Date of Award

6-1999

Document Type

Thesis

Degree Name

Master of Science (MS)

Program

Biomedical Engineering

Research Advisor

Mohammad F. Kiani

Committee

Eugene C. Eckstein James T. Dalton

Keywords

ionizing radiation, microcirculation, microvascular network, late effects, blood flow

Abstract

Therapeutic doses of ionizing radiation result in changes in the structure and function of microvascular networks in normal tissue. Previously, we reported on the early effects of ionizing radiation on microvascular networks at 3, 7, and 30 days post-irradiation [1-3]. Data from the early time points suggested that ionizing radiation significantly alters the structure and function of microvascular networks and interferes with the normal processes of vessel maturation. Here, we
present our findings on the late effects of ionizing radiation on normal tissue microvasculature at 60, 120, and 180 days post-irradiation. The cremaster muscle of Golden Syrian hamster was locally irradiated (single 10Gy dose, delivered at 2 Gy/min). Microvascular networks were selected in reference to a well-defined location in the tissue to reduce heterogeneity due to spatial variation. Intravital microscopy was used to measure both structural and functional parameters.
Geographic Information Systems (GIS) technology was used to establish network topology. At all late time points, the diameter of irradiated vessels was significantly larger than control. Red blood cell velocity in irradiated vessels showed a significant decrease from controls at 120 days post-irradiation and an increase at 180 days post-irradiation. Others parameters such as lineal density, tortuosity, vessel length, and vessel tone showed no significant difference between control and irradiated vessels. The hamster cremaster muscle proved to be an effective model in examining the effects of radiation on normal microvascular tissue. Together our early effect and late effect studies suggest that significant changes occur in structural and functional parameters of irradiated microvascular networks and, hence, that radiation therapy may alter the oxygen delivery capacity of normal tissue microvascular networks.

DOI

10.21007/etd.cghs.1999.0226

Comments

One year embargo expired June 2000

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