JPS6141233B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an irradiation field indicating device for radiation therapy.

Generally, radiation therapy is performed by irradiating the affected lesion with radiation using cobalt-60, etc., but when it comes to irradiating the patient with radiation,
The doctor must determine the radiation field in advance and draw this field on the patient's skin using ink. Conventionally, the device shown in FIG. 1 has been widely used as an irradiation field indicating device for this purpose. In FIG. 1, an X-ray tube 31 and an X-ray image tube 33 face each other so as to sandwich a patient 1 lying on a bed 2, and are attached to a rotating frame 34. In front of the X-ray tube 31, there is a diaphragm device 3.
2 is attached, and an image as shown in FIG. 2 is displayed on the CRT screen by the output from the X-ray image tube 33. That is, the diaphragm device 3
The shadows a, b, c, and d of the radiopaque line bodies of No. 2 are shown. By operating the aperture device 32, this beam can be moved to the left/right or up/down, respectively, and by surrounding the lesion 11 while looking at the screen, the irradiation field can be expanded. Settings can be made, and a mark can be placed on the patient's skin surface by irradiating it with a laser beam or the like based on the settings and relying on this light. The reason why the rotary frame 34 is rotatable is because radiation is irradiated from various directions, and markings are made on the skin in each direction. However, with this conventional method, the mark of the irradiation field is always rectangular, so even if the lesion has a complex shape and it is desired to determine the outline of the irradiation field accordingly, this cannot be achieved.

In view of the above, it is an object of the present invention to provide an irradiation field indicating device that enables accurate marking of an irradiation field by projecting an image of an irradiation field of an arbitrary shape corresponding to the shape of a lesion onto a patient's skin surface. purpose.

An embodiment of the present invention will be described below with reference to the drawings. 3 and 4, the irradiation field indicating device 4 according to the present invention has a projector 41, which includes a high brightness CRT 42 and a focusing lens 43, and is attached to a rotating frame 44. The position of the projector 41 can be changed in the radial direction with respect to the rotating frame 44, so that the position of the therapeutic radiation source (not shown) and the position of the lens 43 can be made to coincide. Further, the distance of the CRT 41 from the lens 43 can be adjusted for focusing. The rotating frame 44 is
A bearing 46 is mounted by a fixed frame 45 fixed to the floor.
The bed support device 21 is operated so that the body axis OO of the patient 1 coincides with this central axis of rotation, and the bed 2 is moved in the horizontal and vertical directions. A back pointer 47 is attached to the rotating frame 44 on the opposite side of the projector 41. This back pointer 47 projects a light beam such as a laser beam, and the optical axis is aligned with the projector 41. This is to align the center position of the mark placed on the patient when the projector 41 rotates 180 degrees.

Furthermore, in this embodiment, a so-called third generation computer tomography apparatus (hereinafter referred to as CT) is installed in the gantry 5.
(of course, other types of skiing units such as so-called first, second, and fourth generations may also be used). That is, the opposing X-ray tube 51 and X-ray detector 52 are attached to a rotating frame 53 so that they rotate together. In the third generation
The ray tube 51 emits a fan-shaped X-ray beam perpendicular to the body axis OO, and the X-ray detector 52 is composed of a large number of elements arranged in an arc shape along the fan-shaped X-ray beam.

When obtaining a tomographic image as a CT, as shown in FIG. The rotating frame 53 in the gantry 5 is rotated via the Yana controller, and the rotational position is sent to the CPU, and the output of the X-ray detector 52 obtained for each rotational position is sent to A.
- Digitize through the D controller, perform convolution processing using a convolver, and then perform back projection processing using a back projector to construct a tomographic image, which is stored in image memory and displayed on a monitor CRT. At this time, the bed support device 21 is operated to move the patient 1 to the left in FIG. 3 so that a cross section of the lesion can be taken.

Fluoroscopic images (scanography) using this CT
In order to obtain this, for example, the rotating frame 53 may be fixed at the position shown in the figure, the X-rays may be irradiated, and the patient 1 may be moved in the body axis direction during the irradiation. The perspective image thus obtained is stored in an image memory and displayed on a monitor CRT as shown in FIG.

By the way, CT is usually set with Joy States Clever for setting ROI (region of interest).
A memory is provided to store the ROI. Therefore, using this, we first retrieve the perspective image from the image memory and display it on the CRT monitor as shown in Figure 6.
By operating the joy states lever to move the bright spot on the CRT screen so that it follows the outline of the lesion 11, the locus 12 of this bright spot can be stored in the ROI memory. When this ROI memory is read out, an image that follows the outline of the lesion is obtained, and when this is displayed on the screen of the CRT 42 of the projector 41, the outline of the lesion, that is, the outline 12 of the irradiation field, is displayed on the skin surface of the patient 1. Since it will be projected, by marking along this contour 12, it becomes possible to mark an arbitrary shaped irradiation field. In addition, at this time, the CRT4 of the projector 41
If the fluoroscopic image is displayed simultaneously in 2, lesions and bones will also be projected onto the skin surface, making it possible to accurately position the irradiation field and setting the irradiation field to avoid bones. It would be desirable if it could be done easily. Further, when setting this irradiation field, it is convenient because the above-mentioned tomographic image can be referred to.

As described above in the embodiments, according to the present invention, the irradiation field image is displayed on a high-brightness CRT and projected onto the patient's skin surface, so even an arbitrary-shaped irradiation field image can be displayed on the skin surface. can be marked, improving the accuracy of radiation therapy.

In addition, if the fluoroscopic image and the irradiation field image are set using CT as in the above embodiment,
Since CT fluoroscopic images are digitized and signal-processed, they have great advantages, such as being able to enhance contrast and make them easier to see.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional example seen from the side, FIG. 2 is a diagram of an image displayed on the monitor CRT of FIG. 1, and FIG. 3 is a schematic diagram of an embodiment of the present invention seen from the side.
Fig. 4 is a schematic diagram of only the irradiation field indicator 4 shown in Fig. 3 seen from the front (right side of Fig. 3), Fig. 5 is a block diagram of the signal processing system, and Fig. 6 is the monitor shown in Fig. 5.
FIG. 3 is a diagram of an image appearing on a CRT. 1...patient, 2...bed, 4...irradiation field indicator, 5...CT gantry, 11...lesion.

Claims (1)

[Claims] 1. A high-brightness CRT that displays an irradiation field image;
An optical system that projects the irradiation field image displayed on the CRT screen onto the patient, a movement mechanism that adjusts the relative position of the optical system and the patient, and a movement mechanism that moves the CRT, optical system, and movement mechanism along the patient's body axis. and a support member rotatably supported around a central axis. 2. Claim 1, characterized in that the high-brightness CRT displays an X-ray fluoroscopic image obtained using a computer tomography device and an irradiation field image superimposed on this fluoroscopic image. irradiation field indicator.