In this paper the basic technical problems and clinical application of digital tomosynthesis is described. Digital tomosynthesis system consists of Hitachi L-UG tomographic X-ray machine modified by the addition of an image intensifier (I. I) and TV camera system with a 512×512 matrix. We have studied digital tomosynthesis enabling to reconstruct tomographic image by the use of linear tomographic motion with a swing angle of 40゜ and circular motions with a swing angle of 8゜ or 40゜. The following results were obtained. 1) It was necessary for the digital tomosynthesis system to raise the table top by 12.6 cm in order to get the same plane as the conventional film-screen X-ray tomography. The spatial resolution of tomografic image obtained was 1.0 line pairs/mm. 2) The computer processing system enabled to improve the image quality of digital tomosynthesis. The technique has a clinical advantage of shortening the examination time, since the data can be collected in one exposure and the image can be reconstructed at any desirable depth. 3) The advantage of the digital tomosynthesis system have got low patient radiation dose and short examination time compared with the conventional film screen tomography.

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