Cumulative radiation exposure and estimated lifetime cancer risk in multiple-injury adult patients undergoing repeated or multiple CTs

Abstract

Purpose: To estimate the cumulative radiation exposure and lifetime attributable risk (LAR) of radiation-induced cancer from computed tomographic (CT) scanning of adult patients with multiple-injury traumas.

Methods: The study comprises 328 multiple-injury adult patients who underwent diagnostic CT during 2013. Each patient's cumulative CT radiation exposure was calculated and the biological effects of ionizing radiation VII methodology was used to estimate the LAR of cancer incidence on the basis of sex and age at each exposure.

Results: The average cumulative dose per patient was 19.4 mSv. One point five percent (5/328) of the patients received a cumulative effective dose ≥100 mSv and 63.7 % of patients received a cumulative effective dose ≤20 mSv. The average LAR of cancer incidence was 0.14 % or 1 in 714 patients. Only one patient had an LAR >1 %, a man <30 years of age. The group of major injuries [injury severity score (ISS) >15] had a statistically significantly greater accumulative effective dose and slightly greater LAR than the group of minor injuries (ISS ≤15).

Conclusions: More than half of the multiple-injury trauma patients were classified as low risk cumulative effective dose (≤20 mSv) and almost all patients had a low LAR risk of cancer incidence from CT studies. Patients who were at the highest risk of cancer from CT scans were those aged under 30 years who had multiple or repeated scans, particularly in the trunk.

Keywords: Computed tomography; Cumulative effective dose; Lifetime attributable risk (LAR); Radiation dose.