目的：口服１３１I治疗甲状腺癌的病人，对周围人所受的照射不应超过５mSv有效剂量当量。计算这个限制剂量不能只按物理半衰期，还应考虑１３１I在病人体内的生物半排除期，即包括两者在内的有效半减期（Teff）。因此，着手用对１３１I治疗病人的一系列外照射量率测量数据，估 OBJECTIVE: Patients treated with 131I for thyroid cancer should receive no more than 5 mSv of effective dose equivalent to those exposed to the surrounding human. Calculating this limiting dose can not be based on the physical half-life alone, but should also consider the biological half-exclusion of 131I in the patient’s body, ie the effective half-period (Teff), including both. Therefore, proceed with 131I treatment of patients with a series of external beam radiation measurement data, estimated