11C-labeled peptide for detection of a tumor that expresses a Her2 / neu receptor

It is described the use of a peptide (1) for the preparation of an agent for detection of a tumor (18), which expresses a Her2 / neu receptor (4). The peptide (1) binds to the Her2 / neu receptor (4) and has a Further, a radiopharmaceutical for the localization of a tumor (18), which expresses a Her2 / neu receptor (4) will be described. This includes a peptide (1), which binds to the Her2 / neu receptor (4) and having a