JPS61276546A - X-ray examination apparatus - 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 Field of Industrial Application This invention relates to an X-ray inspection apparatus, and more particularly to an X-ray inspection apparatus equipped with a device for projecting an X-ray field with light.

Conventional technology In cardiovascular X-ray examinations, etc., there is a photographic method in which X-rays are irradiated from the front of the subject lying on the top of the examination table;
There is a photography method in which the light is illuminated from behind. A-P photography of the former (
The latter is called P-A photography (Antero-Posterior photography).
It is called "terior" (abbreviation for "back-front" photography).

Comparing these two shooting methods, we find that in A-P shooting, the image receiving system's image amblifier and film changer are located below the top plate, making it difficult to rotate due to space constraints; - In the Ai shadow, the image amblifier and film changer are located above the top plate, so it is easy to rotate and replace them.
You can quickly switch from fluoroscopy to photography. In addition, when photographing the head, the X-ray exposure to the crystalline lens of the subject's eyes is lower with P-A photography. It is said that photography is better. However, in P-A shooting,
Even if a light beam similar to an X-ray beam is irradiated, the light is projected onto the back side of the top plate, so the light cannot be projected directly onto the patient, making it difficult to confirm the irradiation field with light. be.

On the other hand, in AP imaging, if a light beam is generated in the same way as an X-ray beam, the light is directly projected onto the subject, making it easy to confirm the irradiation field with the light.

Problems to be Solved by the Invention As described above, although P-A imaging has many advantages, it has a problem with ease of use in that it is difficult to confirm the irradiation field with light.

An object of the present invention is to provide an X-ray inspection apparatus that can overcome the difficulty in confirming the irradiation field using light in PA imaging.

Means for Solving the Problems The X-ray inspection apparatus according to the present invention has an
From the parameters including the aperture of the line diaphragm device and the imaging distance, the position corresponding to the outside edge of the X-ray irradiation area on the subject's surface is calculated, and the irradiation field projection device that projects light at that position is placed on the top plate. It is characterized by being provided on the image receiving system side, which is located above the image receiving system.

In the case of P-A imaging, the X-ray tube is placed below the top of the examination table, the image receiving system is placed above the top, and the image receiving system is placed behind the subject lying on the top. An X-ray irradiation field projection device is installed in the image receiving system placed above the top plate, and the X-ray field projection device is placed at a position corresponding to the area outside the X-ray irradiation area on the subject's surface determined by calculation. , light is projected from this X-ray field projection device. Therefore, the X-ray irradiation field can be easily confirmed by the light projected from above the subject.

Embodiment In FIG. 1, a top plate 2 is held on an examination table 1 so as to be movable up and down. The subject 10 lies on this top plate 2. An X-ray tube 3, an aperture device 4 for concentrating X-rays are located under the top plate 2, an image amblifier 5, an X-ray television device 6. The image receiving systems such as the film changer 7 are held by the C-arm 8 so that they are located above the top plate 2. This C-arm 8 is held by a C-arm stand 9. The image amblifier 5, the X-ray television device 6, and the film changer 7 are designed to be able to rotate together with axis 0 as the rotation axis, and this rotation changes the direction from fluoroscopy using the X-ray television to imaging on film. It switches.

An L-shaped irradiation field projection device 71 is attached around the film changer 7. The reason for the L-shape is to avoid blocking the X-rays entering the film changer 7. The irradiation field projection device 7 includes a horizontal projector 72 and a vertical projector 73.
It consists of

The aperture device 4 includes a lateral leaf 4 for aperture as shown in FIG.
1 and a vertical leaf 42, and the X-ray irradiation field is adjusted by moving these in the horizontal and vertical directions. Then, from the horizontal projector 72, a linear light pattern indicating the lateral outer edge of the irradiation field (corresponding to the position of the horizontal leaf 41) is projected onto the body surface of the subject 10, and from the vertical projector 73, A linear light pattern indicating the longitudinal outer edge of the irradiation field (corresponding to the position of the vertical leaf 42) is projected onto the body surface of the subject 10.

Next, for convenience of explanation, the horizontal projector 72 will be explained. The vertical projector 73 is completely the same except for the vertical and horizontal dimensions, so the explanation will be omitted. As shown in FIG. 3, a laser beam from a laser generator 81 is guided to a laser head 83 through an optical fiber 82, and a planar light beam emitted from here is split into two directions by a beam splitter 84. Each is bent at right angles by mirrors 85 and 85.

In this way, a light beam is projected perpendicularly onto the film, thereby displaying a linear light pattern on the body surface of the subject IO.

Here, the position of the mirrors 85, 85 is adjusted by the motor 86 so that the interval a between the linear light patterns can be changed. The value of this interval a is determined by a = b (A/B). Here, b is the opening amount of the horizontal leaf 41, B
is the distance from the X-ray focal point to the horizontal leaf 41, and A is the distance from the X-ray focal point to the light pattern projection surface of the subject IO.

However, A=A'+δ, where Ao is the distance from the focal point to the top surface of the top plate 2, and δ is the distance from the top surface of the top plate 2 to the light pattern projection surface of the subject 10.

That is, the opening amount of the horizontal leaf 41, the leaf potential,
As well as being detected by the meter 43.

The value of Ao is detected by the examination table potentiometer 11, and these values and the value of δ manually set by the operator according to the thickness of the subject IO are calculated by the calculator 91.
is input to calculate the value of a. This value is applied as a setting signal to the comparator 92, and is compared with the output of the potentiometer 87 which detects the distance between the mirrors 85, thereby controlling the motor 86. In this way, even if each parameter changes, a light pattern with an interval a calculated accordingly will be projected toward the subject 10.

FIG. 4 shows a second embodiment of the transverse projector 72.

Here, the light is not projected at right angles to the film as in FIG. 3, but directed toward the X-ray focal point. That is, in addition to the configuration shown in FIG. 3, an angle motor 88 for adjusting the angle of the mirror 85 is added, and not only the distance a between the mirrors 85 and 85 but also the light projection angle θ is controlled. It looks like this. This angle θ is given by θ=jan-(a/2A), and the calculator 91 calculates θ as well as a=b・(A/B). However, in these equations, A is the focal point. This is the distance from the mirror 85 to the mirror 85. Angle motor setting signal corresponding to θ and angle potentiometer 89
A comparator 93.93 compares the detected angle signal with the angle signal detected by the angle motor 88.88, and the angle motor 88.88 is controlled to project light at an angle θ directed toward the focal point.

Here, the vertical projection method (Fig. 3) and the focal projection method (Fig. 4) are used.
Mechanism-wise, if you compare it with Figure),

Whereas the latter requires angle control and is complicated,
The former has a simple mechanism and can be easily miniaturized.

On the other hand, in the former case, the value of δ must be entered manually, which is both cumbersome and inaccurate, and it also becomes inaccurate in principle if the imaging system is tilted (however, in practice, it is often used tilted). In this respect, the latter does not require manual input and is not complicated, and is accurate in principle, even if the imaging system is tilted.

In short, the vertical projection method has a simple mechanism but is not always accurate, while the focal projection method has a complicated mechanism but is accurate, and it is thought that it is better to use one depending on the purpose.

Although a laser generator was used as the light source in the above embodiment, it goes without saying that any light source capable of projecting a linear light pattern may be used.

For example, as shown in FIGS. 5 and 6, a projector 90 that combines an incandescent lamp and a lens may be used.

Further, although the control system is a closed loop in the above example, it may be an open loop control system using a stepping motor or the like depending on the purpose of use.

Effects of the Invention According to the present invention, it is possible to easily confirm the X-ray irradiation field using light in PA imaging. Therefore.

First-class effects can be obtained, such as speeding up positioning, reducing exposure dose, and making it possible to focus X-rays as necessary and sufficiently, making it possible to take good images without halation.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of one embodiment of the present invention, Fig. 2 is a schematic diagram for explaining the principle, Fig. 3 is a block diagram of the horizontal projector, and Fig. 4 is another embodiment of the horizontal projector. FIGS. 5 and 6 are block diagrams of modified examples. 1...Examination table 2...Top plate 3...X-ray tube 4...Aperture device 5...Image amplifier filter...X-ray television device 7...Film changer 8...C Arm 9... C-arm stand door 1... Irradiation field projection device 72... Lateral projector 73
...Vertical projector

Claims (1)

[Claims] (1) The examination table has an X-ray tube placed under the top plate and an image receiving system placed above the top plate, and a patient lying on the top plate is Inspection by irradiating X-rays from behind
In the radiation inspection apparatus, a position corresponding to the outside area of the X-ray irradiation area on the surface of the subject is calculated from parameters including the aperture amount and imaging distance of the X-ray diaphragm device provided in the X-ray tube,
An X-ray inspection apparatus characterized in that an irradiation field projection device for projecting light onto the position is provided on the image receiving system side.