Theranostic Applications of Lutetium-177 in Radionuclide Therapy

Lutetium-177 has been widely discussed as a radioisotope of choice for targeted radionuclide therapy. The simultaneous emission of imageable gamma photons [208 keV (11%) and 113 keV (6.4%)] along with particulate β-& emission [β(max) = 497 keV] makes it a theranostically desirable radioisotope. In the present article, the possibility of using two 177 agents viz. 177 and 177 for theranostic applications in metastatic bone pain palliation (MBPP) and peptide receptor radionuclide therapy (PRRT), have been explored. In the case of 177, the whole-body images obtained are compared with those recorded using 99m in the same patient. On the other hand, pre-therapy images acquired with 177 are compared with similar images obtained with standard agents, such as 99m (SPECT) and 68 (PET) in the same patient. The advantage of the long physical half-life (T1/2) of 177 has been utilized in mapping the pharmacokinetics of two additional agents, 177 hydroxyapatite (HA) in radiation synovectomy of knee joints and 177 for therapy of hepatocellular carcinoma. Results of these multiple studies conclusively document the potential of 177 as a theranostic radioisotope.