Clinical Study of 68Ga Labeled HER2 Affibody Analogues

6 healthy volunteers with whole-body PET/CT scans at 0-1.0, 2.0, 3.0 and 4.0 hours after tracer injection (mean dose, 4.93 ± 0.10 mCi) will be performed. During the imaging period, 1 mL blood samples will be obtained specifically at 1, 3, 5, 10, 30,60, 90, 120, 150, 180 and 240 minutes after the injection, for time-activity curve calculations. The estimated radiation doses will be calculated by using OLINDA/EXM software. 50 patients with breast or gastric tumors will be enrolled for the clinical study, they will be performed with both 68Ga-HER2 Affibody PET/CT and18F-FDG PET/CT scans before surgery. The preoperative images are compared and correlated with the pathologically report. Next, the expression of HER2 will be determined by immunohistochemical staining of the resected brain tumor tissues.