This study will investigate the safety and preliminary diagnostic efficacy of \[68Ga\]Ga-NOTA-T4 or \[18F\]AlF-RESCA-T4 in pancreatic cancer, breast cancer, head and neck cancer, lung cancers and other types of solid tumors. Then, this study will provide a new method for the noninvasive target-specific diagnosis of pancreatic cancer, breast cancer, head and neck cancer, lung cancers and other types of solid tumors. PET imaging of TROP-2 will be integrated to TROP-2-targeted therapies in some of the included patients. Therefore, PET imaging with \[68Ga\]Ga-NOTA-T4 or \[18F\]AlF-RESCA-T4 will help select patients for targeted therapy and monitor treatment responses after the treatment.