Electron FLASH radiotherapy in vivo studies. A systematic review

Area of Science:

• Medical physics
• Radiation oncology
• Radiobiology

Background:

• Conventional radiotherapy faces limitations in precise tumor targeting and healthy tissue sparing.
• FLASH-radiotherapy (FLASH-RT) utilizes ultra-high-dose-rate (UHDR) electron beams to potentially mitigate radiation damage to normal tissues while maintaining tumor control.
• Preclinical studies have demonstrated the efficacy of FLASH-RT across various particle types, particularly electrons.

Approach:

• This review synthesizes existing literature on in vivo preclinical experiments utilizing electron FLASH-RT.
• It critically examines the technological limitations of current linear accelerators (LINACs) for UHDR beam delivery and dosimetry.
• The review highlights the need for advanced LINACs capable of precise dose-time parameter control for exploring the FLASH effect.

Key Points:

• Existing LINACs modified for UHDR delivery present challenges in beam monitoring, dosimetry accuracy, and lack integrated treatment planning systems (TPS).
• The inability of current devices to precisely control dose-time parameters (e.g., dose per pulse, instantaneous dose rate) hinders quantitative analysis of the FLASH effect.
• A new generation of electron LINACs is emerging, addressing these technological hurdles and enabling more reliable preclinical research.

Conclusions:

• Electron FLASH-RT holds significant promise for improving radiotherapy outcomes by sparing healthy tissues.
• Technological advancements in LINACs are crucial for overcoming current limitations in preclinical research and dose-time parameter exploration.
• Further investigation into the radiobiological mechanisms and clinical translation of electron FLASH-RT is warranted.