Absorbed dose model to scan parameters in dental cone beam computed tomography

Cone beam computed tomography (CBCT) is widely applied in dental and maxillofacial diagnostic imaging, which raises great concerns to radiological dose caused by this device. This work measures the absorbed dose inside an uniform cylindrical phantom when it is scanned by dental CBCT at different scan parameters of mAs and kV; meanwhile, studies the relationship of absorbed dose to scan parameters. The result indicates that absorbed dose is correlated to scan parameters in an empirical model form of D = (a center dot HVL2 + b) center dot mAs with coefficient of determination above 0.99. This empirical model can be applied to other type dental CBCT devices to provide as an estimation method of radiology dose at different scan parameter settings. Moreover, absorbed dose is proportional to field of view size and inversely proportional to phantom size.