Only one in 100,000 people suffer from a pheochromocytoma, a tumor of the adrenal gland. If the tumor has already metastasized, a radioactive compound can be used to detect malignant cells that have spread to other parts of the body, and to irradiate them from the inside. However, the preparation containing the beta emitter Lutetium-177 can only bind to the tumor if it has sufficient target molecules, which is not always the case. By administering two approved drugs prior to therapy, a research group at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has succeeded in increasing the number of target molecules for radionuclide therapy in a mouse model, delaying tumor growth.