JP5121104B2 - X-ray CT system, operation console and control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray CT (Computerized Tomography) system that reconstructs an X-ray tomographic image of a subject by X-ray irradiation, an operation console thereof, and a control method thereof.
[0002]
[Prior art]
The main purpose of the X-ray CT system is to collect projection data obtained from X-rays transmitted through a subject and provide an X-ray tomographic image reconstructed from the projection data. Specifically, first, the subject is laid on the table device and transported toward the cavity of the gantry device. Then, the gantry rotating part (the X-ray tube and the X-ray detector are integrally attached) of the gantry device is rotationally driven to irradiate the subject with X-rays from different angles. X-rays transmitted through the subject are detected. Then, the operation console receives the detected data (projection data), reconstructs the X-ray tomographic image by arithmetic operation, and displays it on the monitor. A series of steps for detecting the X-ray is generally called a scan.
[0003]
In general, the X-ray CT system is configured to be able to set the rotational speeds (hereinafter also referred to as “scanning speeds”) of a plurality of gantry rotating parts in accordance with the inspection purpose and the like. Further, during scanning, X-ray tomographic images of a predetermined number of frames per rotation of the gantry rotating unit are displayed on the monitor in real time. That is, the operation console is designed to ensure real-time reconstruction and display of X-ray tomographic images even at the highest scanning speed.
[0004]
[Problems to be solved by the invention]
While securing such real-time processing is required, it is also required to improve the image quality of displayed X-ray tomographic images. However, under the restricted hardware conditions, the speeding up of image processing and the improvement of image quality are generally in a trade-off relationship, and it is not easy to achieve both.
[0005]
The present invention has been made in view of such problems, and X-rays capable of providing a higher-quality X-ray tomographic image while ensuring real-time performance of X-ray tomographic reconstruction processing and display processing. It is an object of the present invention to provide a CT system and its operation console and control method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, for example, an X-ray CT system of the present invention comprises the following arrangement. That is,
An X-ray generation source includes a gantry rotating unit configured to rotate around a subject, performs a scan for collecting projection data of the subject, and outputs an X-ray tomographic image based on the collected projection data A line CT system,
Setting means for setting a value based on a time at which an X-ray tomographic image should be displayed after the start of scanning;
Determining means for determining processing contents related to reconstruction of an X-ray tomographic image in accordance with the set value;
Image reconstruction / display means for performing image reconstruction and display including processing of the content determined by the determination means based on the collected projection data;
It is characterized by providing.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments will be described in detail with reference to the drawings.
[0008]
FIG. 1 is a block diagram of an X-ray CT system according to an embodiment. This system performs various operation settings for the gantry apparatus 100 for detecting X-ray irradiation to the subject and X-rays transmitted through the subject, and has been output from the gantry apparatus 100. The operation console 200 is configured to reconstruct and display an X-ray tomogram based on the data.
[0009]
The gantry apparatus 100 has the following configuration including the main controller 1 that controls the entire system.
[0010]
2 is an interface for performing communication with the operation console 200, 3 is a subject (patient) laid on the table 11 (hereinafter referred to as the z-axis in a direction perpendicular to the drawing, and generally coincides with the patient's body axis) A gantry rotating part (hereinafter simply referred to as “gantry”) having a cavity for Reference numeral 4 denotes an X-ray tube as an X-ray generation source, which is driven and controlled by an X-ray tube controller 5.
[0011]
Reference numeral 6 denotes an aperture having an opening for limiting the X-ray irradiation range, 7 denotes an aperture motor for adjusting the opening width of the aperture 6, and 8 denotes an aperture motor driver for controlling drive of the aperture motor 7.
[0012]
Reference numeral 9 denotes a rotary motor that causes the gantry 3 to rotate. Reference numeral 10 denotes a rotary motor driver that drives the rotary motor 9. Reference numeral 11 denotes a table for placing a subject. Reference numeral 12 denotes a table motor for transporting the table 11 in the z-axis direction. Reference numeral 13 denotes a table motor driver for controlling drive of the table motor 12.
[0013]
Reference numeral 14 denotes an X-ray detector that detects X-rays from the X-ray tube 4 that have passed through the aperture 6 and the cavity of the gantry 3. The X-ray detection unit 14 has a plurality of (for example, 1,000) detection channels having a length depending on the X-ray irradiation range defined by the aperture 6, and in particular, the detection channel located at the end thereof Usually, an X-ray beam is directly incident without passing through the subject and is used as a reference channel. A data collection unit 15 collects the projection data obtained from the X-ray detection unit 14 and converts it into digital data.
[0014]
On the other hand, the operation console 200 is a so-called workstation, and as shown in the figure, includes a CPU 51 that controls the entire apparatus, a ROM 52 that stores a boot program, and the like, and the following configuration.
[0015]
A RAM 53 functions as a main storage device. The RAM 53 has a buffer area 53a for temporarily storing projection data transferred from the gantry apparatus 100, as shown.
[0016]
The HDD 54 is a hard disk device, and stores a diagnostic program for giving various instructions to the gantry apparatus 100 and reconstructing an X-ray tomogram based on data received from the gantry apparatus 100 in addition to the OS. ing. The HDD 54 further stores a table (details will be described later) describing a combination of processes additionally applied for each scan speed. The VRAM 55 is a memory for developing image data to be displayed, and can be displayed on the CRT 56 by developing the image data or the like here. Reference numerals 57 and 58 denote a keyboard and a mouse for performing various settings. Reference numeral 59 denotes an interface for communicating with the gantry apparatus 100.
[0017]
The configuration of the X-ray CT system in the present embodiment is generally as described above. In the X-ray CT system having such a configuration, the collection (scanning) of projection data is performed as follows.
[0018]
First, an operator (engineer or doctor) operates the operation console 200 to set various scanning conditions (scanning plan), and then gives an instruction to start scanning. The diagnostic program operating on the operation console 200 issues various control commands to the gantry apparatus 100 (main controller 1) according to the set scan conditions. The main controller 1 of the gantry apparatus 100 gives control signals to the X-ray tube controller 5, the aperture motor driver 8, the rotary motor driver 10 and the table motor driver 13 in accordance with this control instruction command. As a result, the X-ray generated in the X-ray tube 4 and transmitted through the subject can be detected by the X-ray detection unit 14 and the projection data can be obtained from the data collection unit 15.
[0019]
Specifically, the gantry 3 is rotated once while the transport of the table 11 is stopped, and the X-ray beam from the X-ray tube 4 is applied to the subject from a plurality of view directions (for example, 1,000) for 360 degrees. Irradiation (projecting X-rays) and detection of the transmitted X-rays by the X-ray detector 14 are repeated. Each detected transmission X-ray is converted into a digital value by the data collection unit 15 and transferred to the operation console 200 via the main controller 1. This series of operations is called one scan as one unit. Then, the scan position is sequentially moved by a predetermined amount in the z-axis direction, and the next scan is performed. Such a scanning method is called an axial scanning method, but the table 11 is continuously moved in accordance with the rotation of the gantry 3 (the X-ray tube 4 and the X-ray detector 14 spiral around the subject). It may be a helical scan system that collects projection data.
[0020]
The diagnostic program operating on the operation console 200 performs processing for reconstructing an X-ray tomographic image by known processing based on the transferred projection data, and sequentially displays the result on the CRT 56.
[0021]
In the X-ray CT system in the above-described embodiment, the gantry 3 is moved to one of a plurality of rotation speeds (scanning speeds), for example, 0.7 [sec / rot.], 1.0 [sec / rot.], 1.5 [sec / rot.], it can be rotated. The unit “sec / rot.” Represents the time required for one rotation of the gantry 3. The operator can select the scan speed according to the inspection purpose or the like when the scan is planned.
[0022]
In the X-ray CT system according to the embodiment, during scanning, an X-ray tomographic image having a predetermined number of frames, for example, 6 frames, is sequentially displayed in real time on the CRT 56 every time the gantry 3 rotates once. ing. In order to realize this, every time the gantry 3 is rotated 1/6, the X-ray tomographic image displayed on the CRT 56 is set to be updated and displayed as the latest reconstructed X-ray tomographic image. . It will be understood that this update time interval is a display time allowed for one frame (one) X-ray tomogram. The update time interval is set according to the scan speed. That is, the scan speed can be used as an index value corresponding to the display time allowed per frame (one frame) of the X-ray tomographic image.
[0023]
Hereinafter, the number of frames displayed per rotation of the gantry 3 is referred to as “frame rate” and is expressed in units of “frame / rot.”.
[0024]
By the way, in order to reconstruct an X-ray tomographic image, projection data for one rotation of the gantry is not necessarily required. For example, an X-ray tomographic image is reconstructed with projection data for 1/2 rotation of the gantry. It is known that it is possible. Therefore, in the embodiment, a frame rate of 6 [frame / rot.] Is realized by performing an image reconstruction process using projection data corresponding to ½ rotation of the gantry 3.
[0025]
Specifically, first, the main controller 1 of the gantry apparatus 100 that performs scanning acquires projection data for each 1/6 rotation of the gantry 3 from the data collection unit 15 and sequentially transfers the projection data to the operation console 200. The projection data transferred to the operation console 200 is stored in the buffer 53a. The buffer 53 always stores the latest projection data for ½ rotation (= 3/6 rotation) of the gantry 3 transferred from the gantry apparatus 100. Therefore, each time 1/6 rotation projection data of the gantry 3 is transferred from the gantry apparatus 100, the oldest 1/6 rotation projection data in the buffer area is discarded and transferred. Projection data for rotation is newly stored. The CPU 51 performs image reconstruction processing based on the projection data stored here and performs display processing on the CRT 56.
[0026]
In order to ensure the real-time property, it is necessary to finish the image reconstruction process and the display process before the projection data for the next 1/6 rotation is transferred. Since the maximum scanning speed in the embodiment is 0.7 [sec / rot.] As described above, the time required for image reconstruction processing and display processing per frame (one frame) is 0.7 / 6≈0.117 [sec. ],It turns out that. Therefore, the image reconstruction process and the display process are designed to fit within this time constraint.
[0027]
By the way, as described above, it is desired to improve the image quality of the displayed X-ray tomographic image while ensuring the real-time display as described above. However, the speeding up of image processing and the improvement in image quality are generally in a trade-off relationship under restricted hardware conditions, and it is not easy to achieve both.
[0028]
Therefore, as described above, the present inventor has designed the image reconstruction processing and display processing per frame based on the maximum scanning speed, and therefore processing time when the scanning speed is slowed down. We paid attention to the fact that we could afford
[0029]
For example, when scanning is performed at a scanning speed of 1.0 [sec / rot.], The time required for image reconstruction processing and display processing per frame is 1.0 / 6≈0.167 [sec]. Is processed at 0.1167 [sec] in the case of the scan speed of 0.7 [sec / rot.], So that a margin time of 0.117−0.167 = 0.05 [sec] is generated.
[0030]
The present invention is characterized in that a predetermined process that leads to an improvement in image quality is applied in this margin time.
[0031]
Next, processing in the X-ray CT system according to the embodiment will be described with reference to the flowchart of FIG. A program corresponding to this flowchart is stored in the hard disk 54 of the operation console 200, loaded into the RAM 53 after the power is turned on, and executed by the CPU 51.
[0032]
First, a scan plan is made on the operation console 200 (step S1). In general, various scan conditions are set via a GUI provided by a diagnostic program (a user interface on which a setting screen is displayed on the CRT 56 and allows input using the keyboard 57 or the mouse 58). However, since this scan plan itself is publicly known, its details are omitted. The scanning conditions in the embodiment include, for example, designation of the scanning speed in addition to the slice thickness and the tube current supplied to the X-ray tube 4. The set scan conditions are stored in the RAM 53.
[0033]
When the scan plan in step S1 is completed, the contents of the processing relating to the image reconstruction corresponding to the set scan speed as the index value corresponding to the display time allowed for one X-ray tomographic image are next performed. Determine (step S2).
[0034]
For example, a table having a structure as shown in FIG. 3 is created in the HDD 54, and the type of processing relating to image reconstruction corresponding to the set scan speed is determined with reference to this table. In the figure, ◯ indicates that the process is executed, and x indicates that the process is not executed. Then, a combination of processes indicated by ◯ is executed at each scan speed.
[0035]
For example, when the scan speed is set to 0.7 [sec / rot.], There are no processes marked with ◯ and all are marked with x, so none of the processes listed in this table are executed. When the scan speed is set to 1.0 [sec / rot.], The reference correction (correction to normalize each channel output with the reference channel output value) and the beam hardening (Beam Hardning) correction are performed. In other words, other processes with x are not performed. In addition, when the scan speed is set to 1.5 [sec / rot.], All the processes described in the table (reference correction, quality hardening correction, scattered X-ray correction, and streak artifact removal correction) are performed. I will decide.
[0036]
That is, in the present embodiment, the number of processing combinations related to image reconstruction increases as the scanning speed decreases.
[0037]
Further, the matrix size of the image reconstruction is determined with reference to the table shown in FIG. For example, as shown in the figure, when the scan speed is set to 0.7 [sec / rot.], It is 256 × 256 pixels, and when the scan speed is set to 1.0 [sec / rot.], It is 320 × 320 pixels, When the scan speed is set to 1.5 [sec / rot.], Image reconstruction processing is performed with 512 × 512 pixels. This is set in consideration of the trade-off relationship that the resolution increases as the matrix size increases and the image quality of the reconstructed image can be improved, while the calculation amount of the image reconstruction processing also increases.
[0038]
Next, using the predetermined input from the mouse 57 or the keyboard 58 as a trigger, the gantry apparatus 100 is instructed to perform scanning according to the scanning conditions planned in step S1 (step S3). In response to this instruction, the gantry apparatus 100 performs scanning. At this time, of course, the gantry 3 rotates at the set scanning speed. Then, the projection data transferred from the gantry apparatus 100 every 1/6 rotation of the gantry 3 is received (step S4), and the contents of the buffer 53a are updated with the received data (step S5).
[0039]
Thereafter, the CPU 51 of the operation console 200 executes an image reconstruction process including the process determined in step S2 (step S6). Further, after the CT value is converted into a predetermined contrast scale (step S7), it is displayed on the CRT 56 as an X-ray tomographic image (step S8).
[0040]
In step S9, it is determined whether there is data transferred from the gantry apparatus 100. If there is still data, the process returns to step S4 to repeat the process. As soon as there is no transfer data, this process is terminated.
[0041]
According to the above-described embodiment, X-ray tomographic image is obtained because the predetermined processing that leads to the improvement of the image quality is additionally applied according to the margin time required for the image reconstruction processing and display processing caused by the scanning speed. It has become possible to improve the image quality without impairing the real-time display.
[0042]
In the above-described embodiment, when scanning is continuously performed, for example, it is related to image reconstruction according to the scan speed on the assumption that the display update speed of the X-ray tomogram is ensured in real time. An example of determining the content of processing was shown.
[0042]
However, according to the present invention, for example, the scan is not performed continuously, but the scan is performed only once, and an X-ray tomographic image is displayed after a predetermined time has elapsed (for example, 2 seconds) after the scan is started. It can also be applied to the case. In other words, the X-ray CT system that realizes the present invention sets the time when the X-ray tomographic image is to be displayed directly or indirectly after the start of the scan when considering each scan. The processing content related to image reconstruction is determined according to (or a value based on the time).
[0042]
Further, most of the control of the X-ray system in the embodiment is performed by the operation console 200. Since the configuration of the operation console 200 can be realized by a general-purpose information processing apparatus (workstation, personal computer, or the like), the software for realizing the functions of the above-described embodiments is installed in the apparatus and realized by that. It is also possible.
[0043]
In other words, an object of the present invention is to supply a storage medium in which the program code of the software is recorded to a device, and the computer (or CPU or MPU) of the device reads and executes the program code stored in the storage medium. However, it goes without saying that this is achieved. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.
[0044]
When the present invention is applied to the above-mentioned storage medium, the storage medium stores program code for realizing the processing according to the flowchart shown in FIG.
[0045]
As a storage medium for storing such a program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used. Furthermore, it may be downloaded via a medium called a network (for example, the Internet).
[0046]
【Effect of the invention】
As described above, according to the present invention, an X-ray CT system capable of providing a higher-quality X-ray tomographic image while ensuring real-time performance of X-ray tomographic reconstruction processing and display processing, and The operation console and the control method can be provided.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram of an X-ray CT system according to an embodiment.
FIG. 2 is a flowchart showing processing in the embodiment.
FIG. 3 is a diagram illustrating an example of a table describing combinations of processes additionally applied for each scan speed in the embodiment.

Claims (16)

An X-ray generation source includes a gantry rotating unit configured to rotate around a subject, performs a scan for collecting projection data of the subject, and outputs an X-ray tomographic image based on the collected projection data A line CT system,
A setting means for selectively setting the rotation speed of the gantry rotating section;
At the timing when the X-ray tomographic image is to be displayed, the X-ray tomographic image is sequentially reconstructed and displayed based on the projection data acquired sequentially, so that the X-ray tomographic image is reconstructed. When the rotational speed of the gantry rotating unit is higher, the processing time related to the image reconstruction of the X-ray tomographic image is shorter and the image quality is lower, and the rotational speed of the gantry rotating unit Image processing of X-ray tomographic images with different processing time and image quality related to image reconstruction such that the processing time related to image reconstruction of the X-ray tomographic image is longer and the image quality is higher. a plurality of processing contents related to configuration, a storage means for storing a plurality of rotational speeds and respectively in correspondence of the gantry rotary section,
Determining means for determining processing contents related to reconstruction of the X-ray tomogram based on the rotation speed of the gantry rotating unit set in the setting means and the correspondence relationship stored in the storage means;
Image reconstruction / display means for performing image reconstruction and display including processing of the content determined by the determination means based on the collected projection data;
An X-ray CT system comprising:   The X-ray CT system according to claim 1, wherein the processing content related to the image reconstruction of the X-ray tomographic image includes a matrix size of the image reconstruction processing.   The X-ray CT system according to claim 2, wherein the storage unit stores a larger matrix size when the rotation speed of the gantry rotating unit is slower.   The timing at which the X-ray tomographic image is to be displayed is a timing at which an X-ray tomographic image can be displayed in real time with a predetermined number of frames per rotation of the gantry rotating unit. Item 4. The X-ray CT system according to any one of Items 3 to 3.   The processing related to the reconstruction of the X-ray tomographic image includes at least one of a reference correction, a radiation hardening correction, a scattered X-ray correction, and a streak artifact removal correction. Item 5. The X-ray CT system according to any one of Items 4 to 5.   The storage means increases the number of processes included in the combination in the order of reference correction, quality hardening correction, scattered X-ray correction, and streak artifact removal correction as the rotational speed of the gantry rotating unit decreases. The X-ray CT system according to claim 5, which is stored. An X-ray generation source includes a gantry rotating unit configured to rotate around a subject, performs a scan for collecting projection data of the subject, and outputs an X-ray tomographic image based on the collected projection data A method for controlling a line CT system, comprising:
A setting step for selectively setting the rotation speed of the gantry rotating unit;
The X-ray tomographic images are sequentially collected at the timing at which the X-ray tomographic image related to the scan speed and the rotation speed of the gantry rotating unit set in the setting step is prepared. The processing content related to the reconstruction of an X-ray tomographic image that is sequentially reconstructed and displayed based on the projection data, and when the rotational speed of the gantry rotation unit is higher, the X-ray When the processing time associated with tomographic image reconstruction is shorter and the image quality is lower, and when the rotation speed of the gantry rotating unit is slower, the processing time associated with the image reconstruction of the X-ray tomographic image is longer. corresponding Guan but the higher becomes like an image reconstruction associated processing time and image quality associated with the image reconstruction of the different X-ray tomographic image processing contents to a plurality of rotational speed of the gantry rotary section A determination step of bets based on, determining a plurality of processing contents relating to reconstruction of the X-ray tomographic image,
An image reconstruction / display step for performing image reconstruction and display including processing of the content determined in the determination step based on the collected projection data;
A control method for an X-ray CT system, comprising: The X-ray generation source includes a rotating unit configured to rotate around the subject, and is connected to a gantry device that performs a scan for collecting projection data of the subject, and transmits information related to the scan to the gantry device. And an operation console in the X-ray CT system for outputting an X-ray tomogram based on the projection data transferred from the gantry apparatus,
A setting means for selectively setting the rotation speed of the gantry rotating section;
At the timing when the X-ray tomographic image is to be displayed, the X-ray tomographic image is sequentially reconstructed and displayed based on the projection data acquired sequentially, so that the X-ray tomographic image is reconstructed. When the rotational speed of the gantry rotating unit is higher, the processing time related to the image reconstruction of the X-ray tomographic image is shorter and the image quality is lower, and the rotational speed of the gantry rotating unit Image processing of X-ray tomographic images with different processing time and image quality related to image reconstruction such that the processing time related to image reconstruction of the X-ray tomographic image is longer and the image quality is higher. Storage means for storing a plurality of processing contents related to the configuration in association with a plurality of rotational speeds of the gantry rotating unit;
Determining means for determining processing contents related to reconstruction of the X-ray tomogram based on the rotation speed of the gantry rotating unit set in the setting means and the correspondence relationship stored in the storage means;
Image reconstruction / display means for performing image reconstruction and display including processing of the content determined by the determination means based on the projection data transferred from the gantry apparatus;
An operation console characterized by comprising:   The operation console according to claim 8, wherein the processing content related to the image reconstruction of the X-ray tomographic image includes a matrix size of the image reconstruction processing.   10. The operation console according to claim 9, wherein the storage means stores a larger matrix size when the rotation speed of the gantry rotating unit is slower.   9. The timing at which the X-ray tomographic image is to be displayed is a timing at which an X-ray tomographic image can be displayed in real time with a predetermined number of frames per rotation of the gantry rotating unit. Item 15. The operation console according to any one of Items 10 to 10.   The process related to the reconstruction of the X-ray tomographic image includes at least one of a reference correction, a radiation hardening correction, a scattered X-ray correction, and a streak artifact removal correction. The operation console according to any one of Items 11.   As the rotational speed of the gantry rotating unit decreases, the storage means increases in the number of processes included in the combination in the order of reference correction, radiation quality hardening correction, scattered X-ray correction, and streak artifact removal correction. The operation console according to claim 12. The X-ray generation source includes a rotating unit configured to rotate around the subject, and is connected to a gantry device that performs a scan for collecting projection data of the subject, and transmits information related to the scan to the gantry device. A method for controlling an operation console in an X-ray CT system that outputs an X-ray tomogram based on projection data transferred from the gantry apparatus,
A setting step for selectively setting the rotation speed of the gantry rotating unit;
The X-ray tomographic images are sequentially collected at the timing at which the X-ray tomographic image related to the scan speed and the rotation speed of the gantry rotating unit set in the setting step is prepared. The processing content related to the reconstruction of an X-ray tomographic image that is sequentially reconstructed and displayed based on the projection data, and when the rotational speed of the gantry rotation unit is higher, the X-ray When the processing time associated with tomographic image reconstruction is shorter and the image quality is lower, and when the rotation speed of the gantry rotating unit is slower, the processing time associated with the image reconstruction of the X-ray tomographic image is longer. corresponding Guan but the higher becomes like an image reconstruction associated processing time and image quality associated with the image reconstruction of the different X-ray tomographic image processing contents to a plurality of rotational speed of the gantry rotary section A determination step of bets based on, determining a plurality of processing contents relating to reconstruction of the X-ray tomographic image,
An image reconstruction / display step for performing image reconstruction and display including processing of the content determined in the determination step based on the collected projection data;
A method for controlling an operation console. The X-ray generation source includes a rotating unit configured to rotate around the subject, and is connected to a gantry device that performs a scan for collecting projection data of the subject, and transmits information related to the scan to the gantry device. A program for controlling an operation console in the X-ray CT system for outputting an X-ray tomogram based on the projection data transferred from the gantry apparatus,
A setting step for selectively setting the rotation speed of the gantry rotating unit;
The X-ray tomographic images are sequentially collected at the timing at which the X-ray tomographic image related to the scan time and the rotation speed of the gantry rotating unit set in the setting step is stored in advance. The processing content related to the reconstruction of an X-ray tomographic image that is sequentially reconstructed and displayed based on the projection data, and when the rotational speed of the gantry rotation unit is higher, the X-ray When the processing time associated with tomographic image reconstruction is shorter and the image quality is lower, and when the rotation speed of the gantry rotating unit is slower, the processing time associated with the image reconstruction of the X-ray tomographic image is longer. corresponding Guan but the higher becomes like an image reconstruction associated processing time and image quality associated with the image reconstruction of the different X-ray tomographic image processing contents to a plurality of rotational speed of the gantry rotary section A determination step of bets based on, determining a plurality of processing contents relating to reconstruction of the X-ray tomographic image,
A program for executing, on the basis of collected projection data, an image reconstruction / display step for performing image reconstruction and display including processing of the content determined in the determination step. A storage medium storing the program according to claim 15 .

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