JPH0114781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray imaging apparatus used for intraoral X-ray imaging for dental diagnosis.

When X-raying two or three specific teeth in the above-mentioned intraoral X-ray photography, it is necessary to set a film inside the oral cavity and irradiate it with X-rays from the outside. Conventionally, a light beam method or a film holder method with an optical sight has been used as a method for positioning the X-ray irradiation tube. The former light beam method provides the operator with information for determining positioning by emitting a light beam from the X-ray irradiation tube and brightly illuminating a point on the film surface or patient's surface that intersects with the X-ray central axis. However, since the light beam irradiation point is far from the center of the film, and the relationship between the film center and the light beam irradiation point position and direction cannot be easily determined visually, accurate positioning is not possible, and it is difficult for experienced operators to It takes intuition. In addition, the latter type of film holder with irradiator is positioned by docking the irradiator to a sight that is connected and fixed to the film holder. It has to be fixed by biting on the patient's mouth, placing a heavy burden on the patient and placing restrictions on the film set in the oral cavity.

The present invention aims to eliminate such difficulties, and includes an X-ray irradiation head that is positioned sandwiching a person to be photographed, and an opposing member that follows the X-ray irradiation head while maintaining an opposing relationship with the X-ray irradiation head. Forms a parallel magnetic field that passes through the subject centered on the line center axis,
The dental X-ray photographing apparatus is characterized in that magnetic detection sensors sensitive to the parallel magnetic field are attached to each of the four corners on the side of the X-ray film set in the oral cavity of the patient.

The details of the present invention will be explained below with reference to the drawings. In FIG. 1, a magnet M1 centered on the X-ray central axis m is attached to the irradiation barrel 2 of the X-ray irradiation head 1, and a member facing the magnet M1 is attached to the irradiation tube 2 of the X-ray irradiation head 1. Similarly to 3, the X-ray central axis m
Attach magnet M2 centered on
1 and M2, a parallel magnetic field 4 centered on the X-ray central axis m is formed. It goes without saying that the magnetic field strength is the same at any point within this parallel magnetic field 4. On the other hand, on the film F side, as shown in FIG. 2, magnetic detection sensors S1 are attached to the four corners of the film holder 5 on the non-X-ray irradiation side as shown in FIG.

With this configuration, if the film holder 5 is inserted into the parallel magnetic field 4 of magnets M1 and M2,
Even if the line center axis m and the film center or holder center f do not completely match, the magnetic detection sensor 8
As long as ... is in the parallel magnetic field 4, each sensor output value shows the same value. Therefore, as long as the X-ray irradiation field covers the parallel magnetic field, the X-ray central axis m and the film center or holder center f can be perfectly aligned, and without the need for troublesome coaxial operations. The irradiation tube 2 and the film F can be accurately positioned within a range that causes no practical problems.

FIG. 3 shows the configuration of an embodiment of the present invention, in which the X-ray irradiation head 1 and the opposing member 3 are regulated so that they are always in a facing relationship with the person 6 sandwiched between them. The guide members 1a and 3a extending from the guide members 1 and 3 are fitted together to form a telescopic cylinder 7, so that the distance between the X-ray irradiation head 1 and the facing member 3 can be varied. Further, the X-ray irradiation head 1 is held by a suspension rod 8, and is configured such that the position change operation can be applied to the person to be imaged 6 in the vertical direction and rotation direction integrally with the facing member 3. A magnet M1 is attached to the X-ray irradiation tube 2, and a magnet M1 is attached to the opposing member 3.
2 is attached, and a parallel magnetic field 4 passing through the photographed person 6 is formed.

In this device, from a state where the film F or the film holder 5 containing the film F is positioned inside the irradiation target tooth 9, the X-ray irradiation head 1 and the opposing member 3 are moved around the subject 6, and the magnetic Find a point where each output of the detection sensor S... shows the same value. As is clear from the above description, when each output value matches, it means that each sensor S is placed within the parallel magnetic field 4, and the positioning of the X-ray irradiation tube 2 and the film F has been completed correctly.
From this state, predetermined X-ray photography is performed.

FIG. 4 shows an example of the detection display circuit of the magnetic detection sensor S in such an X-ray imaging device,
The output of each sensor S... is detected by a detector or amplifier A.
After being taken out through ..., the outputs of adjacent sensors are compared by a comparator WO, and the three types of outputs indicating whether the two outputs are equal or which one is larger are input to the display means D, and the operator The X-ray irradiation head 1 is moved while looking at this comparison display. E is a drive power supply.

Note that as the magnetic detection sensor, a magnetic modulation type sensor, a Hall element, a magnetoresistive element, a SOUID, etc. can be considered.

As described above, according to the present invention, by finding the point where the outputs of the magnetic detection sensor attached to the film side match, the film and sensor are automatically formed between the X-ray irradiation head and the member facing it. The X-ray irradiation head and the film are positioned within the parallel magnetic field generated by the X-ray irradiation field, and the film is placed within the X-ray irradiation field. In addition to eliminating the drawbacks of the positioning method, since accurate positioning can be performed, it is possible to narrow down the X-ray irradiation field and cut out excess X-rays, reducing the exposure dose to the patient. be.

[Brief explanation of drawings]

FIG. 1 is a diagram of the present invention, FIG. 2 is a diagram showing the arrangement of the magnetic detection sensor with respect to the film, FIG. 3 is a schematic front view showing one embodiment, and FIG. 4 is an example of the detection display circuit of the magnetic detection sensor. FIG. (Explanation of symbols), 1...X-ray irradiation head, 3...
...Opposing member, 4...Parallel magnetic field, 6...Photographed person,
F...Film, m...X-ray central axis.

Claims (1)

[Claims] 1. Forming a parallel magnetic field that passes through the person to be imaged around the central axis of the X-rays over an X-ray irradiation head that is positioned to sandwich the person to be imaged, and a facing member that maintains a facing relationship with the X-ray irradiation head; A dental X-ray photographing apparatus comprising magnetic detection sensors sensitive to the above-mentioned parallel magnetic field attached to each of the four corners on the side of the X-ray film set in the oral cavity of a patient.