The prevalence of HER2 alterations in pan-cancer indicates a broader range of application of HER2-targeted therapies. immunohistochemistry (IHC) or amplification by fluorescence in situ hybridization (FISH) is currently the most commonly used method for evaluation of HER-2 status in cancer patients. However, biopsies are spatiotemporally limited because of the highly heterogeneous expression of HER2. Patients with false-negative HER2 results may miss the chance for targeted therapy. Additionally, the HER2 status can change during the disease process. A investigational imaging tracer named 68Ga-HER2 Affibody binds to HER-2 receptors. Previous studies in human have shown the efficacy of 68Ga-HER2 Affibody in detecting HER2 positive breast cancer and gastric cancer without any observed toxicity. However, studies are still insufficient and limited to breast cancer and gastric cancer. The investigators hypothesized that 68Ga-HER2 Affibody PET imaging can noninvasively assess HER2 status in metastatic or recurrent solid tumors including breast cancer, gastrointestinal tumors, head and neck squamous tumors, bladder cancer, lung cancer and uterine tumors lesion. In this study, efficacy of 68Ga-HER2 Affibody in detecting HER2 positive cancer lesions and change of patient management based on 68Ga-HER2 Affibody PET will be determined.