Abstract: A system for delivering shape memory alloy prosthesis includes a catheter, a fluid injector and a controller. The catheter includes a fluid lumen coupled to the fluid injector and one or more openings at its distal end which are at least partially disposed beneath the prosthesis. The catheter further includes a thermocouple at its distal end for monitoring the temperature of the prosthesis in situ to minimize thermal damage to fluids and tissue within the body lumen. A fluid is heated to an initial temperature, and then delivered through the openings to the prosthesis, and thermal energy is directly transferred to the prosthesis to expand the prosthesis at a temperature above the body temperature. The temperature and flow rate of the fluid is precisely controlled such that the prosthesis is expanded, and thermal damage to the body lumen is minimized.