Solid phantom material for the dosimetry of iodine-125 seed ophthalmic plaques.

Abstract

A tissue-equivalent solid phantom material, RE-1, closely simulating the radiological attenuation and scattering properties of the human eye for the iodine-125 photon spectrum and their Compton-scattered secondary photons, was fabricated on a polyethylene base with CaCO3 and MgO as inorganic additives. A 24 mm diameter spherical phantom was made from 1.1 mm thick sheets of RE-1, and holes were drilled in which 1 mm3 TLD cubes were placed. The radial dose function g(r), which determines the dose profile on the transverse axis, was measured in a quasi-infinite phantom of RE-1. The values obtained deviate only slightly from those for a quasi-infinite phantom made from water-equivalent material.