An automatic method of extracting left ventricle from SPECT myocardialperfusion data was introduced. This method was based on the least square analysis ofthe positions of all short-axis slices pixels from the half sphere-cylinder myocardialmodel

and used a iterative reconstrution technique to automatically cut off thenon-left rentricular tissue from the perfusion images. Thereby

this techniqueprovided the bases for further quantitative analysis.