Depth dose distribution of 90Sr - 90Y beta rays in tissue equivalent plastic for carcinogenesis studies

A model study is described to investigate the suitability of irradiation with 90Sr - 90Y beta rays for assessing the risks of tumour induction by ionizing radiation in general. Depth dose characteristics have been determined in tissue equivalent (TE) plastic and this information is used to establish dose distributions in the mammary glands of rats and to assess the doses in the surrounding tissues. The results indicate that the application of 90Sr - 90Y beta rays is particularly useful for skin irradiations, since the absorbed dose is almost constant for depth of up to 1 kgm-2 and the critical layer of the epidermis is generally located at depths of less than 0.1 kgm-2. (Auth./C.F.)