Estimated radiation risk of cancer from dental cone-beam computed tomography imaging in orthodontics patients

Background: Radiation dose evaluation is important to cone-beam computed tomography (CBCT) for routine orthodontic treatment planning, especially for a significant proportion of children in orthodontic patients. This study evaluated the patient radiation dose and estimated the radiation cancer risk on dental CBCT according to the calculations by the Monte Carlo simulation method. Methods: The dental CBCT scanner evaluated in this project was the i- CAT (R) (Imaging Sciences International Inc., PA, U.S.A.) device. Organ doses and effective doses were calculated by using personal computer-based Monte Carlo simulation (PCXMC 2.0 Rotation) software. The cancer risk resulting from the exposure to ionizing radiation was estimated by using the BEIR VII (Biologic Effects of Ionizing Radiation VII) report model, and the risk of exposure-induced death (REID) was assessed by PCXMC 2.0 Rotation software. Results: The largest contribution to the organ dose and effective dose at Zref 83 cm positioned in the dental CBCT x-ray beam centerline was from the salivary glands (738.29 mu Gy, 7.38 mu Sv). The different organ doses showed the maximum values at the different Zref locations, and the largest contribution to the organ dose and effective dose of all simulated positions was from the thyroid (928.77 mu Gy, 37.5 mu Sv). The REID values in the 10-year olds (22.6 x 10(-7), female; 19 x 10(-7), male) were approximately double than those in 30-year olds (10.4 x 10(-7), female; 8.88 x 10(-7), male) for all cancers. The highest change during age range from 10 to 30 was shown in breast cancer of females. Conclusions: Although individual cancer risk estimates as a function of gender and age are small, the concern about the risks from dental CBCT is related to the rapid increase in its use for orthodontic practice, especially in children patients.