中文摘要：

目的 探讨131I清除DTC术后残留甲状腺组织（简称清甲）的内照射吸收剂量与疗效的相关性.方法 前瞻性分析2009年9月至2011年9月拟行清甲的72例DTC患者[男14例,女58例,年龄16～67（41±16）岁].在患者服用3.7 GBq 131I后采用连续显像法评估残留腺体的碘代动力学,利用超声测量残留腺体的质量,按照美国核医学会医用内照射剂量学委员会提出的内照射吸收剂量计算方法,计算残留腺体的吸收剂量.清甲治疗后6～9个月,判断疗效：若刺激状态下Tg＜l μg/L及颈部超声检查提示甲状腺床区无腺体组织残留,判断为清甲成功.清甲成功与未成功者组间比较采用两样本t检验.结果 72例患者的残留腺体24h摄碘率为0.9％～6.3％, 131I有效半衰期为12.0～146.4 h,腺体质量为1.0～6.9g,吸收剂量为23～2 197 Gy,24 h吸收剂量率为0.5～8.1 Gy/h.43例清甲成功者与29例清甲未成功者残留腺体的吸收剂量分别为（363±148） Gy和（341±167） Gy,差异无统计学意义（￡=15.097,P＞0.05）;24 h吸收剂量率分别为（3.7±2.1） Gy/h和（2.9±1.6） Gy/h,差异有统计学意义（t=7.908,P＜0.05）.结论 131I清甲残留腺体的吸收剂量率影响清甲疗效.

英文摘要：

Objective To investigate the relationship between the absorbed dose to the thyroid remnant and the outcome of m I ablation in patients after operation for DTC.Methods Seventy-two patients （14 males,58 females; age range：16-67 years,average age：（41±16） years） with DTC,prepared for thyroid remnant ablation,were prospectively recruited from September 2009 to September 2011.Scintigraphic images of the head and neck were serially acquired after oral administration of 3.7 GBq of 131I to assess the biokinetics of this tracer in thyroid remnant.Ultrasound was used to measure the mass of the thyroid remnant.Calculation of absorbed dose to thyroid remnant was based on the Medical Internal Radiation Dosimetry formula of the Society of Nuclear Medicine.The outcome of 131 I ablation was evaluated on the basis of stimulated Tg measurements and neck ultrasound at 6-9 months after ablation.Patients with stimulated Tg levels less than 1 μg/L and with no detectable thyroid tissue on neck ultrasound were considered successful ablation of thyroid remnant.Two-sample t test was used to analyze the data.Results The 131I uptake ratios at 24 h were 0.9％-6.3％ in 72 patients and the effective half-lives of 131I were 12.0-146.4 h.The thyroid remnant masses were 1.0-6.9 g; absorbed doses were 23-2 197 Gy,and absorbed dose rates at 24 h were 0.5-8.1 Gy/h.No significant difference was observed in absorbed doses to thyroid remnants in 43 patients having successful ablation and 29 patients having unsuccessful ablation （（363± 148） Gy vs （341± 167） Gy,t =15.097,P＞0.05）.However,the absorbed dose-rates of thyroid remnants at 24 h were significantly higher in patients with successful ablation than those in patients with unsuccessful ablation （（3.7±2.1） Gy/h vs （2.9±1.6） Gy/h,t=7.908,P＜0.05）.Conclusion A successful ablation is strongly dependent on the absorbed dose-rate of thyroid remnant.