Radiation exposure to critical organs in panoramic dental examination

Nowadays, radiography is a necessary procedure in diagnosis and treatment of patients with dental problems. According to the ALARA (as low as reasonably achievable) principle, dentists must take radiographs of sufficient quality at the lowest possible radiation dose to the patients. The assessment of patient dose on panoramic radiography is difficult because of dynamic nature of the imaging process and the narrow width of the x-ray beam. The present work describes an experiment undertaken using thermoluminescence dosimeters (TLD-100) to obtain the absorbed dose in organs and sensitive tissues in head and neck region during panoramic radiography, based on patient measurement. The overall mean entrance surface dose on thyroid, right and left lens of eyes, parotid glands (right and left) and occipital region in panoramic were 38, negligible, negligible, 367, 319 and 262 μGy, respectively. The results show that there are differences between patient doses examined by different panoramic systems. There is a tendency for lower organ doses for digital compared with analogue panoramic units.