JPH0626607B2 - Radiation irradiation control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a radiation irradiation control device,
In particular, the present invention relates to a radiation irradiation control device capable of arbitrarily adjusting an irradiation field (irradiation region) of radiation irradiated to a patient and an output dose rate thereof as needed.

[Prior Art] FIG. 3 is a block diagram showing a conventional device of this type. In FIG. 3, (1a) and (1b) are collimator blocks for adjusting the irradiation field (irradiation area) of the radiation radiated to the patient, which are arranged so as to face each other across the patient. Has been done. (2a), (2b) are motors for driving the collimator blocks (1a), (1b), respectively, and these motors (2a),
(2b) is driven by a required drive circuit (5). (3a) and (3b) are potentiometers, which are adapted to work with the collimator blocks (1a) and (1b), respectively. Further, (4a) and (4b) are amplifiers, which are provided corresponding to the potentiometers (3a) and (3b), respectively, and are connected to the A / D converter (6). (7) is an appropriate display, which is used to display the current position of the collimator blocks (1a) and (1b). The drive circuit (5), the A / D converter (6) and the display (7) are all connected to the sequence circuit (8). The sequence circuit (8) is provided with a drive operation switch (81) for the motors (2a) and (2b), and a collimator / driver provided via the A / D converter (6). Block (1a),
A required motor drive signal is issued depending on the current position in (1b). In addition, the patient (1
0) is laid, and for the affected part of this patient (10),
It is designed to emit radiation from the side of the point. Although not shown in FIG. 3, two pairs of collimator blocks are provided, and each pair has a patient (10).
With respect to each other.

It should be noted that this type of radiation irradiation control device normally operates in a pulse drive system, and is provided with means necessary for this purpose. That is, a high-voltage pulse power supply (not shown) is operated based on a reference trigger from the radiation generation unit (20) to generate a pulse width of 1 to 10 μsec and a repetition frequency of 10
A 50 pps pulsed radiation is generated. In addition, a pulse signal with a required repetition frequency is generated as a reference signal from the pulse generator (21), and the repetition frequency for actual pulse drive is set by the volume (22) provided in the subsequent stage. It

FIG. 4 is an exemplary diagram for explaining the operation of the conventional example. In FIG. 4, FIG. 4 (a) is an explanatory diagram when there is no auxiliary block, and FIG. 4 (b) is an explanatory diagram when there is an auxiliary block. Further, in FIG. 4, (1a), (1b) and (1c), (1d) are collimator blocks respectively pointing to each other. Then, (41) is a suppression unit that should not be irradiated with radiation, (42) is an affected part of the patient (10) to be irradiated with radiation, (43) is the suppression unit (41)
It is an auxiliary block for shielding against.

Next, the operation of the above-mentioned conventional example will be described with reference to FIGS. 3 and 4. In this type of device, a shielding collimator block made of a certain predetermined heavy metal is arranged between the radiation source and the irradiation unit. And by changing the position appropriately with a motor,
A necessary irradiation field (irradiation region) is formed, and appropriate radiation treatment for the patient is performed. Now
In order to form a required irradiation field for the affected part (42) of the patient (10), the corresponding motor is driven to set the distance between one pair (1a) and (1b) of the collimator block to L, The other pair
It is assumed that the distance between (1c) and (1d) is W. At this time, the irradiation field for irradiating the patient (10) is L
Although it occupies a rectangular area of xW, it contains not only the affected area (42) to which the radiation should be applied, but also the inhibition section (41) that should not be irradiated. There is. Therefore, the auxiliary block (43) having a required shape is provided in the deterring part (41) so that the deterring part (41) is not irradiated with radiation.
It will be placed so as to cover (41). The auxiliary block (43) is also made of a suitable heavy metal. After performing such a coating process, radiation treatment for the affected area (42) is performed.

By the way, the shape and position of the affected area as described above are various, and for this reason, it is necessary to readjust the shape and the location of the auxiliary block to be used each time the patient to be treated changes. It is also necessary to record the shape in the patient's chart and to mark the projected images of the collimator block and the auxiliary block on the surface of the patient's body prior to the irradiation treatment.

[Problems to be Solved by the Invention] A conventional radiation irradiation control device is configured and operated as described above, and various shapes are required to form an irregular irradiation field other than a rectangular shape. It is necessary to prepare a large number of auxiliary blocks that it has, and there is a problem that it takes time to select and dispose the irradiation treatment when actually performing irradiation treatment.

The present invention has been made to solve the above problems, and is capable of performing irradiation of an irregular irradiation field without an auxiliary block and arranging a patient for irradiation treatment. Can be done accurately in a short time,
As a result, it is an object of the present invention to obtain a radiation irradiation control device capable of performing safe treatment.

[Means for Solving Problems] A radiation irradiation control device according to the present invention comprises a moving means for moving a treatment table for a patient in a predetermined direction, a detection means for detecting a movement distance of the treatment table, and An irradiation field defining means for defining an irradiation field for the affected area of the patient, an irradiation field adjusting means for adjusting the irradiation field according to the movement of the treatment table, and a dose rate of radiation irradiated to the affected area of the patient. It comprises a prescribed dose rate regulating means and an input means for presetting the moving distance of the treatment table and the value of the radiation dose.

[Operation] In the present invention, the irradiation field of the radiation and the output dose rate to the affected area of the patient appropriately change in response to the movement of the treatment table for the patient.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a block diagram showing a radiation irradiation control apparatus according to an embodiment of the present invention, and those designated by the same reference numerals as those in FIG. 3 are the same or corresponding ones.
In FIG. 1, one pair of collimator blocks
The other pair of collimator blocks is located above (1a) and (1b).
(1c) and (1d) are attached. The motors (2a) and (2b) are connected to the first I / O port (11) via the first drive circuit (5). The treatment table (9) is provided with a treatment table motor (12), which is driven by the second drive circuit (14) to move the treatment table (9) in the front-back direction, for example. Is. Further, a rotary encoder (13) is attached to the treatment table motor (12), and the forward / backward movement position of the treatment table (9) can be detected by an up / down type counter (15). Is being done. And
The second drive circuit (14) and the counter (15) have a second I
It is connected to the / O port (16). A keyboard input unit (19) is for inputting necessary treatment conditions such as the radiation dose to the affected area of the patient (10), the movement stroke of the treatment table (9), and the like. Reference numeral (23) is a D / A converter that converts the digital signal output from the CPU (17) into a corresponding analog signal and sets the repetition frequency of the pulse signal generated in the pulse generator (21). It is for doing. In addition, the CPU (17) controls the overall operation of the device, and based on various treatment conditions given from the keyboard input unit (19), the treatment table (9) is moved once so that the affected part of the patient (10) is affected. The calculation of the dose of radiation applied to the body, collection of various data, processing, etc. are performed. The memory (18) includes a RAM section and a ROM section, the former is used to store various data, and the latter is used to store software necessary for the CPU (17). Is what is used. The A / D converter (6), the first and second I / O ports (11), (16) are the CPU
(17) and the memory (18) are connected to each other via an appropriate bus line.

FIG. 2 is an exemplary diagram for explaining the operation of the above embodiment. In FIG. 2, FIG. 2 (a) is an exemplification diagram at the time when irradiation is started, and FIGS. 2 (b) and 2 (c) are times when irradiation is being performed. FIG. In FIG. 2, the same reference numerals as those in FIG. 4 denote the same or corresponding parts.

Next, the operation of the above embodiment will be described with reference to FIGS. 1 and 2. Now, when the irradiation is started, one pair of collimator blocks (1a), (1b)
Is W1 and the other pair above it (1c), (1d)
The interval of is assumed to be set to L0. The other pair (1c), (1d) is stationary, and its interval L
0 is assumed to be fixed. Here, when the irradiation of radiation is started, the treatment table (9) on which the patient (10) lies is driven, for example, by the motor for the treatment table (12), and, for example, the head of the patient (10). To start moving. Looking at this in FIG. 2, as shown by the arrow, it moves from the lower side to the upper side in the drawing. As a result, the affected part (42) of the patient (10) also moves in the above direction. The moving distance can be detected by counting the output pulse from the rotary encoder (13) connected to the treatment table motor (12) with the counter (15). The result of this detection is the second I
It is taken into the memory (18) through the / O port (16). Then, after a lapse of a predetermined time, a change in the position and lateral width of the affected area (42) is detected, and one pair (1a), (1b) of the collimator block is set to W2 accordingly. Furthermore,
After a lapse of a predetermined time, a change in the position and width of the affected part (42) is detected again, and the interval is set to W3 accordingly.

Here, the setting of the dose rate of the radiation applied to the affected area (42) of the patient (10) will be described. First, the treatment table (9)
The dose of radiation applied to the affected part (42) with one movement of is expressed by the following equation (1).

D _A = D _R L / S (1) However, L: stroke of the treatment table (mm) S: movement speed of the treatment table (mm / s) D _R : output radiation from the radiation source Dose rate (cGy / s) D _A : Radiation dose to the affected area (cGy) where L, S and DA are input from the keyboard input unit (19), and based on these values, CP
The following equation (2) is calculated by U (17).

D _R = D _A S / L (2) The dose rate of the output radiation in the apparatus of this embodiment is proportional to the repetition frequency of the above-mentioned pulsed radiation, and Are stored in memory (18) in data table format. Then, in the CPU (17), based on D _R calculated previously, read the repetition frequency of the corresponding from the data table in the memory (18), D /
Required setting for the pulse generator (21) is automatically performed via the A converter (23). As a result, the dose rate of the radiation output from the radiation source is automatically controlled. Thus, a single movement of the treatment table irradiates the affected area with a predetermined dose of radiation with good accuracy.

As described above, control of the irradiation field that matches the affected area, detection of the irradiation field width, movement of the treatment table and detection of its current position, calculation of output dose rate of radiation, setting, required processing, etc. It can be executed by the CPU (17) based on the software corresponding to. Thus, the treatment table is moved in a predetermined direction while continuing the required irradiation treatment for the patient, and one pair (1a), (1b) of the collimator block is moved according to the change in the current position of the affected area and its width. By changing the shape, arbitrary and desired irregular irradiation can be performed accurately and safely in a short time.

Although the position of the collimator block is detected by the potentiometer in the above embodiment, the invention is not limited to this, and a rotary encoder can be used here as well. Then, in this case, the A / D converter becomes unnecessary.

In the above embodiment, if the rotary encoder used is an absolute type encoder, its output can be directly connected to the second I / O port. However, when the rotary encoder is of the incremental type, the counter is still required. Note that such a rotary encoder can be replaced with a potentiometer.

Furthermore, although it has been described that the treatment table moves only in one direction (for example, the front-back direction), the present invention is not limited to this.
It is also possible to move in the horizontal direction or the vertical direction.

[Advantages of the Invention] As described above, the radiation irradiation control device according to the present invention includes a moving unit that moves the patient treatment table in a predetermined direction, and a detection unit that detects the movement distance of the treatment table. An irradiation field defining means for defining an irradiation field for the affected area of the patient, an irradiation field adjusting means for adjusting the irradiation field according to movement of the treatment table, and a dose of radiation to be applied to the affected area of the patient. The dose rate defining means for defining the rate and the input means for presetting the moving distance of the treatment table and the value of the dose of radiation are provided, and any desired irregular irradiation can be performed without using an auxiliary block. Since the field can be formed, the patient can be accurately placed for irradiation treatment in a short time, and as a result, safe treatment can be achieved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a radiation irradiation control apparatus according to an embodiment of the present invention, FIG. 2 is an illustrative view for explaining the operation of the above embodiment, and FIG. 3 is a conventional type of this kind. FIG. 4 is a block diagram showing the apparatus of FIG. 4, and FIG. 4 is an exemplary diagram for explaining the operation of the conventional example. (1a), (1b), (1c), (1d) are collimator blocks, (2a), (2
b) motor, (3a), (3b) potentiometer, (4a), (4b)
Is an amplifier, (5) is a first drive circuit, (6) is an A / D converter, (7) is a display, (8) is a sequence circuit,
(9) is a treatment table, (10) is a patient, (11) is a first I / O port, (12) is a treatment table motor, (13) is a rotary encoder, (14) is a second drive circuit, (15) ) Is the counter, (16) is the second
I / O port, (17) CPU, (18) memory, (19) keyboard input unit, (20) radiation generating unit, (21) pulse generating unit, (22) volume, (23) Is a D / A converter. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (5)

[Claims] 1. A moving means for moving a treatment table for a patient in a predetermined direction, a detection means for detecting a moving distance of the treatment table, and an irradiation field defining means for defining an irradiation field for an affected part of the patient. Irradiation field adjusting means for adjusting the irradiation field according to the movement of the treatment table, dose rate defining means for defining the dose rate of the radiation irradiated to the affected area of the patient, and the moving distance of the treatment table and A radiation irradiation control device comprising: an input unit for presetting a value of a radiation dose. 2. The radiation irradiation control device according to claim 1, wherein the moving means is a motor for moving the treatment table. 3. The radiation irradiation control device according to claim 1, wherein the detection means is a rotary encoder. 4. The radiation irradiation control device according to claim 1, wherein the irradiation field defining means is a pair of collimator blocks. 5. The radiation irradiation control apparatus according to claim 1, wherein the irradiation field adjusting means is a CPU that operates with predetermined software.