FI98341C - Method for locating cross sections - Google Patents

Description

98341

Method for locating cross sections.

For the purpose of localization, see the Annex.

The invention relates to a method for locating transverse sectional images of a certain part of the jaw arch, which imaging is performed by a panoramic X-ray device equipped with patient support equipment and software for imaging the jawbone in the transverse direction.

Typically, sectional images have been taken with either a planar tomography device or computed tomography. Plane tomography provides sectional images whose position in the jaw must be assessed based on device settings or the anatomy of the sectional image. There is no clear location shown in the image. With computed tomography dental imaging programs, the desired section of the jaw can be taken and distances can also be obtained. Computed tomography is substantially more expensive than the panoramic X-ray device used in connection with the present invention, and in addition, the computed tomography device uses a computer to take an image and calculate distances.

It is an object of the present invention to provide a relatively simple method for accurately viewing the location of a cross-section in the jawbone. In addition, in the method according to the invention, a vertical scale can be connected to the clip symbol.

In order to achieve the objects of the present invention, the method according to the invention is characterized in that in the method the cross-sections are imaged on the same film as the longitudinal view of the corresponding jaw arc, and that the section identifiers are exposed to the section images.

The method according to the invention is carried out with a panoramic X-ray device for dental imaging, which has a special program which describes, with a suitable patient layout, section images 98341 2 perpendicular to the jawbone. Clip images are shot in a number of 3-4 pieces suitable for the second half of the device's 15x30 film. Each clip art is at a different point in the jawbone, with a clip thickness of about 4 mm. At one end of the film, the jawbone is depicted at a point corresponding to the longitudinal position as the clips, so that the points of the clip are visible in the longitudinal view.

Each clip is given an identifier, e.g. A, B, C, which is also arranged to appear in the longitudinal view at the point corresponding to the clip. A vertical scale can be arranged on the symbol in the clip, which takes into account the magnification ratio of the description. This method allows sections of the jawbone to be imaged and their location determined by a longitudinal image with all the information on a single film.

The invention will now be described with reference to the accompanying drawings, in which:

Figure 1 shows an arrangement for carrying out the method according to the invention,

Figures 1a and ib show the side and front views of the patient support used in the method according to the invention, respectively.

Fig. 2 shows the imaging result obtained by the arrangement according to Fig. 1,

Figure 3 shows another arrangement for carrying out the method according to the invention, and

Fig. 4 shows the imaging result obtained by the arrangement according to Fig. 3.

The arrangement according to Fig. 1 uses a substantially inverted T-shaped patient support 1, the horizontal part of which T ia ta.i ut »i.i ia> i 98341 comes under the jawbone and guides it vertically to the right level. The vertical part of the T guides the jawbone horizontally so that the image projection of the transverse section becomes correct with respect to the beam of radiation and the movement of the center of rotation. The section mark is placed in the vertical part of T together with a possible vertical scale 2 (1: 1). The vertical part of the letter T is ascending so that the clips of the clips are at different levels, so that they do not overlap. Figure 2 shows the imaging result obtained with the method according to the invention on film. The left half of the film shows three cross-sectional images with their symbols (A, B, C) together with vertical scales. The right half of the figure shows a longitudinal description with the corresponding symbols (A, B, C).

Figure 3 shows another arrangement for carrying out the method according to the invention. In this arrangement, the desired clip point identifiers are made in a transparent template 4 entering the film cassette 3, which is placed with the film between the reinforcement plates. The film and Template are always in the same position on cassette 3. During shooting, the reinforcement plate illuminates the film through the template 4 except for the areas of opaque markings that appear unexposed on the film.

The shooting mechanics of the device take pictures from the locations specified by the shooting program to the locations specified by the shooting program on the film cassette. In this case, the clip marks can be made in the corresponding place on the template to be placed in the cassette. Correspondingly, the longitudinal image 5 is always imaged from the set position to the set position on the film cassette, whereby the positions of the clips 6 can be marked in the template at the set position.

The imaging program captures the subject at a geometric magnification ratio set on the film, which can be calculated from the imaging movements and the mechanical dimensions of the device. The subject is enlarged by its magnification by its magnification. For example, a millimeter scale can be arranged in the section identifiers of the model, the division interval of which is 98,931 deviating from the right by the magnification ratio. However, when the layer thickness of the sectional image is about 4 min and only the vertical distances are measured, the inaccuracy caused by the change in the magnification ratio is not significant.

Alternatively, the markings can also be made directly on the surface of the reinforcing plate, so that the reinforcing plate material below them cannot expose the film.

Fig. 4 shows an imaging result similar to Fig. 2, in which the left half of the film shows three cross-sectional views 6 and the right half shows a longitudinal view 5. The film also shows the markings 8 in the model 4 (clip art symbols A, B and C and vertical scales).

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Claims (6)

A method for locating transverse sectional images (6) of a particular part of the jaw, which is imaged by a panoramic X-ray device equipped with a patient support apparatus (1) and software for transverse imaging of the jawbone, characterized in that the cross-sections (6) (5), and that the section marks (A, B, C) are exposed to the section pictures (6), which marks are also exposed to the longitudinal section (5) at the transverse sections. Method according to Claim 1, characterized in that in the method, a vertical measuring scale (2) is additionally provided in the cross-sectional view (6). Method according to claim 1, characterized in that the desired clip marking on the film is obtained by placing on the patient support (1) at the clip (6) an appropriate clip point identifier (a, B, C) which is adjacent to the cross-section (6) and the longitudinal image (5) clip location. Method according to Claim 3, characterized in that the markings (A, B, C) of the different sections on the patient support (1) are placed at different heights, so that they do not overlap, and wherein the vertical position of the marks indicates the position of the section in the longitudinal view (5). i A method according to claim 3, characterized in that in addition to the section mark, a vertical scale (2) is placed on the patient support (1), which is depicted next to the section image to facilitate the estimation of distances. 6 98341 Method according to claim 1 or 2, characterized in that the desired marking of the clip and possibly the vertical scale (2) on the film is achieved by marking the appropriate marks on the reinforcement plate of the film cassette (3) or on the transparent film (4) entering the cassette. 98341 7