Computational modelling of the cerebral cortical microvasculature: effect of x-ray microbeams versus broad beam irradiation.
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Embargo End Date
ICR Authors
Authors
Merrem, A
Bartzsch, S
Laissue, J
Oelfke, U
Bartzsch, S
Laissue, J
Oelfke, U
Document Type
Journal Article
Date
2017-05-21
Date Accepted
Abstract
Microbeam Radiation Therapy is an innovative pre-clinical strategy which uses arrays of parallel, tens of micrometres wide kilo-voltage photon beams to treat tumours. These x-ray beams are typically generated on a synchrotron source. It was shown that these beam geometries allow exceptional normal tissue sparing from radiation damage while still being effective in tumour ablation. A final biological explanation for this enhanced therapeutic ratio has still not been found, some experimental data support an important role of the vasculature. In this work, the effect of microbeams on a normal microvascular network of the cerebral cortex was assessed in computer simulations and compared to the effect of homogeneous, seamless exposures at equal energy absorption. The anatomy of a cerebral microvascular network and the inflicted radiation damage were simulated to closely mimic experimental data using a novel probabilistic model of radiation damage to blood vessels. It was found that the spatial dose fractionation by microbeam arrays significantly decreased the vascular damage. The higher the peak-to-valley dose ratio, the more pronounced the sparing effect. Simulations of the radiation damage as a function of morphological parameters of the vascular network demonstrated that the distribution of blood vessel radii is a key parameter determining both the overall radiation damage of the vasculature and the dose-dependent differential effect of microbeam irradiation.
Citation
Physics in medicine and biology, 2017, 62 (10), pp. 3902 - 3922
Source Title
Publisher
IOP PUBLISHING LTD
ISSN
0031-9155
eISSN
1361-6560
Collections
Research Team
Radiotherapy Physics Modelling