Dosimetry of spherical Sr-90-Y-90 beta ray eye applicators

A modification of the conventional extrapolation chamber to perform absolute dose measurements from surfaces of spherical beta applicators (type SIA.I, SIA.3, SIA.6) is described. A stack of Ilford N 550 films has been used in a spherical geometry to obtain the variation of surface dose, the depth dose data and the isodose curves. The results obtained are compared with data available in the literature.