Lifetime Attributable Risk of Breast Cancer Incidence in Brain CT Scans

Abstract

Background: The breast, being a highly radiosensitive organ, is exposed to scattered radiation during brain computed tomography (CT) scans. This study aims to estimate the lifetime attributable risk (LAR) of female breast cancer resulting from brain CT scans. Method: 90 women participated in this cross-sectional study. The LAR of breast cancer incidence was estimated based on health risks associated with exposure to low levels of ionizing radiation, as per the BEIR VII Phase 2 guidelines. The absorbed dose to the breasts was measured using thermoluminescence dosimeters, and the effective dose was calculated from the dose length product. All brain CT scans were conducted using a 16-slice scanner (SOMATOM EMOTION). Statistical analysis involved the Mann-Whitney test to compare the means of breast dose, effective dose, and LAR at a significance level of 0.05. Results: The mean age of the participants was 40 ± 22 years, with an age range of 10 to 83 years. The average dose to the breasts without and with shielding was 0.26 ± 0.19 mGy and 0.096 ± 0.13 mGy, respectively (P < 0.05). The effective dose was 0.85 ± 0.35 mSv without shielding and 0.79 ± 0.32 mSv with shielding (P = 0.539). The maximum LAR was 5.41 cases per 100,000 persons aged 10-15 years without shielding. The average LARs were 1.16 and 0.41 breast cancer incidences per 100,000 persons with and without shielding, respectively (P < 0.05). Conclusion: The LAR of breast cancer in brain CT scans is significant and should not be overlooked. The use of breast shielding can substantially reduce this risk. Therefore, it is recommended to employ radioprotective shields to cover the breasts during this type of scan.

Keywords

• breast neoplasms
• tomography
• x-ray computed
• radiation protection