Figure 1.

(A) Theranostics concept explained. A tumor-specific ligand can be used for both imaging and therapy, dependent on the nuclide of choice. PET images before/after therapy in a prostate cancer patient diagnosed and treated with [⁶⁸Ga/¹⁷⁷Lu]PSMA. PET image adapted from SNMMI image of the year 2018 by Hofman et al.; (B) left, [¹²³I]mIBG SPECT image of a neuroblastoma patient with lesions indicated with black arrows; right, [¹⁸F]mFBG PET image of the same patient showing greater contrast and additional lesions that were not observed with [¹²³I]mIBG. Image adapted from Pandit-Taskar et al. (1); (C) left, [¹²³I]mIBG SPECT image of a neuroblastoma patient with only vague tumor uptake; right, [⁶⁸Ga]DOTATOC PET image of the same patient showing SSTR-2A expression, greater contrast and additional lesions. Patient is treated with [¹⁷⁷Lu]DOTATATE with an additional survival of 24 months (unpublished data, UMC Utrecht).