分化型甲状腺癌患者131I治疗后诊断性全身显像周围剂量当量率动态变化的研究

目的 探讨分化型甲状腺癌（DTC）患者131I治疗后6个月行诊断性全身显像（Dx-WBS）期间周围剂量当量率的动态变化。 方法 选取2018年8月至2019年1月于郑州大学第一附属医院核医学科接受131I治疗的DTC患者85例，其中男性18例、女性67例，年龄（43.9±12.0）岁；≥55岁患者18例、<55岁患者67例。所有患者均空腹服用131I 148 MBq（4 mCi），2 d后行 Dx-WBS。治疗后效果为极好反应者，即131I治疗后刺激状态下甲状腺球蛋白<1 μg/L（甲状腺球蛋白抗体阴性）且影像学检查结果为阴性者（阴性组）48例，生化不全反应、结构不全反应及不确定性反应者（阳性组）37例。所有患者分别于服131I后2、24、48 h时测定距体部1 m处的周围剂量当量率，对3个时间点的1 m处周围剂量当量率进行单因素重复测量方差分析，并采用t检验对不同性别、年龄及治疗效果组之间1 m处周围剂量当量率进行比较。 结果 （1）服131I后2、24、48 h时距患者1 m处周围剂量当量率分别为（6.55±1.42）、（1.92±0.65）、（0.58±0.22） μSv/h，差异有统计学意义（F=807.30，P=0.000）；距离患者1 m处周围剂量当量率随着时间的延长而下降。（2）不同性别组在服131I后 2、4、48 h时 1 m处周围剂量当量率的差异均无统计学意义；年龄≥55岁组在24 h时 1 m处周围剂量当量率高于年龄<55岁组（t=2.29，P=0.02），2 h和48 h时的差异均无统计学意义；阴性组和阳性组1 m处周围剂量当量率在各时间点的差异均无统计学意义。 结论 DTC患者131I治疗后服诊断剂量131I后 48 h时1 m处周围剂量当量率均小于WS533-2017《临床核医学患者防护要求》规定的1.40 μSv/h，达到国家规定的出门旅行要求，且不会对周围人群产生辐射损害。

Study on the dynamic change in ambient dose equivalent rate in patients with differentiated thyroid carcinoma receiving diagnostic whole-body scan after 131I therapy

Objective To explore the dynamic change of the ambient dose equivalent rate during diagnostic whole-bady scan with differentiated thyroid carcinoma after 131I therapy 6 months. Methods This study enrolled 85 patients aged (18 males and 67 females; 43.9±12.0 years old ) with DTC who received 131I therapy in the Department of Nuclear Medicine of The First Affiliated Hospital of Zhengzhou University from August 2018 to January 2019. Among them, 18 patients were ≥55 years old and 67 patients were <55 years old. All patients were given 148 MBq (4 mCi) of 131I on an empty stomach and received diagnostic whole-body scan 2 days later. The negative group (n=48) was defined as the excellent response. The patients in this group were administered with thyroid-stimulating hormone-stimulated thyroglobulin (<1 μg/L) in the absence of structural or functional evidence of disease (and in the absence of anti-Tg antibodies). The positive group (n=37) was defined as the biochemically incomplete response, structurally incomplete response, and indeterminate response. Ambient dose equivalent rate was determined l m away from the patients at 2, 24, and 48 h after 131I administration. One-way repeated measures ANOVA was used on the three patient groups. T test was used to compare the ambient dose equivalent rate at 1 m between different groups of gender, age, and treatment effects. Results The range of ambient dose equivalent rate at 1 m at 2, 24, and 48 h was (6.55±1.42), (1.92±0.65), and (0.58±0.22) μSv/h, respectively, indicating that ambient dose equivalent rate decreased over time. The differences were statistically significant (F=807.30, P=0.000). No statistically significant difference was found in ambient dose equivalent rate at 1 m after 131I administration at any time in groups of different genders. The ambient dose equivalent rate at 1 m at 24 h was higher in the ≥55 age group than in the <55 age group (t=2.29, P=0.02), and the other two time points were not statistically significant. No statistically significant difference was found between the negative group and the positive group at each time point. Conclusions The ambient dose equivalent rate of patients with DTC after 131I treatment who received the diagnostic dose of 131I for 48 h was less than 1.40 μSv/h (the 2017 clinical nuclear medicine patient protection requirements, WS 533-2017). Thus, no restrictions for the patients to travel should be imposed as they do not exert harmful radiation on others.