Fluoroscopy in children: low-exposure technology.

A fluoroscopic system was modified to achieve a 95-98% reduction in radiation exposure and dosage to patients compared with other systems that reduce fluoroscopic radiation dosage. This reduction was accomplished by custom selection of a high conversion-factor, triplemode image intensifier; custom design of a variable-dose rheostat, allowing maximum operator control of video camera gain; installation of an erbium rare-earth beam filter on the x-ray tube; and addition of a digital noise reducer (recursive filter). A total of 1,577 fluoroscopic examinations has been performed on this system, with excellent results. Contrast resolution was increased, while spatial resolution was maintained. Noise (quantum mottle) has been reduced by the addition of a digital image processor. Advantages of the ultra-low-dose system include: all fluoroscopic work is performed in a smooth, continuous real-time mode; the radiation exposure and dose saving is significantly greater than with pulsed and other proposed low-dose fluoroscopic systems; and the system automatically adapts for the wide variation in patient size routinely encountered in pediatric and adult radiology. The image quality is now such that this system could be used routinely for both adults and children.