Abstract
In our studies of operator exposure in interventional radiology and diagnostic fluoroscopy, we used the Mirion Instadose+ personal dosimeter badges, for which we measured an acceptable average badge-to-badge variability of 3.3%. The badges proved convenient to use due to their immediate read-out capabilities. Using the badges, we focused our study of operator dose on two factors: the effect of pulse rate changes on dose and the distribution of dose over the body of the operator. In general, we found that a reduction in pulse rate corresponded to a proportional decrease in in-field and scatter dose. Studies were conducted in both clinical and controlled geometry settings on a pulse rate variable instrument and a continuous fluoroscopy instrument. In the controlled geometry setting, the operator dose for a continuous fluoroscopy instrument was approximately five times higher than the dose from a pulse rate variable instrument at the lowest pulse rate setting. In examining the dose distribution over the body of the operator, we again investigated both clinical and controlled geometry settings on several different instruments. In the clinical setting, the operator performed procedures as usual; operator dose was about 0.1-1.1 mrem per procedure on the Siemens Axiom Artis unit. In the controlled geometry setting, we stood a phantom next to the patient table to the right of the source, at the habitual position of the primary operator. Where differences were significant, the operator dose was usually higher on the left side of the body than the right side at equal heights. In one study on the Philips Allura Clarity, the left-side dose was 1.7 times higher than the right side dose at the head, 1.6 times higher at the shoulder, and 2.5 times higher at the waist, exterior to the personal protective equipment. Also, the dose was higher at lower positions, closer to the source, which for all instruments used herein was located under the patient table. Therefore, we conclude that radiology workers should be aware that placing their occupational dosimetry badge on a side of the body that is usually farther from the source may result in artificially low readings.