Dose area product in estimation of effective dose of the patients undergoing dental cone beam computed tomography examinations.

OBJECTIVE: To investigate the relationship of the effective dose and dose area product (DAP) in dental cone beam computed tomography (CBCT) examinations and to propose conversion factors for estimation of effective doses of the patients using DAP. Dependence of organ doses on DAP was also investigated. MATERIALS AND METHODS: Different exposure geometries in Cranex3Dx CBCT device were simulated using Monte Carlo simulation and computational anthropomorphic phantom. Then organ doses and effective dose for every exposure geometry was compared to DAP and analysed. RESULTS: The effective dose in all simulated CBCT protocols and positions with 180 degrees tube rotation ranged from 5 muSv for 50 x 50 mm(2) field of view (FOV) localised on one tooth using lowest resolution to 265 muSv for the largest FOV and highest resolution. In case of 360 degrees tube rotation the effective dose ranges from 6 to 332 muSv for the same FOV sizes and positions as well as resolutions as in 180 degrees tube rotation. CONCLUSIONS: Though the DAP introduces a large uncertainty in the risk measure in dental CBCT, it represents the dose and FOV size which are the most important scanning parameters affecting the dose. To decrease uncertainty in the risk measure, the effective dose has to be estimated for usual clinical positions of the FOV.