PET-Guided Radiotherapy

PET-guided radiation therapy represents a paradigm shift in treatment planning, replacing anatomy-centric approaches with dynamic, biology-driven strategies. By leveraging metabolic or molecular imaging, planners delineate biological target volumes that directly map active tumor biology, resolving ambiguities inherent to CBCT-based workflows. This precision enables margin reduction and dose painting, concentrating radiation on hypermetabolic subvolumes while sparing organs at risk. PET further redefines adaptive planning; mid-treatment scans identify biological shifts, prompting in silico re-planning to optimize dose distributions. Emerging platforms like RefleXion’s SCINTIX® exemplify real-time biology-guided radiotherapy, whereby PET signals autonomously adjust beam delivery. By bridging functional imaging with technical innovation, PET transforms radiotherapy from geometric approximation to personalized, biology-informed therapy, promising enhanced precision, reduced toxicity, and improved outcomes. This chapter synthesizes advancements, challenges, and opportunities in PET-guided treatment planning, underscoring its pivotal role in modern radiation oncology.