The dosimetry of 1 2 5 I seed eye plaques

The ability of a brachytherapy treatment‐planning computer program to calculate accurately the dose from 1 2 5 I seeds at distances relevant to eye plaque therapy was investigated. Thermoluminescent dosimetry measurements were made in a plastic phantom at depths of 0.5, 0.97, and 1.5 cm, and results were corrected for finite dosimeter size and phantom effects. Doses were calculated at the same depths with an 1 2 5 I seed linear source model that accounted for dose anisotropy. Measurements and calculations were found to agree within their mutual uncertainties. The presence of a gold plaque was found to reduce the dose at all measured depths by 8%.