甲亢患者131I治疗后周围剂量当量率的变化及其影响因素的研究

目的 探讨甲状腺功能亢进症（甲亢）患者131I治疗后周围剂量当量率的变化及其影响因素，为辐射防护提供理论依据。 方法 回顾性分析2018年10月至2019年11月于重庆医科大学附属第一医院行131I治疗的42例甲亢患者的临床资料，其中男性12例、女性30例，年龄14~68（38.7±11.9）岁。测量131I治疗后2、4周距离患者颈部正前方0、0.3、1.0、2.0、4.0 m处的周围剂量当量率，分析其变化规律，并探讨患者的性别、年龄、甲状腺摄碘率、131I的有效半衰期及服药剂量与周围剂量当量率的相关性。2组间计量资料的比较采用独立样本t检验，周围剂量当量率与各指标之间的相关性采用Pearson相关性分析。 结果 所有甲亢患者131I治疗后2、4周的周围剂量当量率随测量距离的增加逐渐降低。131I治疗后2周，距离患者≥2.0 m处，周围剂量当量率均<25 μSv/h；131I治疗后4周，距离患者≥0.3 m处，周围剂量当量率均<25 μSv/h。不同性别患者不同测量距离处的周围剂量当量率间的差异均无统计学意义（t=?0.467~1.766，均P>0.05）。131I治疗后2周，测量距离为0、0.3、4.0 m处的周围剂量当量率均与131I的有效半衰期呈正相关（r=0.318~0.487，均P<0.05）；测量距离为2.0、4.0 m处的周围剂量当量率均与服药剂量呈正相关（r=0.546、0.491，均P<0.01）；不同测量距离处的周围剂量当量率与患者的年龄和甲状腺摄碘率均无相关性（r=?1.158~0.162，均P>0.05）。131I治疗后4周，测量距离为0、0.3、1.0、2.0 m处的周围剂量当量率均与131I的有效半衰期呈正相关（r=0.319~0.380，均P<0.05）；测量距离为0 m处的周围剂量当量率与患者的年龄呈正相关（r=0.429，P<0.01）；测量距离为2.0 m处的周围剂量当量率与甲状腺摄碘率呈正相关（r=0.353，P<0.05）；不同测量距离处的周围剂量当量率与服药剂量均无相关性（r=0.020~0.157，均P>0.05）。 结论 甲亢患者131I治疗后4周内应尽量避免与家属亲密接触，临床医师应根据周围剂量当量率的测量结果及131I在患者体内的有效半衰期对甲亢患者的居家隔离进行辐射防护指导。

Study on the changes of ambient dose equivalent rate and its influencing factors in patients with hyperthyroidism after 131I treatment

Objective To investigate the changes in ambient dose equivalent rate and its influencing factors in patients with hyperthyroidism after 131I treatment to provide a theoretical basis for radiation protection. Methods The clinical data of 42 patients with hyperthyroidism who received 131I treatment in the First Affiliated Hospital of Chongqing Medical University from October 2018 to November 2019 were retrospectively analyzed. The patients included 12 males and 30 females aged 14–68 (38.7±11.9) years old. The ambient dose equivalent rates at 0, 0.3, 1.0, 2.0 and 4.0 m from the front of the neck of the patient were measured at 2 and 4 weeks after 131I treatment, and their trends were analyzed. The correlations among the gender, age, thyroid iodine uptake rate, effective half-life of 131I , medication dose, and ambient dose equivalent rate of the patients were also investigated. The measurement data were compared between the two groups via independent samples t test, and the correlation between the ambient dose equivalent rate and each index was analyzed through Pearson correlation analysis. Results The ambient dose equivalence rate decreased gradually with the increase in the measurement distance at 2 and 4 weeks after 131I treatment. At 2 weeks after 131I treatment and distance ≥ 2.0 m from the patients, the ambient dose equivalent rates were all <25 μSv/h. At 4 weeks after 131I treatment and distance ≥ 0.3 m from the patients, the ambient dose equivalent rates were all <25 μSv/h. There was no significant difference in the ambient dose equivalent rates at different measurement distances in patients of different genders (t=?0.467–1.766, all P>0.05). At 2 weeks after 131I treatment, the ambient dose equivalent rates measured at distances of 0, 0.3, and 4.0 m were positively correlated with the effective half-life of 131I (r=0.318–0.487, all P<0.05); the ambient dose equivalent rates measured at distances of 2.0 and 4.0 m were positively correlated with the medication dose (r=0.546, 0.491; both P<0.01); the ambient dose equivalent rates at different measurement distances had no correlation with the patients' age and thyroid iodine uptake rate (r=?1.158–0.162, all P>0.05). At 4 weeks after 131I treatment, the ambient dose equivalent rates measured at distances of 0, 0.3, 1.0 and 2.0 m were positively correlated with the effective half-life of 131I (r=0.319–0.380, all P<0.05); the ambient dose equivalent rate measured at distances of 0 m was positively correlated with the patients' age (r=0.429, P<0.01); the ambient dose equivalent rate measured at distances of 2.0 m was positively correlated with the thyroid iodine uptake rate (r=0.353, P<0.05); the ambient dose equivalent rates at different measurement distances had no correlation with the medication dose (r=0.020–0.157, all P>0.05). Conclusions Patients with hyperthyroidism should try to avoid close contact with their family members within 4 weeks after 131I treatment. Clinicians should provide guidance on radiation protection during the home isolation of patients with hyperthyroidism on the basis of the measurement results of the ambient dose equivalent rate and the effective half-life of 131I in the patients' body.