1. A method of reducing the effects of Compton scattered photons detected in a gamma ray detection arrangement, the method comprising the steps of: receiving data responsive to energy states of the detected photons and storing said data in memory locations corresponding to predetermined image grid points; calibrating the gamma ray detection arrangement by acquiring a spectral shape corresponding to a calibration function which is expected to correspond to a first data set corresponding to unscattered ones of the detected photons; processing said stored data for at least selected ones of said predetermined grid points for separating said stored data into said first data set corresponding to unscattered ones of the detected photons and a second data set corresponding to scattered ones of the detected photons; summing said first data set for each of said selected ones of said predetermined grid points for determining a number of said unscattered ones of said detected photons; and forming an image utilizing said number of said unscattered ones of said detected photons.