Reinforcing the Importance and Feasibility of Implementing a Low-dose Protocol for CT-guided Biopsies

Abstract

Rationale and objectives: This study sought to more definitely illustrate the impact and feasibility of implementing a low-dose protocol for computed tomography (CT)-guided biopsies using size-specific dose estimates and multivariate analyses.

Materials and methods: Fifty consecutive CT-guided lung and extrapulmonary biopsies were reviewed before and after implementation of a low-dose protocol (200 patients total, mean age 61 ± 15 years, 128 women). Analyses of variance with Bonferroni correction were used to compare standard and low-dose protocols in terms of patient demographics, physician experience, target lesion size, total dose-length product, total acquisitions, size-specific dose estimate, signal-to-noise ratio, contrast-to-noise ratio, and lesion conspicuity ratings. All procedures were performed on the same 16-slice CT scanner.

Results: Voluntary protocol adherence was 100% (lung) and 89% (extrapulmonary). The low-dose protocol achieved significantly lower total average dose-length product [(lung) 735.6 ± 599.4 mGy × cm to 252.1 ± 101.9 mGy × cm, P < .001; (extrapulmonary) 724.7 ± 545.0 mGy × cm to 392.9 ± 239.5 mGy × cm, P < .001] and size-specific dose estimate [(lung) 5.2 ± 0.8 mGy × cm to 4.3 ± 1.5 mGy, P < .001; (extrapulmonary) 10.1 ± 6.7 mGy to 6.5 ± 2.7 mGy, P < .001]. Only the change in protocol was independently associated with lower size-specific dose estimates when controlling for the other variables (P < .0001). This was achieved with no significant differences in signal-to-noise ratio, contrast-to-noise ratio, or lesion conspicuity.

Conclusions: Implementation of a low-dose protocol for CT-guided biopsies resulted in 21% and 36% of size-specific dose estimate reduction for lung and extrapulmonary biopsies, respectively, with excellent adherence. Interventional and body radiologists should implement low dose CT-guidance protocols aiming to improve patient safety.

Keywords: CT-guided biopsies; Dose reduction; low dose protocol; size-specific dose estimate.