PRRT
The early efforts at PRRT were done with a form of Indium-111. This form of radiation was found to have a very short radius of action, causing little or no collateral damage to nearby tissue, but was most effective on very small tumors. Doctors using the Indium-111 found that it was not ideal for PRRT because the small particle range resulted in short tissue penetration and limited effectiveness on tumors 2cm and larger.
In the late 1990s and early 2000s, Doctors started using two other radionuclides that were coupled to Octreotide. These were Yttrium-90 and Lutetium-177. Later some doctors tried a combination of these two radionuclides (done in sequence). Both of these radionuclides are stronger than the Indium-111 and have longer
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
Peptide Receptor Radionuclide Therapy (PRRT) is a form of molecular targeted therapy which is performed by using a small peptide (a somatostatin analog similar to octreotide) that is coupled with a radionuclide emitting beta radiation. PRRT is a novel nuclear medicine therapy (the first patients were treated in 1996) for the systemic treatment of metastasized neuroendocrine tumors. These types of tumors include gastroenteropancreatic tumors (socalled GEP-NETs), e.g. arising from the small