JPH01250272A - Radiation treatment apparatus - Google Patents

Abstract

PURPOSE:To measure the variation of the irradiation position of the affected part with high accuracy, by using a recurrent light reflecting member to irradiate the same with predetermined beam and detecting the shift of the irradiation position of radiation accompanied by the change or movement of the body position of a patient to always detect the position of the recurrent reflecting member. CONSTITUTION:The laser beam K1 modulated from a generating source 3B is converged to a spot form in parallel be a converging lens 3E to be projected to the air. Only when the beam axis of the projected beam K1 is within the range of the shape of the reflecting tape 3A bonded to the surface of the body of a patient, reflected beam K2 is generated. The reflected beam K2 is detected by many photoelectric detector 3C to be detected by a detection circuit 4B. A demodulated signal is selected so as to be emphasized by the modulation frequency component by a filter circuit 4C to be compared with the reference voltage from a reference voltage generating circuit 5 by a comparator 4 and, when said signal is equal to or more than the reference voltage, the comparator 4 transmits and O-signal to a radiation output control means 2 which, in turn, irradiates the patient with radioactive rays.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a radiation therapy device, and in particular, detects movement of a treatment area due to causes such as patient's breathing or heartbeat, and always delivers radiation to a fixed location. The present invention relates to a radiation therapy device equipped with a mechanism capable of irradiating radiation.

[Conventional technology]

Traditionally, body position movements (hereinafter referred to as ``body movements'') during radiation therapy
In the case of body movement caused by breathing, exhalation and inhalation were detected using pressure sensors, and body movement caused by heartbeat was detected using electrocardiographic signals. and,
A method is adopted in which the output of the radiation therapy apparatus is controlled based on this body movement detection, thereby preventing excessive irradiation of radiation to areas other than the affected area.

In this case, in the case of body movement caused by breathing, exhalation and inhalation are measured with a pressure sensor, and the body movement is detected using the correlation between the pressure fluctuation and the body movement.

Furthermore, body movements caused by heart beats have been detected using the correlation between the output signal of an electrocardiograph and body movements.

[Problem B to be solved by the invention] However, in these conventional examples, the patient's body movements are not directly measured, but the respiratory pressure and electrocardiogram signals, which are correlated, are used. It had the disadvantage of poor accuracy.

[Purpose of the invention]

The purpose of the present invention is to improve the disadvantages of the conventional example, and in particular to measure with high precision the fluctuations in the irradiation position of the affected area due to the movement of the patient's body position, and thereby to effectively irradiate the affected area with radiation. It is an object of the present invention to provide a radiotherapy apparatus having the above-mentioned features.

[Means to solve the problem]

The present invention includes a radiation output means that irradiates a predetermined radiation to the affected area of a patient, an output control means that controls the output of the radiation output means, and a position shift that detects a positional shift of the radiation irradiation position due to body movement of the patient. and detection means. This positional deviation detection means includes a retroactive light reflecting member that is used by being attached to or near a radiation irradiation unit, a light flux generation source that irradiates a constant light flux toward the retroactive light reflecting member, and a and a reflected light detector that receives light reflected by the light reflecting member. Furthermore, it is equipped with a comparator that compares the signal level detected by the reflected light detector with a fixed reference signal and sends a signal corresponding to the amount of positional deviation of the affected area to the output control means as an output control signal. ing. This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The embodiment shown in FIG. 1 includes a radiation output means 1 that irradiates a predetermined radiation to the affected area of a patient, an output control means 2 that controls the output of this radiation output means 1, and a radiation irradiation position that changes as the patient's body position changes. and positional deviation detection means 3 for detecting the positional deviation of.

The positional deviation detection means 3 includes a retroactive light reflecting member 3A that is used by being attached to or near the radiation irradiation unit, and a luminous flux generation source 3B that irradiates a constant luminous flux toward the retroactive light reflecting member 3A. and a reflected light detector 3C that receives the light reflected by the retroreflective member 3A.

Furthermore, a comparator 4 is provided which compares the signal level detected by the reflected light detector 3C with a constant reference signal and sends a signal corresponding to the amount of positional deviation of the affected area to the output control means 2 as an output control signal.

FIG. 2 shows a reflective tape as the retroreflective member 3A. This reflective tape is based on spherical glass beads 30 and has a light reflecting member 32 on the reflective surface side. This light reflecting member 32 portion is entirely fixed to a coupling member 33. Reference numeral 34 indicates an adhesive. Therefore, this reflective tape can be freely fixed anywhere desired.

The radiation output means 1 is formed in an inverted shape as shown in FIG. It has become.

A treatment table 10 is installed below the projecting end IA of the radiation output means 1, on which the patient is placed horizontally. A miniaturized retroreflective member 3A is attached to a part of the patient's radiation irradiation area.

Further, the signal information detected by the reflected light detector 3C is sent to the above-mentioned comparator 4 via an amplifier circuit 4A, a detection circuit 4B, and a filter 4C. This comparator 4 is also provided with a reference voltage generation circuit 5.

Next, the operation of the above embodiment will be explained.

A light beam of 1 is outputted from the light beam generation source 3B as a modulated light beam, for example, a laser beam whose amplitude is modulated at a certain frequency, and is focused into a parallel point by a focusing lens 3E and projected into the air. Only when the optical axis of the projected light beam is within the shape of the reflective tape 3A attached to the patient's body surface, a reflected light flux of 0 is generated.The reflected light flux Kg is generated by a plurality of photoelectric detectors. Detected by 3C. The detection signal is amplified by the amplifier circuit 4A.
The signal is amplified and detected by the detection circuit 4B.

The demodulated signal is selected by the filter circuit 4C with emphasis on only the modulation frequency component of the light beam, and is compared with the reference voltage from the reference voltage generation circuit 5 by the comparator 4. When the voltage is higher than the reference voltage, comparator 4 is turned on.
Transfer the signal to radiation output control means. The output control means 2 irradiates the patient's affected area with radiation in response to the ON signal of the comparator 4.

〔Effect of the invention〕

As described above, according to the present invention, a retroreflective member is used to irradiate a predetermined light beam onto the member to detect displacement of the radiation irradiation position due to changes in the patient's body position or movement. Therefore, by attaching the retroreflective member at or near the patient's radiation irradiation position and constantly detecting the position of the retroreflective member, it is extremely easy to detect shifts in the radiation irradiation position due to changes in the patient's body position. Moreover, it can be detected with high precision, and as a result, it is possible to perform controls such as reducing the radiation output when the positional deviation occurs, which makes it possible to effectively irradiate the affected area with radiation. It is possible to provide an excellent radiotherapy device.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view showing a part of a retrolight reflecting member 3A, which forms a part of FIG. 1. 1... Radiation output means, 2... Output control means, 3.
... positional deviation detection means, 3A... reflective tape as a retroactive light reflecting member, 3B... light velocity generation source, 3C...
Reflected light detector, 4... comparator. Patent applicant Nihon Denki Co., Ltd. Agent Patent attorney Yushin Takahashi fFIJ is shown in Figure 2.

Claims (1)

[Claims] (1) a radiation output means for irradiating a predetermined radiation to the affected area of the patient; an output control means for controlling the output of the radiation output means; and a position for detecting a positional deviation of the radiation irradiation position due to a change in the patient's body position. misalignment detection means; the said misalignment detection means is a retroreflective member that is used by being attached to or in the vicinity of the radiation irradiation unit; and a light beam that irradiates a constant light beam toward the retroreflective member. and a reflected light detector that receives the light reflected by the retroreflective light reflecting member, and compares the signal level detected by the reflected light detector with a certain reference signal, and compares the signal level detected by the reflected light detector with a certain reference signal, A radiation therapy apparatus characterized in that it is equipped with a comparator that sends a signal relating to positional deviation to the output control means as an output control signal.