Modeling the impact of spatial oxygen heterogeneity on radiolytic oxygen depletion during FLASH radiotherapy

  title={Modeling the impact of spatial oxygen heterogeneity on radiolytic oxygen depletion during FLASH radiotherapy},
  author={Edward Taylor and Richard Peter Hill and Daniel L{\'e}tourneau},
  journal={Physics in Medicine \& Biology},
Purpose. It has been postulated that the delivery of radiotherapy at ultra-high dose rates (‘FLASH’) reduces normal tissue toxicities by depleting them of oxygen. The fraction of normal tissue and cancer cells surviving radiotherapy depends on dose and oxygen levels in an exponential manner and even a very small fraction of tissue at low oxygen levels can determine radiotherapy response. To quantify the differential impact of FLASH radiotherapy on normal and tumour tissues, the spatial… 


A computational model of radiolytic oxygen depletion during FLASH irradiation and its effect on the oxygen enhancement ratio.
This article hypothesizes that the radioprotecting effect of FLASH irradiation could be due to the specific sparing of hypoxic stem cell niches, which have been identified in several organs including the bone marrow and the brain.
Intra-voxel heterogeneity influences the dose prescription for dose-painting with radiotherapy: a modelling study.
The authors' simulations show that dose redistribution based on derived cellular oxygen distributions within voxels result in dose distributions that require less total dose to obtain the same degree of cell kill as dose distribution that were optimized with a model that considered voxELs as homogeneous with respect to oxygen.
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Initial results support experimental evidence that FLASH sparing is only achieved for dose rates on the order of tens of Gy s−1 or higher, for a sufficiently high dose, and only for tissue that is slightly hypoxic at the time of radiation.
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The results suggest that FLASH radiation may be a viable option for treating lung tumors and reduce the occurrence and severity of early and late complications affecting normal tissue.
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A computerized examination of the time-dependent interaction of the above described processes indicates that calculated breaking survival curves are in good agreement with those observed experimentally.