Radiobiology of proton therapy and its clinical implications

The chapter delves into the intricate relationship between proton therapy and its impact on biological systems, shaping the landscape of modern cancer treatment. Proton accelerators and beam delivery systems are discussed, followed by analyses of proton beam characterization, penumbra, and Bragg peak phenomena, and their impact on biological responses. Cellular responses to proton radiation encompass cell cycle dynamics, pathways to cell death, mitotic catastrophe, and senescence, oxygen enhancement ratios in hypoxic tumors, and modulation of inflammatory and immune responses. Radiobiological modeling emerges as a predictive tool. Linear-Quadratic models, biophysical models for radiosensitivity, clinical outcome modeling, and the advent of radiogenomics and personalized medicine shape treatment strategies. Pediatric patients demand specialized consideration. Unique aspects, late effects, clinical outcomes, and long-term follow-up, coupled with advancements in pediatric proton therapy, form the crux of this section. Spot-scanning and pencil beam scanning techniques, FLASH proton therapy, heavy ion therapy, and innovative approaches like radioprotectors and combining proton therapy with immunotherapy pave the way for the next era in cancer treatment. This chapter navigates the dynamic interplay of radiobiology, technology, and patient care, fostering a comprehensive understanding of proton therapy’s potential in oncological practice.