摘要Background:The chicken chorioallantoic membrane(CAM)model is a potential alter-native to the mouse model based on the 3R principles.However,its value for deter-mination of the in vivo behaviors of radiolabeled peptides through positron emission tomography(PET)imaging needed investigation.Herein,the chicken CAM tumor models were established,and their feasibility was evaluated for evaluating the imag-ing properties of radiolabeled peptides using a 68 Ga-labeled HER2 affibody.Methods:Two human breast cancer cell lines were inoculated into chicken CAM and mice,respectively.The tumor-targeting potential and pharmacokinetic profile of a 68 Ga-labeled affibody,68 Ga-MZHER,in both tumor models were also determined.Results:The tumor-formation time in chicken CAM model was shorter than that of mouse model.The uptake values of human epithelial growth factor receptor-2(HER2)-positive Bcap37 tumors in chicken CAM and mouse models were 5.36±0.26%ID/g and 5.26±0.43%ID/g at 30 min postinjection of 68 Ga-MZHER,respectively.At the same time points,the uptake values of HER2-negative MDA-MB-231 tumors in the chicken CAM models and mouse models were 1.57±0.15%ID/g and 1.67±0.25%ID/g,respectively.Ex vivo biodistribution confirmed that more radioactivity accu-mulated in Bcap37 tumors than in MDA-MD-231 tumors in both CAM and mouse models.Conclusion:In this study,the CAM tumor model was successfully prepared.The chicken CAM model is a novel tool for quickly determining the in vivo properties of radiolabeled peptides targeting biomarkers.It may be beneficial for early monitoring of the therapeutic effect of a new drug through PET imaging with specific peptides.