A review of a series of qualitative and quantitative investigations of the capabilities of fluoroscopic systems to produce images having a sufficiently high quality to be used as the input for producing computerized transaxial tomograms is given. Examples of tomographic sections obtained from fluoroscopic image inputs are presented. In addition a quantitative comparison of computerized tomograms of a specially constructed phantom was made between reconstructions made with the EMI head scanner and those made from images provided by a large screen low light level TV camera fluoroscopic system. A phantom made from Lucite containing rods of various materials and sizes was used. The computer printout of each was analyzed and a high degree of correlation (r = 0.98) was noted between the results of both systems. The differential attenuation detectability of the fluoroscopic system was found to be comparable to or better than the EMI unit. As expected from a consideration of the quantum statistics for each system, the noise in the obtained reconstructions was also comparable. It is concluded that such a fluoroscopic system performs favorably when compared to the presently available commercial systems.