ERBB2 and metastatic neoplasm: Comparative studies show that 68Ga-FAPI demonstrates greater overall tumor uptake in breast cancer and detects metastatic disease more effectively than 18F-FDG, particularly for bone and peritoneal metastases [22]. A variety of radiotracers have been developed for imaging HER2-positive cancers, but 89Zr-trastuzumab currently has the most robust supporting evidence [22].