For patients undergoing hemodialysis, long term vascular access is commonly provided by expanded polytertafluoroethylene (ePTFE) vascular grafts. However, half of these grafts will fail within two years due to neointimal hyperplasia (NH) at the graft-vessel anastomosis which is caused by excessive growth and migration of vascular smooth muscle cells. The current methods to treat neointimal hyperplasia involve the use of drugs to hinder the migration and growth of smooth muscle cells. Unfortunately, none of these pharmacological approaches are effective and therefore complications arise. The main goal of this study is to investigate a novel noninvasive and nonpharmacological approach of using mild hyperthermia to prevent NH. Previous studies in our lab have shown that cells cultured on ePTFE are more sensitive to heat induced death than cells cultured on a petri dish, which mimics native tissue. The goal of this study is to find an optimal thermal dose – the temperature and duration at which cell death is significant on the e-PTFE graft but not on the petri dish. The outcome of these experiments should result in a thermal dose that can be used in ultrasound experiments where the application of ultrasound would preferentially be absorbed by the e-PTFE graft. The absorption would cause the e-PTFE graft to increase in temperature initiating cell death, thereby preventing cell growth on e-PTFE and providing a noninvasive nonpharmacolgical approach to preventing NH.