Asian Journal of Nuclear Medicine

Volume 2 Number 1, March 2002


1第四軍醫大學西京醫院核醫學科,西安 710032, 中國
2第四軍醫大學西京醫院實驗外科,西安 710032, 中國

擬建立一種高效碘標多遧C-160的方法,以溴代琥珀q亞胺(NBS)為氧化劑,常規氯胺T法作為對照,對125I-RC-160的標記率、比活度進行評價,並觀察125I-RC-160在正常小鼠體內的生物分佈特徵。結果顯示:在丙酮:生理鹽水=1:1體系中,測得125I-RC-160的標記率NBS法為92%,比放射性為1.75×1012Bq/mmoL,標記率隨NBS用量增加而增高,最佳用量比為RC-160(μg):125I(MBq):NBS(μg)= 3:7.4:1,且產物無需純化;Ch-T法標記率為56%。,比放射性為0.65×1012 Bq/mmoL,經SepPaK-C18反向色譜柱純化,125I-RC-160的放射化學純度>98 %。標記物在血中清除較快,注射後不到1小時血中的放射性就下降了87.2%;125I-RC-160在腎內濃集度很低,主要經過消化系統排出體外。研究結果表明NBS法可高效碘標多銵A標記後無需純化,減少了對操作者的輻射,是一種碘標的理想方法。

【關鍵詞】 生長抑素類似物;碘放射性同位素;同位素標記

Comparison radioiodination methods of RC-160 and its biodistribution in normal mice

Wang Jing1, Wang Xiqing2, Wang Liangang2, Li Fujun1
1Department of Nuclear Medicine, Xijing Hospital, Xi'an 710032, China
2Department of Experimental Surgery, Xijing Hospital, Xi'an 710032, China

We aims to establish a method of labeling of RC-160 with 125I. NBS was used as oxidant. Ch-T method was also performed as control. Labeling yield and specific activity of 125I-RC-160 were determined. Biodistribution of 125I-RC-160 in normal mice was observed. When using acetone and saline (1:1) as developer, labeling yield and specific radioactivity of 125I-RC-160 was 92% and 1.75 x 1012 Bq/mmol respectively with NBS method. The labeling yield was raised with the increase of NBS dose. The optimal dose of RC-160 (mg): 125I(MBq): NBS (mg) was 3:7.4:1. The 125I-RC-160 prepared with NBS method needed no purification. Labeling yield and specific radioactivity of 125I-RC-160 was 56% and 0.65 x 1012 Bq/mmol respectively with Ch-T method. Reverse-phase (RP) chromatography was used to purify the products. Radiochemical purity of 125I-RC-160 was over 98% with Ch-T method. Radioactivity of 125I-RC-160 in blood was decreased by 87.2% within less than 1 hr, which indicated that a substantial amount of the injected dose had been cleared from blood. Very little radioactivity was found in kidney. However, much radioactivity was found in intestines, suggesting that the route of clearance of 125I-RC-160 was digestive system. The results revealed that NBS method is an ideal iodine labeling method, with high labeling efficiency, unnecessary for no further purification and minimization of the radiation damage.

Key Words: Somatostatin analogue; Iodine radionuclide; Labeling

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