A recently developed camera referred to by the name PET (Positron Emission Tomography) allows the biochemical activity associated with an organ inside the body to be viewed without surgical intervention. The organ considered for the present study is the heart and the goal of the thesis is to aid detecting the coronary artery diseases at an early stage. For this purpose, a three dimensional object of the left ventricle is formed from an available set of two-dimensional image slices generated by PET. An automatic boundary detection algorithm outlines the object surface and assigns appropriate intensity values to the surface points. The surface is then rotated with the long axis of the heart in a vertical position, allowing the myocardium to be viewed from different angles around the heart. Such a display of activity is shown to be an effective way of presenting the functional behavior of the myocardium.