碘-131甲狀腺癌治療病人之外釋輻射管制劑量探討

Investigating the Release Criteria for Thyroid Cancer Patients Receiving High-Dose I-131 Radiation Therapy

鄭如金(Ru-Chin Cheng) ； 李冠瑩(Guan-Ying Lee) ； 王淑芳(Shu-Fang Wang) ； 朱麗蓉(Li-Rong Ju) ； 郭昇峯(Sheng-Fong Kuo) ； 詹勝傑(Sheng-Chieh Chan)

《核子醫學暨分子影像雜誌》 30卷3期 (2017/09) Pp. 101-108

https://doi.org/10.6332/ANMMI.3003.001

摘要

背景：回溯性探討接受高劑量碘-131 住院治療的甲狀腺癌病人，住院期間體外輻射劑量率下降情形與影響下降速度的因素。方法：服藥後1、6、16、21、27 及40 小時這6 個時間點，我們請病人站於病房內輻射偵檢器前一公尺處約一分鐘，測量其體外輻射劑量率（微西弗/ 小時；μSv/hr）。所得數值傳到病人輻射偵測系統伺服器 （server）內儲存。結果：共有582 位甲狀腺癌病人（合計922 人次）接受大劑量放射性碘-131藥物治療。病人體外輻射劑量率衰減至服藥後第一次測量劑量（D1）的一半（D_1/2）需9.12 ± 4.1 小時。輻射劑量率下降至100 μSv/hr 的平均時間為6.4± 4.1 小時；降至70 μSv/hr 為12.3 ± 5.3 小時；到50 μSv/hr 平均時間為17.8 ± 5.7 小時。服藥後24 小時超過95% 的體外輻射劑量率降到70 μSv/hr 以下，36 小時後則所有病人皆低於70 μSv/hr。年紀較大（p = 0.013）、男性（p ＜ 0.001）、初次手術後進行廓清或強化治療（ablation or adjuvant therapy, p = 0.002）或沒注射人工合成甲狀腺激素（rhTSH, Thyrogen, p ＜0.001）的病人其劑量下降到D1/2 的時間顯著較長。此外，停藥、年齡、性別、治療原因、治療劑量與是否使用Thyrogen 也是影響體外輻射劑量率下降到70 μSv/hr 的顯著因子。結論：此大規模的回溯性研究指出接受高劑量碘-131 住院治療的甲狀腺癌病人，36 小時後則所有病人皆低於70 μSv/hr。年齡大、男性、沒有使用人工合成甲狀腺激素、治療劑量大或初次手術後治療的病人其輻射劑量率下降較慢。

關鍵字

甲狀腺癌 ； 碘-131 治療 ； 外釋 ； 輻射管制

並列摘要

Background: We retrospectively investigated the change of radiation exposure rate of thyroid cancer patients who are treated with high-dose I-131. Clinical factors which may influence dose rate were also evaluated. Methods: During the hospitalization, we used Ludlum Model 375 monitor with probe of Ludlum Model 133-2 to measure the dosimetry (μSv/hr) of patients. Dose rates were assessed at 1, 6, 16, 21, 27, and 40 hr. A standardized distance of 1 m was maintained between the patients and the detector. Results: A total of 582 thyroid cancer patients (922 hospitalizations) were evaluated. The time required for the dose rate dropping to 100, 70, or 50 μSv/hr were 6.4 ± 4.1 hr (range: 0.1 to 26.3), 12.3 ± 5.3 hr (range: 0.3 to 31.2), or 17.8 ± 5.7 hr (range: 2.9 to 37.1), respectively. All patients had their dose below 70 μSv/hr at 36 hr post administration of I-131. Patients with elder age (p = 0.013), male gender (p ＜ 0.001), hospitalization due to ablation or adjuvant therapy (p = 0.002) or use of Thyrogen (p ＜ 0.001) had a longer half-life of measured radiation dose. In addition, age, sex, indication for therapy, dose of administered I-131, and use of Thyrogen significantly influenced the time to reach 70 μSv/hr. Conclusion: This retrospective study indicated that for patients receiving high-dose of I-131, it takes about 36 hours for the radiation down to 70 μSv/hr. Age, sex, indication for therapy, administered dose of I-131, and use of Thyrogen significantly influenced the decreasing rate of radiation.

並列關鍵字

thyroid cancer ； radioactive iodine therapy ； release ； radiation control