Occupational radiation doses in CT-guided interventions: A multicentre evaluation with special emphasis on lung biopsies and eye lens doses

Purpose: This study aimed to investigate eye lens and whole-body radiation doses received by interventional
radiologists during CT-guided procedures, with a particular focus on lung biopsies.

Methods: Simultaneous measurements of eye lens dose equivalent Hp(3), deep-dose equivalent Hp(10), and
shallow-dose equivalent Hp(0.07) were conducted under clinical conditions during CT-guided procedures in five
Finnish hospitals during four separate four-week measurement periods. Hp(3) was measured using EYE-D ther-moluminescent dosimeters, while Hp(10) and Hp(0.07) were recorded using DIS-1 dosimeters. The Hp(3)/Hp(10) and Hp(3)/Hp(0.07) ratios, and Hp(3) to dose-length product (DLP) were analysed to assess whether routinely measured quantities can provide a rough indication of eye lens dose in CT-guided procedures. The doses per CT procedure were analysed for all aforementioned dose equivalents to evaluate the annual exposures. Dosimeter calibration and quality control were performed at a secondary standard dosimetry laboratory. Staff positioning, radiation protection practices, and procedural variables were explored in relation to differences in observed exposure levels across hospitals and procedures.

Results and conclusions: Occupational radiation exposure during CT-guided procedures were generally negligible when appropriate radiological practices and protective equipment were used. One hospital showed significantly higher dose values due to the primary use of fluoroscopy and absence of a lead glass screen. Despite this aberrant result, exposure levels remained below annual occupational dose limits in all hospitals. Routinely measured Hp(10) and Hp(0.07) showed a strong relationship with Hp(3) in the measurable dose data, suggesting that they may provide a rough indication of the order of magnitude of eye lens dose.