| 摘要 |
In order to enhance the image quality in intraoral radiography and to reduce the radiation dose for the patient, an ancillary unit has been designed for the conventional dental X-ray apparatus. The unit comprises a fixed "camera system" (for intraoral radiography) with a special aperture system 4 - 9 (Figure I, II-III) and an exchangeable film holder which is fixed to the X-ray tube during the exposure. The image quality is improved by the film being kept flat during the radiography, and by avoiding lack of sharpness of the image which is caused by movement. The film holder is locked securely to the tube during the exposure. The image quality is also improved by means of the fact that only the film plane is exposed to radiation. This is made possible by means of an aperture 4-5, 6 which is inserted into the outer mouth of the X-ray tube. The aperture opening is coordinated with the size and position of the film. There are three different aperture openings 7a, 7b, 7c in order to account for different film sizes. The coordination of aperture to film is done automatically 8, 9. <IMAGE> |
