JP2002065661A - X-ray ct system, its operation console and control method of the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray CT system, an operation console thereof and a control method such that not only a breathing stop plan during scanning can be efficiently performed but burden on an operator can be reduced. SOLUTION: In a scanning plan screen, a column that designates the number of breathing stops is set other than a breathing stop time input column. If the number of breathing stops is designated, the number of scan clusters is set to the designated breathing stop number. Scanning within a scanning range is divided into each scan cluster almost per equal number of times. As a result, it is possible to avoid that the number of scanning in each scan cluster becomes extremely different.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT (Computerizon) for reconstructing an X-ray tomographic image of a subject by X-ray irradiation.
The present invention relates to a system and an operation console thereof and a control method thereof, and more particularly to a technique for realizing a highly efficient scan planning environment.

[0002]

2. Description of the Related Art An X-ray CT system performs a scan for irradiating a patient (subject) with X-rays from a plurality of directions, and reconstructs an image based on projection data obtained from X-rays from each direction transmitted through the patient. By performing the processing, a tomographic image of a diagnosis site is provided. Prior to such a scan or the like, the operator needs to make a plan for scan conditions and image reconstruction processing in accordance with a diagnostic part and a diagnostic purpose. Such a plan is called a scan plan. X-ray CT systems generally provide an environment for scan planning on an operation console.

FIG. 7 shows an example of a scan plan screen displayed on the monitor of the operation console. here,
A [start position] column 702 is a column for inputting a scan start position with respect to a predetermined reference position, and similarly, an [end position] column 703 is a column for inputting a scan end position with respect to a predetermined reference position. A [slice thickness] column 704 is a column for inputting a slice thickness in a scan. A [tube voltage] column 705 and a [tube current] column 706 are columns for inputting values of a tube voltage and a tube current of the X-ray tube 4, respectively.

An operator first performs a scout scan before making a scan plan. What is Scout Scan
With the X-ray tube, which is the X-ray source, fixed at a certain angle,
One X-ray two-dimensional image is obtained from projection data obtained by continuously irradiating X-rays while gradually transporting the subject. When the scout scan is completed, the X-ray two-dimensional image (called a scout image) is displayed on a scan plan screen 700.
Is displayed in the image area 701.

While looking at the scout image, the operator proceeds with the scan plan by inputting desired values into the respective input fields. Actually, the scan plan items are diversified, and not only the illustrated input items but also various plan items may be displayed by classification.

[0006] By the way, especially when scanning the torso, the patient is required to keep breathing during the scanning process in order to prevent the image quality of the tomographic image from being deteriorated due to the respiratory movement. If the scan takes a relatively long time, the scan must be interrupted and a period for breathing must be provided. In this specification, a period during which a person keeps breathing during a scan is referred to as a “breath-hold period (hour)”, and a period for breathing provided by interrupting a scan is referred to as a “breath-hold period (hour)”. Call it. The setting regarding the breath holding time and the breath holding time is made based on the numerical values input in the [breath holding time] column 707 and the [breath holding time] column 708, respectively.

Here, the breath holding / breathing period planning process will be described in detail.

As an example, it is assumed that the following settings are made on the scan plan screen of FIG.

Start position: 0 mm (reference position) End position: 64 mm (from reference position) Slice thickness: 4 mm Breath-hold period: 9 sec Breath-hold period: 5 sec

Note that the scan method here is a so-called axial scan, and the scan speed is 1 [sec / sca
n], and an inter scan, which is a time interval between scans, is 1 second.

According to the above conditions, the reference positions 0 to 64
Since the slice thickness is 4 mm, the total number of scans performed in the scan area of mm is 16 times.

The number of scans that can be performed within the planned 9 sec breath-hold period is determined by the scan speed and the interscan. In the case of a scan speed of 1 [sec / scan] and an inter-scan of 1 sec under the above conditions, five scans are performed within 9 sec. A series of scan groups performed during this breath holding period is called a “scan cluster”.

That is, the 16 scans are divided into three scan clusters each consisting of five scan groups and scan clusters each consisting of only one remaining scan that cannot be included in the scan clusters, according to the planned breath holding period. Is done.

When the preview button 709 is pressed, a preview screen 300 shown in FIG. 3 is displayed on the monitor instead of FIG. 7, and the preview screen 300 is displayed 16 times according to the planned breath holding period of 9 sec and the breathing period of 5 sec. You can visually check how the scan is performed. In the figure, reference numeral 301 denotes a time axis indicating the elapsed time of the scanning process, reference numeral 302 denotes a bar graph indicating the relationship between the breath holding / breathing and the scanning, and a period in which the height of the bar is H indicates a scanning period; The period L represents a period during which scanning is not performed.

According to FIG. 1, a scan starts after a predetermined time has elapsed from the scan start command (four seconds in the illustrated example). The above-described scan cluster (corresponding to the breath-hold period) is repeated three times with a planned 5-second breath period, and the last one scan is performed after the breath period. As mentioned above, 4
7 sec is required.

Thus, for a planned scan,
The preview screen allows for visual confirmation.

[0017]

However, it is inconvenient that a small number of scans that do not fit in the scan cluster remain as shown in the above example. This is because a breathing period is provided for only a few scans, so that the examination time becomes longer and the burden on the patient increases.

Conventionally, in order to prevent such a small number of scans from remaining, conventionally, the clustering result of the scan cluster is confirmed on a preview screen 300 shown in FIG. 3, and if it is not appropriate, a back button 303 is pressed. The operation of displaying the scan plan screen 700 of FIG. 7 again, correcting necessary items, pressing the preview button 709 again to switch to the preview screen 300, and reconfirming the clustering result of the scan cluster is repeated. Such a task is very complicated, and there is a problem that a burden on an operator is large.

The present invention has been made in view of such a problem, and an X-ray CT system, an operation console thereof, and an X-ray CT system capable of efficiently performing a breath-holding plan in scanning and reducing the burden on an operator. It is an object to provide a control method.

[0020]

To achieve the above object, for example, an X-ray CT system according to the present invention has the following arrangement. That is, scanning is performed by irradiating the subject with X-rays from multiple directions, and X-
An X-ray CT system for reconstructing a tomographic image of the subject based on projection data obtained from a line,
Scan planning means for setting the number of breath holdings of a subject provided for scanning; and a series of scan groups in which a scan in a predetermined scan area is substantially equally divided by the number of breath holdings set by the scan planning means. And clustering means for dividing into scan clusters.

[0021]

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

FIG. 1 is a block diagram of the X-ray CT system according to the embodiment. As shown in the figure, the present system includes a gantry device 10 in which an X-ray detecting mechanism for integrally irradiating the subject with X-rays and detecting X-rays transmitted through the subject is integrated.
0 and various operation settings for the gantry apparatus 100, and an operation console 200 for reconstructing and displaying an X-ray tomographic image based on data output from the gantry apparatus 100.

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

Reference numeral 2 denotes an interface for performing communication with the operation console 200. Reference numeral 3 denotes a cavity for carrying a subject (patient) lying on the table 12 (in a direction perpendicular to the drawing, hereinafter also referred to as a Z-axis). Gantry with a part,
Inside, an X-ray tube 4 (controlled by an X-ray tube controller 5) as an X-ray source, a collimator 6 having a slit for defining an irradiation range of X-rays, and X-ray irradiation of the collimator 6 A motor 7a, which is a motor for adjusting the slit width that defines the range, is provided. This motor 7
The driving of a is controlled by the collimator controller 7.

The gantry 3 has an X-ray detector 8 for detecting X-rays transmitted through the subject, and a data collector 9 for collecting projection data obtained from transmitted X-rays obtained by the X-ray detector 8. Also have. The X-ray tube 4, the collimator 6, and the X-ray detector 8 are provided at positions opposing each other with the hollow part interposed therebetween, that is, with the subject interposed therebetween, and rotate around the gantry 3 in a state where the relationship is maintained. It works. This rotation is performed by a rotation motor 10 driven by a drive signal from a motor controller 11.
The table 12 on which the subject is placed is transported in the Z-axis direction, and is driven by a table motor 13.

The main controller 1 analyzes various commands received via the interface 2 and, based on the analyzed commands, the X-ray tube controller 5, collimator controller 7, motor controller 11, table motor controller 14, and data collection. Various control signals are output to the unit 9. The main controller 1 also performs a process of transmitting the projection data collected by the data collection unit 9 to the operation console 200 via the interface 2.

The operation console 200 is a so-called workstation, and as shown, a CPU 51 for controlling the entire apparatus, a boot program and a BIOS.
, And a RAM 53 functioning as a main storage device.

The HDD 54 is a hard disk drive, in addition to the OS, performs a scan plan, gives various instructions to the gantry device 100,
A diagnostic program for reconstructing an X-ray tomographic image based on the received data is stored. VRA
M55 is a memory for expanding the image data to be displayed, and can be displayed on the CRT 56 by expanding the image data and the like here. 57 and 58
Are a keyboard and a mouse for performing various settings. An interface 59 communicates with the gantry device 100.

Although the configuration of the X-ray CT system in the embodiment is generally as described above, the outline of the processing in the X-ray CT system having such a configuration is as shown in the flowchart of FIG.

First, the subject is laid on the table 12 to perform positioning for imaging (step S50).
1). As soon as the positioning is completed, a scout scan is performed (step S502). As described above, in the scout scan, while the X-ray tube 4 and the X-ray detector 8 are not rotated and fixed at a fixed angle, the X-rays are continuously transmitted while gradually transporting the table 12 on which the subject is placed. One X-ray two-dimensional image (scout image) is obtained from the projection data obtained by irradiation.

When the scout scan is completed, step S
Proceeding to 503, a scan plan screen is displayed on the CRT 56 together with the scout image. The operator proceeds with the scan plan while viewing the scout image. A detailed description of the scan plan will be described later.

After the scan plan is completed, the collection (scan) of the projection data is started according to the scan execution instruction from the operator (step S504). Scanning is performed as follows. First, the position in the Z-axis direction is fixed, and the X-ray tube 4 is fixed.
The subject is irradiated with an X-ray beam from the X-ray (projection of X-ray), and the transmitted X-ray is detected by the X-ray detector 8. Then, the detection of the transmitted X-rays is performed in a plurality of (for example, 1000) view directions while rotating the X-ray tube 4 and the X-ray detector 8 around the subject (that is, changing the projection angle). 36
Perform for 0 degree. 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 transferred to the operation console 200 via the main controller 1 as projection data. Then, the scan position is sequentially moved in the Z-axis direction by a predetermined amount, and the next scan is performed. Such a scanning method is called an axial scanning method, and moves the scanning position in synchronization with the change of the projection angle (the X-ray tube 4 and the X-ray tube 4).
The helical scan method may be used in which the line detection unit 8 spirals around the subject in a spiral manner.

When the scanning is completed, the operation console 2
00 reconstructs an X-ray tomographic image based on the transferred projection data (step S505) and displays and outputs it to the CRT 56 (step S506).

Hereinafter, the scan plan in step S503 will be described in detail.

FIG. 2 is a diagram showing an example of a scan plan screen displayed on the CRT 56. This scan plan screen 250 is almost the same as the scan plan screen 700 described above, but as shown, a [number of breath-holds] field 209 for inputting the number of breath-holds is newly provided. Specifying the number of breath holdings is optional. As explained below,
It is possible to proceed with the plan as usual and to specify the number of breath holdings later with reference to the preview result.

Here, first, it is assumed that the same conditions as those in the above-described example are set on the scan plan screen of FIG. That is,

Start position: 0 mm (reference position) End position: (from reference position) 64 mm Slice thickness: 4 mm Breath holding period: 9 sec Breathing period: 5 sec

It is assumed that the setting is made as follows. The scan method here is a so-called axial scan, the scan speed is 1 [sec / scan], and the inter scan, which is the time interval between scans, is 1 sec.

When the preview button 210 is pressed, a preview screen 300 shown in FIG. 3 is displayed on the CRT 56 instead of FIG. The operator sees this preview screen and knows that, according to the above settings, in addition to three scan clusters consisting of five scan groups, a scan cluster of only one remaining scan will be generated at the end. Will be. Then, the operator presses the back button 303 to return to the scan plan screen 250 in FIG. 2 in order to avoid such a one-time scan remaining at the end.

Here, in the case of the conventional planning method, the item contents such as the breath holding time are directly corrected. In the embodiment, the number of breath holdings (the number of breath holdings) Is equivalent to the number of scan clusters). For example, by referring to the number of scan clusters confirmed on the preview screen, it is possible to easily determine how many times to hold the breath. It is much easier than determining the breath hold time directly.

Next, a method of clustering into scan clusters when the number of breath holdings is designated will be described with reference to the flowchart of FIG.

First, in step S601, the total number n of scans in the scan area from the start position to the end position is determined. The total number n of scans is obtained by the following equation.

N = ceil ((end position−start position) /
Slice thickness)

Where ceil () is a function that outputs the smallest integer that is not smaller than the value in parentheses. Also,
The number m of scan clusters is determined as the designated number of breath holdings (step S602). Subsequently, step S6
03, the determined n is divided by m to obtain a quotient P and a remainder Q
Ask for. This is shown in the figure by mathematical expressions. That is,

P = floor (n / m), Q = mod (n, m)

Are shown. However, floor ()
Is a function that outputs the largest integer that is not greater than the value in parentheses, and mod () is a function that outputs the remainder of division n / m (0 if divisible).

Next, the flow advances to step S604 to determine whether the remainder Q is 0, that is, whether the total number n of scans is divisible by the number m of scan clusters. If n is divisible by m and Q = 0, the process advances to step S605 to determine the number of scans of each scan cluster as P for all scan clusters. On the other hand, if n is not divisible by m and Q ≠ 0, the process proceeds to step S606, where the number of scans of each scan cluster is determined to be P + 1 for the first to Qth scan clusters, and step S606 is performed.
At 607, the number of scans in each scan cluster is determined to be P for the remaining scan clusters.

By the above processing, the total number of scans n is
By the designated number of times of breath holding, that is, the number of scan clusters, the data can be divided almost equally.

FIG. 4 shows an example of the preview screen 300 after the number of breath holdings is specified as 3 in the [number of breath holdings] column 209 of FIG. 2 under the above conditions.
It can be seen from the above processing that a total of 16 scans are allocated to the scan cluster (a) composed of six scan groups and the scan clusters (b) and (c) composed of five scan groups. Also, as shown in FIG. 3, the original plan required 47 sec by the end of all scans, but it can be seen that it has been reduced to 43 sec.

The time required for each scan cluster, that is, the breath holding time, may be displayed on the preview screen 300 near the corresponding scan cluster. By displaying the required time in this way, the planned breath holding time can be immediately known.

As described above, the number of times of breath holding is optional. As described above, the breath holding time may be specified directly as usual, and then the number of breath holdings may be specified, or the number of breath holdings may be specified without specifying the breath holding time. The operator may freely decide according to the complexity of the scan plan. It can be said that an efficient scan plan can be realized and the degree of freedom of the scan plan has been increased.

Further, in order to allow the operator to easily determine the number of times of breath holding, how the maximum breath holding time is to be simulated by the above-described processing for a plurality of types of times of breath holding is shown in FIG. In this manner, the correspondence between the number of breath holdings and the maximum breath holding time based on the number of breath holdings may be displayed. It is desirable that such an area for display is provided in any area on the scan planning screen shown in FIG. The operator can grasp the relationship between the number of times of breath holding and the time of breath holding at a glance, so that the convenience is remarkably improved.

As described above, according to the embodiment,
Extremely different scan numbers in each scan cluster will not occur.

Most of the control of the X-ray CT system in the embodiment is performed on the operation console 200. Since the configuration itself of the operation console 200 can be realized by a general-purpose information processing device (workstation, personal computer, or the like), it is also possible to install software in the device and realize the configuration.

That is, an object of the present invention is to supply a storage medium (or a recording medium) in 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 the computer (or Alternatively, the present invention can also be realized by a CPU or an MPU) reading and executing a program code stored in a 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. The functions of the above-described embodiments are not only realized by executing the program codes read by the computer,
Based on the instructions of the program code, the operating system (OS) running on the computer performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments. .

[0056]

As described above, according to the present invention,
X-ray CT that can efficiently perform a breath holding plan in scanning and reduce the burden on the operator
A system, an operation console thereof, and a control method thereof 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 diagram illustrating an example of a scan plan screen according to the embodiment.

FIG. 3 is a diagram illustrating an example of a preview screen according to a conventional technique and an embodiment.

FIG. 4 is a diagram illustrating an example of a preview screen according to the embodiment.

FIG. 5 is a flowchart illustrating an outline of processing of the X-ray CT system according to the embodiment.

FIG. 6 is a flowchart illustrating a clustering process according to the embodiment;

FIG. 7 is a diagram showing an example of a scan planning screen according to a conventional technique.

FIG. 8 is a diagram illustrating a display example of a correspondence relationship between the number of times of breath holding and a maximum breath holding time.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasushi Sato 127 within 4-7 Asahigaoka, Hino-shi, Tokyo Inside GE Yokogawa Medical System Co., Ltd. (72) Inventor Masaru Seto 4-7-1 Asahigaoka, Hino-shi, Tokyo 127 GE Yokogawa Medical System Corporation F-term (reference) 4C093 AA22 CA17 FA19 FA52 FB09 FG11

Claims (10)

[Claims] 1. A scan for irradiating an object with X-rays from a plurality of directions is performed, and a tomographic image of the object is reconstructed based on projection data obtained from X-rays from each direction transmitted through the object. An X-ray CT system, comprising: scan planning means for setting at least the number of times of breath holding of a subject provided for scanning; and scanning in a predetermined scan area by the number of times of breath holding set by the scan planning means. An X-ray CT system, comprising: clustering means for dividing into a scan cluster of a series of scan groups equally divided. 2. The X-ray CT system according to claim 1, further comprising means for displaying a result of the classification of the scan cluster. 3. The clustering means obtains a quotient P and a remainder Q by dividing the total number of scans T in the scan area by the set number of breath holdings C, and calculates each scan number in the Q scan clusters by P + 1. 2. The method according to claim 1, wherein the number of scans in the other scan clusters is P.
Or the X-ray CT system according to claim 2. 4. A scan for irradiating the subject with X-rays from a plurality of directions, and reconstructing a tomographic image of the subject based on projection data obtained from X-rays from each direction transmitted through the subject. An operation console of an X-ray CT system, comprising: a scan planning unit configured to set at least the number of breath holdings of a subject provided for scanning; and a breath holding unit configured to perform a scan in a predetermined scan area by the scan planning unit. An operation console for an X-ray CT system, comprising: clustering means for dividing into a scan cluster of a series of scan groups substantially equally divided by the number of times. 5. The operation console of the X-ray CT system according to claim 4, further comprising means for displaying a result of the division of the scan cluster. 6. The clustering means obtains a quotient P and a remainder Q by dividing the total number of scans T in the scan area by the set number of breath holdings C, and calculates each scan number in the Q scan clusters by P + 1. And dividing the number of scans in the other scan clusters into P.
An operation console for the X-ray CT system according to claim 5. 7. A scan for irradiating an object with X-rays from a plurality of directions, and reconstructing a tomographic image of the object based on projection data obtained from X-rays from each direction transmitted through the object. A method for controlling an operation console of an X-ray CT system, comprising: at least a scan planning step of setting a number of breath holdings of a subject to be provided for a scan; A clustering step of dividing into a scan cluster of a series of scan groups substantially equally divided by the number of times of breath holding, and a control method of the operation console of the X-ray CT system. 8. The method according to claim 7, further comprising a step of displaying a result of the division of the scan cluster. 9. The clustering step comprises: dividing the total number of scans T in the scan area by the set number of breath-holds C to obtain a quotient P and a remainder Q, and dividing each scan number in the Q scan clusters by P + 1 And dividing the number of scans in other scan clusters into P.
A method for controlling an operation console of an X-ray CT system according to claim 8. 10. A scan for irradiating an object with X-rays from a plurality of directions, and reconstructing a tomographic image of the object based on projection data obtained from X-rays from each direction transmitted through the object. A storage medium storing a control program code for an operation console of an X-ray CT system, comprising: at least a program code for a scan planning step for setting the number of breath holdings of a subject provided for scanning; And a program code for a clustering step of dividing the scan into scan clusters of a series of scan groups substantially equally divided by the number of breath holdings set in the scan planning step.