A conversion coefficient from dose-area products to effective doses for patients in intraoral radiography

Abstract

A conversion coefficient from dose-area products to effective doses was proposed as a practical estimator of patient health detriments from intraoral radiography. According to the tissue-dose data reported by Gibbs et al. (Dentomaxillofac. Radiol., 1987 & 1988) and the tissue weighting factors recommended in ICRP Publication 60, the effective doses and the dose-area products were calculated at 70, 80, and 90 kV for E-speed films employed at each of seven geometries using bisecting angle, paralleling, and bitewing techniques with round or rectangular collimated beams. The focus-skin distances were 20 cm for the short cone and 40 cm for the long cone, respectively. From a total of 90 sets of exposure factors in intraoral radiographic examinations for adults, the effective doses were in the range of 0.38 μSv to 8.0 μSv, and the corresponding dose-area products were 0.58 cGy·cm2 and 7.6 cGy·cm2. The obtained linear regression coefficient to convert the dose-area product to the effective dose was 0.97 μSv/cGy·cm2. We conclude that effective doses can be estimated from the dose-area products if an uncertainty of a factor of two is acceptable in intraoral radiography.