisition condition 67 and the image reconstruction condition shown in the right figure of FIG. 7C as scan conditions. As shown in the right figure of FIG. 7C, in Plan B, a data acquisition condition 67 for photographing at a position corresponding to a region of interest at a normal dose is set. Here, the data collection condition 67 of the plan B includes "HP: slow", and the image reconstruction condition of the plan B includes, for example, "DFOV: 1024 matrix, reconstruction mode: high-definition reconstruction" and the like. Is included.

The left figure of FIG. 7D shows the shooting range 63 of the plan C, and the right figure of FIG. 7D shows the scan conditions of the plan C. The acquisition function 37a acquires the data acquisition condition 68 and the image reconstruction condition shown in the right figure of FIG. 7D as scan conditions. As shown in the right figure of FIG. 7D, in the plan C, the data acquisition condition 68 for photographing with a normal dose is set at a position corresponding to the region of interest. Here, the data collection condition 68 of the plan C includes "HP: slow", and the image reconstruction condition of the plan C includes, for example, "DFOV: 1024 matrix, reconstruction mode: high-definition reconstruction" and the like. Is included.

Then, when there are a plurality of regions of interest, the setting function 37b is based on the first scan condition and the second scan condition for each region of interest, and the data acquisition condition of the main scan including the plurality of regions of interest. To set. For example, the setting function 37b collects one data of the data collection condition 66 of the plan A shown in FIG. 7B, the data collection condition 67 of the plan B shown in FIG. 7C, and the data collection condition 68 of the plan C shown in FIG. 7D. Summarize as condition 69. The setting function 37b executes the processing procedure shown in FIG. 5 even when a plurality of lesion sites are present at the examination site.

The left figure of FIG. 7E shows the shooting range 61 of the plan A, the shooting range 62 of the plan B, and the shooting range 63 of the plan C. Further, the right figure of FIG. 7E shows the data collection condition 69. The data collection condition 69 shown on the right side of FIG. 7E is a data collection condition executed by the helical scan. As shown in the right figure of FIG. 7E, the setting function 37b modulates the tube current of the data acquisition condition 66 of Plan A so as to take an image at the acquired lesion site 64 and the lesion site 65 at a normal dose. In such a case, the tube current at the position of the lesion site 64 becomes the tube current shown in the data collection condition 67 of the plan B, and the tube current at the position of the lesion site 65 becomes the tube current shown in the data collection condition 68 of the plan C.

Further, the setting function 37b sets the helical pitch in the region of interest. For example, the setting function 37b sets the data collection condition 69 so that the helical pitch becomes slow at the positions of the lesion site 64 and the lesion site 65 in order to enhance the spatial resolution of the acquired lesion site 64 and the lesion site 65. That is, the helical pitch at the positions of the lesion site 64 and the lesion site 65 is slower than the helical pitch at the positions other than the lesion site 64 and the lesion site 65. The setting function 37b sets data collection conditions for further increasing the tube current without changing the helical pitch at the positions of the lesion site 64 and the lesion site 65 in order to enhance the spatial resolution of the lesion site 64 and the lesion site 65. You may try to do it.

The reconstruction function 37c uses the data collected under the set data acquisition conditions to reconstruct the image included in the first scan condition and the image reconstruction included in the second scan condition for each region of interest. Reconstruct the image according to the configuration conditions. Then, the processing circuit 37 displays the image of each reconstructed plan on the display 32. For example, the processing circuit 37 displays the image of the plan A, the image of the plan B, and the image of the plan C on the display 32, respectively. Alternatively, the processing circuit 37 causes the display 32 to display a composite image obtained by combining the image of the plan A, the image of the plan B, and the image of the plan C. Further, the processing circuit 37 displays the image of the plan A, the image of the plan B, the image of the plan C, and the composite image obtained by synthesizing the image of the plan A, the image of the plan B, and the image of the plan C, respectively. To display.

As described above, in the modification of the first embodiment, when there are a plurality of regions of interest, the X-ray CT apparatus 1 is based on the first scan condition and the second scan condition for each region of interest. Then, set the data collection conditions for this scan that includes multiple areas of interest. As described above, in the X-ray CT apparatus 1 according to the modified example of the first embodiment, for example, when executing three independently set plans, one based on the data collection conditions of the three plans. Set the data collection conditions for shooting as a plan. As a result, the operator of the X-ray CT apparatus 1 only needs to press the shooting start button once. As a result, the operator of the X-ray CT apparatus 1 can improve the efficiency of the inspection.

Further, when the region of interest included in the inspection site is photographed after the inspection site of the subject is photographed, the area of interest is irradiated with X-rays twice. Further, when the shooting range is helically scanned, shooting is performed in a range in which a margin is added to the set shooting range. Therefore, X-rays are irradiated to a wider range than the set shooting range. Therefore, in the X-ray CT apparatus according to the prior art, when the distance between the regions of interest is short, the X-rays are repeatedly irradiated to the margin portion. On the other hand, in the X-ray CT apparatus 1 according to the modified example of the first embodiment, the number of times of X-ray irradiation to the region of interest and the margin portion can be reduced by setting the data collection conditions for shooting as one plan. It will be possible. As described above, according to the modified example of the first embodiment, the exposure can be reduced. Specifically, the CTDI can be reduced to about 25 mGy by taking an image of FIG. 7E for a dose (CTDI) of about 33 mGy in FIGS. 2A to 2D.

(Second variant of the first embodiment)
Further, in the above-mentioned first embodiment, the case where, for example, the entire chest is photographed in Plan A and the lesion site such as lung cancer is photographed as a region of interest in Plan B has been described. Here, for example, the above-mentioned first embodiment can be applied even when VHP (Variable Helical Pitch) is used as Plan A. 8A and 8B are diagrams for explaining a second modification of the first embodiment.

8A and 8B show a case where VHP is used as Plan A to take an image of the entire chest that is not affected by pulsation, and as Plan B, a lesion site such as lung cancer is taken as a region of interest. The left figure of FIG. 8A shows the imaging range 51a of the plan A, the imaging range 52a of the plan B, and the lesion site 53a which is the region of interest. Further, the middle figure of FIG. 8A shows the scan conditions of Plan A. Here, as the scan condition of Plan A, the data acquisition condition 54a to which VHP is applied is set to the data acquisition condition 54 in which the entire chest shown in FIG. 4B is imaged at an ultra-low dose. For example, in the data acquisition condition 54a, VHP that slows down HP is applied in the data acquisition section corresponding to the heart indicated by the double-headed arrow. Further, as the scan condition of the plan A, for example, "DFOV: 512 matrix, reconstruction mode: normal reconstruction" is set.

The right figure of FIG. 8A shows the scan conditions of Plan B. Here, as the scan condition of Plan B, the data acquisition condition 55a for photographing at a position corresponding to the region of interest with a normal dose is set. For example, under the data acquisition condition 55a, HP is delayed in the data acquisition section corresponding to the lesion site 53a. Further, as the scan condition of Plan B, for example, "DFOV: 1024 matrix, reconstruction mode: high-definition reconstruction" is set.

In such a case, the setting function 37b sets the data collection condition of the plan that integrates the plan A and the plan B. More specifically, the setting function 37b sets the data collection conditions shown in FIG. 8B. For example, the setting function 37b sets the data collection condition 56a so that the helical pitch becomes slow in the data collection section corresponding to the heart and the data collection section corresponding to the lesion site 53a, as shown in the right figure of FIG. 8B. Further, the setting function 37b sets a reconstruction condition for reconstructing an image normally in the shooting range of Plan A and reconstructing a high-definition image in the shooting range of Plan B.

(Third variant of the first embodiment)
Further, in the first embodiment described above, the case where the photographing area of the plan B is included in the photographing area of the plan A has been described, but the embodiment is not limited to this. 9A to 9C are diagrams for explaining a third modification of the first embodiment. For example, as shown in FIG. 9A, the above-described embodiment can be applied even when the photographing area 51b of the plan A and the photographing area 52b of the plan B partially overlap. Further, for example, as shown in FIG. 9B, the above-described embodiment can be applied even when the photographing area 51c of the plan A and the photographing area 52b of the plan B are adjacent to each other. Further, for example, as shown in FIG. 9C, the above-described embodiment can be applied even when the photographing area 51d of the plan A and the photographing area 52c of the plan B are slightly separated from each other.

(Second embodiment)
In the first embodiment described above, when the follow-up person is photographed of the examination site and the region of interest included in the examination site, the data collection condition for photographing the examination site and the data collection for photographing the region of interest are taken. An example of combining the conditions into one was explained. By the way, in the lung cancer CT examination of the chest, it is conceivable that a plurality of regions of interest may be imaged without photographing the examination site.

Therefore, in the second embodiment, an example will be described in which the data collection conditions of each region of interest are combined into one when a plurality of regions of interest are photographed without photographing the inspection site. The overall configuration of the X-ray CT apparatus according to the second embodiment is the same as the configuration example shown in FIG. 1, except that the operation of a part of the setting function 37b is different. Therefore, in the following, only the setting function 37b will be described, and detailed description of the configurations other than the setting function 37b will be omitted.

Further, the processing procedure according to the X-ray CT apparatus 1 according to the second embodiment is the same as the processing procedure shown in FIG. 3, except that the processing procedure in step S103 is different. For example, in step S101, the input circuit 31 accepts the scan conditions of each plan. Further, in step S102, the acquisition function 37a acquires the scan conditions of each plan. For example, the acquisition function 37a collects data for a first scan condition including a data collection condition for a first shooting range including a first area of interest and a second shooting range including a second area of interest. The second scan condition including the condition is acquired. Hereinafter, the processing procedure of step S103 will be described with reference to FIG. FIG. 10 is a flowchart showing a processing procedure by the setting function 37b according to the second embodiment.

Steps S301 to S308 shown in FIG. 10 are steps corresponding to the setting function 37b. The setting function 37b is realized by the processing circuit 37 calling and executing a predetermined program corresponding to the setting function 37b from the storage circuit 35. In addition, in FIG. 10, a case where two lesion sites are photographed as a region of interest will be described.

In step S301, the setting function 37b determines whether or not each region of interest is within the volume shooting range. For example, the setting function 37b determines whether or not the shooting range falls within the size of the detector 13. In other words, the setting function 37b determines whether or not the shooting range including each region of interest can collect data in one rotation of the volume scan. Here, the determination process of step S301 will be described with reference to FIGS. 11A to 11C. 11A to 11C are diagrams for explaining the processing operation by the setting function 37b according to the second embodiment.

11A to 11C show a case where the lesion site 73 is photographed as the plan A and the lesion site 74 is imaged as the plan B. In the example shown in FIG. 11A, the imaging range 71 including the lesion site 73 and the imaging range 72 including the lesion site 74 are set. Here, it is assumed that the shooting range 71 and the shooting range 72 are within the volume shooting range.

In the example shown in FIG. 11B, the imaging range 71 including the lesion site 73 and the imaging range 72a including the lesion site 74 are set. Here, it is assumed that the shooting range 71 is within the volume shooting range and the shooting range 72a is not within the volume shooting range. Further, in the example shown in FIG. 11C, an imaging range 71 including the lesion site 73 and an imaging range 72b including the lesion site 74 are set. Here, it is assumed that the shooting range 71 is within the volume shooting range and the shooting range 72b is not within the volume shooting range.

Here, when the setting function 37b determines that each region of interest is within the volume shooting range (step S301, Yes), the setting function 37b determines that each shooting range is shot by conventional scanning (step S302). For example, in the example shown in FIG. 11A, the setting function 37b moves the top plate 22 to shoot the shooting range 72 by the conventional scan after shooting the shooting range 71 by the conventional scan.

On the other hand, when the setting function 37b does not determine that each area of interest is within the volume shooting range (step S301, No), the setting function 37b sets each shooting range (step S303). Then, the setting function 37b determines whether or not there is an overlapping region in the shooting range (step S304). In other words, the setting function 37b determines whether or not the distance between the first shooting range and the second shooting range is equal to or less than a predetermined threshold value. More specifically, the setting function 37b determines whether or not the distance between the shooting range 71 and the shooting range 72a is equal to or less than a predetermined threshold value in the example shown in FIG. 11B. Further, the setting function 37b determines whether or not the distance between the shooting range 71 and the shooting range 72b is equal to or less than a predetermined threshold value in the example shown in FIG. 11C.

Here, when the setting function 37b does not determine that there is an overlapping region in the shooting range (step S304, No), the setting function 37b determines whether or not any of the regions of interest is within the volume shooting range (step S305). As an example, the setting function 37b determines that the distance between the shooting range 71 and the shooting range 72b is not equal to or less than a predetermined threshold value in the example shown in FIG. 11B, and one of the regions of interest is within the volume shooting range. Judge whether or not. Then, when the setting function 37b determines that any of the regions of interest is within the volume shooting range (step S305, Yes), the setting function 37b selects a conventional scan and a helical scan for each shooting range (step S306). For example, in the example shown in FIG. 11B, when the setting function 37b determines that the shooting range 71 is within the volume shooting range and the shooting range 72a is not within the volume shooting range, the shooting range 71 is set by conventional scanning. After shooting, the top plate 22 is moved and the shooting range 72a is shot by helical scan.

On the other hand, when the setting function 37b does not determine that any of the areas of interest is within the volume shooting range (step S305, No), each shooting range is shot by helical scan (step S307). For example, when the setting function 37b determines that both of the two shooting ranges are not within the volume shooting range, after shooting one shooting range by the helical scan, the top plate 22 is moved and the other shooting range is moved by the helical scan. To shoot.

As described above, when the first shooting range and the second shooting range are each equal to or less than a predetermined threshold value, the setting function 37b has a first scan condition based on the first scan condition and the second scan condition. The data collection conditions for the main scan for the shooting range and the data collection conditions for the main scan for the second shooting range are set respectively. Further, in the setting function 37b, at least one of the first shooting range and the second shooting range is not equal to or less than a predetermined threshold value, and the distance between the first shooting range and the second shooting range is predetermined. If it is not below the threshold value, the data collection condition of the main scan for the first shooting range and the data collection condition of the main scan for the second shooting range are set based on the first scan condition and the second scan condition, respectively. Set. Further, the setting function 37b sets a data collection condition for collecting data by one rotation volume scan for a shooting range which is equal to or less than a predetermined threshold value in the first shooting range and the second shooting range. Set the data collection conditions for collecting data by helical scan for the shooting range of No. 1 and the shooting range not equal to or less than the predetermined threshold value in the second shooting range.

Further, when the setting function 37b determines that there is an overlapping region in the shooting range (step S304, Yes), the setting function 37b collectively scans the shooting range into one (step S308). For example, in the example shown in FIG. 11C, when the setting function 37b determines that there is an overlapping region between the shooting range 71 and the shooting range 72b, the shooting range 71 and the shooting range 72a are combined into one shooting plan by helical scan. Take a picture.

Subsequently, the process of combining the shooting ranges in step S308 into one will be described with reference to FIGS. 11D to 11F. 11D to 11F are diagrams for explaining the processing operation by the setting function 37b according to the second embodiment.

The left figure of FIG. 11D shows the imaging range 71 including the lesion site 73, and the right figure of FIG. 11D shows the scan conditions of Plan A. The acquisition function 37a acquires the data acquisition condition 75 and the image reconstruction condition shown in the right figure of FIG. 11D as scan conditions. The left figure of FIG. 11E shows the imaging range 72b including the lesion site 74, and the right figure of FIG. 11E shows the scan conditions of Plan B. The acquisition function 37a acquires the data acquisition condition 76 and the image reconstruction condition shown in the right figure of FIG. 11E as scan conditions.

Subsequently, the setting function 37b acquires the position information of the region of interest. For example, the setting function 37b acquires the position information of the region of interest based on the positioning image or the CT image related to the past examination of the subject. As an example, as shown in the left figure of FIG. 11F, the setting function 37b acquires the position information of the lesion site 73 and the position information of the lesion site 74 detected in the CT image related to the past examination of the subject. ..

Then, the setting function 37b combines the data collection condition 75 of the plan A and the data collection condition 76 of the plan B into one data collection condition 77. The data collection condition 77 shown on the right side of FIG. 11F is a data collection condition executed by the helical scan. More specifically, as shown in the right figure of FIG. 11F, the setting function 37b has the data acquisition conditions 75 of Plan A and the data collection condition 75 of Plan B so that the images are taken at the positions of the lesion site 73 and the lesion site 74 at a normal dose. The tube current is modulated so as to be combined with the data acquisition condition 76. In such a case, the tube current between the position of the lesion site 73 and the position of the lesion site 74 becomes the tube current when imaging at an ultra-low dose.

When the data collection condition 75 of the plan A and the data collection condition 76 of the plan B are combined as one data collection condition 77, the setting function 37b compares the helical pitch in the region of interest with the helical pitch in the region of interest. May be set to be slower.

The reconstruction function 37c reconstructs the image based on the scan conditions of each plan. For example, the reconstruction function 37c uses the data collected under the set data acquisition conditions to obtain an image reconstruction condition included in the first scan condition and an image reconstruction condition included in the second scan condition. Reconstruct each image with. More specifically, the reconstruction function 37c reconstructs an image under the image reconstruction condition of Plan A using the data collected under the data collection condition 77. Further, the reconstruction function 37c reconstructs an image under the image reconstruction condition of Plan B using the data collected under the data collection condition 77. Then, the processing circuit 37 displays the image of each reconstructed plan on the display 32. For example, the processing circuit 37 displays the image of the plan A and the image of the plan B on the display 32, respectively. Alternatively, the processing circuit 37 causes the display 32 to display a composite image obtained by combining the image of the plan A and the image of the plan B. Further, the processing circuit 37 displays the image of the plan A, the image of the plan B, and the composite image obtained by synthesizing the image of the plan A and the image of the plan B on the display 32, respectively.

As described above, in the X-ray CT apparatus 1 according to the second embodiment, for example, when executing two independently set plans, as one plan based on the data collection conditions of the two plans. Set the data collection conditions for shooting. As a result, the operator of the X-ray CT apparatus 1 only needs to press the shooting start button once. As a result, the operator of the X-ray CT apparatus 1 can improve the efficiency of the inspection.

Further, in the second embodiment, in the setting function 37b, at least one of the first shooting range and the second shooting range is not equal to or less than a predetermined threshold value, and the setting function 37b includes the first shooting range and the second shooting range. If the distance between them is less than or equal to a predetermined threshold, the data acquisition conditions for this scan for the first shooting range and the second shooting range are set based on the first scan condition and the second scan condition. do. As a result, in the second embodiment, it is possible to reduce the number of times of X-ray irradiation to the margin portion when the distance between the regions of interest is short. As described above, secondly, according to the embodiment, it is possible to improve the efficiency of the inspection and reduce the exposure.

Further, in the second embodiment, in any case, if it is possible to take a picture within one breath announcement by the taking time including a separate movement, the picture is taken in one breath, and the breath is held. If the time exceeds, for example, 15 seconds, the shooting may be divided into two shots.

(Other embodiments)
The embodiment is not limited to the above-described embodiment.

In the above-described embodiment, the case where the setting function 37b modulates the tube current has been described, but the embodiment is not limited to this. For example, the setting function 37b may modulate the tube voltage.

Further, in the above-described embodiment, when the main scan is executed, the start position and the end position of the imaging range of the main scan and the inspection site of the main scan may be recorded from the positioning image. In such a case, in the subsequent follow-up inspection, the setting function 37b can automatically set the data collection condition after taking the positioning image.

Further, in the above-described embodiment, it has been described that an example of the region of interest is a lesion site, but the embodiment is not limited to this. For example, the region of interest may be a site suspected to be a lesion detected in a positioning image or a CT image related to a past examination.

Further, in the above-described embodiment, the image reconstruction conditions include, for example, "DFOV (Display Field Of View): 512 matrix, reconstruction mode: normal reconstruction" and "DFOV: 1024 matrix, reconstruction mode: high definition". Although it has been described as including "reconstruction" and the like, the embodiment is not limited to this. For example, the image reconstruction conditions include a reconstruction function, parameters of exposure reduction technology applying the successive approximation reconstruction method, parameters of image processing conditions according to each part, and parameters of image processing conditions for reducing metal artifacts. Etc. may be included.

Further, in the above-described embodiment, the change in the relative position between the gantry 10 and the top plate 22 has been described as being realized by controlling the top plate 22, but the embodiment is not limited to this. For example, when the gantry 10 is a self-propelled type, a change in the relative position between the gantry 10 and the top plate 22 may be realized by controlling the traveling of the gantry 10.

Further, in the above-described embodiment, the case where an example of the region of interest is a lesion site has been described, but the embodiment is not limited to this. For example, the region of interest may be an organ included in the examination site. FIG. 12 is a diagram for explaining other embodiments.

In FIG. 12, a four-phase imaging of the pancreas will be described as an example as a region of interest. For example, in the case of 4-phase imaging of the pancreas, after taking one image in the absence of the contrast medium, as shown in FIG. 12, the phase 1 to 4 for the region of interest depends on the elapsed time after the administration of the contrast medium. Shooting is performed four times in multiple time phases up to the phase. As an example, the first phase imaging is performed in 25 seconds after the contrast medium administration, the second phase imaging is performed in 40 seconds after the contrast medium administration, and the third phase imaging is performed. The elapsed time after administration of the contrast medium is 90 seconds, and the imaging of the fourth phase is performed in 3 minutes after the administration of the contrast medium. As described above, in the four-phase imaging of the pancreas, the imaging of the region of interest is performed in a plurality of time phases according to the elapsed time after the administration of the contrast medium.

Here, the first phase is the phase in which the arteries are visualized, and the second phase is the phase in which the arteries and veins are visualized. The third phase is the phase in which the contrast medium is spread throughout the body and the lymph nodes are visualized, and the fourth phase is the phase in which the tumor is delayed and deeply stained. In such a case, the shooting range and the scanning conditions are set independently for the first phase shooting, the second phase shooting, the third phase shooting, and the fourth phase shooting. Here, the same shooting range 81 is set in the shooting of each time phase. The imaging range 81 includes a part of the liver 83 and the entire pancreas 82. In addition, the same scan conditions are set in each time phase. For example, if the X-ray CT apparatus 1 can image a range of 160 mm in the body axis direction with one rotation, the entire pancreas 82, which is the region of interest, is within the volume imaging range, so that each phase In the imaging, the data acquisition condition for capturing the imaging range 81 in one conventional scan with the tube current set to 300 mA is set as the scanning condition. In other words, in pancreatic four-phase imaging, multiple time-phase imaging is performed under the same scanning conditions. In the following, for convenience of explanation, the first phase shooting is referred to as Plan A, the second phase shooting is referred to as Plan B, the third phase shooting is referred to as Plan C, and the fourth phase shooting is referred to as Plan D. do.

By the way, in such a four-phase imaging of the pancreas, in order to closely examine the pancreas, which is the region of interest, and to confirm the presence or absence of metastasis to other organs in the abdomen, which is the examination site, the pancreas is photographed in one of the phases. At the same time, a wide area including the pancreas is also imaged. In other words, imaging is performed on the examination site in a predetermined time phase out of the plurality of time phases. Imaging of such an examination site is performed, for example, with an elapsed time of 90 seconds after administration of the contrast medium. In such a case, for example, a wide imaging range 84 including the entire abdomen is set as an examination site. In such a case, a wide range of imaging including the area from the top of the neck of the subject P to the pelvis may be set as the examination site. In such a case, for example, a data acquisition condition for capturing the imaging range 84 by a helical scan with a tube current of 200 mA is set as a scan condition. In the following, for convenience of explanation, imaging of the inspection site in a predetermined time phase will be referred to as Plan E.

Then, after the imaging plans are set in the order of plan A, plan B, plan C, plan E, and plan D, shooting with each plan is executed. By the way, in the conventional technique, the shooting of the third phase of the plan C and the shooting of a wide range of the plan E are independently performed, and the shooting range 81 of the plan C and the shooting range 84 of the plan E are set. The exposure overlaps with a part of the liver 83 commonly contained and the whole pancreas 82.

Therefore, in another embodiment, the data collection condition for shooting the plan C and the plan E together at the time of shooting the third phase is set. For example, when the setting function 37b performs imaging on a region of interest in a plurality of time phases and imaging on an examination site in a predetermined time phase among a plurality of time phases according to the elapsed time after administration of the contrast medium, the setting function 37b is as follows. Set the data collection conditions for this scan for shooting in a predetermined time phase. That is, the setting function 37b includes a scan condition including a data acquisition condition for the third phase shooting in which the shooting range 81 is set, and a scan including a data collection condition for shooting a wide area in which the shooting range 84 is set. Based on the conditions, the data collection conditions for this scan are set for the test site of the subject including the pancreas 82, which is the region of interest. In other words, the setting function 37b is based on a first scan condition including a data acquisition condition for shooting in a predetermined time phase and a second scan condition including a data collection condition for shooting in a plurality of time phases. , Set the data collection conditions for this scan for shooting in the specified time phase.

More specifically, the setting function 37b sets the scan conditions for shooting by the helical scan with the tube current set to 200 mA in the range that does not overlap with the shooting range 81 in the shooting range 84, and is out of the shooting range 84. In the range overlapping with the shooting range 81, the tube current is set to 300 mA, and the data acquisition condition shot by the helical scan in which the helical pitch is slowed down is set as the scan condition. In this way, the setting function 37b sets the data collection conditions of the plan that integrates the plan C and the plan E.

Here, when the setting function 37b sets the data collection condition of the plan that integrates the plan C and the plan E, the setting function 37b accepts the designation of the priority order at the timing of the start of shooting of the plan C and the timing of the start of shooting of the plan E. You may do so. In other words, the setting function 37b sets the data acquisition condition of the main scan in which the start time of the shooting according to the scan condition of the plan C and the start time of the shooting according to the scan condition of the plan E are prioritized. For example, the setting function 37b is data of a plan that integrates Plan C in which the elapsed time after administration of the contrast medium is 90 seconds and Plan E in which the elapsed time after administration of the contrast medium is 100 seconds. When setting the collection conditions, it is possible to accept a designation that gives priority to either the shooting start timing of the plan C or the shooting start timing of the plan E. As an example, when the setting function 37b accepts the designation to prioritize the timing of starting the imaging of the plan C, the setting function 37b back-calculates so that the imaging of the plan C starts in 90 seconds after the administration of the contrast medium. Set the shooting start time of Plan E. Here, it is assumed that it takes 3 seconds from the start of shooting of Plan E to the start of shooting of Plan C. In such a case, the setting function 37b is set so that the imaging of Plan C starts when the elapsed time after administration of the contrast medium is 90 seconds, and the imaging of Plan E starts when the elapsed time after administration of the contrast medium is 87 seconds. do. Further, when the setting function 37b accepts the designation of giving priority to the timing of starting the imaging of the plan E, the imaging of the plan E starts after the elapsed time after the administration of the contrast medium is 100 seconds. In this case, the setting function 37b is set so that the imaging of the plan E starts after the elapsed time after the administration of the contrast medium is 103 seconds. Further, the setting function 37b does not have to accept the priority instruction regarding the timing of starting shooting of the plans C and E. In such a case, the setting function 37b sets the intermediate between the shooting start timing of the plan C and the shooting start timing of the plan E as the shooting start timing. For example, the setting function 37b is set to start shooting in 95 seconds. For example, the setting function 37b may be set so that the imaging of Plan E starts when the elapsed time after administration of the contrast medium is 95 seconds, or the imaging of Plan C may be started when the elapsed time after administration of the contrast medium is 95 seconds. It may be set to start.

Then, after the completion of the four-phase imaging of the pancreas, the reconstruction function 37c uses the data collected under the data acquisition conditions set for the predetermined time phase, and the image reconstruction conditions included in the scan conditions of Plan E are used. In addition to reconstructing the image according to the above, the image according to the image reconstruction condition included in the scan conditions of Plan A to Plan D is reconstructed by using the data collected for each time phase.

More specifically, the reconstruction function 37c uses the data collected in the first phase to capture an image in the shooting range 81 (image of the first phase) under the image reconstruction conditions included in the scan conditions of Plan A. Reconstructing and using the data collected in the second phase, the image in the shooting range 81 (the image in the second phase) is reconstructed under the image reconstructing conditions included in the scan conditions of Plan B. Further, the reconstruction function 37c reconstructs the image of the shooting range 81 (the image of the third phase) under the image reconstruction conditions included in the scan conditions of Plan C by using the data collected in the third phase. Using the data collected in the 4th phase, the image in the shooting range 81 (the image in the 4th phase) is reconstructed under the image reconstruction conditions included in the scan conditions of Plan D. Then, the reconstruction function 37c reconstructs the image (image of the inspection site) in the imaging range 84 under the image reconstruction condition included in the scan condition of the plan E by using the data collected in the third phase. The reconstruction function 37c identifies the shooting range 81 of the conventional scan from the data collected in the third phase, and reconstructs the image of the third phase under the image reconstruction conditions included in the scan conditions of Plan C.

Then, the processing circuit 37 controls to display each reconstructed image data on the display 32. Here, the processing circuit 37 displays, for example, an image of the first phase, an image of the second phase, an image of the third phase, and an image of the fourth phase, and also displays an image of the inspection site. Further, for example, when the processing circuit 37 displays the image of the first phase, the image of the second phase, the image of the third phase, and the image of the fourth phase, the slice position to be displayed is set between the images. It may be synchronized with and displayed on the display 32. In other words, the display 32 is synchronized with the slice position of the third phase image, the slice position of the first phase image, the slice position of the second phase image, and the slice position of the fourth phase image. Is displayed. This makes it possible for the image reader to easily perform an operation of comparing images between images of each time phase when interpreting images of each time phase.

In the above-described embodiment, the case where the four-phase imaging in which the region of interest is the pancreas is performed has been described, but the embodiment is not limited to this. For example, the region of interest may be the kidney or liver. Further, a plurality of regions of interest may be set. For example, the liver and pancreas may be set as regions of interest. In such a case, the setting function 37b sets the data acquisition condition of the main scan including a plurality of regions of interest based on the scan conditions of the entire abdomen and the scan conditions of each region of interest.

Further, in the above-described embodiment, the reconstruction function 37c has been described as generating images having different resolutions from the projection data based on the detection data detected in the high-definition mode during the reconstruction process. For example, the reconstruction function 37c bundles high-definition projection data to reconstruct a low-resolution image, or reconstructs a high-definition image and then bundles the images to generate a low-resolution image. However, the embodiment is not limited to this. For example, in the detector 13 or the data acquisition circuit 14, a low-resolution image may be generated by bundling the detection data detected by the detector 13 in the high-definition mode.

Here, a case where a third plan is set by integrating the plan A for the test site of the subject P and the plan B for the region of interest included in the test site will be described. In Plan A, for example, data acquisition conditions for photographing the entire chest at an ultra-low dose are set. Further, in the plan B, for example, a data acquisition condition is set in which the helical pitch in the region of interest is made slower than that in the region of interest, and the image is reconstructed with higher definition than in the plan A. Then, as the third plan, for example, as described in the first embodiment, a plan in which the plan A and the plan B are integrated is set.

Then, the detector 13 detects high-definition detection data from the detection element of 160 rows and 1792 channels in the third plan. Then, the detector 13 outputs high-definition detection data to the data acquisition circuit 14. Here, the data collection circuit 14 generates low-resolution projection data in which high-definition detection data is bundled in the data collection section of the plan A. For example, the data acquisition circuit 14 generates low-resolution projection data by summarizing each of the four detection elements as one unit and adding the high-definition detection data corresponding to the four detection elements summarized as one unit. do. Then, the data acquisition circuit 14 outputs the generated projection data to the preprocessing circuit 34.

Further, in the data collection section of the plan B, the data collection circuit 14 generates high-resolution projection data without bundling high-definition detection data and outputs it to the preprocessing circuit 34. As described above, the data acquisition circuit 14 bundles the first detection data corresponding to the first resolution, which is a high-definition resolution, and the data corresponding to the first resolution, and has a lower resolution than the first resolution. The second detection data corresponding to the second resolution is collected by the third plan.

Then, the reconstruction function 37c reconstructs the image having the first resolution from the first detection data, and reconstructs the image having the second resolution from the second detection data. For example, the reconstruction function 37c reconstructs an image corresponding to the shooting range of the plan B from the high-resolution projection data collected in the third plan. Further, the reconstruction function 37c reconstructs an image corresponding to the shooting range of the plan A from the low-resolution projection data collected in the third plan. Here, the shooting range of the plan A includes the shooting range of the plan B. Therefore, the image is reconstructed from the high-resolution projection data in the overlapping range with the plan B in the shooting range of the plan A. Therefore, when reconstructing the image corresponding to the shooting range of Plan A, the reconstruction function 37c bundles the projection data of the overlapping range between Plan A and Plan B, and then obtains the image corresponding to the shooting range of Plan A. Reconstruct.

In the above description of the embodiment, each component of each of the illustrated devices is a functional concept and does not necessarily have to be physically configured as shown in the figure. That is, the specific form of distribution / integration of each device is not limited to the one shown in the figure, and all or part of them may be functionally or physically distributed / physically in arbitrary units according to various loads and usage conditions. Can be integrated and configured. Further, each processing function performed by each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

Further, the control method described in the above embodiment can be realized by executing a control program prepared in advance on a computer such as a personal computer or a workstation. This control program can be distributed via a network such as the Internet. Further, this control program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, flexible disk (FD), CD-ROM, MO, or DVD, and being read from the recording medium by the computer.

According to at least one embodiment described above, it is possible to improve the efficiency of the inspection and reduce the exposure.

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 embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 X-ray CT device 37 Processing circuit 37b Setting function 37c Reconstruction function

Claims (16)

A detector with the first resolution and
A first plan that includes a first data collection condition and the first image reconstructing conditions for the first imaging range of the object, the second data acquisition conditions for the second imaging range of the subject and the second A setting unit for setting a third data collection condition for collecting data of the first shooting range and the second shooting range in one scan based on the second plan including the image reconstruction condition of the above. When,
Using the data collected under the third data collection condition, the first image under the first image reconstruction condition and the second image under the second image reconstruction condition are reconstructed, respectively. With the reconstruction part
Equipped with a,
The reconstruction unit has the first resolution as one of the first image and the second image from the data corresponding to the first resolution collected under the third data collection condition. and reconstructing an image, as the other of the first image and the second image, we reconstruct an image having the first second resolution lower than the resolution,
X- ray CT device. The setting unit may include a first plan for imaging target site of a subject, the imaging based on the second plan for the region of interest contained in the target site, the subject photographing including the region of interest setting said third data collection condition for the target site, X-rays CT apparatus according to claim 1. The X-ray CT apparatus according to claim 2, wherein the region of interest is a region including a lesion site in the positioning image of the subject. A detector with the first resolution and
A setting unit that integrates the first plan for the subject and the second plan for the subject to set a third plan for the subject.
Using the data collected in the third plan, the first image according to the first image reconstruction condition included in the first plan and the second image reconstruction included in the second plan are used. With the reconstruction part that reconstructs the second image according to the conditions, respectively.
Equipped with
The reconstruction unit reconstructs the first image and the second image whose resolution is the first resolution from the data corresponding to the first resolution collected in the third plan. By performing image processing so that the resolution of one of the first image and the second image becomes a second resolution lower than the first resolution, the first image has a different resolution. Reconstructing the image and the second image ,
X- ray CT device. A detector with the first resolution and
A setting unit that integrates the first plan for the subject and the second plan for the subject to set a third plan for the subject.
Using the data collected in the third plan, the first image according to the first image reconstruction condition included in the first plan and the second image reconstruction included in the second plan are used. With the reconstruction part that reconstructs the second image according to the conditions, respectively.
Equipped with
The reconstruction unit reconstructs the image having the first resolution as one of the first image and the second image from the data corresponding to the first resolution collected in the third plan. An image having the second resolution is obtained from the data obtained by bundling the data corresponding to the first resolution collected in the third plan into a second resolution lower than the first resolution. Reconstructed as the other of the first image and the second image.
X- ray CT device. A detector with the first resolution and
A setting unit that integrates the first plan for the subject and the second plan for the subject to set a third plan for the subject.
The first data corresponding to the first resolution and the second data corresponding to the second resolution lower than the first resolution, which is a bundle of the data corresponding to the first resolution, are referred to the first. The collection department that collects in the plan of 3 and
Using the data collected in the third plan, the first image according to the first image reconstruction condition included in the first plan and the second image reconstruction included in the second plan are used. With the reconstruction part that reconstructs the second image according to the conditions, respectively.
Equipped with
The reconstructing unit reconstructs an image having the first resolution from the first data as one of the first image and the second image, and reconstructs the second resolution from the second data. Is reconstructed as the other of the first image and the second image.
X- ray CT device. The X-ray CT apparatus according to claim 2 or 3, wherein the setting unit sets a third data collection condition that modulates a tube current or a tube voltage in the region of interest with respect to a region other than the region of interest. A setting unit for integrating the first plan for the subject and the second plan for the subject to set the third plan for the subject is provided.
The setting unit integrates the first plan for the imaging target portion of the subject and the second plan for the region of interest included in the imaging target region, and captures the subject including the region of interest. a third plan for the target site, setting the third plan Ru is in a low speed than a helical pitch in addition to the region of interest in the region of interest,
X- ray CT device. The setting unit according to claim 2 or 3, wherein the setting unit acquires the position information of the region of interest based on the positioning image or the CT image related to the past examination of the subject, and sets the third data collection condition. X-ray CT device. When a plurality of the regions of interest exist, the setting unit sets the third data collection condition including the plurality of regions of interest based on the first plan and the second plan for each region of interest. Set,
The reconstruction unit uses the data collected under the set third data collection condition to obtain the image reconstruction condition included in the first plan and the second plan for each region of interest. The X-ray CT apparatus according to claim 2 or 3 , wherein the image is reconstructed according to the included image reconstruction conditions. When the setting unit performs imaging on the region of interest in a plurality of time phases according to the elapsed time after administration of the contrast medium and imaging on the imaging target site in a predetermined time phase among the plurality of time phases, the predetermined unit Based on the first plan in the time phase and the second plan for the shooting in the plurality of time phases, the third data acquisition condition for the shooting in the predetermined time phase is set.
The reconstruction unit uses the data collected under the third data collection condition set for the predetermined time phase with the image according to the first image reconstruction condition included in the first plan. The X-ray CT apparatus according to claim 2 or 3 , wherein the data collected for each time phase is used to reconstruct the image under the second image reconstruction condition included in the second plan. .. A setting unit that integrates the first plan for the subject and the second plan for the subject to set a third plan for the subject.
Using the data collected in the third plan, the first image according to the first image reconstruction condition included in the first plan and the second image reconstruction included in the second plan are used. With the reconstruction part that reconstructs the second image according to the conditions, respectively.
Equipped with
The setting unit captures images of the region of interest included in the imaging target site of the subject in a plurality of time phases according to the elapsed time after administration of the contrast medium, and captures the imaging target site in a predetermined time phase among the plurality of time phases. When performing imaging, the predetermined plan is integrated with the first plan for the imaging target portion in the imaging of the predetermined time phase and the second plan for the region of interest in the imaging of the plurality of time phases. As a third plan for the part to be imaged in the time phase imaging, a third plan in which the start time of the imaging by the first plan and the start time of the imaging by the second plan are prioritized. set,
The reconstruction unit uses the data collected in the third plan set for the predetermined time phase, and the image according to the first image reconstruction condition included in the first plan, and each of them. Using the data collected for the time phase, each image under the second image reconstruction condition included in the second plan is reconstructed .
X- ray CT device. A setting unit that integrates the first plan for the subject and the second plan for the subject to set a third plan for the subject.
Using the data collected in the third plan, the first image according to the first image reconstruction condition included in the first plan and the second image reconstruction included in the second plan are used. With the reconstruction part that reconstructs the second image according to the conditions, respectively.
Equipped with
The setting unit captures images of the region of interest included in the imaging target site of the subject in a plurality of time phases according to the elapsed time after administration of the contrast medium, and captures the imaging target site in a predetermined time phase among the plurality of time phases. When performing imaging, the predetermined plan is integrated with the first plan for the imaging target portion in the imaging of the predetermined time phase and the second plan for the region of interest in the imaging of the plurality of time phases. Set a third plan for the part to be imaged in the time phase image,
The reconstruction unit uses the data collected in the third plan to obtain an image under the first image reconstruction condition included in the first plan and the data collected for each time phase. Using, the images under the second image reconstruction conditions included in the second plan are reconstructed, respectively.
From the data collected in the third plan, the slice position of the image of the region of interest in the predetermined time phase reconstructed using the image reconstruction conditions included in the second plan, and the second plan. From the data collected in the plan, on a predetermined display so as to synchronize with the slice position of the image of the region of interest other than the predetermined time phase reconstructed using the image reconstruction conditions included in the second plan. Is displayed,
X- ray CT device. An acquisition unit for acquiring a first plan for a first shooting range including a first region of interest and a second plan for a second shooting range including a second region of interest.
The size of the first shooting range and at least one of the sizes of the second shooting range are not equal to or less than a predetermined threshold value, and the distance between the first shooting range and the second shooting range. When is equal to or less than a predetermined threshold value, a setting unit for setting a third plan for the first shooting range and the second shooting range based on the first plan and the second plan. ,
Using the data collected in the third plan that has been set, the image is reconstructed with the image reconstruction conditions included in the first plan and the image reconstruction conditions included in the second plan, respectively. Reconstruction part and
X-ray CT apparatus. The setting unit, when the size of the size and the second imaging range of the first imaging range is equal to or less than the respective predetermined threshold value, or magnitude of the first imaging range and the first When at least one of the sizes of the two shooting ranges is not equal to or less than a predetermined threshold value and the distance between the first shooting range and the second shooting range is not equal to or less than the predetermined threshold value, the first shooting range is described. 14. The data collection condition of the main scan for the first shooting range and the data collection condition of the main scan for the second shooting range are set based on the plan and the second plan, respectively, according to claim 14. The X-ray CT apparatus described. The setting unit sets data collection conditions for collecting data by one rotation volume scan for a shooting range in which the size of the first shooting range and the second shooting range is equal to or less than the predetermined threshold value. and, setting the data acquisition conditions for collecting data in helical scan on the first imaging range and the second is not less than the predetermined threshold magnitude imaging range of the imaging range, to claim 15 The X-ray CT apparatus described.

Images