^(99)Tc^m-DTPA-生物素-亲和素预定位技术用于肿瘤放免显像  

Pretargeted tumor imaging with avidin-McAb and ^(99)Tc^m-DTPA-Biotin

作　　者：张锦明[1] 田嘉禾[1] 王钰琦[2] 柳曦[2] 孙新[2] 

机构地区：[1]解放军总医院核医学科,北京100853 [2]解放军总医院胸外科,北京100853

出　　处：《中华核医学杂志》2002年第2期108-110,I001,共4页Chinese Journal of Nuclear Medicine

摘　　要：目的　评价用99Tcm 替代111In标记生物素 亲和素系统 (BAS)在肿瘤放免显像预定位中的价值。方法　DTPA 生物素溶液中加入99Tcm 淋洗液 ,室温放置 10min。荷LA 795肺癌鼠分成荷瘤7d肺无转移组和荷瘤 15d肿瘤肺转移组。采用三步法预定位技术给药 ,先注射生物素化C5 0抗体 ,1d后注射亲和素 ,再过 2d注射99Tcm DTPA 生物素 ,设对照和空白组 ;并与常规99Tcm 直接法标记C5 0抗体放免显像比较。结果　99Tcm DTPA 生物素的标记率大于 90 % ,亚锡量是影响标记率的重要因素。注射后 2h ,三步法组肿瘤摄取量为 (1.35± 0 .45 ) %ID/g ,瘤 /血比值 (T/B)为 5 .86 ,瘤 /肌肉比值(T/M)为 8.43。而对照直接注射99Tcm DTPA 生物素组的T/B为 0 .85 ,T/M为 1.1。99Tcm 直接法标记C5 0放免显像组在注射后 8h的T/B为 1.6 5 ,T/M为 2 .0。注射后 2h平面显像 ,三步法组肿瘤显影清晰 ,余各组肿瘤均未显影。结论　99Tcm DTPA 生物素可用于三步法肿瘤放射免疫显像 。Objective Biotin-avidin is used as pretargeting system (BAS) in radioimmunoimaging in order to decrease radiation background and dose associated with the use of directly labeled McAb. We tried to use 99Tc m to substitute 111In to label DTPA-biotin to evaluate the value of the 99Tc m-DTPA-biotin in BAS. Methods DTPA-biotin solution was mixed with SnCl 2 and then fresh eluted 99Tc m. The solution incubated for 10 min at room temperature. Mice bearing lung tumor (LA-795) with and without metastases in lung underwent 3-step pretargeting test. Briefly, biotin-C50 was injected first, then avidin and 99Tc m-DTPA-biotin was respectively given 1 day, 2 days later. Directly labeled C50 with 99Tc m was used as control agent. Results The labeling yield of 99Tc m-DTPA-biotin was over 90%. The amount of SnCl 2 was the key feature in labeling. The tumor could be seen at 2 h after injection of 99Tc m-DTPA-biotin with γ camera in 3- step groups. The tracer uptake in tumor was (1.35±0.45) %ID/g at 2 h after injection, Tumor/Blood (T/B) was 5.86, T/Muscle (T/M) was 8.43. In control group which received 99Tc m-DTPA-biotin only, the T/B was 0.85, T/M 1.1. For the directly labeled C50, the T/B was 1.65, T/M was 2.0 at 8 h after injection. Conclusion Avidin-biotin pretargeting system can be labeled with 99Tc m, and the BAS can image the tumor as early as 2 h after injection.

关 键 词：^99Tc^m-DTPA-生物素-亲和素预定位技术 肿瘤诊断 放射免疫显像 三步法肿瘤放射免疫显像 

分 类 号：R817[医药卫生—影像医学与核医学]