AUTHOR=Feng Tingyu , He Tianyang , Ye Wentao , Xiang Lisha TITLE=Influence factor and mechanism of FLASH effect JOURNAL=Frontiers in Oncology VOLUME=Volume 15 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2025.1669228 DOI=10.3389/fonc.2025.1669228 ISSN=2234-943X ABSTRACT=FLASH radiotherapy (FLASH-RT) represents an innovative treatment modality utilizing ultra-high dose-rate irradiation (>40 Gy/s). The FLASH effect, induced by FLASH-RT, is characterized by the selective radioprotective effect of normal tissue while preserving tumor control efficacy. Currently, FLASH effect has been confirmed in many preclinical studies and clinical studies. However, the mechanism and the influencing factors of FLASH effect remain ambiguous. This review systematically summarizes current understanding of the mechanism and influencing factors of FLASH effect, providing theoretical basis for the future study and application of FLASH-RT.