JP2004194995A - Scanning range setting device, x-ray ct system, and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set and confirm a scanning range on an actual patient and to reduce an exposure dose by providing a scanning range setting device requiring no scout scanning, an X-ray CT system and a method for controlling the same. <P>SOLUTION: A scanning range setting device (300) having a light source unit (301) slidable along the carrying direction (z) of the patient is provided at a position opposing a table (201) across the patient placed on the table (201). Floodlights A and B at the light source unit (301) serves for setting a scanning starting position and a scanning finishing position. The floodlight B is provided turnably with a rotary shaft C as a fulcrum and by controlling its angle, a position of the patient to be irradiated with irradiating light from the floodlight B is adjusted. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an X-ray CT system for obtaining an X-ray tomographic image of a subject by X-ray irradiation, a scan range setting device, and a control method thereof.
[0002]
[Prior art]
X-ray CT (Computerized Tomography) systems and apparatuses are roughly classified into an apparatus having a cavity for inserting a subject (generally called a gantry) and various control signals to the gantry. It comprises an operation console for reconstructing and displaying an X-ray tomographic image based on signals (data) obtained from the gantry, and a transport device for transporting the subject into the cavity of the gantry.
[0003]
The gantry includes a rotating unit having a built-in X-ray source (X-ray tube) provided with the cavity interposed therebetween and an X-ray detection unit for detecting X-rays emitted from the X-ray source.
[0004]
Actually, when scanning, the subject is laid on the above-mentioned transport device and transported toward the gantry. Then, while rotating the X-ray tube, the rotating part of the gantry (the X-ray tube and the X-ray detector) is rotationally driven (this operation is generally called scanning), and X-rays are emitted toward the subject from different angles. Then, the X-ray transmitted through the subject at each angle is detected. Then, the operation console receives the detected data (generally referred to as projection data) and reconstructs an X-ray tomographic image by arithmetic operation.
[0005]
By the way, before actually performing the scan, it is necessary to perform positioning (positioning) of the subject placed on the transport device. Further, it is necessary to make a plan for a scan condition such as which area of the subject is to be scanned at what slice thickness and a condition of the image reconstruction processing according to a diagnosis site and a diagnosis purpose. Such a plan is called a scan plan. An X-ray CT system generally provides a graphical user interface environment for making a scan plan from a scan plan screen displayed on a monitor of an operation console.
[0006]
Conventionally, positioning of a subject has been performed as follows. First, the subject is placed on the table of the transport device, and the table is moved to the position of the light projector arranged on the gantry. Next, a laser beam from the projector is irradiated toward the subject, and the table position and / or the laser beam is matched with a reference point (generally, a clinical reference position) corresponding to a target region of the subject. Adjust the position of the subject. When the adjustment is completed, the reference position is determined by pressing the reset button there. Thereafter, a scout scan is performed to make a scan plan. The scout scan is to obtain one fluoroscopic image from projection data obtained by continuously irradiating an X-ray while gradually transporting a subject with an X-ray tube fixed at a fixed angle. When the scout scan is completed, this perspective image (called a scout image) is displayed on a predetermined area of the scan plan screen on the operation console. The operator plans various scan conditions including the scan range (scan start position and end position) while viewing the scout image (for example, see Patent Document 1).
[0007]
[Patent Document 1]
JP-A-7-227391
[Problems to be solved by the invention]
However, there is a demand that the scan range (scan start position and end position) is not set based on the scout image, but is determined visually with the actual subject in front. Further, if the scan range can be set without performing the scout scan, the exposure amount can be reduced by that much.
[0009]
Therefore, the present invention provides a scan range setting device and an X-ray CT system and a control method thereof that do not need to perform a scout scan, thereby enabling a scan range to be set and confirmed on an actual subject, and The aim is to realize a reduction in the amount.
[0010]
[Means for Solving the Problems]
One aspect of the present invention relates to a scan range setting device in an X-ray CT system for setting a scan range of a subject placed on a table and a control method thereof. The scan range setting device includes a light source unit including first and second light emitters arranged at predetermined intervals along a transport direction of the table, and a first light source unit that adjusts a position of the light source unit in the transport direction of the table. And second adjusting means for adjusting the optical axis of the second light emitting device in the transport direction by rotating the second light emitting device. Then, by performing the adjustment by the first adjusting unit, the position information of one end of the scan range is input with the light emitting position of the first projector, and the adjustment by the second adjusting unit is performed, The position information of the other end of the scan range is input based on the projection position of the second projector.
[0011]
According to another aspect of the present invention, there is provided a table for mounting an object, a gantry apparatus for performing a scan for collecting projection data by irradiating the object mounted on the table with X-rays, and a gantry. The present invention relates to an X-ray CT system including: an operation console that outputs information related to scanning to an apparatus and receives projection data from the gantry apparatus to reconstruct an X-ray tomographic image. The X-ray CT system further includes a light source unit including first and second light emitters arranged at a predetermined interval along a transport direction of the table, and a light source unit that adjusts a position of the light source unit in the transport direction of the table. A first adjusting means and a second adjusting means for adjusting the optical axis of the second projector in the transport direction by rotating the second projector. Then, by performing the adjustment by the first adjusting unit, the position information of one end of the scan range is input with the light emitting position of the first projector, and the adjustment by the second adjusting unit is performed, The position information of the other end of the scan range is input based on the projection position of the second projector, and the respective position information input by the first and second input means is output to the operation console.
[0012]
Further, another aspect of the present invention includes first and second light emitters arranged at predetermined intervals along a transport direction of the table to set a scan range of an object placed on the table. A light source unit, first adjusting means for adjusting a position of the light source unit in the transport direction, and an optical axis of the second projector in the transport direction by rotating the second projector. A program for controlling a scan range setting device in an X-ray CT system including: a second adjustment unit. This program includes a first input step of inputting position information of one end of a scan range with a light emitting position of the first light emitter by performing adjustment by the first adjusting means, By performing the adjustment, a second input step of inputting the position information of the other end of the scan range with the projection position of the second projector is executed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a diagram illustrating an X-ray CT system according to the embodiment.
[0015]
In the figure, reference numeral 100 denotes a gantry, which is shown in a cross-section for easy understanding of the structure. A transport device 200 transports a table 201 on which a subject (patient) is placed to the gantry 100. In this specification, this transport direction is referred to as a z-axis direction. Reference numeral 300 denotes a scan range setting device for setting a scan range. An operation console 400 has a function of communicating with the gantry 100, the table device 200, and the scan range setting device 300, and a function of receiving projection data transferred from the gantry 100 and reconstructing an X-ray tomographic image. Having.
[0016]
As is well known, the gantry 100 includes an X-ray tube 101 that is a source of X-rays, an X-ray detection unit 102 including an X-ray detection element group that detects X-rays generated from the X-ray tube 101, and A rotator 103 that accommodates the X-ray tube 101 and the X-ray detection unit 102 and rotates around a cavity is provided. Of course, the gantry 100 also includes other components for functioning as a gantry, but these are not directly related to the present invention, and a description thereof will be omitted.
[0017]
When an actual scan is performed, the subject is inserted into the cavity of the gantry 100 by the table device 200, and the X-ray tube 101 is driven while the rotating body 103 is rotated. X-rays that have passed through are detected. The transmitted X-ray data at each rotation angle of the rotating body 103 is transferred to the operation console 400 as projection data, and the operation console 400 arithmetically reconstructs an X-ray tomographic image.
[0018]
The scan range setting device 300 is located right above the table 201, and is attached to the ceiling of the inspection room in the figure. This apparatus may be attached to the gantry 100 or another dedicated support column, instead of being attached to the ceiling, as long as the apparatus is placed facing the table 201 across the subject placed on the table 201.
[0019]
The scan range setting device 300 has a configuration in which a light source unit 301 that generates a laser beam toward the table 201 is slidably mounted along a guide rail 305 arranged in the z-axis direction. The light source unit 301 includes a projector A that generates a laser beam for setting a scan start position and a projector B that generates a laser beam for setting a scan end position. Here, the light projector B is provided so as to be rotatable along the z-axis with the rotation axis C as a fulcrum. By controlling the rotation angle, the optical axis in the z-axis direction can be adjusted.
[0020]
Reference numeral 350 denotes an operation panel for performing a scan range setting operation using the scan range setting device 300. The operation panel 350 is provided on the side surface of the transfer device 200 as illustrated, but may be provided on the gantry 100.
[0021]
The configuration of the X-ray CT system in the embodiment is generally as described above. Next, the structure of the scan range setting device 300 will be described in more detail with reference to FIG.
[0022]
FIG. 2 is a block diagram of the scan range setting device 300. In the figure, reference numeral 1 denotes a CPU that controls the entire scan range setting device 300, 2 denotes a ROM that stores a control program for implementing a scan range setting process described later, and 3 denotes a RAM that is used as a work area. is there. Reference numeral 4 denotes an interface (I / F) for communicating with the operation console 400.
[0023]
Reference numeral 5 denotes a switch for switching ON / OFF of the light source unit 301. Reference numeral 6 denotes a motor for moving the light source unit 301 along the guide rail 305 (that is, along the z-axis direction). The motor 6 is driven by a motor driver 7 operated under the control of the CPU 1. Reference numeral 8 denotes a motor for rotating the projector B about the rotation axis C. The motor 8 is driven by a motor driver 9 operated under the control of the CPU 1. It should be noted that the structures of the motors 6 and 8 themselves and the structures themselves for moving the motors 6 and 8 can be known structures, and thus detailed description thereof is omitted.
[0024]
Although not shown in FIG. 1, the light source unit 301 has a built-in light receiver 302 for receiving the reflected light of the laser light emitted from the light projector A.
[0025]
Reference numeral 10 denotes a position sensor for detecting the z-axis position of the light source unit 301. The position detection by the position sensor 10 can be, for example, as shown in FIG. That is, a uniform resistance plate 306 is arranged along the inside of the guide rail 305, one end of which is grounded, and the voltage v is applied to the other end. Then, the detector in the position sensor 10 is brought into contact with the resistance plate 306. Since the voltage at the contact position is a partial pressure corresponding to the position, the position of the light source unit 301 can be detected by detecting the potential. The detected potential may be converted into digital data by the A / D converter 307.
[0026]
The above example is one example, and any other method may be used. For example, a linear encoder, a rotary encoder, or the like used in a printer or the like may be used to detect the z-axis position.
[0027]
The operation panel 350 is also connected to the CPU 1. FIG. 4 shows an example of the operation panel 350. In the figure, reference numeral 41 denotes a switch for switching ON / OFF of the light source unit 301. The CPU 1 controls the switch 5 according to the state of the button 41.
[0028]
Reference numeral 42 denotes a button for instructing the light source unit 301 to move to the left, and reference numeral 43 denotes a button for instructing the light source unit 301 to move to the right. While the move button 42 or 43 is pressed, the CPU 1 issues a command to the motor driver 7 to move in the corresponding direction, moves the light source unit 301 by driving the motor 6, and when the button is released, the CPU 1 The movement will be stopped.
[0029]
Reference numeral 52 denotes a button for instructing the projector B to rotate to the left, and reference numeral 53 denotes a button for instructing the projector B to rotate to the right. While the instruction button 52 or 53 is pressed, the CPU 1 issues a command to the motor driver 9 to rotate in the corresponding direction to change the direction of the projector B by driving the motor 8. Stops the change operation.
[0030]
Buttons 44 and 45 are used to set a scan start position and a scan end position, respectively. When these buttons are pressed, the CPU 1 stores corresponding position information at that time in the RAM 3. Reference numeral 46 denotes a button for confirming the setting of the scan start position and the end position. When the button 46 is pressed, the CPU 1 transmits the information of the scan start position and the end position stored in the RAM 3 via the interface 4. The data is output to the operation console 400.
[0031]
Hereinafter, the operation of the scan range setting device 300 in the embodiment will be described with reference to the flowchart of FIG. A program corresponding to this flowchart is included in the control program stored in the ROM 2 and is executed by the CPU 1.
[0032]
First, with the subject lying on the table 201 and the table 201 positioned at a predetermined home position, the light source unit 301 is turned on based on the switching operation of the switch 41 of the operation panel 350 as step S1. As a result, laser beams are generated from the projectors A and B, respectively, and are irradiated on the subject. Next, in step S2, the distance from the light source unit 301 to the subject is measured. This can be measured, for example, by measuring the time difference between when the projector A irradiates the laser beam and when the light receiver 302 receives the reflected light.
[0033]
Next, in step S3, the position of the light source unit 301 in the z-axis direction is adjusted based on the movement instruction from the button 42 or 43. The operator performs a moving operation so that the irradiation light from the projector A matches the desired scan start position, and then presses the button 44. By doing so, the scan start position, which is one end of the scan range, is input to the RAM 3 based on the output of the position sensor 10. That is, the position information of one end of the scan range is input with the light projection position of the light projector A.
[0034]
Next, in step S4, the direction of the light projector B is controlled based on an instruction from the button 52 or 53, whereby the optical axis of the light projector B in the z-axis direction is adjusted, and the irradiation position of the laser beam on the subject is changed. Adjusted. The operator performs an adjustment operation so that the irradiation light from the projector B matches the desired scan end position, and then presses the button 45. Then, the scan end position, which is the other end of the scan range, is calculated based on the distance to the subject measured in step S2 and the adjustment angle of the projector B, and is set in the RAM 3. That is, the position information of the other end of the scan range is input with the light projection position of the light projector B.
[0035]
When the OK button 46 is pressed at step S5, the scan start position and the end position set in the RAM 3 are output to the operation console 400.
[0036]
Next, the operator operates the operation console 400 provided in another room. The operation processing procedure in the operation console 400 is substantially as shown in the flowchart of FIG.
[0037]
First, in step S11, the data of the scan start position and the scan end position transferred in step S5 is input.
[0038]
Next, in step S12, a scan plan is performed. Conventionally, it was necessary to set the scan start position and the end position in this scan planning process. However, since these have already been input in step S11, there is no need to set them. Therefore, in this step, other scan conditions, such as the slice thickness, the current value applied to the X-ray tube 101, and the parameters of the image reconstruction performed in step S15 described later are input.
[0039]
When the scan plan is completed, a scan instruction is sent to the gantry 100 by using a predetermined operation of the mouse, the keyboard, or the like by the operator as a trigger in step S13. The gantry 100 performs scans in response thereto, and transfers the projection data collected in each scan to the operation console 400. The operation console 400 inputs the projection data in step S14. Thereafter, in step S15, reconstruction processing of an X-ray tomographic image is performed based on the projection data, and output (display or print) processing is performed in step S16.
[0040]
According to the embodiment described above, conventionally, a scout scan is performed in order to make a scan plan, and a scan range (scan start position and end position) is determined based on a scout image obtained therefrom. The scan range can be set visually before the actual subject. By doing so, it is not necessary to perform a scout scan, so that the amount of exposure can be reduced accordingly.
[0041]
In the above-described embodiment, in step S4, the operator performs the adjustment operation so that the irradiation light from the projector B matches the desired scan end position. However, the operation console 400 sets the width of the scan range in advance. If the setting can be made, the scan range setting device 300 can also input the setting information from the operation console 400 and automatically adjust the angle of the projector B based on the information. A specific example of the operation of the scan range setting device 300 is shown in the flowchart of FIG.
[0042]
In this flowchart, steps S1, S2, and S3 respectively perform the same processing as steps S1, S2, and S3 in the flowchart of FIG. 5, but perform steps S6 and S7 instead of steps S4 and S5. That is, in step S6, the width information of the preset scan range is input from the operation console 400. Then, in step S7, the angle of the projector B is adjusted based on the distance to the subject measured in step S2 and the width information of the scan range input in step S6. As a result, the desired scan end position is irradiated with the laser beam.
[0043]
It should be noted that most of the operations in the above embodiment are based on the control program in the scan range setting device 300. Therefore, the program itself for realizing the function processing of the present invention and the recording medium itself storing the program also realize the present invention. That is, the claims of the present invention may include the program itself for realizing the functional processing of the present invention and a computer-readable recording medium storing the program.
[0044]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a scan range setting apparatus, an X-ray CT system, and a control method thereof that do not need to perform a scout scan, thereby setting a scan range on an actual subject. In addition to enabling confirmation, it is possible to reduce the exposure dose.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of an X-ray CT system according to an embodiment.
FIG. 2 is a block diagram of a scan range setting device according to the embodiment.
FIG. 3 is a diagram illustrating an example of a unit that detects a z-axis position of the projector according to the embodiment.
FIG. 4 is a diagram illustrating an example of an operation panel according to the embodiment.
FIG. 5 is a flowchart illustrating an operation procedure of the scan range setting device according to the embodiment.
FIG. 6 is a flowchart illustrating an operation procedure of the operation console according to the embodiment.
FIG. 7 is a flowchart illustrating another operation procedure of the scan range setting device according to the embodiment.

Claims (8)

A scan range setting device in an X-ray CT system for setting a scan range of a subject mounted on a table,
A light source unit including first and second light projectors arranged at predetermined intervals along the direction of transport of the table;
First adjusting means for adjusting the position of the light source unit in the transport direction;
A second adjusting unit that adjusts an optical axis of the second projector in the transport direction by rotating the second projector;
A first input unit for inputting position information of one end of a scan range with a light projection position of the first light projector by performing adjustment by the first adjustment unit;
A second input unit for inputting position information of the other end of the scan range with the light projection position of the second light projector by performing adjustment by the second adjustment unit;
A scan range setting device, comprising: Furthermore, a measuring means for measuring the distance to the subject is provided,
2. The scan according to claim 1, wherein the second input unit calculates the position information of the other end based on the measured distance to the subject and an adjustment angle by the second adjustment unit. 3. Range setting device. A light source unit including first and second projectors arranged at predetermined intervals along a transport direction of the table to set a scan range of an object placed on the table; X comprising: first adjusting means for adjusting the position in the direction; and second adjusting means for adjusting the optical axis of the second light emitting device in the transport direction by rotating the second light emitting device. A control method of a scan range setting device in a line CT system,
A first input step of inputting position information of one end of a scan range with a light projection position of the first light projector by performing adjustment by the first adjusting means;
A second input step of inputting position information of the other end of the scan range with the light projection position of the second light projector by performing adjustment by the second adjustment means;
A method for controlling a scan range setting device, comprising: A table for mounting a subject, a gantry device for performing a scan for collecting projection data by irradiating the subject mounted on the table with X-rays, and information related to scanning for the gantry device And an operation console for receiving the projection data from the gantry device and reconstructing an X-ray tomographic image, and
A light source unit including first and second light projectors arranged at predetermined intervals along the direction of transport of the table;
First adjusting means for adjusting the position of the light source unit in the transport direction;
A second adjusting unit that adjusts an optical axis of the second projector in the transport direction by rotating the second projector;
A first input unit for inputting position information of one end of a scan range with a light projection position of the first light projector by performing adjustment by the first adjustment unit;
A second input unit for inputting position information of the other end of the scan range with the light projection position of the second light projector by performing adjustment by the second adjustment unit;
Output means for outputting the respective position information input by the first and second input means to the operation console;
An X-ray CT system comprising: Furthermore, a measuring means for measuring the distance to the subject is provided,
5. The X according to claim 4, wherein the second input unit calculates the position information of the other end based on the measured distance to the subject and an adjustment angle by the second adjustment unit. 6. Line CT system. A table for mounting the subject, a gantry device for performing a scan for collecting projection data by irradiating the subject mounted on the table with X-rays, and information relating to the scan to the gantry device. An operation console for outputting and receiving projection data from the gantry apparatus to reconstruct an X-ray tomographic image, and a light source unit including first and second projectors arranged at a predetermined interval along a transport direction of the table A first adjusting means for adjusting a position of the light source unit in the transport direction; and a second adjusting means for adjusting an optical axis of the second projector in the transport direction by rotating the second projector. Control means for controlling an X-ray CT system comprising:
A first input step of inputting position information of one end of a scan range with a light projection position of the first light projector by performing adjustment by the first adjusting means;
A second input step of inputting position information of the other end of the scan range with the light projection position of the second light projector by performing adjustment by the second adjustment means;
An output step of outputting respective position information input by the first and second input means to the operation console;
A control method for an X-ray CT system, comprising: Furthermore, it has a measurement step of measuring the distance to the subject,
7. The X according to claim 6, wherein the second input step calculates the position information of the other end based on the measured distance to the subject and the adjustment angle by the second adjustment unit. 8. Control method of X-ray CT system. A scan range setting device in an X-ray CT system for setting a scan range of a subject mounted on a table,
Providing a projector that emits visible light to determine the position of at least one end of the scan range,
The scan range setting device, wherein the light projector is provided rotatably along a transport direction of the table, and an irradiation position of visible light to a subject is adjusted by controlling a rotation angle thereof. .

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