[18F]F-AraG PET Imaging to Visualize Tumor Infiltrating T-cell Activation in Non-small Cell Lung Cancer.

The efficacy of immunotherapy and patient selection for combinatorial immunotherapy strategies would greatly improve if the tumor microenvironment (TME) could be characterized more accurately. Positron emission tomography (PET) using tracers that target immune cell subsets may provide a non-invasive means to immune profile the TME. Imaging T-cells can help in identifying 'hot' tumors, or parts of the tumor mass that have high concentrations of tumor infiltrating T-cells and also provide information on its activation. A promising tracer to image activated T-cells is \[18F\]F-AraG. Based on the hypothesis that \[18F\]F-AraG will accumulate in activated T-cells, it is expected that \[18F\]F-AraG and PET will enable to (reproducibly) identify tumors and tumor areas with high concentrations of tumor infiltrating activated T-cells on pathological assessment. In the ATTAIN trial this \[18F\]F-AraG uptake in tumor lesions and healthy organs is explored by full kinetic modelling.