Purpose: To develop a mesh-based model of the blood vasculature within the brain of the ICRP adult mesh-type reference computational phantoms (aMRCP). Dosimetric applications of the model include (1) computation of blood DVHs during external beam radiotherapy of brain tumors and (2) differentiation of radionuclide decay sites within the brain tissues from those occurring in the blood content of the brain.
Methods: Computer models of arterial and venous trees inside the aMRCP female (AFB) and male brain (AMB) were created from optimization and physical principles using the Constrained-Constructive-Optimization method. A multi-region brain model based on MRI images of an adult was used to define the 13 regions inside the AFB and AMB to vascularize. An in-house vessel-generation algorithm was created to generate virtual arterial and venous trees in all brain sub-regions. Hemodynamics and geometric parameters of the principal vessels were used as inputs. Within the algorithm, parameters such as pressures, blood flow, and radius are updated each time a new vessel is created.
Results: A closed vascular brain model of 26 vascular trees of 4000 vessels represented as rigid-cylindrical pipes was created. The vessels range from several millimeters radius at the root vessel to 0.1-0.2 mm at the terminal vessels. Topological analysis of our models shows similar trends to other computational models and real human brain vasculature
Conclusion: Computational models of brain macro-vasculature have been developed by implementing a vessel-generation algorithm that creates binary trees inside the aMRCP brains. Although the present models do not include the micro-vasculature, more than 50% of the reference brain-blood volume was modeled. The AFB and AMB with explicit vascular models allow for more accurate dose assessments in radiopharmaceutical therapy and blood dose calculations in external beam radiotherapy.
Funding Support, Disclosures, and Conflict of Interest: This research is supported by NIH R01 CA248901 and NIH R21 CA248118
Blood Vessels, Brain, Phantoms
Not Applicable / None Entered.