Perhaps the simplest way to explain the workings of PRRT is to think about the analogy of a magnet and its ability to attract iron shavings. Think of a neuroendocrine tumor with somatostatin positive receptors as the magnet and the iron shavings are a somatatostatin analog chemical (Octreotide) to which is bound or attached to some radioactive material (the radionuclide Y90 or LU177). The receptors in the tumors attract the octreotide and this chemical with the radioactive material is absorbed into the tumor by the receptor. The radiation then starts to kill the tumor cells.

This makes PRRT a form of targeted therapy, able to impact those tumors that can absorb certain types of chemicals bound to radioactive materials. Since the octreotide with the radionuclide is put into a patient's blood stream, this form of therapy is systemic, reaching all parts of the body via the blood stream. This can be compared to a regional form of radiation-based therapy called microspheres or SirSpherestm that uses very small glass or resin beads that are impregnated with radiation. These beads are put directly into the blood circulating in the liver, using circulatory network in the liver to deliver the radiation to locations near each tumor.