Comparative organ dose levels for dentomaxillofacial examinations performed with computed tomography, cone beam CT and panoramic radiographs

The purpose of this study was to evaluate the radiation dose delivered to radiosensitive organs (thyroid, parotid glands and eye lens) during dentomaxillofacial imaging with multislice computed tomography (CT), cone beam CT (CBCT) and panoramic radiographs (orthopantomography, OPT). The dose was estimated individually for each modality and each clinical protocol by measuring the absorbed dose at the surface of a head phantom with thermoluminescence dosimeters. The measured radiation dose was between 0.01–1.22 mGy for the thyroid gland (systematically outside the primary beam), 1.34–29.11 mGy for the parotid glands (systematically exposed to the primary beam) and 0.02–26.22 mGy for the eye lens (in the primary beam depending on imaging protocol). For all organs, CT was found to be the most irradiating modality followed by CBCT and OPT. However, CBCT with a “limited dental” protocol and OPT deliver similar doses to the parotid glands.