Exciting Opportunities in Nuclear Medicine Imaging and Therapy.

Nuclear medicine has experienced a number of unprecedented developments in recent years. Above all, the concept of "theranostics", the combination of a predictive biomarker with a therapeutic agent, has been a central part of this success. For example, a phase III randomized, controlled trial provided unequivocal evidence of the effectiveness of 177Lu-DOTATATE for treatment of neuroendocrine tumors, and there have been multiple reports of the benefits of prostate-specific membrane antigen targeted PET imaging and radio-ligand therapy in prostate cancer. Other new exciting theranostic applications include, among many others, C-X-C motif chemokine receptor 4, as well as cancer-associated fibroblasts. These can be specifically addressed by inhibitors of the fibroblast activation protein and represent a particularly promising target for nuclear medicine theranostics. This Special Issue presents some of the most recent advances in the field of nuclear medicine.