Impact of physician practice on patient radiation dose during CT guided biopsy procedures

Patient radiation dose during Computed Tomography (CT) guided biopsy procedures is determined by both acquisition technical parameters and physician practice. The potential effect of the physician practice is of concern. This study is to investigate the effects of those intangibles on patient radiation dose.

Patient radiation dose from 252 patients who underwent CT guided biopsy from 2009 to 2010 were retrospectively studied. Ten physicians who used conventional intermittent shots, low mA dose saving feature, or both were included in the study. The patient dose reports were retrieved and the total dose length products (DLPs) were analyzed. Linear regression analysis performed between various variables and reported dose. Patient detriment index (PDI) was developed, which sets threshold (standard of practice) for comparing physician practice with their peers. Odds ratio was calculated to determine odds of a group of patients receiving dose above threshold when compared to another group.

Median DLP among ten physicians was 1194 mGy-cm. There was a significant difference (p< 0.01) between reported DLPs doses when physicians used dose saving feature vs. when feature not used (539.8 ± 169.4 mGy-cm vs. 1269.7 ± 659.0 mGy-cm). In general, physicians who used dose saving feature had lower relative PDIs (< 1) compared to the PDIs (> 1) without the dose feature. Odds ratio estimate of 7.7 at 95% confidence level indicates that the odds of a group receiving a high dose depends on practitioner.

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