Tamura et al. reported that 64Cu-DOTA-trastuzumab could delineate HER2-positive lesions including brain metastases in breast carcinoma patients; further, the use of 64Cu (half-life = 12.7 h) could reduce the radiation exposure to 4.5 mSv versus the 18 mSv from 89Z-trastuzumab [24, 28]. The gene discussed is ERBB2; the disease is breast carcinoma.