Date of Award


Degree Name

MS in Biomedical Engineering


Biomedical and General Engineering


Dr. Kristen O'Halloran Cardinal


Three different polymers (a high-density polymer and two other polymers) were tested for use as an x-ray catheter in a radiation therapy application. This report describes the testing of these three materials to determine which material is the best option for a long use catheter. Tests included tensile, simulated clinical life, and other tests. Some testing was performed using nitrogen and an industrial coolant. Testing revealed significant non-circularities for some catheters. With increasing pressure, the circularity of these catheters increased. The tensile tests were performed on samples with varying doses of radiation. Tensile testing showed significant decreases in ultimate tensile strength with increasing radiation dose for both polyurethanes. Other testing was performed on the two polyurethanes to determine their compatibility with the industrial coolant. The test showed good compatibility with the coolant. Simulated clinical life tests were performed on a test fixture and with software to run the radiation source automatically for several hours at a time. Overall, one material was found to have very low ductility, made lower with increasing radiation. The material with the higher ductility was chosen as the better catheter material despite some disadvantages when compared to the stiffer polymer. This report describes necessary tests for thin polymer geometries used in applications where resistance to radiation, mechanical integrity, and coolant compatibility are the main considerations.