Author: Jung Han Nam, Wonmo Sung 👨🔬
Affiliation: Department of Biomedical Engineering and Biomedicine & Health Sciences, College of Medicine, The Catholic University of Korea, Department of Biomedical Engineering and Biomedicine & Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Korea 🌍
Purpose: This study aims to develop a whole-body blood flow framework based on the ICRP 145 standard vascular phantom to simulate the spatiotemporal trajectories of blood cells in the human vasculature. The framework provides a base tool for not only calculating radiation doses to blood cells during radiotherapy but also validating reconstruction methods for single-cell tracking using radioactive isotopes.
Methods: We divided the static arterial and venous phantom from the ICRP reference 145 into 31 layers by slicing it into 5 cm sections in the cranial-caudal direction. Vessel center coordinates and cross-sectional areas were extracted, assuming circular cross-sections, and adjacent layers were connected to form vascular components. nearest components were manually linked for the disconnected regions in head and neck vessels. The directional probabilities between vascular components were determined by the average cross-sectional areas of the connected components. Blood particles were modeled to flow through arteries and veins according to these probabilities as Markov chain process, with terminating arteries redirecting particles to the nearest venous components and vice versa. Particle flow simulations were initiated at the heart.
Results: The developed flow model, arterial volume was 470 cc , and venous volume was 1239 cc, resulting total vascular volume of 1709 cc. This is 48, 30%, and 34% larger than the ICRP blood vesselThe larger volume is attributed to the truncated conical shapes instead of curved vessels. Simulations showed an average of 56.42 transitions per circulation, corresponding to approximately 55 cm of travel per cycle, assuming uniform flow velocity.
Conclusion: This study developed a blood flow framework based on the ICRP 145 vascular phantom, simulating blood cell movement and providing a tool for radiotherapy dose calculations and single-cell tracking validation. Further refinement is needed to incorporate realistic flow velocities and validate the model against patient data.