Principles of safety use of radioiodine in the treatment of well-differentiated thyroid carcinoma (DTC)

The post-operative radioiodine treatment of patients with well-differentiated thyroid carcinoma decreases cancer death, tumor recurrences and development of distant metastases. The recommended dose of 131I ranging from 1.1 to 11.1 GBq. Because these doses are much higher than the permissible dose of 131I for outpatients (800 MBq), all patients are treated during hospitalization. In the Department of Endocrinology and Radioisotope Therapy from 1998 to the end of June 2008 694 patients have received at least one dose of 131I for DTC. Nowadays, cumulative yearly dose exceed 200 GBq. High doses of 131I may cause radiation exposure to personnel and environmental hazard. The last mentioned is caused mainly by radioactive liquid wastes with comprise washing water and excreta (urine, feces). In order to minimize this hazard radioactive liquid waste from isolated Radioisotope Therapy Unit are discharged into internal hospital sewage system and stored in 4 containers until 131I concentration decreases up to the recommended level.