Retrospective analysis of dose delivered to the uterus during CT examination in pregnant women

Abstract

Purpose: The purpose of this study was to analyze the dose to the uterus (UD) calculated for pregnant women per computed tomography (CT) acquisition and per CT examination in our Institution.

Materials and methods: Consecutive pregnant women who underwent CT examination from June 2014 to February 2022 and for whom UD calculation was performed by a medical physicist were retrospectively included. UDs were computed per CT acquisition using the CT Expo 2.4 software and were summed up to obtain the total UD per CT examination. The CTDI_vol and dose-length product (DLP) values were retrieved from the dose report and compared with those calculated by the software.

Results: A total of 256 pregnant women with a mean age of 29.4 ± 5.5 (SD) years (range: 18-48) at 24.5 ± 10.4 (SD) weeks of amenorrhea (range: 1-40) were included. UDs were computed for 339 CT acquisitions. The CTDI_vol and DLP computed by the software were significantly greater than those retrieved from the dose reports (P < 0.05). The greatest UDs were reported for the abdomen-pelvis (10.93 ± 5.74 [SD] mGy; range: 1.2-24.1), chest-abdomen-pelvis (9.79 ± 7.09 [SD] mGy; range: 3.9-22.1), pelvis (18.50 ± 17.96 [SD] mGy; range: 5.8-31.2) and lumbar spine (10.24 ± 11.38 [SD] mGy; range: 2.3-29.6) CT examinations. The total UDs per CT examination were > 20 mGy for 10 pregnant women and the maximum total UD was 52.3 mGy.

Conclusion: Greatest UDs during CT examinations are observed when the pelvis is directly exposed to X-rays. With current dose levels and in optimized practices, UDs per CT acquisition and CT examination are always below 100 mGy. UD calculations cannot be performed for CT examinations that do not directly expose the pelvis (i.e., those < 1 mGy).

Keywords: Multidetector computed tomography; Organ dose; Pregnant women; Uterine dose.