Targeted radiotherapy (TRT) is a medical method that uses targeted molecules to deliver radionuclides to tumor cells and tissues to accurately kill cancer cells at close range, thus achieving the purpose of treatment. TRT drug molecules generally contain three parts. The molecular binder, which is responsible for accurately identifying and binding tumor targets, the linker, which connects the molecule binder and the chelator, and improves the pharmaceutical application of the overall drug molecule, and the chelator, to form the firm complexation of radionuclides (for example: β-emitter 177Lu or α-emitter 225Ac). As shown below:

Once a TRT drug molecule reaches the target cancer cell via bloodstream, the radioactive isotope can kill the cancer cells in a confined local tumor microenvironment through radiation similar to the traditional external radiation beam therapy. TRT has the unique advantage over other current existing therapeutic modalities of being both diagnostic and therapeutic through the same molecule by switching the radioactive isotopes. TRT as a novel class of therapeutic drugs can be the true enabler of imaging guided therapy that allows a doctor to assess a drug's efficacy through imaging before and after the drug is administered to a patient.