Application of molecular imaging technology in tumor immunotherapy.

Cancer immunotherapy, due to its high anti-tumor efficacy, has attracted considerable attention globally from experts in various fields. However, immunotherapy could be severely toxic; not all patients may respond, thus requiring combination therapy. Therefore, a reasonable selection strategy for early treatment is urgently needed. It is vital to capture the dynamic, heterogeneous, and complex tumor behavior considering the absence of ideal companion biomarkers. Since tumor immune response involves tumor cells, several other cell types, and molecules in the tumor microenvironment, detection is very complex and variable. However, molecular imaging technology, namely the non-invasive whole-body molecular imaging by positron emission tomography and single-photon emission computed tomography, has shown considerable promise in tumor detection and cancer immunotherapy response. Identification of potential novel imaging biomarkers will allow a personalized treatment plan for every patient. Future imaging strategies for these molecules used alone or in combination or continuously, might help stratify patients before or during the early stages of immunotherapy, and might address the immunotherapy challenges encountered by the oncologists.