Time Subtraction Digital Fluoroscopy with a Dual Memory System

This paper describes an x-ray fluoroscopic system for imaging arterial structures following intravenous injection of contrast medium. This system digitally processes video data from a TV camera that views the output of an x-ray image intensifier. The digital processing includes subtraction and contrast amplification. The unit (1) produces a real-time, continuous subtraction sequence, (2) improves the signal-to-noise ratio by averaging together up to 128 video frames generated at fluoroscopic levels, (3) does not require an interface to eh x-ray generator, and (4) can use either a moving or frozen mask image for subtraction.