JP2002360559A - X-ray ct system, its operation console and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray CT system that can reconstitute an X-ray tomogram of a high picture quality by suppressing the difference of CT values between detector lines caused by the variance of the detecting precision of X-ray detection channels even in helical scanning of multi-slice, and its operation console and controlling method. SOLUTION: In calibration processing performed in advance of actual scanning to a patient, a correction coefficient to each projection data of another detector line with projection data of a prescribed detector line as reference is determined. After receiving the projection data by helical scanning (step S13) and before helical interpolation (step S16), each projection data of each other detector string is corrected by using the corresponding correction coefficient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an X-ray CT system for reconstructing an X-ray tomographic image of a subject by X-ray irradiation, an operation console thereof, and a control method.

[0002]

2. Description of the Related Art X-ray CT (Computerized Tomography)
The system is roughly divided into a device having a donut-shaped cavity (generally called a gantry device), various control signals to the gantry device, and a signal (data) obtained from the gantry device. An operation console for reconstructing and displaying an X-ray tomographic image based on the table, and a table for fixedly supporting the subject (patient) in the cavity of the gantry apparatus and for transporting the subject toward the cavity It is composed of devices.

A gantry apparatus is a rotating unit having a built-in X-ray source (X-ray tube) provided with the above-mentioned cavity interposed therebetween and an X-ray detector for detecting X-rays emitted from the X-ray source. Is provided.

An X-ray CT system uses an X-ray that has passed through a subject.
The main purpose is to collect projection data obtained from a line and reconstruct an X-ray tomographic image from the projection data. Specifically, first, the subject is laid on the above-mentioned table device and transported to the gantry device. Then, while rotating the X-ray tube, the rotating part (X-ray tube and X-ray detector) of the gantry device is rotationally driven to irradiate the subject with X-rays from different angles, and the subject at each angle is irradiated. X-rays transmitted through are detected. Then, the detected data (projection data)
Is received by the operation console, and an X-ray tomographic image is reconstructed by an arithmetic operation. The above-described series of steps for detecting X-rays is generally called scanning.

In the scanning method, a scan is performed while the table position is fixed, the table position is sequentially moved by a predetermined amount, and then the next scan is performed at the position. Meanwhile, there is a so-called helical scan in which scanning is performed continuously. In the case of helical scan, projection data at a target slice position is collected at only one projection angle, so data interpolation is required prior to image reconstruction (helical interpolation). Helical interpolation is generally performed by weighted addition using projection data in the preceding and succeeding slices.

[0006] Further, the X-ray detecting section is constituted by a plurality of rows of detector arrays arranged in the direction of transport of the table.
2. Description of the Related Art A so-called multi-slice X-ray CT system capable of acquiring data of a plurality of slices by scanning is known.

By the way, the physical characteristics (detection accuracy) of each channel of the X-ray detector inherently vary. Of course,
This variation will cause the CT value for a homogeneous object (eg, a water phantom) to differ between the detection channels. Conventionally, processing for compensating for such variations has been performed. Further, in the multi-slice X-ray CT system, the difference in CT values as described above may occur between detector rows. On the other hand, for example, in the multi-slice axial scan method, it is possible to match CT values between detector rows after image reconstruction for each detector row.

[0008]

However, in the case of multi-slice helical scan, helical interpolation is
This is performed by using the projection data of the adjacent detector rows. Therefore, the effect of the difference in the physical detection accuracy existing between the detector rows enters into the helical interpolation, and the interpolation accuracy varies depending on the slice position. As a result, the CT value shifts depending on the slice position, and the image quality is degraded. In the case of such a helical scan, it is no longer possible to absorb the CT value difference between the detector rows by the CT value correction processing after image reconstruction as in the case of the axial scan.

The present invention has been made in view of such a problem. Even in a multi-slice helical scan, the difference in CT value between detector rows due to a variation in detection accuracy of an X-ray detection channel is determined. Suppress, high quality X
It is an object to provide an X-ray CT system capable of reconstructing a tomographic X-ray image, an operation console thereof, and a control method.

[0010]

To achieve the above object, for example, an X-ray CT system according to the present invention has the following arrangement. That is, a gantry device configured so that an X-ray source and an X-ray detection unit provided at positions opposed to each other with a cavity in which a subject is located are integrally rotated around the cavity A table device having a top plate for placing the subject, and configured to be capable of adjusting the relative position of the top plate with respect to the cavity in order to position the subject in the cavity of the gantry device, Wherein the X-ray detection unit comprises a plurality of rows of detector arrays arranged in the direction of adjusting the relative position, and the relative position of the top plate with respect to the gantry device during the rotational movement in the gantry device. An X-ray CT system that performs a helical scan to collect projection data by detecting X-rays transmitted through a subject at different projection angles at different projection angles while adjusting at a predetermined speed. On the basis of projection data of a predetermined detector row obtained by detecting the X-ray transmitted through a predetermined reference test object at a different projection angle during the rotational movement in the apparatus by the X-ray detection unit, Calculating means for calculating a correction coefficient for the projection data for each detector row, and projecting by multiplying the projection data for each of the other detector rows obtained by the helical scan on the object by the corresponding correction coefficient. It is characterized by comprising correction means for correcting data, and image reconstruction means for reconstructing an X-ray tomographic image based on the corrected projection data.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(System Configuration) FIG. 1 is a block diagram of an X-ray CT system according to an embodiment. As shown in the figure, this system irradiates the subject with X-rays and transmits X-rays through the subject.
Gantry device 100 for integrally mounting an X-ray detection mechanism for detecting a line, table device 200 for transporting a subject toward gantry device 100, and various operation settings for gantry device 100 ,
X based on the data output from the gantry device 100
An operation console 300 reconstructs and displays a line tomographic image.

The gantry device 100 has the following configuration, including the main controller 1 that controls the entire system.

2a is an interface for communicating with the table device 200, and 2b is an interface for communicating with the operation console 300. Reference numeral 3 denotes a gantry having a cavity 3a for transporting a subject (patient) lying on the table device 200. Inside the gantry 3 is an X-ray tube 4 (X-ray tube controller 5) which is an X-ray source.
The collimator 6 having a slit for defining an X-ray irradiation range, and the X of the collimator 6
A motor 7a, which is a motor for adjusting a slit width that defines a line irradiation range, is provided. The driving of the motor 7a is controlled by the collimator controller 7.

In the gantry 3, an X-ray detector 8 for detecting X-rays transmitted through the subject located in the cavity 3a and projection data obtained from the transmitted X-rays obtained by the X-ray detector 8 are provided. It also has a data collection unit 9 to collect. The X-ray tube 4, the collimator 6, and the X-ray detection unit 8 are provided at positions opposing each other with the cavity 3 a interposed therebetween, that is, around the cavity 3 a in a state where the relationship is maintained. It is designed to rotate. This rotation is performed by the rotation motor 1 driven by a drive signal from the motor controller 11.
Performed by 0.

The main controller 1 analyzes various commands received via the interface 2b, and sends various control signals to the X-ray tube controller 5, collimator controller 7, motor controller 11, and data collection unit 9 based on the analysis. Will be output. Also,
A control signal is also output to a table motor controller of the table device 200 described below via the interface 2a. Further, the main controller 1 transmits the projection data collected by the data collection unit 9 to the interface 2.
A process of sending the operation console 300 to the operation console 300 is also performed.

The table device 200 has a top plate (also called a cradle) 21 on which a subject is placed.
The top plate 21 is supported by a frame (not shown) so as to be slidable toward the cavity 3a by a frame (not shown) so as to be transported into the cavity 3a of the gantry device 100. The slide adjustment is driven by a table motor 22, which is controlled by a table motor controller 23 driven under the control of the main controller 1 of the gantry device 100. Reference numeral 24 denotes an interface for performing communication with the gantry device 100.

The operation console 300 is a so-called workstation, and as shown in the figure, a CPU 51 for controlling the entire apparatus, a ROM 52 for storing a boot program and the like, and a RAM 5 for functioning as a main storage.
3 and the following configuration.

The HDD 54 is a hard disk device, which is a diagnostic program for giving various instructions to the gantry device 100 and reconstructing an X-ray tomographic image based on data received from the gantry device 100 in addition to the OS. Is stored. This diagnostic program includes program modules according to flowcharts shown in FIGS. 4 and 5 described below.

The VRAM 55 is a memory for expanding image data to be displayed. The image data and the like can be expanded on the VRAM 55 to display the image data on the CRT 56. 57 and 58 are a keyboard and a mouse for performing various settings. An interface 59 communicates with the gantry device 100.

The configuration of the X-ray CT system in the embodiment is generally as described above. Next, the structures of the X-ray tube 4, collimator 6, and X-ray detector 8 will be described in more detail with reference to FIG.

FIG. 2 is a diagram showing the main components of the X-ray tube 4, collimator 6, and X-ray detector 8. Although not shown, these components are supported by a predetermined base of the gantry 3, and as described above, the X-ray tube 4, the collimator 6, and the X-ray detector 8
Are rotated around the cavity 3a in a state where the positional relationship between the two is maintained with the cavity 3a interposed therebetween. Note that, in the drawing, the arrow z indicates the transport direction of the table 21 of the table device 200 (this direction is referred to as the z-axis direction), and usually coincides with the body axis direction of the subject.

In FIG. 1, an X-ray tube 4 is provided with a housing 41.
In addition, it has a structure in which a cathode sleeve 42 containing a focusing electrode and a filament and a rotating target 43 are contained, and emits X-rays from a focal point f.

The collimator 6 is made of a member made of an X-ray shielding material such as lead, and as shown, a collimator (also called an aperture) that defines an X-ray irradiation range in the z-axis direction of the X-ray emitted from the X-ray tube 4. 2) two fixed shielding plates which are located between the collimator 6a and the X-ray tube 4 and define an irradiation range (called a fan angle, for example, 60 °) in the direction along the rotation direction of the gantry 3. Is provided with a collimator 6b. With this arrangement, the slit 15 for defining the X-ray irradiation range is formed.

The detailed configuration of the X-ray detector 8 in the embodiment is as follows. A detector row composed of a plurality of (for example, 1,000) detection channels over a length depending on the fan angle is arranged in two rows of array configurations along the z-axis direction indicated by A and B. Thereby, a so-called two-row multi-slice CT is realized. However, the invention is not limited by the size of the particular detection array.

(Processing) In the above configuration, scanning in the embodiment is performed as follows. First, top plate 2
1 with the subject lying on the top plate 21 and the cavity 3a
After the gantry 3 is rotated, the X-ray tube 4 and the X-ray detection unit 8 are rotated around the subject (that is, while changing the projection angle), and the gantry 3 is rotated. Irradiating the subject with X-rays (projecting X-rays) by 360 ° is performed while moving the top 21 in the z-axis direction in synchronization with the change in the projection angle. This is called one scan as one unit. Each of the detected transmitted X-rays is converted into a digital value by the data collection unit 9 and is used as projection data via the main controller 1 via the operation console 30.
0 is transferred. If you repeat this scan continuously,
The trajectory of the X-ray tube 4 spirals as shown in FIG. For this reason, this scan is called a helical scan.

As the scanning method, a scan (projection of 360 °) is performed while the position of the top plate 21 is fixed, and the scan position is moved by a predetermined amount in the z-axis direction, and then the next scan is performed. There is also an axial scan method. In this system, it is possible to select whether to perform an axial scan or a helical scan at the time of a scan plan according to a photographing purpose.

As described above, each detection channel of the X-ray detector 8 has a variation in detection accuracy. In the case of the axial scan, even if this variation causes a difference in the projection data for each detector row, after the image reconstruction based on the projection data of the detector row A and the image reconstruction based on the projection data of the detector row B, In the CT value correction processing to be performed, it is possible to absorb the difference between the CT values of both images.

On the other hand, in the case of the helical scan, since the projection data is collected spirally, the projection data at the target slice position is collected at only one projection angle. Therefore, it is necessary to interpolate the projection data in the z-axis direction before image reconstruction (helical interpolation). This helical interpolation is performed using the data of the detector rows A and B. Therefore, in the case of the helical scan, it is impossible to absorb the CT value difference between the detector rows by the CT value correction processing after the image reconstruction like the axial scan.

Therefore, in the embodiment of the present invention, before the helical interpolation, the projection data of each detector row is corrected based on the projection data of a predetermined detector row. The process of determining the correction coefficient for this correction is performed prior to the actual scan of the subject. This correction coefficient determination process is preferably performed, for example, in a calibration process generally called phantom calibration.

The contents of the correction coefficient determination processing will be described with reference to the flowchart of FIG. As described above, the program according to this flowchart is included in the diagnostic program stored in the HDD 54 of the operation console 300. This diagnostic program is loaded into the RAM 53 after the system is turned on, and is executed by the CPU 51. Things.

First, as a preparation, a water phantom as a reference test object is set on the top plate 21 of the table device 200. Thereafter, the operation console 300 sends a phantom calibration execution command to the gantry device 100 based on the input from the keyboard 57 or the mouse 58 (Step S1). In response to this execution command, the main controller 1 of the gantry device 100 first issues an instruction to the table motor controller 23 of the table device 200 to transport the top plate 21 to a predetermined position in the hollow portion 3a. The scanning operation is performed according to predetermined conditions (current, voltage, etc., applied to the X-ray tube 4) for calibration.

When the scan for the phantom calibration is completed, the projection data collected by the data collection unit 9 is sent from the gantry device 100.
This is received (step S2).

Then, in step S3, for each view (corresponding to the projection angle),
The ratio of the projection data of the detector row A to the projection data of the detector row B is calculated. Assuming that the total number of views is N and the number of detection channels of each detector row is Q, the ratio R (n, k) of the projection data in the k-th channel of the n-th view can be expressed, for example, as follows: .

For (n = 0, N-1) {for (k = 0, Q-1) R (n, k) = caldata_A (n, k) / caldata_B (n, k);}

However, in the above equation and the equation shown in the block of step S3 in FIG. 4, the symbol "=" means that the value on the right side is substituted into the left side. Also, ca
ldata_A (n, k) is the detector row A at the time of calibration.
Projection data in the k-th channel of the n-th view, caldat
a_B (n, k) is the n-th of the detector row B at the time of calibration.
It is projection data in the k-th channel of a view. Also, “for (k = 0, Q−1)” indicates that each value from 0 to Q−1 is substituted into k, and the following expression is executed in each case, “for (n = 0, N−1)” indicates that each value from 0 to N−1 is substituted for n, and the following equation is executed in each case.

The calculated R (n, k) is stored in the RAM 53 as a correction coefficient.

Next, the contents of processing by the main program in the diagnostic program when performing a helical scan will be described with reference to the flowchart of FIG.

First, a scan plan is made (Step S)
11). The scan plan itself is known, but generally, a GUI (CR
A setting screen is displayed at T56, and the user can input data using the keyboard 57 or the mouse 58) to the scan start position and end position, slice thickness, scan method, X-ray tube 4, and the like. Various scan conditions such as a current and a voltage to be supplied are set. Here, helical scan is selected as the scan method. The set scan condition is RA
It is stored in M53.

In step S12, a helical scan start command using the scan condition set in step S1 as a parameter is input based on an input from the keyboard 57 or mouse 58 indicating a scan start instruction.
Output to 0. In response to this, the gantry device 100 executes the helical scan according to the scan conditions.

When scanning is started, the gantry device 10
From 0, the projection data collected by the data collection unit 9 is transferred and received (step S1).
3). Each received projection data is subjected to predetermined preprocessing such as offset correction as needed (step S1).
4).

Then, in step S15, the correction is performed for all the views by multiplying the projection data of the detector array B by a correction coefficient for each detection channel. This correction operation can be expressed, for example, as follows.

[0043]

However, the above equation and step S15 in FIG.
In the expression shown in the block (1), the symbol “=” means that the value on the right side is substituted for the value on the left side.

By this correction processing, the projection data of the detector row B is corrected so as to match the projection data of the detector row A.

After the correction processing in step S15, the image reconstruction processing in steps S16 and S17 is performed. That is, helical interpolation (step S16) for interpolating the projection data at the target slice position by weighting and adding the projection data of the adjacent detector row as well as the projection data of the detector row, and an image reconstruction algorithm For example, filtered back projection (step S17) is executed. Then, after converting into a CT value that falls within a predetermined contrast scale (step S18), the image is displayed on the CRT 56 as an X-ray tomographic image,
Alternatively, a print is output to a printing device (not shown) (step S19).

As described above, in the embodiment, the correction coefficient is determined in the calibration process performed prior to the actual scan of the subject, and after the actual scan and before the helical interpolation, a predetermined detector is determined. The projection data for each detector row is corrected based on the row of projection data. As a result, even in helical scan,
Variations in CT values between detector rows can be absorbed.

It should be noted that the above-described correction processing in step S15 is performed after the data reception in step S13.
Any time before the 16 helical interpolations,
For example, it may be performed before the pre-processing of step S14.

In the above-described embodiment, two rows of detectors have been described as an example. However, as described above, the present invention is not limited to a specific detector array configuration. Can be applied. That is, step S in FIG.
In 3, the ratio of the projection data of each of the other detector rows to the projection data of the predetermined detector row is calculated for each detection channel for all views. Then, in step S15 of FIG. 5, the projection data is corrected by multiplying the projection data of each of the other detector rows by the corresponding correction coefficient for each detection channel for all views.

It should be noted that most of the control of the X-ray system in the embodiment is performed on the operation console 300.
The configuration itself of the operation console 300 is a general-purpose information processing device (such as a workstation or a personal computer)
Therefore, it is also possible to install the software in the same device and realize it with it.

That is, an object of the present invention is to supply a storage medium (or a recording medium) on which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and to provide a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. This also includes a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

When the present invention is applied to the storage medium, the storage medium stores program codes for realizing the processes according to the flowcharts shown in FIGS. 4 and 5 described above.

As a storage medium for storing such a program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, C
D-ROM, magnetic tape, nonvolatile memory card, R
OM or the like can be used. Further, it may be downloaded via a medium such as a network (for example, the Internet).

[0054]

As described above, according to the present invention,
Even in a multi-slice helical scan, an X-ray that can reconstruct a high-quality X-ray tomographic image by suppressing a difference in CT value between detector rows due to a variation in detection accuracy of an X-ray detection channel A CT system and its operation console and control method can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of an X-ray CT system according to an embodiment.

FIG. 2 is a diagram illustrating a structure of an X-ray detection mechanism in the embodiment.

FIG. 3 is a diagram illustrating a trajectory of an X-ray tube in a helical scan.

FIG. 4 is a flowchart illustrating a correction coefficient determination process according to the embodiment.

FIG. 5 is a flowchart showing processing by a main program of a diagnostic program in the embodiment.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Masatake Nukai 4-7, Asahigaoka, Hino-shi, Tokyo 127 Inside GE Yokogawa Medical System Co., Ltd. (72) Inventor Akira Hagiwara 4-chome, Asahigaoka, Hino-shi, Tokyo No. 127 G Yokogawa Medical System Co., Ltd. F term (reference) 4C093 AA22 BA10 CA02 CA13 EB18 FC17 FE14

Claims (13)

[Claims] 1. An X-ray source and an X-ray detection unit provided at positions opposed to each other with a cavity in which a subject is positioned are integrally rotated around the cavity. A table having a gantry device and a top plate for placing a subject, wherein the relative position of the top plate with respect to the cavity is adjustable to position the subject in the cavity of the gantry device. The X-ray detection unit is configured with a plurality of detector arrays arranged in the adjustment direction of the relative position, and the gantry device of the top plate during the rotational movement in the gantry device. An X-ray CT system that performs a helical scan to collect projection data by detecting the X-rays transmitted through the subject at different projection angles by the X-ray detection unit while adjusting a relative position with respect to the predetermined speed, Said Based on the projection data of a predetermined detector row obtained by detecting the X-ray transmitted through a predetermined reference test object at a different projection angle during the rotational movement in the inventory device by the X-ray detection unit, Calculating means for calculating a correction coefficient for the projection data for each detector row; and multiplying the projection data for each of the other detector rows obtained by the helical scan on the subject by the corresponding correction coefficient. An X-ray CT system comprising: correction means for correcting projection data; and image reconstruction means for reconstructing an X-ray tomographic image based on the corrected projection data. 2. The X-ray CT according to claim 1, wherein said image reconstruction means includes helical interpolation means for performing data interpolation at a target slice position using projection data of an adjacent detector row. system. 3. An X-ray source and an X-ray detector provided at positions opposed to each other with a cavity in which a subject is located interposed therebetween and configured to rotate around the cavity. A table having a gantry device and a top plate for placing a subject, wherein the relative position of the top plate with respect to the cavity is adjustable to position the subject in the cavity of the gantry device. The X-ray detection unit is configured with a plurality of detector arrays arranged in the adjustment direction of the relative position, and the gantry device of the top plate during the rotational movement in the gantry device. A method of controlling an X-ray CT system that performs a helical scan that collects projection data by detecting the X-rays transmitted through the subject at different projection angles by the X-ray detection unit while adjusting the relative position with respect to at a predetermined speed. Ah The X-ray detector detects X-rays transmitted through a predetermined reference test object at different projection angles during the rotation in the gantry device, based on projection data of a predetermined detector row. Calculating a correction coefficient for the projection data for each of the other detector rows, and the correction coefficient corresponding to the projection data for each of the other detector rows obtained by the helical scan on the subject. A control method for an X-ray CT system, comprising: a correction step of correcting projection data by multiplication; and an image reconstruction step of reconstructing an X-ray tomographic image based on the corrected projection data. . 4. The X-ray CT according to claim 3, wherein the image reconstruction step includes a helical interpolation step of performing data interpolation at a target slice position using projection data of an adjacent detector row. How to control the system. 5. An X-ray source and an X-ray detection unit provided at positions opposed to each other with a cavity in which a subject is positioned interposed therebetween and configured to rotate around the cavity. A table having a gantry device and a top plate for placing a subject, wherein the relative position of the top plate with respect to the cavity is adjustable to position the subject in the cavity of the gantry device. The X-ray detection unit is configured with a plurality of detector arrays arranged in the adjustment direction of the relative position, and the gantry device of the top plate during the rotational movement in the gantry device. A program for controlling an X-ray CT system that performs a helical scan for collecting projection data by detecting, at the X-ray detection unit, X-rays transmitted through a subject at different projection angles while adjusting a relative position with respect to a predetermined speed. A ram, wherein the X-ray detection unit detects X-rays transmitted through a predetermined reference test object at different projection angles during the rotational movement in the gantry apparatus, and projection data of a predetermined detector row. Based on the program code of a calculation step of calculating a correction coefficient for the projection data for each of the other detector rows, and projection data for each of the other detector rows obtained by the helical scan on the subject, A program code for a correction step for correcting projection data by multiplying by the corresponding correction coefficient, and a program code for an image reconstruction step for reconstructing an X-ray tomographic image based on the corrected projection data. A program characterized by that: 6. The program code of the image reconstructing step includes a program code of a helical interpolation step of performing data interpolation at a target slice position using projection data of an adjacent detector row. The program described in. 7. A storage medium storing the program according to claim 5 or 6. 8. An X-ray source and an X-ray detector provided at positions opposed to each other with a cavity in which a subject is located interposed therebetween are configured to rotate around the cavity integrally. A table having a gantry device and a top plate for placing a subject, wherein a relative position of the top plate with respect to the cavity is adjustable to position the subject in the cavity of the gantry device. The X-ray detection unit is configured with a plurality of detector arrays arranged in the adjustment direction of the relative position, and the gantry device of the top plate during the rotational movement in the gantry device. The gantry of the X-ray CT system for performing a helical scan for collecting projection data by detecting, with the X-ray detection unit, X-rays transmitted through the subject at different projection angles while adjusting a relative position with respect to a predetermined speed. An operation console connected to the apparatus, wherein projection data is obtained by detecting transmitted X-rays having different projection angles during the rotation of the gantry apparatus with respect to a predetermined reference test object mounted on the table apparatus. First instructing means for instructing to perform a scan for collecting the image data, and the first instructing means, based on the projection data of a predetermined detector row in the projection data transferred from the gantry device, each of the other Calculating means for calculating a correction coefficient for the projection data for each detector row; second instructing means for instructing to perform the helical scan; and other information transferred from the gantry device by the second instructing means. Correction means for correcting the projection data by multiplying the projection data for each detector row by the corresponding correction coefficient; and Operation console, characterized in that it comprises an image reconstruction means for reconstructing an X-ray tomographic image based on the data. 9. The operation console according to claim 8, wherein the image reconstruction means includes a helical interpolation means for performing data interpolation at a target slice position using projection data of an adjacent detector row. 10. An X-ray source and an X-ray detection unit provided at positions opposed to each other with a cavity in which a subject is located interposed therebetween and are configured to rotate around the cavity. A table having a gantry device and a top plate for placing a subject, wherein the relative position of the top plate with respect to the cavity is adjustable to position the subject in the cavity of the gantry device. The X-ray detection unit is configured with a plurality of detector arrays arranged in the adjustment direction of the relative position, and the gantry device of the top plate during the rotational movement in the gantry device. An X-ray CT system that performs a helical scan for collecting projection data by detecting, with the X-ray detection unit, X-rays transmitted through a subject at different projection angles while adjusting a relative position with respect to a predetermined speed. A method of controlling an operation console connected to a re-mounting device, wherein a transmitted X-ray having a different projection angle is detected during a rotation of the gantry device with respect to a predetermined reference test object mounted on the table device. A first instruction step of instructing to perform a scan for collecting projection data by the first instruction step, based on the projection data of a predetermined detector row in the projection data transferred from the gantry device. A calculation step of calculating a correction coefficient for the projection data for each of the other detector rows; a second instruction step of instructing to perform the helical scan; and a second instruction step of transferring from the gantry device. Compensation for correcting the projection data by multiplying the projection data for each of the other detector rows by the corresponding correction coefficient. A control method for an operation console, comprising: a normal step; and an image reconstruction step of reconstructing an X-ray tomographic image based on the corrected projection data. 11. The operation console according to claim 10, wherein the image reconstruction step includes a helical interpolation step of performing data interpolation at a target slice position using projection data of an adjacent detector row. Control method. 12. A program executable by a computer device, the program causing a computer device executing the program to function as the operation console according to claim 8. 13. A storage medium storing the program according to claim 12.