Computer Modeling of Yttrium-90–Microsphere Transport in the Hepatic Arterial Tree to Improve Clinical Outcomes

• Published in: International journal of radiation oncology, biology, physics Vol. 76; no. 2; pp. 631 - 637
• Main Authors: Kennedy, Andrew S., Kleinstreuer, Clement, Basciano, Christopher A., Dezarn, William A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2010
• Subjects: 90Y-microspheres; ARTERIES; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BLOOD FLOW; BLOOD VESSELS; BODY; CARDIOVASCULAR SYSTEM; Computer modeling; Computer Simulation; COMPUTERIZED SIMULATION; DAYS LIVING RADIOISOTOPES; DIGESTIVE SYSTEM; DISEASES; DISTRIBUTION; Embolization, Therapeutic - methods; GLANDS; Hematology, Oncology and Palliative Medicine; Hepatic Artery - anatomy & histology; Hepatic Artery - physiology; Hepatic artery system; HOURS LIVING RADIOISOTOPES; Humans; INTERMEDIATE MASS NUCLEI; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; LIVER; Liver - blood supply; Liver Circulation - physiology; Liver Neoplasms - blood supply; Liver Neoplasms - radiotherapy; MICROSPHERES; Models, Cardiovascular; NEOPLASMS; NUCLEI; ODD-ODD NUCLEI; ORGANS; Particle transport; RADIOISOTOPES; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; SIMULATION; TRANSPORT; YTTRIUM 90; YTTRIUM ISOTOPES; Yttrium Radioisotopes - pharmacokinetics; Yttrium Radioisotopes - therapeutic use; Hepatic artery system; Particle transport; 90Y-microspheres; Computer modeling; Blood flow
• ISSN: 0360-3016; 1879-355X; 1879-355X
• DOI: 10.1016/j.ijrobp.2009.06.069

Radioembolization (RE) via yttrium-90 ( 90Y) microspheres is an effective and safe treatment for unresectable liver malignancies. However, no data are available regarding the impact of local blood flow dynamics on 90Y-microsphere transport and distribution in the human hepatic arterial system. A three-dimensional (3-D) computer model was developed to analyze and simulate blood-microsphere flow dynamics in the hepatic arterial system with tumor. Supplemental geometric and flow data sets from patients undergoing RE were also available to validate the accuracy of the computer simulation model. Specifically, vessel diameters, curvatures, and branching patterns, as well as blood flow velocities/pressures and microsphere characteristics ( i.e., diameter and specific gravity), were measured. Three-dimensional computer-aided design software was used to create the vessel geometries. Initial trials, with 10,000 noninteracting microspheres released into the hepatic artery, used resin spheres 32-μm in diameter with a density twice that of blood. Simulations of blood flow subject to different branch-outlet pressures as well as blood-microsphere transport were successfully carried out, allowing testing of two types of microsphere release distributions in the inlet plane of the main hepatic artery. If the inlet distribution of microspheres was uniform (evenly spaced particles), a greater percentage would exit into the vessel branch feeding the tumor. Conversely, a parabolic inlet distribution of microspheres (more particles around the vessel center) showed a high percentage of microspheres exiting the branch vessel leading to the normal liver. Computer simulations of both blood flow patterns and microsphere dynamics have the potential to provide valuable insight on how to optimize 90Y-microsphere implantation into hepatic tumors while sparing normal tissue.