Patient Radiation Doses in Interventional Radiology Procedures: Comparison of Fluoroscopy Dose Indices between the American College of Radiology Dose Index Registry-Fluoroscopy Pilot and the Radiation Doses in Interventional Radiology Study

Purpose: To compare radiation dose index distributions for fluoroscopically guided interventions in interventional radiology from the American College of Radiology (ACR) Fluoroscopy Dose Index Registry (DIR-Fluoro) pilot to those from the Radiation Doses in Interventional Radiology (RAD-IR) study. Materials and Methods: Individual and grouped ACR Common identification numbers (procedure types) from the DIR-Fluoro pilot were matched to procedure types in the RAD-IR study. Fifteen comparisons were made. Distribution parameters, including the 10th, 25th, 50th, 75th, and 95th percentiles, were compared for fluoroscopy time (FT), cumulative air kerma (K_a,r), and kerma area product (P_KA). Two derived indices were computed using median dose indices. The procedure-averaged reference air kerma rate (K_a,r¯) was computed as K_a,r / FT. The procedure-averaged x-ray field size at the reference point (A_r) was computed as P_KA / (K_a,r × 1,000). Results: The median FT was equally likely to be higher or lower in the DIR-Fluoro pilot as it was in the RAD-IR study, whereas the maximum FT was almost twice as likely to be higher in the DIR-Fluoro pilot than it was in the RAD-IR study. The median K_a,r was lower in the DIR-Fluoro pilot for all procedures, as was median P_KA. The maximum K_a,r and P_KA were more often higher in the DIR-Fluoro pilot than in the RAD-IR study. K_a,r¯ followed the same pattern as K_a,r, whereas A_r was often greater in DIR-Fluoro. Conclusions: The median dose indices have decreased since the RAD-IR study. The typical K_a,r rates are lower, a result of the use of lower default dose rates. However, opportunities for quality improvement exist, including renewed focus on tight collimation of the imaging field of view.