JP2002360715A - Dose distribution measuring instrument and dose distribution measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dose distribution measuring instrument constituted so as to measure the dose distribution of corpuscular beam treatment equipment having a rotary gantry, miniaturizing a water tank while ensuring a necessary measuring range to reduce a strength condition imposed on a drive device and the water tank and capable of measuring OCR, TPR and PDD even in a corpuscular beam radiation apparatus having the rotary gantry. SOLUTION: The dose distribution measuring instrument is constituted so that a cylindrical hermetically closed water tank having a radius set to a minimum range necessary for measurement is attached to a drive bed having three drive shafts and the sensor in the hermetically closed water tank is attached to a drive shaft movable only in an up and down direction to miniaturize the water tank and can measure OCR, TPR and PDD even in the corpuscular beam apparatus having the rotary gantry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dose distribution measuring device and a dose distribution measuring system capable of measuring from all directions using a closed water tank and capable of performing TPR measurement.

[0002]

2. Description of the Related Art A conventional technique will be described. Prior to cancer treatment with radiation, a dose distribution measurement of a radiation therapy apparatus is performed to simulate the actual radiation dose distribution in the body. In particular, in the case of an electron beam and an X-ray irradiator using an accelerator, the expanded beam is irradiated toward a cancer lesion, and since the electron beam and the X-ray have a large effect on the body surface, not only cancer tissue but also It is also necessary to measure the exposure dose to normal tissues, and to control the exposure of normal tissues by precisely adjusting the depth energy distribution in the body even in particle beam therapy that irradiates protons and multivalent ions. This dose distribution measurement is important.

[0003] For these measurements, a method is used in which water is poured into a box-shaped water tank having an open top surface imitating a human body, the water is irradiated, and the dose is measured by a sensor provided in the water. Have been. FIG. 4 shows an outline of a water tank of a conventional dose distribution measuring device. 7 is a sensor for converting received radiation or particle beam (radiation in this case) into electric charge, 8 is a driving base on which the sensor 6 is mounted, 20 is a box-shaped water tank containing water, 2
1 is a sensor X drive axis for moving the sensor 7 mounted on the drive base 8 in the X axis direction, 22 is two sensor Y drive axes for moving the sensor X drive axis 21 in parallel in the Y axis direction, and 23 is a Z axis. The four sensor Z drive axes, 24, which translate the sensor Y drive axis 22 in the direction, are radiation or particle beam (here, radiation beam).

As shown in the figure, a sensor 7 is moved on a sensor X drive shaft 21 by a motor (not shown) together with a drive stand 8 in the X-axis direction, and is moved in a Y-axis direction. The shaft 21 translates and moves on the sensor Y drive shaft 22, and moves in the Z-axis direction.
Makes a parallel movement on the sensor Z drive shaft 23, thereby moving the sensor 7 in a direction perpendicular and parallel to the radiation beam 24 to measure the dose distribution.

Here, in the dose distribution measurement, OCR (Off)
There are Center Ratio) measurements, PDD (Depth Percentage) measurements and TPR (Tissue Peak Dose Ratio) measurements. FIGS. 5, 6, and 7 show OCR, PDD, and T, respectively.
The method of PR measurement is shown. In FIG. 5, reference numeral 25 denotes a moving portion of the sensor 7 during the OCR measurement. As shown in the figure, the OCR measurement is a method of measuring a dose distribution in a direction perpendicular to the radiation beam 24.

FIG. 6 is a side view showing the movement of the water tank at the time of PDD measurement. 20a is the position of the moved water tank. As shown in FIG. 6, this method measures the dose distribution by driving the water tank 20 up and down to change the water depth while the position of the sensor 7 is fixed.

FIG. 7 is a side view showing the movement of the sensor at the time of TPR measurement. 7a and 7b are the positions of the moved sensor 7. As shown in FIG. 7, the TPR measurement is a method of measuring the dose distribution by moving the sensor 7 up and down in the water tank 20 without moving the water tank 20 to change the water depth.

When measuring the dose distribution according to these methods, the water tank can be rotated together with the rotating gantry even if the particle beam irradiation apparatus has a rotating gantry, because the water tank was conventionally an open top. Did not. Therefore, when measuring the dose distribution of oblique radiation by rotating the gantry, measure the distance from the time when the particle beam enters the water in the aquarium until it reaches the sensor, and correct the data accordingly to correct the data. Therefore, there is a problem that the accuracy is lower than that in a case where a radiation beam is incident perpendicularly to the water surface.

When a closed water tank is used for the rotating gantry, the volume of the water tank is determined by the size of the sensor itself and the width of the drive shaft in order to secure the measurement range, that is, the movement range of the sensor in the water tank. When performing PDD measurement in which the water tank itself needs to be driven up and down, although it is necessary to keep the water tank above a certain level, the driving device and the water tank need to have a certain strength.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is required for a dose distribution measuring apparatus for measuring a dose distribution of a particle beam therapy system having a rotating gantry. By reducing the size of the water tank while ensuring the measurement range, the strength conditions imposed on the driving device and the water tank are reduced, and the OCR measurement, the TPR measurement, and the PDD can be performed even in a particle beam emission device having a rotating gantry.
An object of the present invention is to provide a dose distribution measurement device capable of measurement.

It is another object of the present invention to make the control common and automatic by controlling the control computer via a sequencer when there are a plurality of dose distribution measuring devices.

[0012]

A dose distribution measuring device and system according to the present invention irradiate a particle beam from a particle beam therapy device and measure a dose distribution of the particle beam by a sensor provided in water in an aquarium. A measurement device, wherein the irradiation port of the particle beam is provided, and a rotating gantry that rotationally moves in a plane perpendicular to the treatment table of the particle beam therapy device, and provided on a beam axis of the particle beam. ,
A sealed water tank that rotates with the rotating gantry,
A sensor moving means for moving the sensor in the beam axis direction of the particle beam; and a water tank moving means for moving the closed water tank in a beam axis direction of the particle beam and in a direction perpendicular to the beam axis. .

Further, the closed water tank has a cylindrical shape.

The closed water tank is bolted to the floor of the rotating gantry.

A plurality of dose distribution measuring devices; a plurality of power supplies for supplying a voltage to the plurality of dose distribution measuring devices;
A control computer for transmitting and receiving control commands and measurement data via the plurality of dose distribution measurement devices and the sequencer; and a plurality of I / Fs for converting the measurement data of the plurality of dose distribution measurement devices into I / F and outputting to the sequencer A dose distribution measurement system having a converter, wherein the sequencer is a data control and a counter control sequencer that determines timing for driving the dose distribution measurement device, and the dose distribution measurement is performed in accordance with the drive timing determined by the counter control sequencer. A drive control sequencer for driving and controlling the device is provided, and a plurality of dose distribution measuring devices are collectively controlled.

The I / F converter switches the output range of the output signal by the counter control sequencer.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIGS. 1A and 1B are block diagrams illustrating a configuration of a dose distribution measuring device in a particle beam therapy system according to Embodiment 1 of the present invention. In the figure, 1 is a particle beam irradiation port, 2 is a radiation irradiation port 1, and a rotating gantry that rotates 360 degrees together with the radiation irradiation port 1, 3 is a frame that maintains the strength of the rotating gantry, 4 is particle beam irradiation Isocenter, which is a reference point in the case of, 5 is a cylindrical closed water tank imitating a human body, 6
Is a drive base having three drive shafts for installing the closed water tank 5, 7 is a sensor provided in the water tank for sensing the irradiated particle beam, and 8 is a motor (not shown) in which the sensor 7 is mounted in the water tank.
A drive stand for moving up and down, 9 is a closed water tank 5
Drive shaft 10 for moving the X-axis together with the drive base 6 by a motor (not shown) in the X direction. The X-drive shaft 9 is moved in parallel to move the closed water tank 5 and the drive base 6 on the X drive shaft 9. Y drive shaft for moving in the Y direction, 11 is Y
The drive shaft 10 is a Z drive shaft for moving the closed water tank 5 and the drive gantry 6 on the Y drive shaft 10 in the Z direction by moving the drive shaft 10 in parallel in the Z direction.

FIG. 1B is a perspective view of the dose distribution measuring device when the rotating gantry is rotated. FIG. 1 (a)
The same components as those described above are denoted by the same reference numerals.

FIG. 2 is a view showing the structure of the closed water tank 5, the drive frame 6, and each drive shaft. The same components as those in FIG. 1A are denoted by the same reference numerals.

As shown in FIG. 2, the drive base 6 on which the closed water tank 5 is mounted can be moved three-dimensionally by combining the X drive shaft 9, the Y drive shaft 10, and the Z drive shaft 11. Then, as shown in FIG. 1A, these are fixed to the floor of the rotating gantry 2. Here, the sensor 7 in the closed water tank 5 is made to move only in the vertical direction of the water tank, and when the rotating gantry 2 rotates, as shown in FIG. The position of the closed water tank 5 on the floor surface of the rotating gantry 2 is determined so that

In the conventional OCR measurement, the sensor itself is moved in the water tank. At each rotation angle of the rotating gantry, the cylindrical closed water tank 5 is moved to the X drive shaft 9 while the position of the sensor 7 is fixed. And moving along the Y drive shaft 10 to perform the measurement. At that time, by making the radius of the cylinder of the closed water tank 5 the minimum length necessary for the measurement, it is not necessary to consider the width of the drive shaft and the size of the sensor as compared with the conventional water tank, so that the volume can be reduced. it can.

In the PDD measurement, the position of the sensor 7 with respect to the isocenter 4 is changed by moving the sealed water tank 5 in the vertical direction by the Z drive shaft and moving the sensor 7 in the opposite direction by the movement of the sealed water tank 5. Fix and measure only by changing the water depth. This is measured while changing the rotation angle of the rotating gantry.

For TPR measurement, a closed water tank 5 was used.
The sensor 7 is moved along the sensor Z drive shaft 11 while the sensor is fixed, and measurement is performed at each position. This is also measured while changing the rotation angle of the rotating gantry.

As described above, conventionally, the sensor 7 is provided in the water tank.
Has a drive shaft in the X, Y, and Z directions, so that the water tank needs to be box-shaped, and because of the size of the sensor itself and the width of the drive shaft of the sensor, it is more than the originally required measurement range. However, in the first embodiment,
The drive shaft of the sensor 7 is only the sensor Z drive shaft 12, and the closed water tank 5 is installed on a drive base 6 having three drive shafts of an X drive shaft, a Y drive shaft, and a Z drive shaft. Since the cylindrical closed water tank 5 was moved while the water tank was fixed, the size of the water tank could be reduced, and OCR, PDD, TP
A dose distribution measuring device capable of performing each measurement of R is obtained.

Embodiment 2 By performing the interface between the plurality of dose distribution measuring devices according to the first embodiment and the control computer by a sequencer, the control signals and input / output signals of the measuring device can be simplified, and the cost for controlling the measuring device can be reduced. it can. FIG. 3 is a block diagram illustrating a configuration of a dose distribution measurement system according to Embodiment 2 of the present invention. Reference numerals 5a and 5b denote sealed water tanks installed in the A treatment room and the B treatment room, respectively, and reference numerals 6a and 6b denote drive stands for the sealed water tanks in the A treatment room and the B treatment room, respectively, 7a and 7b.
Are sensors in the A treatment room and the B treatment room; 13a, 13b are I / F converters for converting the amount of electric charge emitted into data according to the amount of the particle beam received by the sensors 7a, 7b;
a and 14b are high-voltage power supplies for operating the sensors 7a and 7b,
15 is a counter logic circuit, 16 is a drive stand 6a, 6
The counter control sequencer 17a, 17b for determining the drive timing of b is used for the A treatment room, which outputs the amount of movement of the drive bases 6a, 6b to the drivers 18a, 18b in accordance with the drive timing determined by the counter control sequencer. A drive control sequencer 19 for the room receives measurement data and a measurement end signal from the counter logic circuit 15 and also emits a particle beam (not shown).
Is a control computer for outputting the emission timing signal to the counter logic circuit 15, and 24 is a particle beam.

Next, the operation will be described. The second embodiment is characterized in that the dose distribution measuring devices installed in the two treatment rooms A and B are controlled by one control system. First, when the dose distribution measurement is performed in the treatment room A, when the timing signal of the particle beam emission of the accelerator is output from the control computer 19, the counter control sequencer 16 outputs the measurement start timing to the drive control sequencer 17a. The drive control sequencer 17a outputs a control signal to the driver 19a so that the sensor 7 and the sealed water tank 5 are located at the measurement start position, and returns the sealed water tank 5, the drive cradle 6, and the sensor 7 to the initial positions, respectively. Electric power is supplied, and measurement of the sensor 7 is started. When the particle beam 24 emitted from the accelerator reaches the sensor 7, the sensor 7 outputs a charge corresponding to the dose to the I / F converter 13a, and the I / F converter 13a converts the charge amount into data. And outputs it to the counter logic circuit 15. The counter logic circuit 15 outputs the input measurement data to the control computer. Perform the above steps according to each measurement method,
At the end of the measurement data and the measurement, a measurement end signal is output to the control computer 19. When the necessary measurement is completed in the A treatment room, the same measurement is performed in the B treatment room.

Here, when the particle beam emission from the accelerator is pulse-shaped, the measurement time can be shortened by driving the drive shaft between the particle beam 24 and the next beam. At this time, if the particle beam 24 is output before the movement of the drive shaft is completed, this is detected and unnecessary data is automatically deleted.

In addition to automating the measurement process,
By automatically switching the output ranges of the I / F converters 13a and 13b from the control computer through the sequencer, it is possible to reduce measurement errors due to erroneous operations that occur at the time of measurement.

When the high-voltage power supplies 14a, 14b fail, the measurement is stopped by outputting a voltage abnormality signal to the counter control sequencer 16, and the alarm signal is sent to the control computer 1.
9 is output.

In the second embodiment, for convenience of explanation, only two treatment rooms are shown. However, it goes without saying that the present invention can be applied to two or more treatment rooms.

As described above, in the second embodiment, the interface between the dose distribution measuring devices in a plurality of treatment rooms and the control computer is performed by the counter control sequencer and the drive control sequencer corresponding to each dose distribution measuring device. As a result, the control signals and input / output signals of the measuring device can be simplified,
In addition, the control can be shared, and the cost related to the measurement device control can be reduced.

[0032]

As described above, in the dose distribution measuring apparatus and system according to the present invention, the drive shaft of the sensor provided in the closed water tank is reduced only in the vertical direction of the water tank, and the closed water tank is driven by three drives. Mounted on a drive base with a shaft,
OCR, PDD, TP to move the closed water tank
A dose distribution measuring device capable of performing each measurement of R is obtained.

Further, if the shape of the closed water tank is cylindrical and the radius of the cylinder is the same as the minimum range required for measurement,
The size of the water tank can be reduced, and the conditions imposed on the driving of the water tank can be reduced.

Also, the interface between the dose distribution measuring devices in a plurality of treatment rooms and the control computer is performed by a counter control sequencer and a drive control sequencer corresponding to each dose distribution measuring device, so that the control signals of the measuring devices can be obtained.
Input / output signals can be simplified, control can be shared, and costs related to measurement device control can be reduced.

[Brief description of the drawings]

FIG. 1 (a) is a side view when a dose distribution measuring device according to Embodiment 1 of the present invention is installed in a rotating gantry of a particle beam therapy apparatus. (B) It is a side view when rotating a gantry.

FIG. 2 is a perspective view of a closed water tank installed on a drive base having three drive shafts of the dose distribution measurement device according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a dose distribution measurement system according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a water tank of the conventional dose distribution measuring device.

FIG. 5 is a perspective view of a water tank showing a measurement range of a sensor at the time of OCR measurement.

FIG. 6 is a side view of the water tank showing movement of the water tank at the time of PDD measurement.

FIG. 7 is a side view illustrating the movement of a sensor during TPR measurement.

[Explanation of symbols]

1 particle beam irradiation port, 2 rotating gantry, 3
Frame, 4 isocenter, 5, 5a, 5b Sealed water tank, 6, 6a, 6b Drive stand, 7, 7a, 7
b sensor, 8 drive stands, 9 X drive axes, 10
Y drive axis, 11 Z drive axis, 13a, 13b I
/ F converter, 14a, 14b high voltage power supply, 15 counter logic circuit, 16 counter control sequencer, 17a, 17b drive control sequencer, 18
a, 18b driver, 19 control computer, 20
Conventional aquarium, 21 sensor X drive axis, 22 sensor Y drive axis, 23 sensor Z drive axis, 24 particle beam.

Claims (5)

[Claims] 1. A dose distribution measuring device that irradiates a particle beam from a particle beam therapy device and performs a particle beam dose distribution measurement by a sensor provided in water in an aquarium, wherein the particle beam irradiation port is provided. A rotating gantry that rotates and moves in a plane perpendicular to the treatment table of the particle beam therapy device; a sealed water tank that is provided on the beam axis of the particle beam and rotates and moves together with the rotating gantry; A dose distribution, comprising: a sensor moving means for moving the particle beam in a beam axis direction; and a water tank moving means for moving the closed water tank in a beam axis direction of the particle beam and in a direction perpendicular to the beam axis. measuring device. 2. The dose distribution measuring device according to claim 1, wherein said closed water tank is cylindrical. 3. The dose distribution measuring apparatus according to claim 1, wherein said closed water tank is bolted to a floor of a rotating gantry. 4. A plurality of dose distribution measuring devices, a plurality of power supplies for supplying a voltage to the plurality of dose distribution measuring devices, and transmission / reception of control commands and measurement data via the plurality of dose distribution measuring devices and a sequencer. A dose distribution measurement system comprising: a control computer; a plurality of I / F converters for I / F converting measurement data of the plurality of dose distribution measurement devices and outputting the data to the sequencer; wherein the sequencer performs data measurement and the dose measurement; A counter control sequencer for determining a timing for driving the distribution measurement device; and a drive control sequencer for driving and controlling the dose distribution measurement device in accordance with the drive timing determined by the counter control sequencer, and collectively control a plurality of dose distribution measurement devices. Dose distribution measurement system characterized by performing. 5. The dose distribution measuring system according to claim 4, wherein said I / F converter switches an output range of an output signal by said counter control sequencer.