JPH0751128B2 - Radiation irradiation device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a radiation irradiation apparatus used for, for example, treatment of cancer.

[Prior Art] Generally, in the medical field, for example, when radiation treatment is performed on an affected area such as cancer cells, the radiation must be applied in a state where the affected area is located on the axis of the radiation.
Also, when irradiating radiation that requires a long distance from the radiation source to the affected area, such as a heavy ion beam, the radiation source cannot be moved, so fix the patient on the treatment table and move this treatment table. Therefore, the affected part must be moved on the axis of radiation.

Therefore, in order to move the affected area to the axis of radiation,
First, it must be limited where the affected area is in the patient. It is possible to use X-ray film or X-ray TV for this, but most of the affected areas requiring treatment are
Since it does not appear on X-ray film or X-ray TV, it is difficult to limit the position of the affected area. In addition, if the X-ray CT shows the affected area relatively well, the X-ray CT provides a tomographic image and
Since CT cannot be brought into the treatment room, it is difficult to directly limit the position of the affected area by X-ray CT.

Hereinafter, a method for limiting the position of an affected area with an X-ray film when treating cancer by heavy ion beam irradiation, which has been conventionally used in the United States and the like will be described. FIG. 10 is a block diagram showing an X-ray imaging apparatus for X-ray film. In the figure, (1) shows a treatment table as a movable table provided so as to be movable and adjustable in the horizontal direction,
(2) is a patient fixed on the treatment table (1) as an irradiation target, and (3) is an X-ray as an X-ray source that emits X-rays provided downward above the treatment table (1). A tube, (4) is connected to the X-ray tube (3), and an X-ray control device for controlling imaging conditions such as tube voltage, tube current and X-ray generation time of the X-ray tube (3),
(5) is a collimator placed in front of the X-ray tube (3),
(6) is an X-ray film set under the treatment table (1), and this X-ray film (6) is usually mounted in a film cassette (not shown).

In the X-ray imaging apparatus configured as described above, first, X-ray imaging conditions are set by the X-ray controller (4), and X-ray imaging conditions are set.
Emit X-rays from the ray tube (3). The emitted X-rays travel in the direction of the arrow in the figure, penetrate the patient (2), and expose the X-ray film (6). After that, if the X-ray film (6) is developed, an X-ray image of the patient (2) is obtained.

In order to limit the position of the affected area using the X-ray image thus obtained and move and adjust the treatment table (1) so that the affected area is located on the axis of the heavy ion beam, first, X
A large number of tomographic images taken by line CT are combined by a computer, and a plane image of the affected area of the cancer is created as a reference image. Then, several clearly visible positions on the reference image are selected, landmarks are attached thereto, and the distance from each of these landmarks to the cancer affected area is measured. At this time, the position where the landmark is attached must be a portion that can be reliably reflected on the X-ray film, such as a bone.

Next, as shown in FIG. 11, on the X-ray image of the X-ray film (6), landmarks (7) are respectively placed on the portions corresponding to the positions where the landmarks of the reference image are attached. Attach. Then, the position of the cancer affected part is limited from each landmark (7) based on the distance from each landmark measured in advance in the reference image. The developed X-ray film (6) often does not show the cancer affected area, but it is limited to the position of the cancer affected area by such a method.

If the position of the cancer affected area is limited, the amount of deviation of the cancer affected area from the axis of the heavy ion beam can be known. Therefore, the treatment table (1) can be moved and adjusted to correct this deviation.

When the heavy ion beam irradiation treatment is performed for the same patient (2) for the second time, the patient (2) is first imaged by the X-ray imaging apparatus as in the previous time. Then, as shown in FIG. 12, the second X-ray film (8) obtained by development is also marked with the second landmark (9) at the same position as the X-ray film (6). After that, the position of the affected part of the cancer may be limited from each second landmark (9) in the same manner as the previous time, and the treatment table (1) may be moved and adjusted.

Furthermore, when the third and subsequent treatments are performed, the same operation as above may be repeated to limit the position of the cancer affected area.

By the way, such a conventional X-ray film (6),
With the method for limiting the position of the cancerous part according to (8), it takes at least 1 to 2 minutes to develop the image even if an automatic developing device is used, and in the case of X-ray image failure, re-imaging after development is required. In addition, since the work of attaching the landmarks (7) and (9) is manually performed by the technician, it takes time and labor to limit the position of the cancer-affected part, and the utilization efficiency of the heavy ion beam treatment apparatus decreases, Further, during that time, the patient (2) has to wait while being fixed to the treatment table (1), which causes a problem that the patient (2) is burdened. In addition, since the position of the cancer affected area is manually limited by the technician, an error may occur,
There was also the problem that the position of the affected area was not reliable and reproducible.

On the other hand, when the position of the affected area is limited by X-ray TV, it does not take much time for development, and it is possible to adjust to the best image while looking at the image, and it is also possible to digitize the image. Since the problems of various X-ray films (6) and (8) can be solved, the use of X-ray TV for limiting the position of the affected area is being studied.

[Problems to be Solved by the Invention] However, in the conventional X-ray TV imaging method, since the input surface of the image intensifier is curved, the center axis of the X-ray is displaced from the center of the input surface. Therefore, the X-ray image obtained on the TV monitor has a pincushion-like distortion, and the amount of the distortion increases toward the outer periphery of the X-ray image, and an accurate plane image cannot be obtained. There was a problem that it was difficult to irradiate.

The present invention has been made to solve the above problems, and can eliminate pincushion distortion of an X-ray image obtained on a TV monitor of an X-ray TV, and irradiate radiation at a more accurate position. It is an object of the present invention to obtain a radiation irradiation device that can be used.

[Means for Solving the Problems] A radiation irradiation apparatus according to the present invention transmits X-rays and is horizontally position-adjustable. , A radiation source that irradiates the object to be irradiated with X-rays, an X-ray source that irradiates the object to be irradiated on the moving table with X-rays, and an image intensifier facing the X-ray source with the moving table in between. An X-ray TV having an image pickup means connected to the intensifier and a TV monitor connected to the image pickup means, a reference body imaged by the X-ray TV, and an X of the reference body reflected on the TV monitor. X-ray image correction having a computer for obtaining a correction coefficient for correcting the distortion of the line image, and a correction unit for correcting the X-ray image of the irradiation target by the correction coefficient when the irradiation target is photographed by the X-ray TV The device and the marking points and By storing the positional relationship between the line irradiated portion, to specify the position of the landmark points on the X-ray image of the irradiated object which is corrected by the correction unit,
And a movable table control device for determining the position of the radiation irradiation section on the X-ray image and moving the movable table so that the radiation irradiation section is located on the axis of the radiation from the radiation source.

[Operation] In the present invention, the image of the TV monitor is corrected by the correction coefficient when the subject is photographed, and a flattened X-ray image of the subject is obtained without distortion. By specifying the position of the mark point, the mobile platform control device obtains the position of the radiation irradiation unit, and moves the mobile platform accordingly.
The radiation irradiation unit is located on the axis of the radiation from the radiation source.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an X-ray TV of a radiation irradiating apparatus according to an embodiment of the present invention. The same or corresponding parts as in FIG. 10 are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, (11) is a plate-shaped coordinate frame placed facing the X-ray tube (3) at a predetermined distance, and the coordinate frame (11) is used as a reference body as shown in FIG. A coordinate body (12) is provided. The coordinate body (12) is, for example, one in which thin tungsten wires are provided in a wire mesh shape, or one drawn on a substrate with copper foil, gold plating, or the like. (13) is an image intensifier placed below the coordinate frame (11), and this image intensifier (13) cooperates with an image pickup tube (not shown) attached to the back as a photographing means. Then, the invisible light image by the X-ray is converted into a visible light image. Reference numeral (14) is a TV monitor connected to the image intensifier (13) through an image pickup tube. The TV monitor (14), the X-ray tube (3), the X-ray controller (4), and the collimator (5) ), The image intensifier (13) and the image pickup tube constitute an X-ray TV.

Next, a method of limiting the position of the affected part which is the radiation irradiation part will be described. First, X-rays are emitted from the X-ray tube (3).
Then, the X-rays travel in the direction of the arrow in the figure, pass through the coordinate frame (11), and enter the image intensifier (13). This X-ray is visualized by the image intensifier (13) and the image pickup tube, and the X-ray image (15) of the coordinate body (12) is displayed on the TV monitor (14). At this time, the X-ray image (15) has a shape having a pincushion distortion as shown in FIG.

Therefore, the distorted X-ray image (15) is corrected (planarized) into a corrected X-ray image (16) having the same shape as the coordinate body (12) as shown in FIG. This includes misaligned X-ray images (15)
The correction coefficient for moving the point at each position on the corrected X-ray image (16) is obtained by a computer, and the correction coefficient (not shown) may be applied in front of the TV monitor (14). At this time, the correction coefficient differs depending on the position on the image. Further, the X-ray image correction apparatus of this embodiment has a coordinate frame (11), a computer and a correction unit.

In this way, when the correction of the correction coefficient image (16) is completed, the actual image of the patient (2) is photographed in the corrected state as shown in FIG. Then, since the patient X-ray image (17) of the patient (2) having a pincushion distortion as shown in FIG. 6 is flattened by the correction coefficient, the flattened patient X-ray as shown in FIG. 7 is obtained. Statue (1
8) is obtained.

Next, using this flattened patient X-ray image (18), a method of limiting the position of the affected part and moving and adjusting the treatment table (1) so that the affected part is located on the axis of the heavy ion beam will be described. To do.
First, in most cases, the flattened patient X-ray image (18) does not show the cancer affected area. Therefore, a reference image created from the X-ray CT image was used as in the conventional example, and the image was shown in this reference image. The position of the cancer affected area is limited on the flattened patient X-ray image (18) from the relative position of the cancer affected area. That is, the landmark points clearly visible in the flattened patient X-ray image (18) and the cancer affected area are designated on the reference image, and after the positional relationship between these two points is determined, the flattened patient X-ray image (18) is obtained. A mark point is designated above, and the position of the cancer affected part is limited on the flattened patient X-ray image (18) based on the positional relationship from this mark point. At this time, since both the reference image and the flattened patient X-ray image (18) can be digitized, the above-mentioned work can be automated, and the position of the cancer affected area can be numerically displayed on the screen of the TV monitor (14). Can be limited.

If the position of the cancer affected area is limited, the amount of deviation of the cancer affected area from the axis of the heavy ion beam can be known. Therefore, the treatment table (1) can be moved and adjusted to correct this deviation. This movement adjustment can also be automated by digitizing the flattened patient X-ray image (18). As described above, a series of operations for determining the position of the cancer affected part on the flattened patient X-ray image (18) and moving the treatment table (1) in accordance with the position is performed by a moving table control device (not shown). . Thereafter, radiation, here a heavy ion beam, is emitted from a radiation source (not shown).

Also, the position of the cancer affected area can be limited in the same manner as above even during the second and subsequent treatments. At this time, the flattened patient X-ray image (18) is digitized and the past X-ray image of the patient (2) is obtained.
By storing the line image as data, the position of the cancer affected area can be more easily limited.

Further, in the above-mentioned embodiment, since the flattened patient X-ray image (18) is flattened, it can be compared with the reference image by X-ray CT.

Further, in the above-mentioned embodiment, the position of the affected area can be easily limited in a short time, thereby reducing the burden on the patient, the position of the affected area can be accurately limited, and the reliability of the position of the affected area and the reproducibility are also improved. be able to.

Although the coordinate body (12) is shown as the reference body in the above-mentioned embodiment, if the coordinate body (12) is made of a material that can be seen on an X-ray TV, such as the one shown in FIG. The reference body may have other shapes. Also, the coordinate frame (1
A plurality of landmarks may be attached to 1) as a reference body, and the correction coefficient may be obtained from the positional deviation of each landmark.

In the above embodiment, the X-ray TV is composed of an X-ray tube (3), an X-ray controller (4), a collimator (5), an image intensifier (13), a TV monitor (14) and an image pickup tube. Although shown, for example, an X-ray generator other than the X-ray tube (3) may be used as an X-ray source, or a solid-state image sensor such as a CCD may be used as the image pickup means instead of the image pickup tube. Good.

[Effects of the Invention] As described above, the radiation irradiating device of the present invention is
The computer calculates the correction coefficient from the reference object displayed on the monitor, and the image on the TV monitor is corrected by this correction coefficient so that the image on the TV monitor is corrected when the subject is photographed. It is possible to eliminate the pincushion distortion of the obtained X-ray image of the object to be photographed, to obtain an accurate plane image of the object to be photographed, and to store the positional relationship between the marking points on the object and the radiation irradiation part. By specifying the position of the mark point on the X-ray image of the irradiated object corrected by the correction unit, the position of the radiation irradiation unit on the X-ray image is obtained, and the position of the radiation from the radiation source is on the axis line. Since the moving table control device that moves the moving table so that the irradiated body is positioned is used, there is an effect that the radiation can be applied to a more accurate position.

[Brief description of drawings]

FIG. 1 shows X of a radiation irradiation apparatus according to an embodiment of the present invention.
FIG. 2 is a front view showing the coordinate body of FIG. 1, FIG. 3 is a front view showing an X-ray image of the coordinate body of FIG. 1 before correction, and FIG. FIG. 4 is a front view showing a corrected X-ray image after correction of the coordinate body of FIG. 1, and FIG. 5 is an X-ray TV of FIG.
6 is a front view showing the patient X-ray image of the patient before correction shown in FIG. 5, and FIG. 7 shows a planarized patient X-ray image of the patient shown in FIG. 5 after correction. Front view showing, FIG. 8 and FIG.
The drawings are respectively a front view and a second view showing another embodiment of the correction figure.
FIG. 10 is a block diagram showing an X-ray imaging apparatus for X-ray film,
FIG. 11 is a front view showing the state after development of the X-ray film of FIG. 10, and FIG. 12 is a front view showing the second X-ray film of FIG. In the figure, (2) is a patient, (3) is an X-ray tube, (4) is an X-ray controller, (5) is a collimator, (12) is a coordinate body,
(13) is an image intensifier and (14) is a TV monitor. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A movable table, which is transparent to X-rays and is position-adjustable, on which an object to be irradiated is placed, a radiation source for irradiating the object to be irradiated on the movable table with radiation, and the movement. An X-ray source for irradiating the irradiated object on the table with X-rays,
An image intensifier facing the X-ray source with the movable table sandwiched therebetween, an imaging means connected to the image intensifier, and an imaging means connected to the imaging means.
An X-ray TV having a TV monitor, a reference body imaged by the X-ray TV, a computer for obtaining a correction coefficient for correcting the distortion of the X-ray image of the reference body reflected on the TV monitor, and the X-ray X-ray of the irradiated body is corrected by the correction coefficient when the irradiated body is photographed by the line TV.
An X-ray image correction apparatus having a correction unit for correcting a line image, and a positional relationship between a mark point on the irradiation target and the radiation irradiation unit are stored, and the irradiation target of the irradiation target corrected by the correction unit is stored. By specifying the position of the mark point on the X-ray image, the position of the radiation irradiation unit on the X-ray image is obtained, and the radiation irradiation unit is positioned on the axis of the radiation from the radiation source. And a moving table control device for moving the moving table.