JP3405779B2 - Positioning device for radiation irradiation in radiation therapy - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation irradiation positioning apparatus for performing radiation therapy. 2. Description of the Related Art Radiation such as an X-ray beam is sometimes used for treatment of cancer or tumor. What is important in the treatment using this radiation is to concentrate the radiation dose to be applied only to the lesion, and to reduce the irradiation to surrounding healthy tissues as much as possible. Therefore, prior to performing radiation therapy, the radiation irradiation direction and the irradiation range are determined by simulation using a radiation irradiation positioning device that emits a smaller amount of radiation than an actual radiation treatment machine.
FIG. 3 shows an example of a positioning device for this radiation irradiation. FIG.
In the figure, reference numeral 1 denotes a fixed gantry, and the fixed gantry 1 is provided with a rotary gantry 2, and the rotary gantry 2 is provided with an X-ray tube 6 via a support member 4. X-ray tube 6
Is provided with a wire collimator 7 serving as a diaphragm for reducing the irradiation X-ray dose. In addition, an image intensifier (hereinafter, referred to as I · I) 8 provided at a tip end of a fixing member 5 provided on the rotating gantry 2 is provided so as to always face the X-ray tube 6. A camera unit including an optical system, a CCD, and the like is provided below I / I8 so that a fluoroscopic image can be obtained. This perspective image is displayed on display means such as a monitor. On the other hand, a patient P is placed on the bed 3 to position the radiation irradiation. The patient P lies on the line connecting the X-ray tube 6 and I · I8 with the affected part being arranged. The direction of radiation irradiation is determined by the angle of the gantry 2. Therefore, the determination of the radiation field, which is the condition of the remaining radiation, is performed by the wire collimator 7 corresponding to the aperture of the actual radiation therapy machine.
Done by [0003] A specific simulation method will be described below. 1) The patient P is set up on the bed 3 at a predetermined position. 2) The rotating gantry 2 is moved in the irradiation direction to determine the radiation irradiation direction. 3) X-rays are irradiated from the X-ray tube 6 to the affected part of the patient P. , I · I8
The fluoroscopic image obtained through such as is displayed on the monitor. The display screen at this time is shown in FIG. The hatched portion in the figure is the lesion portion, and the location of the * mark indicates the center position of the X-ray beam. 4) As shown in FIG. 4 (b), the center of the lesion portion is the X-ray beam. The bed 3 is moved back and forth and right and left so as to be located at the position indicated by the mark * which is the center position. 5) As shown in FIG. 4 (c), the radiation field is determined by setting the wire collimator 7 so as to be adjacent to the lesion of FIG. 4 (b). 6) A satisfactory irradiation field is obtained by the above 5). If not, 4) to 5)
Repeat the operation. [0004] When the radiation irradiation conditions are set by the simulation in this manner, the apparatus returns to the actual radiotherapy machine, performs film photography again under the set radiation irradiation conditions, and executes the set radiation irradiation. If conditions are acceptable, actual radiation therapy is performed under these conditions. However, in such a conventional radiation irradiation positioning apparatus in radiation treatment, it is not possible to know where the center of the lesion is located.
He had found the center of the lesion by trial and error. Therefore, in addition to making it difficult to match the center of the lesion and the center position of the X-ray beam, it is necessary to move the wire collimator to match the shape of the lesion by matching the center position,
It took time and effort to set the conditions for treatment. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. It is an object of the present invention to set a wire collimator according to the shape of a desired site such as a lesion, and to set the center of the desired site and the center of the X-ray beam. It is an object of the present invention to provide a positioning apparatus for radiation irradiation in radiation therapy, which can automatically set conditions for matching the conditions. [0007] In order to achieve the above object, the present invention provides a bed on which a patient is placed, and a fluoroscopic image obtained by irradiating the patient placed on the bed with X-rays. Display means for displaying, a wire collimator indicating a position corresponding to an aperture for restricting an X-ray irradiation field on a fluoroscopic image displayed on the display means, and a desired portion on a fluoroscopic image displayed on the display means. Means for setting the wire collimator so as to surround the position of the wire collimator at a coordinate centered on the center of the X-ray beam irradiated to the patient; Means for calculating the center position of the irradiation field surrounded by the wire collimator, and means for calculating the amount of movement of the bed to make the calculated center position coincide with the center of the X-ray beam And characterized in that: According to the above arrangement, if the wire collimator is set so as to surround a desired portion such as a lesion based on the displayed fluoroscopic image, the center of the desired portion is irradiated from the position of the wire collimator. The moving condition of the bed for making the center of the X-ray beam coincide with the center can be automatically calculated. as a result,
The time required for setting the conditions for treatment can be reduced, and the accuracy of the irradiation field can be improved. In addition, since it is possible to omit the labor of repeating trial and error in order to match the center of the desired part with the center of the X-ray beam, the amount of X-ray irradiation to the patient can be reduced, and the burden on the operator can be reduced. Can be. Embodiments of the present invention will be described below with reference to the drawings. Note that the same components as those described in the related art are denoted by the same reference numerals. FIG. 1 is a block diagram showing an example of a positioning apparatus for radiation irradiation according to the present invention. The basic configuration is the same as that of FIG. FIG. 1A is a schematic configuration diagram thereof, and FIG. 1B is a diagram for explaining a characteristic portion of the present invention. FIG. 3 and FIG. 1 (a)
In the above, the fixed gantry 1 is provided with a rotary gantry 2, and the rotary gantry 2 is provided with an X-ray tube 6 via a support member 4. A wire collimator 7 serving as an aperture is provided.
Further, an image intensifier (hereinafter, referred to as I / I) 8 provided at a distal end portion of a fixing member 5 provided on the rotating gantry 2 is provided so as to always face the X-ray tube 6. A camera section 10 including an optical system 9 and a CCD is provided below the I / I 8 so that a fluoroscopic image can be obtained. This perspective image is displayed on a monitor 12 or the like via the system controller 11. On the other hand, a patient P is placed on the bed 3, and the patient P is connected to the X-ray tube 6 and the I · I
Lying on the line connecting 8 with the affected part arranged. The system controller 11 controls the entire system including the CPU, and is also connected to the console 13.
Further, the application of voltage to the X-ray tube 6 is controlled by a high voltage generator (not shown) via the X-ray controller 14. In FIG. 1B, an operation unit 15 provided on a console 13 or the like is connected to a calculation unit 17 via an input / output unit I / O 16. The input / output unit I / O 16 is also connected to a wire collimator position detector 18, a bed position detector 19, a wire collimator drive unit 20, and a bed drive unit 21. Therefore, the input / output unit I / O 16 and the arithmetic unit 17
1A is provided in the system controller 11 in FIG. 1A, and controls the drive for detecting and moving the position of the wire collimator 7 under the control of the system controller 11. 3 for controlling position detection and driving for front / rear / left / right movement. The system controller 11 also has a memory such as a disk for storing and storing various calculated data. An operation for determining a radiation irradiation position, an irradiation field (irradiation range), and the like by the radiation irradiation positioning apparatus for simulation having the above configuration will be described below.
The procedure will be described. 1) The patient P is set up at a predetermined position on the bed 3) 2) The rotating gantry 2 is moved in the irradiation direction to determine the irradiation direction of the patient 3) X-rays from the X-ray tube 6 Irradiate the affected area, I ・ I8
The fluoroscopic image obtained through such as is displayed on the monitor 12. FIG. 2A shows only the lesion portion on the display screen at this time in an emphasized manner. The hatched portion in the figure is the lesion portion, and the point O where the broken line intersects indicates the center position of the X-ray beam. The horizontal axis passing through this point O is the x axis, and the vertical axis is the y axis.
Consider a coordinate system as an axis. 4) The operation section 15 creates an irradiation field using the wire collimator CX1, CX2, CY1, and CY2 by the wire collimator operating means so as to surround the lesion. In FIG. 2A, a rectangular area surrounded by a solid line is the created irradiation field. 5) The operation unit 15 instructs the center of the lesion to match the center position of the X-ray beam. Therefore, the operation unit 17
Detects the position of the wire collimator 7 via the input / output unit I / O 16 and obtains the coordinates of the wire collimators CX1, CX2, CY1, CY2. From the coordinates of the obtained wire collimators CX1, CX2, CY1, CY2, it is calculated how much the bed should be moved from the current position. The calculation formula is as follows: TX = (CX2 + CX1) / 2 TY = (CY2 + CY1) / 2 6) Based on the movement amount calculated in this manner, the couch is automatically moved back and forth and left and right. Then, as shown in FIG. 2 (b), the center of the lesion and the center position of the X-ray beam are matched. Is set to be The opening of the wire collimator is calculated by the following formula: CX = (CX2-CX1) / 2 CY = (CY2-CY1) / 2 8) Fig. 2 (c)
The irradiation field is set as shown in FIG. The portion indicated by the symbol a in the figure is the opening in the x direction, and the symbol b is the opening in the y direction. The irradiation direction and irradiation field set by the above-described simulation are stored and stored in a memory such as a disk, and are returned to the actual radiation therapy machine and used for confirmation work. As described above, according to the present invention, if a wire collimator is set so as to surround a desired site such as a lesion based on a displayed fluoroscopic image, the position of the wire collimator can be increased. It is possible to automatically calculate the moving condition of the bed for making the center of the desired part coincide with the center of the irradiated X-ray beam. As a result, the time required for setting conditions for treatment can be reduced, and the accuracy of the irradiation field can be improved. In addition, since it is possible to eliminate the need for trial and error to match the center of the desired part with the center of the X-ray beam, the amount of X-ray irradiation to the patient can be reduced, and the burden on the operator can be reduced. Can be.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an example of a radiation irradiation positioning apparatus according to the present invention. FIG. 2 is a diagram for explaining a procedure for setting an irradiation field. FIG. 3 is a configuration diagram showing an example of a radiation irradiation positioning device. FIG. 4 is a diagram for explaining a conventional procedure for setting an irradiation field. [Description of Signs] 1 Fixed base 2 Rotary base 3 Bed 4 Support member 5 Fixed member 6 X-ray tube 7 Wire collimator 8 Image intensifier (II) 9 Optical system 10 Camera unit 11 System controller 12 Monitor 13 Console 14 X-ray controller 15 Operation unit 16 Input / output unit I / O 17 Operation unit 18 Wire collimator position detector 19 Bed position detector 20 Wire collimator drive unit 21 Bed drive unit

Claims (1)

(57) Claims 1. A bed on which a patient is placed, display means for displaying a fluoroscopic image of X-rays radiated on the patient placed on the bed, and the display means A wire collimator indicating a position corresponding to an aperture that limits an X-ray irradiation field on the displayed perspective image, and the wire collimator is set so as to surround a desired portion on the perspective image displayed on the display unit. Means, determine the position of the set wire collimator in coordinates with the center of the X-ray beam irradiated to the patient as the center point, based on the determined wire collimator position, the center position of the irradiation field surrounded by the wire collimator Means for calculating, and a means for calculating a moving condition of the bed to make the calculated center position coincide with the center of the X-ray beam. Positioning device for radiation irradiation.