A study by Laforest et al. [78] evaluated the efficacy of a zirconium-89 (89Zr) radiolabelled HER2-antibody, trastuzumab, in patients with HER2-positive BC, and concluded that [89Zr]Zr-trastuzumab produced optimal PET/CT images with the best available tumour-to-non-tumour contrast, four days post-injection. The gene discussed is ERBB2; the disease is neoplasm.