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.

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The authors have employed LiF and CaF2 thermoluminescent dosimeters in tandem to estimate the radiation energy and to measure the radiation exposure to the superficial tissues of patients during dental panographic roentgenology. Radiation exposures ranged from an average of 0.46 R to the posterior tissues to 0.038 R to the orbit. Other anterior superficial tissues received an exposure of approximately 0.050 R. The CaF2/LiF value varied from a high of approximately 200 at the posterior positions to a low of approximately 30 at the orbit position. These ratios corresponded to average photon energies of approximately 40 keV and 15 keV. On the basis of previous hazards analysis of roentgenographic procedures, these radiation exposures would seem to be excessive for application as a mass screening tool.