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Updated: Jul 15, 2026
06:51
Dosimetry for Cell Irradiation using Orthovoltage (40-300 kV) X-Ray Facilities
Published on: February 20, 2021
FLASH effect tissue sparing comparison for X-ray, hadron, and VHEE irradiation modalities
Atia Ibrahimi1, Stefan Both2, Marc-Jan van Goethem2
1Particle Therapy Research Center (PARTREC), Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, 9747 AA, Groningen, The Netherlands. a.ibrahimi@umcg.nl.
Scientific Reports
|July 13, 2026
Summary
Ultra-high dose rate radiation therapy (FLASH-RT) shows healthy tissue sparing. Less conformal modalities like X-rays and VHEE benefit more from FLASH, but require lower dose thresholds than hadrons for this effect.
Area of Science:
- Radiation Oncology
- Medical Physics
- Preclinical Research
Background:
- FLASH-RT utilizes ultra-high dose rates, demonstrating a promising healthy tissue sparing effect.
- Particle type influences dose deposition, potentially impacting the extent of FLASH-induced tissue sparing.
- Comparative studies on how different particle types affect FLASH sparing are limited.
Purpose of the Study:
- To compare the impact of different irradiation modalities (X-rays, VHEE, hadrons) on healthy tissue sparing within the FLASH effect.
- To investigate how dose, dose-rate, and particle type influence the volume of healthy tissue benefiting from FLASH irradiation.
- To determine the dose and dose-rate thresholds required for FLASH effect achievement across different modalities.
Main Methods:
- Monte Carlo-based simulation study.
- Utilized a simple geometrical model to assess dose deposition characteristics.
- Compared X-rays, Very High Energy Electron (VHEE) beams, and hadron therapy under FLASH conditions.
Main Results:
- Less conformal modalities (X-rays, VHEE) showed greater benefit from the FLASH effect compared to hadrons.
- FLASH X-rays and FLASH VHEE deposited higher doses to healthy tissue than conventional hadrons.
- Hadrons required approximately double the target dose (20 Gy) and dose rate (75 Gy/s) for healthy tissue sparing compared to VHEE and X-rays.
Conclusions:
- The effectiveness of the FLASH effect is modality-dependent, with X-rays and VHEE showing more pronounced sparing under certain conditions.
- Current assumptions for FLASH-triggering dose and dose-rate thresholds may limit the application of highly fractionated treatments, particularly with hadron therapy.
- Future research should incorporate clinical dose distributions, multiple angles, fractionation, and RBE for more clinically relevant insights.
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