针对肿瘤特异性的ACE2表达，本研究旨在建立和验证ACE2靶向PET成像技术，以区分不同ACE2表达的肿瘤。68Ga-cyc-DX600被合成为ACE2 PET示踪剂。NOD-SCID小鼠被用于制备HEK-293或HEK-293T/hACE2细胞的皮下肿瘤模型，验证ACE2特异性，并使用其他肿瘤细胞评估ACE2表达的诊断效率。此外，免疫组织化学分析和西方印迹被用于确认ACE2 PET的发现，并与FDG PET进行比较。68Ga-cyc-DX600的代谢清除最初在60分钟内完成，并实现ACE2 PET的与ACE2依赖和器官特异性的背景。同时，皮下肿瘤模型的示踪剂摄取量明显依赖于ACE2表达（r = 0.903，p <0.05），后者是ACE2 PET用于ACE2相关肿瘤的鉴别诊断的主要因素。在临床前实践中，ACE2 PET的肺癌患者在注射后50和80分钟时获得了可比较的肿瘤/背景比率。ACE2 PET和FDG PET的定量值在食管癌患者中呈负相关（SUVmax的r = -0.971，p = 0.006; SUVmean的r = -0.994，p = 0.001），无论是原发灶还是转移。68Ga-cyc-DX600 PET是肿瘤鉴别诊断的ACE2特异性成像方法，并为传统核医学诊断（如FDG PET）提供了补充价值。 © 2023。作者（单独或共同）独家许可Springer-Verlag GmbH德国，属于Springer Nature。

For the tumor-specific ACE2 expression, this research aimed to establish and verify ACE2-targeted PET imaging in differentiating tumors with distinct ACE2 expression.68Ga-cyc-DX600 was synthesized as tracer of ACE2 PET. NOD-SCID mice were used to prepare the subcutaneous tumor models with HEK-293 or HEK-293T/hACE2 cells to verify ACE2 specificity, with other kinds of tumor cells to evaluate the diagnostic efficiency for ACE2 expression, additionally, immunohistochemical analysis and western blot were used to certify the findings on ACE2 PET, which was then performed on four cancer patients and compared with FDG PET.The metabolic clearance of 68Ga-cyc-DX600 was initially completed in 60 min, realizing an ACE2-dependent and organ-specific background of ACE2 PET; meanwhile, tracer uptake of subcutaneous tumor models was of a definite dependence on ACE2 expression (r = 0.903, p < 0.05), and the latter served as the primary factor when ACE2 PET was used for the differential diagnosis of ACE2-related tumors. In pre-clinical practice, a comparable tumor-to-background ratio was acquired in ACE2 PET of a lung cancer patient at 50 and 80 min post injection; the quantitative values of ACE2 PET and FDG PET were negatively correlated (r =  - 0.971 for SUVmax, p = 0.006; r =  - 0.994 for SUVmean, p = 0.001) in an esophageal cancer patient, no matter the primary lesion or metastasis.68Ga-cyc-DX600 PET was an ACE2-specific imaging for the differential diagnosis of tumors and added complementary value to conventional nuclear medicine diagnosis, such as FDG PET on glycometabolism.© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.