PET/CT Imaging for Assessment of Tumor Immunotherapy Response: a New Perspective on Tumor Metabolic Reprogramming and Immune Escape

Accurately assessing tumor response to immunotherapy remains a significant clinical challenge due to the unique response patterns and limitations of conventional anatomical imaging. This review explores the evolving application of PET/CT in evaluating immunotherapy efficacy through the novel lens of tumor metabolic reprogramming and immune escape mechanisms. First, we examine how metabolic imbalances in the tumor microenvironment mediate immune escape by suppressing immune cell function. The review subsequently analyzes advances in molecular imaging, focusing on the development of novel radiopharmaceuticals that target specific immunometabolism pathways, enabling direct visualization of immune cell dynamics. Furthermore, we analyze advances in novel tracers targeting specific immunometabolism processes for direct immune cell visualization, along with the application of radiomics for early response prediction. Finally, we address current technical and clinical challenges, outlining future directions aimed at constructing an integrated tumor metabolic-immune map and developing robust, PET-based patient stratification strategies to guide personalized therapeutic regimens. In conclusion, PET/CT is emerging as an indispensable multi-dimensional tool, providing critical real-time insights into immunometabolism activity to optimize therapeutic decision-making and improve clinical outcomes in cancer immunotherapy. Integrating these metabolic-immune signatures with other biomarker data holds promise for refining response assessment strategy and advancing personalized oncology.