[A proposal to improve radioactive waste disposal following metabolic radio-iodine therapy]

After metabolic radio-iodine treatments of carcinomas of the thyroid, increased activities of I 131 are secreted from the patient's body by the renal route. The highly radioactive urine represents a serious danger of contamination for the nursing staff and third persons. The ideal conditions for the isolation of treated patients in a department disposing of a sewage disposal system of its own are not fulfilled at our hospital. Collection of radioactive urine of the patients for the purpose of annihilating radioactivity over several half-lifes of I 131 is extremely intricate. For this reason, we developed a filter system by means of which we were able to free the radioactive urine of the first five female patients treated from more than 99% of radioactivity. The contaminated locked filter patterns can be stored as "closed radio-sources" essentially more securely and space saving. The advantages of this system and their practical possibilities of use are discussed.