Radioexposure levels observed with sub-optimal fluoroscopic systems

Contemporary radiology increasingly performs invasive procedures for therapeutic purposes. These new requirements stress the patient's and the workers' (physicians, nurses and technologists) radiological exposure, specifically during long periods of fluoroscopy. The worker-exposure level and the patient's dose are related to the equipment geometry (i.e., an above- or under-table-top x-ray tube), the medical practice, the operating mode and the overall performance of the equipment. Using the effective dose concept for the patient and the exposure rate at the operator body surface for some spatial locations around the equipment, the authors show the variation on the dose to the patient and the operator while a collimator is opened larger than the detector size. They stress that a non-optimum opening size of the collimator may be penalizing for the patient and for the operator, specifically when the latter works near equipment mounted with an over-table-top x-ray tube. This particular piece of an equipment is the easiest one to control and maintain. Better use and better quality control should contribute to significantly reducing patient and operator exposure. The authors present statistics obtained on equipment surveyed in 1990 to comply with the Quebec Public Protection Law.