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 177Lu-based agents viz. 177Lu-EDTMP and 177Lu-DOTATATE for theranostic applications in metastatic bone pain palliation (MBPP) and peptide receptor radionuclide therapy (PRRT), have been explored. In the case of 177Lu-EDTMP, the whole-body images obtained are compared with those recorded using 99mTc-MDP in the same patient. On the other hand, pre-therapy images acquired with 177Lu-DOTA-TATE are compared with similar images obtained with standard agents, such as 99mTc-HYNIC-TOC (SPECT) and 68Ga-DOTA-TOC (PET) in the same patient. The advantage of the long physical half-life (T1/2) of 177Lu has been utilized in mapping the pharmacokinetics of two additional agents, 177Lu-labeled hydroxyapatite (HA) in radiation synovectomy of knee joints and 177Lu-HA for therapy of hepatocellular carcinoma. Results of these multiple studies conclusively document the potential of 177Lu as a theranostic radioisotope.