Abstract 4915: Reduction of X-Ray Exposure by Patient Contouring
Purpose of the study. With increasing case complexity, radiation exposure is becoming a very important issue. One obvious element, which can result in dose reduction, is optimal placement of image receptor as close to the patient as possible. As part of the clinical workflow, even with best of intentions, the detector is often parked at a significant distance away from the patient and this may be improved by an automatic user-gantry interaction which automatically places the detector at an optimal distance from the patient surface.
Methods. We determine the operator dose reduction impact of a patient contouring system which utilizes active sensors placed around the rim of the detector to optimally position the detector close to the patient surface compared to a conventional approach in the real world. On the cathlab platform Innova 2100IQ (GE, Waukesha, WI), capacitive sensor elements are placed around the detector cover, which measures the minimal distance between the cover and the patient. Using a computer algorithm, the detector location is automatically controlled such that it rests at a preprogrammed distance of 7 cm from the patient surface with a fast response time of 20 deg/sec. Dose to the operator was recorded by an electronic dosimeter placed on the external side of the lead apron.
Results. 250 consecutive patients admitted for coronary angiogram (n=234)or angioplasty (n=16) were randomly assigned for conventional approach (n=117) or patient contouring (n=133). The 2 patients populations were identical for age, indications, approach (radial or femoral), size, weight and body mass index. The operator effective dose was 5.71±6.34 μSv in the conventional group and 3.68±4.09 μSv in the patient contouring group (p = 0.0035), with an operator effective dose reduction of 35.5%.
Conclusions. A simple technique of patient contouring may reduce operator effective dose by >30%.