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

ABSTRACT

PURPOSE: 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. METHODS: 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. RESULTS: 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 PDIsodds ratio estimate of 7.7 with a 95% confidence interval of 3.27 to 18.1 indicates that patient radiation dose strongly depends on the practitioner.

CONCLUSIONS:

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