No abstract

Dental panoramic radiography has increased in popularity and use since its introduction in the late 1950's and proposals have been made to apply this methodology as a mass screening tool. Ease of examination and the reportedly low radiation exposure to the anterior superficial tissues have been cited as reasons for this application. However, in panoramic radiography the X-ray beam enters posteriorly which results in high doses to posterior and to internal tissues. We have employed LiF thermoluminescent dosimeters to measure the radiation exposure to the superficial tissues of a Rando phantom and of patients during dental panoramic examination. Radiation exposures ranged from an average of 255 mR to the lateral tissues to 22 mR to the symphysis of mandible. Other anterior superficial tissues received exposures of 25-50 mR. On the basis of previous hazards analysis of radiographic procedures, these radiation exposures would seem to be excessive for application as a mass screening tool.