Comparison of the Outcome between the Calculated Dosimetry and the Estimated Dosimetry of [fef3]I in the Treatment of Hyperthyroidism

　　　　　放射性碘(131I)被汎應用於治療甲狀腺高能症，至今已有四十多年歷史。然而截至目前為止，對於如何決定最適當的劑量，以期能夠控制甲狀腺功能過高，同時避免甲狀腺功能過低，則尚無一致的定論。本篇研究的主旨，是比較兩種不同方法決定放射性碘劑量，用於治療甲狀腺高能症的結果。我們收進五十二位瀰漫性甲狀腺高能症的病人，於民國七十三年三月到七十九年十一月間，接受放射性碘治療。其中三十一位所接受的劑量，是藉著核子醫學掃描決定甲狀腺大小及測定甲狀腺對放射性碘的吸收率(uptake)，再經由公式計算而得(計算組)。另外二十一位所接受的劑量是利用理學檢查判斷甲狀腺大小，再參酌臨床上有無伴隨心律不整、心臟衰竭或缺血性心臟病的情況而估測劑量之多寡(估測組)。兩組病人在接受放射碘前的臨床情況及檢驗室檢查結果的比較，並無明顯差異。但估測組在性別比例上，男性較多，而且年齡較頸，經過統計學上的檢定，對於其他比較項目的結果並無影響。估測組所接受之放射性碘劑量大於計算組(7.0±1.1mCl vs. 4.8±1.1mCl; p<0.05)。在放射性碘治療後半年、一年、二年、五年分別追?兩組不同甲狀腺功能狀態的發生率，就治療甲狀腺功能亢進，同時避免功能過低的觀點而言，估測組的效果較好，但在統計學上，兩組的結果並無明顯的差別。 結論：就方法簡單和節省時間的觀點而言，利用理學檢查判斷甲狀腺大小，再參酌臨床上有無伴隨心臟病變，來估測放射性碘劑量之多寡用顧治療瀰漫性甲狀腺高能症，也是不錯的選擇。
　　　　　To compare the outcomes of different methods in prescribing the optimal dose of radioactive iodine (131I) for the treatment of hyperthyroidism, we retrospectively analyzed 52 patients with toxic diffuse goiter. They received single dose of 131I for the treatment of hyperthyroidism. In addition, all of them met the following criteria: 1) symptoms and signs of hyperthyroidism; 2) elevated blood triiodothyronine (T3) and thyroxin (T4) by radioimmunoassay (RIA) method; 3) diffuse goiter with increase of ulptake lproved by thyroid scintiscan; 4) only one dose of 131I was given during the follow-up period; 5) well-documented thyroid function test in the medical chart during the follow-up period (6 months, 1years, 2years and 5 years after 131I therapy). The enrolled patients were divided into estimated and calculated group. The dose of 131I in the calculated group was obtained from the measurement of size and 131I uptake of thyroid gland. The dose of 131I in the estimated group was prescribed according to the size of thyroid gland by8 physical examination, and the association with cardiac arrhythmia, congestive heart failure, or ischemic heart disease. The mean doses of 131I were 4.8±1.4 mCi and 7.0±1.1 mCi in the calculated and estimated group respectively. In this study, there were no significant difference in the incidence of euthyroidism, hyperthyroidism, and hypothyroidism between these two groups in the follow-up period after 131I therapy. In view of simplicity and time-saving, it is a practical choice to prescribe the dose of 131I therapy for toxic diffuse goiter according to the size of thyroid gland and the associated cardiac condition.