The effect of thin K-edge filters on radiation dose in dental radiography

The use of thin K-edge filters has been found to reduce considerably the radiation dose in intra-oral radiography. The aim of this study was to investigate the effect of filtration on the skin entrance dose and several sites (representing organs or areas of interest within the head) along the central beam axis, at other points within the primary beam and at two points just outside the primary beam. The subject was a sliced head phantom exposed to X rays from a conventional dental X-ray unit in the range of tube voltage 55-85 kVp for each of four filter systems. Measurements of radiation dose were made using thermoluminescent dosemeters (TLD rods) adjusted to simulate exposure resulting from a typical dental radiograph of a maxillary molar. Results suggest the use of thin K-edge filters significantly reduces the entrance skin dose and to a certain extent reduces the total head dose. The dose to the ipsilateral orbit at higher tube voltages may be increased. (Author)