Figure 1.

Overview of theranostic applications in oncology. (A) Theranostic applications in oncology have gained importance in the management of remnant tumors using cancer-type specific biomarkers, including SSTR2-positive or NET-positive neuroendocrine tumors, NIS-positive differentiated thyroid tumors and PSMA-positive prostate cancer. (B) The combination of vector-mediated gene transduction with the corresponding PET/SPECT-CT imaging probe not only benefits tracking of the efficiency of gene transduction but also establishes the fundamental principles to enlarge the field of theranostic applications by inducing the expression of an enzyme, receptor or transporter targeted by the corresponding theranostic radiopharmaceuticals. (C) Surrogate imaging relies on the visualization by molecular imaging of the downstream effects (metabolism, proliferation, associated inflammation) of a gene or cell-based therapy paradigm. Image modified from Jacobs et al. (2021) [6].