Energy imparted from intraoral radiography.

During the recent decade the equipment for dental radiography in Sweden has been standardized by the Swedish National Institute for Radiation Protection. The aim of this study was to experimentally determine the energy imparted to a phantom from a full survey with 20 intraoral films as well as from a single bitewing projection, using this standardized technique. Thermoluminescence dosimeters in predetermined volume elements of an anatomically formed tissue equivalent Alderson-phantom were irradiated (65 k Vp) using both a rectangular and a circular collimator of 0.2 m FSD. Exposure times fitted to film in speed group D were used. The energy imparted was determined from the integrated absorbed doses in the volume elements as well as calculated using published depth dose data. The energy imparted was found to be 9.6 mJ (circular collimator) and 5.9 mJ (rectangular collimator) for the full survey. For the single bitewing exposure the energy imparted was 0.42 mJ (circular collimator) and 0.29 mJ (rectangular collimator). With the rectangular collimator and film in speed group D the energy imparted from a full survey will correspond approximately to two weeks of environmental irradiation. With more sensitive film in speed group E the energy imparted would further be reduced by 40 per cent with retained diagnostic information.