本研究的目的是合成一种基于喹啉的 MRI 造影剂 Gd-DOTA-FAPI04，并评估其体内靶向成纤维细胞激活蛋白 (FAP) 阳性肿瘤的能力。 Gd-DOTA-FAPI04 是通过将钆 (III) 的 1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸 (DOTA) 络合物连接至 FAP 抑制剂 FAPI04 来合成的。使用Siemens Prisma 3.0T MR系统测量造影剂的纵向弛豫时间（T1），并进行CCK-8测定以评估其潜在的细胞毒性。将表达FAP的纤维肉瘤细胞生长的荷瘤雄性裸鼠分为实验组（n = 4）和对照组（n = 4），并在不同时间（0、10、30、60、 90 和 120 分钟）注射 Gd-DOTA-FAPI04 后。对照组接受额外的预注射过量的 FAPI04。通过使用抗 FAP 抗体的免疫组织化学研究肿瘤组织中的 FAP 表达。测得钆双胺和Gd-DOTA-FAPI04的纵向弛豫率分别为3.734 mM-1 s-1和5.323 mM-1 s-1。 CCK-8 测定表明 Gd-DOTA-FAPI04 对培养的人纤维肉瘤细胞具有最小的毒性。体内 MRI 显示 FAP 表达肿瘤中 Gd-DOTA-FAPI04 的峰值积累发生在注射后 1 小时，并且可以通过预先注射过量的 FAPI04 来阻断。对收获的肿瘤组织的免疫组织化学分析支持了上述发现。 Gd-DOTA-FAPI04 是一种很有前景的 FAP 体内成像造影剂。

The aim of this study was to synthesize a quinoline-based MRI contrast agent, Gd-DOTA-FAPI04, and assess its capacity for targeting fibroblast activation protein (FAP)-positive tumors in vivo. Gd-DOTA-FAPI04 was synthesized by attaching a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) complex of gadolinium(III) to FAP inhibitor FAPI04. The longitudinal relaxation time (T1) of the contrast agent was measured using a Siemens Prisma 3.0T MR system, and the CCK-8 assay was performed to evaluate its potential cytotoxicity. Male nude mice bearing tumors grown from FAP-expressing fibrosarcoma cells were divided into experimental (n = 4) and control (n = 4) groups, and T1-weighted image enhancement was measured at different times (0, 10, 30, 60, 90, and 120 min) postinjection of Gd-DOTA-FAPI04. The control group received an additional preinjection of excess FAPI04. FAP expression in tumor tissue was investigated by using immunohistochemistry with an anti-FAP antibody. The longitudinal relaxivities of gadodiamide and Gd-DOTA-FAPI04 were measured to be 3.734 mM-1 s-1 and 5.323 mM-1 s-1, respectively. The CCK-8 assay demonstrated that Gd-DOTA-FAPI04 has minimal toxicity to cultured human fibrosarcoma cells. In vivo MRI showed that peak accumulation of Gd-DOTA-FAPI04 in FAP-expressing tumors occurred 1 h postinjection and could be blocked by preinjection of excess FAPI04. Immunohistochemical analysis of harvested tumor tissue supported the above findings. Gd-DOTA-FAPI04 is a promising contrast agent for in vivo imaging of FAP.