SU-E-I-30: Impact of Physician Practice on Patient Radiation Dose during CT Guided Biopsy Procedures

The major concern with CT fluoroscopy is patient radiation dose, which is determined by applied technical parameters as well as practitioner/operator practice, e.g. habits and choice of dose saving features. This study is to investigate the effects of these intangible factors on patient doses.

381 patients underwent CT biopsy were retrospectively studied. Patient doses (dose length product, DLP) were analyzed and compared. Comparisons were made among physicians using only conventional intermittent shots, physicians using a low mA dose saving feature, and physicians using a combination of both. Linear regression analyses were performed to investigate any possible relationship between the variables and the patient dose. The Patient detriment index (PDI) was developed to set a threshold for the purpose of the Joint Commission sentinel dose events monitoring. An odds ratio was calculated to determine the odds of a group of patients receiving a dose above the median threshold when compared to another group.

The median DLP for all physicians was 1194 mGy-cm. There is a significant difference (p<0.01) between the doses patients received (DLP=539.8 ±76 mGy-cm) when physicians used dose saving feature vs. when the feature was not used (DLP=1269.7±659 mGy-cm). In general, those physicians who used dose saving feature have a lower relative PDI (<1) compared to the PDIs (>1) without dose feature. This is not absolute since some physicians who did not use the dose saving feature have PDIs

Adjustments of practice habits, the use of CT dose saving features or both may be needed to improve patient care for CT fluoroscopy.