Real-Time MR-Based Measurement of Radiation-Induced Free Radical Generation on Clinical Low-Field 0.35T MR-Linac

Motivation: Current radiation therapy dosing regimens lack precision to account for spatial- or patient-specific variations in biological responses, leading to suboptimal therapeutic outcomes. A real-time, non-invasive method to monitor radiation-induced free radical generation (FRG) and molecular damage could enable more precise, biologically-tailored treatments. Goal(s): To develop a non-invasive framework for real-time MR-based quantification of radiation-induced FRG. Approach: We developed an MP2RAGE-based T1 mapping protocol on a clinical 0.35T MR-Linac to measure temporal dynamics of radiation-induced FRG during simultaneous irradiation of biologically-relevant chemical phantoms. Results: We demonstrated measurable T1 changes due to superoxide radical production, providing the first quantification of real-time FRG during irradiation. Impact: This work establishes the foundation for real-time, non-invasive measurement and monitoring of radiation-induced free radical generation (FRG) during radiation therapy, toward enabling biological adaption that accounts for spatial- and patient-specific responses, and ultimately improving therapeutic outcomes.