Application of a photodiode in dental radiology

A photodiode in a light-tight housing was used as an x-ray detector. Calibration against a standard ionization chamber showed that, for the range of radiation qualities used in dentistry, its output was a reliable measure of the rate of exposure. Photodiodes are available in very small sizes and can be used intraorally. The feasibility of automatic exposure control for intraoral radiography was considered. Measurement of transmission fractions through the mandible with various radiation qualities resulted in a numerical evaluation of radiation risk approximated by the absorbed dose.