JPS609100A - Linear particle accelerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a linear particle accelerator used in radiation therapy, etc., and in particular, the present invention relates to a linear particle accelerator used in radiotherapy, etc., and in particular, in rotational irradiation, conformal irradiation, multistage aperture conformal irradiation, etc. This invention relates to a linear particle accelerator that enables display on a CRT.

Traditionally, as part of radiotherapy, there are three methods: rotational irradiation, which focuses radiation on the target affected area by rotating the radiation to the target, conformal irradiation, which performs the above operations while changing the irradiation range, and subdivided collimators. Multi-stage diaphragm irradiation, etc., which performs the above operations using radiation having an arbitrary irradiation shape, is performed. During these treatments, the intensity distribution of the absorbed radiation dose near the treatment site is planned and executed based on theoretical or experimental knowledge. However, there is still no linear particle accelerator that can display the actual irradiation results near the treatment area of each patient. Therefore, the conventional linear particle accelerator has the disadvantage that it cannot be verified for each patient whether or not the treatment site is irradiated with radiation according to the absorbed dose distribution according to the treatment plan.

The purpose of the present invention is to solve the above-mentioned conventional drawbacks, and to display the actual absorption m amount distribution near the treatment area on a CRT; 1;
The purpose is to provide a linear particle accelerator jδ that allows the resulting perifcation to be easily performed compared to a single-stroke absorption line generator.

The linear particle accelerator of the present invention includes a radiation source, an irradiation head that emits radiation generated by the radiation source as a beam of an arbitrary shape, and a country that rotates the irradiation head around an object. In a linear particle accelerator that performs rotational irradiation, conformal irradiation, multi-stage aperture conformal irradiation, etc. on a target object, - an irradiator on an image receiving surface arranged on the opposite side of the illumination head with respect to the target object; a radiographic image receiver for detecting the copper wire intensity distribution; an analog-to-digital converter for converting the output signal of the image receiver into a digital signal; an output of the analog-to-digital converter; and the gantry corresponding to the output. an image reconstruction circuit that calculates and outputs a radiation absorption dose intensity distribution on an arbitrary tomographic plane of the object based on the output of the memory circuit; and an output signal of the image reconstruction circuit. 2
It is characterized by comprising a CRT monitor that displays a dimensional image.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention. That is, a radiation source 4, an irradiation head 3 that emits a radiation beam in an arbitrary shape, and a treatment bed z with the radiation source 4 and the irradiation head 3 supported at the distal end and with the rotation center shaft 7 as the rotation axis. A gantry 5 that rotates around the upper object (Tang, person), and a radiation image receiver l that is arranged on the opposite side of the irradiation head 3 with respect to the object and detects and outputs the radiation intensity distribution on the image receiving surface. The radiation imager 1 is supported by a gantry 5 and rotates around the object together with the irradiation head 3. Therefore, the central axis 6 of the radiation beam rotates in a plane that includes the center point 8 of the part and is perpendicular to the central axis of rotation 7 as the gun 1-5 rotates. As a result, it is possible to irradiate the central point 8 of the affected area with radiation, which is the same as in the past, but in this embodiment, the radiation intensity on the image receiving surface of the radiation image receptor l at any moment is 4j is detected and outputted by the 4-wire radiation receiver l.

The output signal of the emitted Q4-ray image K+1 is sent to the gun L at that time.
- By storing the rotation angles of the Lee 5 together, the patient i'i
It is possible to know the distribution of absorption line warmth on any fault plane near tl by mf calculation.

Figure 2 shows how the output of the above-mentioned radio@4-ray receiver 1 is processed and the C
FIG. 3 is a block diagram showing a processing unit for displaying the distribution of absorbed dose on the RT monitor l2. In other words, Teruman Het 3
The irradiated radiation beam l4 of arbitrary shape is detected by the radiation imager l corresponding to the pixel on the image receiving surface, and its output signal is converted into a digital signal by the analog-to-digital converter 9. Analog e-digital converter 9
The digital value for each pixel on the image receiving surface of the radiation image receptor 1 outputted by the radiation image receptor 1 indicates the absorbed dose distribution on the plane perpendicular to the central axis 6 of the radiation beam near the center point 8 of the affected area at that time. There is. The signal is then stored in the memory circuit 10 together with the rotation angle of the gantry 5 at the point. Gantry
5, the corresponding outputs of the analog-to-digital converters 9 are stored in the memory circuit IO.

The image reconstruction circuit 1l includes a memory circuit 10
Based on the data, the absorbed dose distribution of radiation near the affected area is
Calculations are output for each of multiple tomographic planes and displayed on a CRT.
Supplied to monitor l2. The CRT monitor 12 converts the human power signal from the image reconstruction circuit 1l into, for example, a color display corresponding to the magnitude of the absorbed dose and displays it on the CRT. That is, it is possible to easily recognize the absorbed dose distribution of any tomographic plane by color display on the CRT, which is extremely effective in performing accurate treatment.

In addition, the absorbed dose distribution determined by the treatment plan is stored in the treatment planning device 17 in advance.
By inputting the fraction 4j star to the CRT monitor 12 via the interface circuit 15 and console 13, the planned distribution amount and the actual absorbed dose can be displayed simultaneously on the CRT monitor 2, which is convenient. It is. Furthermore, 31
The evaluation circuit 16 evaluates the difference between the image distribution and the actual minute 1,...bi, and displays the Jf value result on the CRT monitor 12.
It is also town Noh to have it displayed in the town. The above evaluation can use a simple difference method, an inner product method, or the like as the degree of similarity between two dose distributions. The console 13 includes a radiation receiver 1, an analog/digital converter 9, a memory circuit 10,
Image reconstruction circuit 11, CRT monitor 12
, the interface circuit 15, and the evaluation circuit 16, and also mediates the transmission and reception of signals between them to smoothly display desired results on the CRT.

As described above, in the present invention, a radiation image receptor is placed at a position facing the irradiation head of a conventional linear particle accelerator, and the radiation image receptor and the irradiation head are moved toward the target object according to the rotation of the country. The output signal of the radiation imager is stored in a memory circuit in accordance with the rotation angle of the gantry, and from the information in the memory circuit,
Since the radiation absorption dose distribution on an arbitrary layer surface is calculated and the magnitude of the absorbed dose is displayed two-dimensionally on the CRT, the actual absorbed dose can be easily recognized by the CRT. It is possible to do so. Further, it is also possible to display the planned absorbed dose, the difference between the plan and the actual, etc. on the CRT. Therefore, according to the present invention,
This has the effect of making it easier to confirm treatment results and understand differences between plans and treatment results, allowing for correct treatment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a processing unit for displaying the absorbed dose distribution of an arbitrary tomographic plane on a CRT using the output of the radiation imager in the above embodiment. It is a diagram. In the figure, l. Radiation image receptor, 2: Therapy bed, 3: Irradiation head, 4: Radiation source, 5: Gantry, 6. Central axis of radiobeam, 7: Central axis of rotation, 8: Central point of affected area, 9 : Analog ●Digital converter, lO: Memory circuit,
ll: Image recons 1/action circuit, 12: CRT
Monitor, 13: Console, l4: Radiation beam 0 beam, 1
5: Interface circuit, 16: Evaluation circuit, 17: i-therapy planning system. -466-

Claims (1)

[Claims] A radiation source, an irradiation head that emits radiation generated by the radiation source as a beam of an arbitrary shape, and a country that rotates the irradiation head around the object,
A linear particle accelerator that performs rotational illumination, conformal irradiation, multistage aperture conformal irradiation, etc. on the object; 6, the opposite of the irradiation head 1 on the object l71! A radiation image receptor that detects the radiation intensity distribution on the image-receiving surface and an analog device that converts the output signal of the image receptor into a digital signal.
a digital converter, a memory circuit that stores the output of the analog-to-digital converter and the 10 rotation angles of the gantry corresponding to the output; and radiation absorption of seven arbitrary tomographic planes of the object by the output of the memory circuit. A linear particle accelerator characterized by being equipped with an image reconstruction circuit that calculates and outputs a dose intensity distribution, and a CRT monitor that displays the output of the image reconstruction circuit as a two-dimensional image.