Biologic half-life of 1311 in thyroid cancer patients

Background:thyroid cancer comprises about 1% of all malignancies and accounts for up to 1% of all cancer deaths. radioactive iodine is utilized to treat some papillary, mixed papillary-follicular and follicular carcinomas. in these patients, because of the absence of thyroid tissue, the range of absorption of iodine and time of decreasing the exposurerate to standard limits differs from other patients with extra pathologies. in this study wetried to measure the biologic half-life of 131i in patients with thyroid cancer and the effects of different variables like age, sex, histological subtypes, and residual disease on the biologic half-life of 131i.methods: we evaluated 29 patients with differentiated thyroid cancer who referred to radiation and oncology department of jorjani hospital, tehran, iran. patients were treated with 131i dosing between 100-150 mci and the exposure rate in patients, just after prescribing 131i, were regularly estimated by portable dose rate meter.results: we observed wide range of biologic half-life of 131i in patients and no variable had significant effects on biologic half-life of 131i.conclusion: it seems that all patients should repeatedly undergo dosimetry until the range of radiation reaches to nonnal.