JPH01274741A - Radiant ray therapy part monitoring device - Google Patents

Abstract

PURPOSE:To monitor a remedied part during the radiant ray therapy by forming the distribution image of the radiant rays by arranging an imaging plate which forms the distribution of the fluorescent light intensity according to the distribution of the intensity of the radiant rays on the opposite side to a line source, having a remedied part interposed, and by converting said distribution image to the electric signals and displaying said image on a TV monitor. CONSTITUTION:An X-ray 5 which passes through the remedied part of a patient 7 reaches an imaging plate 11 and generates fluorescent light, and at this time, the reduction rate of the X-ray is large at the remedied part, and a dark part is formed, and an organ image in bright and dark parts is obtained on the imaging plate 11, with the image on the periphery of the organ. The fluorescent image of the imaging plate 11 is reflected by a mirror 13 in a supporting part 12 which forms a dark box which is constituted so that the intrusion of outside light is suppressed, and then photographing by a high sensitivity camera 14 is performed. The high sensitivity camera 14 can be achieved by using a low sensitivity camera which can sufficiently amplify fluorescent light. The photographed image is displayed on a TV monitor 15 through a cable 18. Therefore, the state of the organ in therapy can be monitored by using the X-ray 5 used for therapy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a radiotherapy site monitoring device that monitors the condition of an affected area in real time using the radiation being treated during radiotherapy.

[Conventional technology]

FIG. 4 shows a conventional radiotherapy site monitoring device, and the figure shows an example using a medical linac. In the figure, the fixed linac mount (1) and the rotating linac mount (2) are shown.
are connected via a rotational drive system (3). Line source (4
) emits radiation (5) such as X-rays. Here, we will take X-rays as an example. m Below the source (4) there is a collimator (6) that limits the X-ray irradiation field, below which the patient (7) to be treated is located. A treatment top plate (8) is placed under the patient (7) on a treatment table (9). Further, a film cassette (21) containing an X-ray film is supported by a holder (22) and positioned on the lower surface of the patient (7).

With the above configuration, the rotating pedestal (2) is rotated about the rotation center axis (A) by the drive system (3), and radiation therapy is performed from around the patient (7). Xl(5)k'! , source (4)
The spread of X# (5) is limited by the collimator (6) in accordance with the irradiation field to be treated. , patient (7
)) The patient lies down on the top plate (8) supported by the treatment table (9), and the treatment table (9) sets the vertical position of the patient (7). (7) Set the front/back and left/right positions. Furthermore, the treatment table (9) can rotate around its supporting legs and can also rotate around the central axis (B) of the radiation (5).

The affected area of patient (7) was examined using another simulator or X-ray CT.
The location of the affected part in the body is identified using @, but before starting radiotherapy, the treatment location is confirmed using therapeutic X-rays.

For this reason, fix the holder (22) containing the K film (2L:) and place it facing the radiation source (4) across the affected area so that the X@ transmission image of the affected area is reflected on the film. Set the film cassette (21).

The irradiation field of X-rays (6) should be wide enough to include the surrounding area of the affected area, and the field of X-rays (6) should be sufficiently small for the treatment radiation dose.
5) irradiate the area and record the X-ray transmission area of the affected area and its vicinity on film. When a linac is used, this is called linac graphics. This film is immediately dispensed, and radiation treatment begins after confirming the location of the main part and the area to be irradiated.

[Problem to be solved by the invention]

Conventional radiation therapy site monitoring devices are configured as described above, so before treatment, after confirming the location of the affected area and the radiation irradiation field, the treatment area can be treated on the assumption that the area to be treated will not change at all times. Therefore, it is not possible to confirm the treatment area during treatment. In addition, performing linacgraphy on the same patient for each treatment will significantly lengthen the treatment time.
This can only be done every time the treatment plan is changed (approximately for several treatments), and there are problems in that it is not easy to monitor the treated area in practice.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to obtain a radiation treatment site monitoring device that enables monitoring of a treatment area during radiation treatment.

[Means to solve the problem]

The radiation treatment site monitoring device according to the present invention has an imaging plate, such as a fluorescent screen, that can distribute the fluorescence intensity according to the intensity distribution of the radiation, disposed on the opposite side of the radiation source across the treatment site. It creates an image, converts it into an electrical signal, and displays it on a TV monitor.

[Effect]

In this invention, the fluorescence distribution on an imaging plate attached to a rotating mount is photographed using a highly sensitive camera.
Immediately display it on the TV monitor. Furthermore, the image displayed on the TV monitor can be arbitrarily digitized and stored in an image memory, and a scale can also be reflected thereon so that the dimensions of the body parts can be determined.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In addition, the corresponding or the same part 11Ck1 as in Fig. 4
Since the same reference numerals are used, the explanation in this section will be omitted. In Figure 3, an imaging plate (11), such as a fluorescent screen, is attached to the support (12) of the rotating pedestal (2), and the patient (7) is placed between the imaging plate and the scissor radiation source (4). (IL) is set. A high-sensitivity camera (14) faces a mirror (13) tilted at the bottom of the imaging plate (11).
is located. Furthermore, TV monitor (L5), TV
An image memo IJ (16) for digitizing and storing arbitrary images on the monitor and a linac remote controller (17) are provided. Camera (14) and TV monitor (16)
They are connected by a cable (18). On the imaging plate (Ll), a scale (31) made of a material with a high X-ray attenuation rate, such as metal, which is reflected on the imaging plate (11) by the X-rays (5), is arranged. ) In order to display the scale on the TV monitor (15) in a different way, by inputting the distance of the affected area from the radiation source (4), the dimensions of the affected area on the TV monitor (15) are calculated and displayed. A scale calculating device (32) for storing the scale scale as an image memo (16) is arranged.

are supported by arms (34) K made of a material with a low X-ray attenuation rate, for example, acrylic. The material is sized.

Figure 3 shows an example of the equipment arrangement when performing radiotherapy, including a treatment room (51) that generates radiation, a control room (52) that remotely controls the radiotherapy equipment, and a room for access to and from the treatment room (61). The door (63) is made of concrete to prevent radiation leakage to the outside, and the door (63) is made of concrete. It consists of thick walls (54), etc., and the state of the patient in the treatment room (61) is photographed by an ITV camera (56).
Monitor with a monitor (55).

Next, the operation will be explained. The X-rays (5) that have passed through the treatment area of the patient (7) reach the imaging plate (11) and generate fluorescence on the imaging plate (Ll). The organ is large and dark, and together with the shadows of the surrounding organs, a bright and dark organ image is created on the imaging plate (11).

The fluorescent image of this imaging plate (11) is reflected by the mirror (13) in the support part (2), which is a dark box configured to suppress the leakage of light from the outside, and is captured by the high-sensitivity camera. Photographed at (14). High sensitivity camera (14
) can be achieved using a low light camera, sufficient to amplify the fluorescence. The image photographed here is output to the TV monitor (15) via the cable 4 (18) 44. Therefore, the state of the organ undergoing treatment can be monitored using the X-rays (5) used for treatment.

During treatment, the irradiation field of X-rays (5) is brought as close as possible to the treatment area, so the treatment area and nearby organs can be monitored.However, being able to know the status of an even wider area would make it easier to monitor organs during treatment. becomes even more effective. Therefore, as in the case of linacography, before treatment, X-rays (5) are irradiated once as an irradiation field large enough to know the surrounding situation of the treatment site. The X-ray dose at this time must be a sufficiently small value compared to the amount of X and g for treatment, but it is possible as it is only necessary to memorize this in the image memo 'J (16) after taking the image. It is. By digitizing one screen of the image displayed on the TV monitor (16) or a superimposition of multiple images of the same image, it is possible to store the image in memory. If you prepare a memory with sufficient capacity to store the image memo') (16) and connect it to the TV monitor (15) via a video memory, you can also display the image from the image memo') (16) on the TV monitor (15). Pre-treatment organ images obtained in the same way as linacgraphy are stored in the image memo 'J (16), so they can be displayed alternately with real-time treatment area images during treatment, or combined. By displaying the images, it is possible to constantly monitor the relationship between surrounding organs and the treatment area, and radiotherapy can be performed safely and accurately.

You can also take notes of any images taken during treatment! If J(16) memorizes this, it can be used as evidence of the treatment results.

Since the dimensions of the affected area are unknown as described above, the scale (31) displays the dimensions of the treatment area on the TV monitor (16).
If the is mounted on the imaging plate (11), the shadow of the scale (31) produced by the
16) and stored as part of the image in the image memo IJ (16).

As shown in FIG. 1, the X-rays (5) are emitted in a conical shape. For this purpose, the imaging plate of the image of the treatment area)
The projection onto (11) is an enlarged projection of the actual size. Since the scale (31) cannot be placed on the treatment site (in most cases, the treatment site is within the body), the size of the scale (31) can be adjusted on the imaging grating (11). For example, if the scale interval is determined as a convention (approximately 5 mN interval is practical), then the actual size can be determined by projecting the scale on the TV monitor (15). Therefore, as shown in Fig. 2, the scale piece (33) connected to the K arm (34) has a large X-ray attenuation rate, so it appears as a shadow, but the arm (34) has a very small attenuation rate, so Almost not shown. The scale piece (33) and arm (34) are connected to the dimension setting device (35), so if the dimension setting device (35) is tilted greatly, the interval between the scale pieces (33) will increase, and conversely, the dimension Setting device (35)
If the slope of is made smaller, the interval between the scale pieces (33) will be reduced.

Therefore, if the angle of the dimension setting device (35) is set to correspond to the distance between the radiation source (4) and the treatment area, the interval between the scale pieces (33) that accurately indicates the size of the treatment area can be set. can do.

Based on the same idea as above, the scale can also be displayed on the TV monitor (15) K using the scale calculating device (32).

That is, the radiation source (4) and the imaging plate (11)
The distance between the radiation source (4) and the treatment area is fixed, so if the distance between the radiation source (4) and the treatment area is known, the magnification of the image above (11) can be easily calculated.

Since the pixel interval on the TV monitor (L5) through the high-sensitivity camera (14) is fixed, the number of pixels corresponding to the scale interval (for example, 5 m), which is fixed as a convention, on the TV monitor (15) is calculated. If you image this as a scale on the image memory (16) and display it via the video ram, you can display the scale on the TV monitor (15) in a different way from the scale shown in Figure 2. The actual dimensions of the treatment area can be read.

In the radiation therapy device shown in Fig. 3, the device is operated using a remote controller (17) in a control room (52) outside the treatment room (51) where no therapeutic radiation leaks, and the treatment is monitored using a TV monitor ([5)]. Monitor the area. Furthermore, the condition of the patient is photographed by an ITV camera (56) and monitored by an ITV monitor (65).

Here, the same effect can be obtained even if the imaging plate ([1) and the high-sensitivity camera (14) are replaced with fluorescence multiplier tubes. In addition, if a mechanism that can be stored in the rotating mount (2) is added to the support part (12), the patient (the technician's feet will be free when setting the force) and the setting will become easier. A movable mechanism may be added.Although the cable (18) is directly connected to the TV monitor (L6), it may be AD converted and connected to the video memory of Image Memo!J (16).

In addition, although the above embodiment describes a medical linac, it can be similarly applied to radiation therapy devices such as a cobalt-60 treatment device, a betatron, a microtron, etc.
It can also be applied to heavy particle, π meson, and neutron therapy equipment, etc., which have been under construction in recent years.

〔Effect of the invention〕

As described above, according to the present invention, an imaging plate is arranged facing a radiation source across the treatment area, and the radiation intensity distribution in four areas by this imaging plate is converted into an electrical signal and extracted on a TV monitor. This makes it possible to monitor the state of the organs in the treatment area using therapeutic radiation during radiotherapy, and it is always possible to confirm whether the treatment is being performed correctly, thereby improving the safety of radiotherapy. This has the effect of improving treatment accuracy and treatment accuracy.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of an embodiment of the present invention, FIG. 2 is a plan view of the scale of treatment area dimensions in FIG. , 4th
The figure is a schematic side view of a conventional radiotherapy site monitoring device. (4)...Radiation source, (6)...Radiation, (11)φΦ imaging plate, (14)...High sensitivity camera (means for converting into electrical signals), (16)...TV monitor, (L6
)...Image memory, (31)...Scale. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Zeng Wa Dao Teru ゛Heart 2 City Figure 4

Claims (1)

[Claims] an imaging plate that is placed opposite to the radiation source across the treatment area and is sensitive to the intensity of the radiation; a means for converting the radiation intensity distribution by the imaging plate into an electrical signal; A radiotherapy site monitoring device comprising a TV monitor for extracting intensity distribution.