Dosimetry of dental cone beam CT and multi-slice CT in oral and maxillofacial radiology using conversion factors

Abstract

Objective: To compare the effective doses between dental cone beam computed tomography (CBCT) and multi-slice computed tomography (MSCT) for the oral and maxillofacial region.Materials and Methods: VacuDAP® ionization chamber was located in front of the X-ray sources in CBCT units for measuring dose area product (DAP). Measurements are performed in three CBCT units. Dose-length product (DLP) values are acquired from two MSCT units. Effective doses were calculated by conversion factors.Results: Effective doses of three CBCTs with the similar field of views (FOVs) were 161.9 μ㏜, 213.6 μ㏜, and 358.4 μ㏜, respectively. Effective doses of MSCTs were 1147.2 μ㏜ and 1629.6 μ㏜. The effective doses of MSCTs are 3.2~10 times more than those of CBCTs.Conclusions: The effective doses of CBCTs were lower than those of MSCTs, but showed wide ranges depending on units and modes. DAP can be used as an easier and faster way to estimate the patient exposure dose in CBCTs, and can be acceptable to manage it.