Radiology, Vol 119, 705-707, Copyright © 1976 by Radiological Society of North America
The metal/tissue interface effect in irradiation of the oral cavity
FA Gibbs, B Palos and DR Goffinet
Metal dental prostheses or overlays may lead to increased mucosal reactions
of adjacent tissue surfaces during intensive irradiation of the oral
cavity. The dosimetry of this phenomenon was investigated by irradiating
dental phantoms with 4-and 6-MeV photons. Gold and amalgam interfaces may
produce local mucosal doses as high as 150-170% depending on the beam
geometry, but doses of 111-126% for gold crowns and about 109-118% for
amalgam fillings were found for opposed-beam configurations. 2-4 mm of
tissue-equivalent absorber is sufficient to re-establish a homogeneous dose
distribution and should be employed throughout therapy whenever dental
extraction is unwarranted. The radiobiological exaggeration of the
interface effect in treatment with opposed beams using one field per day is
discussed.
