Gould R G
Appl Radiol. 1982 Nov-Dec;11(6):83-4, 87-9.
A digital fluoroscopic system is described that reduces noise in the subtraction image by averaging together video frames generated while the x-ray tube is operated at fluoroscopic current levels. Compared with pulsed digital systems, it has the advantage of easing x-ray equipment performance requirements, including those of the video camera. The frame-averaging system produces a real-time, noise-reduced subtraction sequence that permits continuous observation of a bolus of contrast agent as it passes through vessels in the field of view.