A variable aperture fluoroscopic unit for reduced patient exposure

A real time fluoroscopic imaging system which provides capability for reduced patient exposure by as much as a factor of five has been developed. Modifications to the system include the incorporation of a variable aperture iris between the image intensifier output phosphor and television camera and the use of the video signal as the feedback element in the fluoroscopic automatic exposure rate control system. Quantitative and qualitative performance of the system is described.