Predicting Cancer Risks from Dental Computed Tomography

Dental computed tomography (CT) has become a common tool when carrying out dental implants, yet there is little information available on its associated cancer risk. The objective of this study was to estimate the lifetime-attributable risk (LAR) of cancer incidence that is associated with the radiation dose from dental CT scans and to evaluate the effect of scan position, sex, and age on the cancer risk. This retrospective cohort study involved 505 participants who underwent CT scans. The mean effective doses for male and female patients in the maxilla group were 408 and 389 mu Sv (P = 0.055), respectively, whereas the mean effective doses for male and female patients in the mandible groups were 475 and 450 mu Sv (P < 0.001), respectively. The LAR for cancer incidence after mandible CT scanning varied from 1 in 16,196 for a 30-y-old woman to 1 in 114,680 for a 70-y-old man. The organ-specific cancer risks for thyroid cancer, other cancers, leukemia, and lung cancer account for 99% of the LAR. Among patients of all ages, the estimated LAR of a mandible scan was higher than that of a maxilla scan. Furthermore, the LAR for female thyroid cancer had a peak before age 45 y. The risk for a woman aged 30 y is roughly 8 times higher than that of a woman aged 50 y. After undergoing a dental CT scan, the possible cancer risks related to sex and age across various different anatomical regions are not similar. The greatest risk due to a dental CT scan is for a mandible scan when the woman is younger than 45 y. Given the limits of the sample size, machine parameters, and the retrospective nature of this study, the results need to be interpreted within the context of this patient population. Future studies will be of value to corroborate these findings.