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目的:制备新型n 68Ga标记三七素类前列腺特异膜抗原(PSMA)靶向探针，并进行理化性质和体内外评估。n 方法:采用固相合成法制备配体P151，测定其亲和性。将配体加入到n 68GaCln 3与醋酸钠混合的溶液中，95 ℃反应10 min，使用放射性高效液相色谱(HPLC)测定其标记率及体外稳定性。评估n 68Ga-P151的脂水分配系数(log n P)，并进行细胞摄取实验。对正常昆明(KM)小鼠进行体内生物分布测定；对前列腺癌22Rv1荷瘤裸鼠注射n 68Ga-P151后进行microPET显像，并与n 68Ga-PSMA 617进行对比。2组间比较采用两独立样本n t检验。n 结果:成功合成目标配体P151，其抑制常数n Ki为0.58 nmol/L，标记率和放化纯均≥95%；37 ℃放置2 h后，n 68Ga-P151在生理盐水和人血清白蛋白(HSA)溶液中的放化纯仍≥95%，表明其体外稳定性好；n 68Ga-P151的脂水分配系数(log n P)为-2.65±0.17，表明其亲水性较好。注射n 68Ga-P151后60 min，前列腺癌LNCaP细胞的总摄取值为(0.83±0.04)百分注射活度(%IA)/10n 5个细胞，并可被PSMA抑制剂(ZJ-43)所抑制。正常小鼠体内生物分布显示n 68Ga-P151主要经肾脏排泄出体外，在其他组织中摄取较低；荷瘤裸鼠microPET显像显示，n 68Ga-P151与n 68Ga-PSMA 617的最大标准摄取值(SUVn max：0.79±0.23和0.54±0.05；n t＝2.12)、肿瘤/肾脏比值(2.04±0.65和1.88±0.33；n t＝0.44)、肿瘤/肌肉比值(12.83±5.18和6.95±1.63；n t＝2.17)差异均无统计学意义(均n P>0.05)。n 结论:68Ga-P151制备简单、标记率高、生物分布理想，可对PSMA阳性肿瘤显像，其显像效果与n 68Ga-PSMA 617相当，有望应用于前列腺癌的诊断。n “,”Objective:To synthesize a n 68Ga-labeled oxalyldiaminopropionic acid (ODAP)-urea based prostate specific membrane antigen (PSMA) targeting probe, and evaluate its properties n in vitro and n in vivo.n Methods:Ligand P151 was synthesized by solid-phase synthesis and its Ki value was determined. The ligand P151 was added into the mixture of n 68GaCln 3 and NaOAc solution and was reacted at 95 ℃ for 10 min. The labeling yield and n in vitro stability of n 68Ga-P151 were determined by high performance liquid chromatography (HPLC). The lipid-water partition coefficient (log n P) and cell binding ability were determined. The biodistribution of n 68Ga-P151 in normal KM mice was determined. MicroPET imaging of n 68Ga-P151 was carried out in prostate cancer 22Rv1 tumor-bearing mice and compared with n 68Ga-PSMA 617. Independent sample n t test was used to analyze the data.n Results:P151 was successfully synthesized with the n Ki of 0.58 nmol/L, the labeling yield more than 95% and the radiochemical purity more than 95%. After placement in saline or human serum albumin (HSA) solution at 37 ℃ for 2 h, the radiochemical purity of n 68Ga-P151 was still more than 95%, indicating a good stability n in vitro. The lipid-water partition coefficient (log n P) of n 68Ga-P151 was -2.65±0.17, indicating a good hydrophilicity. n 68Ga-P151 specifically bound to PSMA in prostate cancer LNCaP cells with the uptake value of (0.83±0.04) percentage injection activity (%IA)/10n 5 cells. Biodistribution of normal mice showed that n 68Ga-P151 was mainly excreted through kidneys and other organs showed low uptake. MicroPET imaging of tumor-bearing mice showed the maximum standardized uptake value (SUVn max: 0.79±0.23 n vs 0.54±0.05; n t=2.12), tumor/kidney ratio (2.04±0.65 n vs 1.88±0.33; n t=0.44) and tumor/muscle ratio (12.83±5.18 n vs 6.95±1.63; n t=2.17) between n 68Ga-P151 and n 68Ga-PSMA 617 were not significantly different (all n P>0.05).n Conclusions:68Ga-P151 can be prepared simply and labeled in high yield and show improved pharmacokinetic properties n in vivo. The imaging of n 68Ga-P151 on PSMA positive tumor is comparable to that of n 68Ga-PSMA 617, making it a potential radiopharmaceutical for the diagnosis of prostate cancer.n