Presenter of 1 Presentation
IN VIVO OXYGEN TRANSPORT MODEL DESCRIBING PHYSIOLOGICAL IMPACT ON FLASH RADIOTHERAPY
Abstract
Background and Aims
Oxygen(O2) depletion caused by ultra-high dose rate has been proposed to explain the radioresistant effect observed in FLASH. We have developed a comprehensive model for describing the spatial and temporal dynamics of O2 consumption and transport during FLASH in vivo. The O2 unloaded from hemoglobin carried by blood flow in capillary is explicitly described. We investigate the change of oxygen enhancement ratio(OER), as function of physiological conditions i.e. blood flow and intercapillary distance under various radiolytic O2 depletion(ROD) conditions.
Methods
We considered a time-dependent O2 source and consumption in this model, incorporating blood flow, linking the O2 concentration[O2] in the vessel to that within the tissue through the Hill equation, the radial and axial diffusion of O2, and metabolic and zero-order radiolytic O2 consumption(Fig.1). Time-evolved distributions of [O2] were obtained by numerically solving 2D perfusion-diffusion equations. The model enables computation of the dynamic variation of O2 distribution, and relative change of OER, δROD under various physiological and irradiation conditions.
Results
The initial oxygen level is largely affected by blood flow velocity(Fig.2(a1-2)), and larger anoxic region is generated by high dose rate(Fig.2(b1-2 vs. c1-2)). The change of high δROD region(>30%) strongly depends on the blood flow velocity contributing on initial oxygen level(Fig.3). The interplay effect among the blood flow, intercapillary distance and dose rate resulting in the δROD is under investigation.
Conclusions
Different oxygen level established by the physiological conditions can potentially determine the FLASH efficacy in tissue protection. The model enables FLASH dosimetry predictions based on various physiological condition beyond radiolytic oxygen depletion.
Author Of 1 Presentation
IN VIVO OXYGEN TRANSPORT MODEL DESCRIBING PHYSIOLOGICAL IMPACT ON FLASH RADIOTHERAPY
Abstract
Background and Aims
Oxygen(O2) depletion caused by ultra-high dose rate has been proposed to explain the radioresistant effect observed in FLASH. We have developed a comprehensive model for describing the spatial and temporal dynamics of O2 consumption and transport during FLASH in vivo. The O2 unloaded from hemoglobin carried by blood flow in capillary is explicitly described. We investigate the change of oxygen enhancement ratio(OER), as function of physiological conditions i.e. blood flow and intercapillary distance under various radiolytic O2 depletion(ROD) conditions.
Methods
We considered a time-dependent O2 source and consumption in this model, incorporating blood flow, linking the O2 concentration[O2] in the vessel to that within the tissue through the Hill equation, the radial and axial diffusion of O2, and metabolic and zero-order radiolytic O2 consumption(Fig.1). Time-evolved distributions of [O2] were obtained by numerically solving 2D perfusion-diffusion equations. The model enables computation of the dynamic variation of O2 distribution, and relative change of OER, δROD under various physiological and irradiation conditions.
Results
The initial oxygen level is largely affected by blood flow velocity(Fig.2(a1-2)), and larger anoxic region is generated by high dose rate(Fig.2(b1-2 vs. c1-2)). The change of high δROD region(>30%) strongly depends on the blood flow velocity contributing on initial oxygen level(Fig.3). The interplay effect among the blood flow, intercapillary distance and dose rate resulting in the δROD is under investigation.
Conclusions
Different oxygen level established by the physiological conditions can potentially determine the FLASH efficacy in tissue protection. The model enables FLASH dosimetry predictions based on various physiological condition beyond radiolytic oxygen depletion.