A method for increasing the rate of thrombus formation and/or proliferative cell growth of a selected region (21) of cellular tissue (22) including the step of endovascularly irradiating the selected region (21) with radiation, having a dose range of endovascular radiation of about 1 Gy to about 600 Gy at a low dose rate of about 1 cGy/hr to about 320 cGy/hr, to increase thrombus formation and/or cell proliferation of the affected selected region (21). Preferably, the delivery means includes a deformable endovascular prosthesis (25) adapted for secured positioning adjacent to the selected region (21) of cellular tissue (22), and a radioactive source. This source cooperates with the deformable endovascular device (25) in a manner endovascularly irradiating the selected region with radiation, having the above-indicated dose range and low dose rate of endovascular radiation to increase thrombus formation and/or cell proliferation of the affected selected region (21).