Studies over the past decade suggest that ultra-high dose rates, exceeding 40 Gy/s, termed “FLASH” radiotherapy, improve the therapeutic index of radiation therapy (RT) by reducing normal tissue damage while maintaining tumor response compared to conventional RT.
Our team has developed and tested the first system for delivering FLASH proton RT (F-PRT), incorporating precise control of beam flux on a millisecond time scale and real-time monitoring of dose and delivery time structure. We have observed that F-PRT spares normal intestine, skin, and cardiac tissues by reducing injury, stem cell depletion, and inflammation. Additionally, F-PRT demonstrates lower expression of TGF-β1, leading to reduced fibrosis development in all tested normal tissues compared to standard proton RT (S-PRT). Notably, tumor growth inhibition is similar between F-PRT and S-PRT across various tumor models, including melanoma, pancreatic, and sarcomas. We are further investigating the sparing effects of FLASH RT in different treatment schemes, combinations with other therapies, and utilizing cutting-edge techniques to better understand the underlying mechanisms of these unique effects.