No symptoms or signs of toxicity were observed after administration of 68Ga anti-HER2 nanobody using 0.01–1 mg of nanobody per injection [140], which is why it is considered safe and is currently being investigated in an open label non-randomized monocenter phase II trial to evaluate its potential to detect brain metastases in breast cancer patients (EudraCT 2015-002328-24, NCT03331601) [141]. This evidence concerns the gene ERBB2 and breast carcinoma.