Effective dose equivalent from intraoral radiography.

By means of available data of mean organ doses from intraoral radiography the effective dose equivalent from dental radiography was calculated. The dose values used correspond to 65 kVp, 0.2 m FSD and 20 exposures with film in speed group D. The effective dose equivalent was calculated for circular (55 mm diameter) as well as rectangular collimator (35 mm X 44 mm) and amounted to 0.23 and 0.14 mSv, respectively. In comparison with the annual natural radiation the corresponding time would be 6 and 3 weeks, respectively. Following the definition of the effective dose equivalent by ICRP (1977) it was found that the most radiosensitive organs contributed 20-25 per cent of the total effective dose equivalent. The organs with the highest weighting factors thus received very small or negligible dose equivalents. The calculation necessitates a detailed knowledge of the absorbed doses and the weighting factors, which made the application for dental radiography somewhat uncertain. The concept of energy imparted might be a more direct measure to compare the risk from different examinations in dental radiography.