Objective The aim of this study was to label 2'-fluoro-2'-deoxy-1-β-D-arabinofurano- syluracil(FAU)with ~(125)I,and to investigate the characteristics of the labeled compound as well as its bio- distribution in mice.Methods FAU was radiolabeled with Na~(125)I using the Iodogen method.The Sep-Pak C18 reverse phase column was used to purify the labeled product.The labeling efficiency,radiochemical purity,the in vitro stability and its biodistribution in mice were observed.Results FAU was successfully la- beled with Na~(125)I with the labeling efficiency of(63.12±5.01)%.The radiochemical purity was(98.60± 0.52)%.~(125)I-5-iodo-FAU(FIAU)was stable in PBS and fresh human serum under 37℃ and the radio- chemical purity remained more than 95.04% after 24 h.Mouse experiment showed that the radiolabeled product was washed out from blood quickly.The uptake expressed as percentage activity of injected dose per gram of tissue(%ID/g)was(4.33±1.00)%ID/g at 0.5 h and(0.71±0.06)%ID/g at 2 h after in- jection.The ~(125)I-FIAU was mainly excreted through'kidney.Conclusions ~(125)I-FIAU could be obtained by labeling FAU with the Iodogen method with satisfactory labeling efficiency,radiochemical purity and stabili- ty.Mouse biodistribution experiment showed it was mainly excreted through kidney.

目的 研究125I-氟-碘阿糖呋喃基尿嘧啶(FIAU)的性质及在小鼠体内的生物学分布.方法 利用Iodogen碘化标记法对氟脱氧呋喃糖尿嘧啶(FAU)进行标记,用Sep-Pak C18反相色谱柱进行纯化;观察125I-FIAU的标记率、放化纯、体外稳定性及其在小鼠体内的生物学分布.结果 以Iodogen固相氧化法标记FAU,得到125I-FIAU,标记率为(63.12±5.01)%;产物经Sep-Pak C18反相色谱柱纯化后放化纯为(98.60±O.52)%;125I-FIAU在PBS及人血清中37℃条件下稳定,24 h后放化纯＞95.04%.生物学分布实验表明:标记物从小鼠血液中清除迅速,用每克组织百分注射剂量率(%ID/g)表示,O.5 h为(4.33±1.00)%ID/g,2 h下降为(0.77±0.06)%ID/g,至24 h时基本清除完毕;肾脏是其主要排泄器官.结论 Iodogen固相氧化法可以进行FAU碘化标记,得到标记率、放化纯及稳定性较好的125I-FIAU,该标记物主要经肾脏排泄。

Objective: To study and to compare the biological characteristic of 99mTc labeled somatostatin analogue 99mTc-HYNIC-TOCA with 99mTc-P829 in tumor model, and to discuss the possibility of diagnosing tumors with 99mTc-HYNIC-TOCA. Methods: TOCA was labeled with 99mTc using HYNIC as bifunctional chelator, EDDA and tricine as coligand. The nude mice bearing human small cell lung cancer underwent static whole body planar imaging after the injection of 99mTc-HYNIC-TOCA or 99mTc-P829. ROIs were drawn and the radioactivity ratios of target to non-target(T/NT) were calculated in every planar imaging. The dynamic biodistribution study was operated in Kunming mice and the percent uptake ratios(%ID/g) of two imaging agents in different tissue at different time were measured. Results: The radiochemical purity of 99mTc-HYNIC-TOCA could reach 94.2% and keep to 93.5% after 6h at room temperature. In the images of tumor bearing mice, two imaging agent were both mainly concentrated in kidney and tumor. In early images, the ratios of tumor to contralateral limbs(T/C) in 99mTc-HYNIC-TOCA group were higher than which in 99mTc-P829 group. The greatest ratios of T/C in two groups(7.45±0.40 and 5.71±0.69) were gained until 4h post-injection. In Kunming mice, the %ID/g of kidney in both groups were the highest and the half-clearance time in blood were less than 60min. The uptake ratio of 99mTc-P829 in liver was significantly greater than the ratio of 99mTc-HYNIC-TOCA(t=2.17, P0.05). Conculusion: 99mTc-HYNIC-TOCA and 99mTc-P829 could be highly uptaken in tumor and quickly cleared from blood. Both of these two imaging agents have good prospect in diagnosing tumors with SSTR expression.

To investigate a new kind of tumor tracer99mTc-YIGSR developed from a five amino structure (YIGSR) of the Laminin-chain, which can bind to the laminin receptors of tumor specifically, and radiolabeled with MAG3. (1) Preparation of the99mTc-YIGSR probe: with S-Acetly-NH3-MAG3 as the chelator and with proper reductants YIGSR was labeled with99mTc; (2) Cell culture and viability measurement: EAC was maintained in RPMI 1640 supplemented with calf serum; the trypan blue exclusion was applied to calculate the cell viability; (3) Study of the cell dynamic: The EAC's uptake of99mTc-YIGSR and99mTc-MIBI was observed at 37 °C and 22 °C, respectively. (1) The labeling efficiencies of99mTc-YIGSR and99mTc-MIBI were (62±3)% and (96±2)%, respectively; (2) The cell viability was declined with time of incubation; (3) At 37 °C, the EAC'S uptake of99mTc-YIGSR and99mTc-MIBI reached the peak of (43.16±2.4)% and (24.4±1.8)% at 60 min, respectively; and at 22 °C, the highest uptake was (26.5±2.1)% and (9.47±1.9)% at 60 min, respectively. Thein vitro study suggests that99mTc-YIGSR is superior to99mTc-MIBI in cell uptake and has potential value in tumor imaging.