We studied on the dilatation characteristics of our new angioplasty, photo-thermo dynamic balloon (PTDB) angioplasty, which provides short-term heating (<15s, 50-70°C) dilatation by the combination of laser heat generator and fluid perfusion. In this study, we employed the ex vivo experiments to demonstrate the feasibility of our PTDB angioplasty with extracted porcine carotid artery. Balloon temperature and heating duration were easily controlled with the laser power and irradiation duration. Arterial dilatation was performed with the prototype PTDB catheter (3mm in diameter) ex vivo, sufficient dilation was attained with low dilatation pressure (2atm) that is lower than the limit pressure of elastic region (8atm in this case). The principal of our PTDB angioplasty that was based on the experimental results was dilatation in elastic region, while traditional POBA was accompanied with plastic deformation of artery. It is predicted that successful way of PTDB dilatation was attributed to collagen softening. Collagen coagulation and/or restructure after the heating dilatation might suspend the dilated arterial lumen. We demonstrated the feasibility of our PTDB angioplasty. We think collagen denaturation degree may be the important factor in this methodology.