Transverse axial tomography using X-ray

The situation regarding transverse axial tomography, at present expanding rapidly, is reviewed. Owing to modern computing and data processing means and methods it is no longer necessary to use water around the head and the examinations may be extended to the whole body. The technique of image reconstitution by absorption measurement is the only method employed in practice because, although calculations show that the use of Compton radiation would lead to comparable results, a much more complex detection system and above all a monoenergetic incident beam would be necessary. The gain on the scanning time can be considerable. The use of N elements detecting simultaneously should reduce it by about a factor N. The main features of tomographs proposed by different makers are described