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Conventional methods of displaying three-dimensional information in X-ray diagnostics like tomography or tomosynthesis are not capable of imaging fast moving objects because of the time-sequential recording process. To overcome this difficulty the method of coded aperture imaging using nonredundant point distributions is applied to X-ray imaging. The object coded by an array of X-ray sources is deconvoluted by means of an optical processing system using monochromatic, but spatially incoherent light. Experimental results obtained with simple objects show good resolution in detail as well as in depth. Moreover, an on-line system has been simulated using coded images on X-ray films with a TV-camera pick up in conjunction with an electrooptic relay tube.

The method of evaluating the two-dimensional modulation transfer function (MTF) of X-ray systems by imaging statistically distributed lead grains is extended to three-dimensional imaging systems. The MTF's of tomographic and tomosynthesis systems are displayed in different layers obtained by optical Fourier-processing. The results show that the method is a convenient tool for investigating pseudo-resolution effects and for checking the adjustment of these complicated systems.

A circular symmetric tomosynthetic arrangement has been investigated using holographic storage techniques. With a set of 24 single radiographs a 3D image of a human orbita region has been generated by image integration leading to a continuously variable depth display of arbitrary layers. The received resolution in a particular layer was about 3 1p/mm. An estimate will be given for the number of necessary radiographs to compare the blurr quality of discrete sample procedures in tomosynthesis with a continuous motion in tomography. Finally a short outline will be given for a possible real-time procedure.

A three-dimensional radiographic imaging system has been developed, and is presently being clinically evaluated. Twenty conventional radiographs are reduced and reprojected into a display volume according to a geometry which matches the X-ray source geometry. The images are integrated on a viewing screen and produce the tomographic plane corresponding to the screen's position. Planes parallel and tilted with respect to the scanning plane can be observed by simply adjusting the screen. The image is continuous in all directions, possesses a resolution of about 2lp/mm, and is usually true-sized, although factors of 2 or 3 in magnification can be easily produced.