胰腺β细胞含量（β cell mass）评估及测定对胰岛β细胞相关疾病的临床诊治、病理机制研究至关重要，但临床尚无可靠的方法实现无创、在体的评价及测定胰腺β细胞含量。因此，本项目利用基于68Ga-NOTA-exendin-4的胰高血糖素样肽-1受体显像展开测定胰腺β细胞含量的方法学研究，并初步实现临床转化。研究拟照体外组织学、在体影像学、数学模型优化、临床转化研究逐步进行，首先研究并验证该方法可靠性的组织学依据，然后利用68Ga-NOTA-exendin-4 PET/CT进行动物模型的在体影像学方法的研究，解决目前研究基础中图像测量参数不准确的问题并进行验证，同时建立临床可行的显像方法；在此基础上从图像处理和分析的角度利用数学模型优化测量输出参数，提高该方法测定胰腺β细胞含量的准确性，建立最优化的测定胰腺β细胞含量的影像学方法；最后实现该方法的临床转化研究，并评价其临床可靠性及应用价值。

Measurement of pancreatic β cell mass is essentially important to diagnosis, evaluation and study of pancreatic β cell related disease. However, noninvasively accurate measurement of pancreatic β cell mass in vivo still lacks. Therefore, this program will be focused on methodology study of accurate measurement of pancreatic β cell mass with 68Ga-NOTA-exendin-4 for glucagon-like peptide-1 receptor imaging. The research method will be sequentially based on ex vivo histology study, in vivo medical imaging study with 68Ga-NOTA-exendin-4 PET/CT, optimization of measurement parameters with mathematical model, and initial translational study on patients with diabetes mellitus. First, ex vivo histology study on islets uptake of 68Ga-NOTA-exendin-4 will be the strong basic and theoretical evidence for this study; comparison and correlation study of histology and autoradiography with 68Ga-NOTA-exendin-4 will be performed. Then, in vivo 68Ga-NOTA-exendin-4 PET/CT on animal model will be performed to verify the sensitivity and accuracy of this modality. Importantly, we will establish a pharmacologic intervention to markedly improve the accuracy of the parameters, and determine the diagnostic value. Based on those results, image processing and mathematical calibration will be investigated to optimize the measured parameters. Finally, translational study will be performed to investigate the clinical value of the modality.