Determination of energy window width and position for scintigraphic imaging using different energy resolution detection with the Triple Energy Window (TEW) scatter compensation method

Since primary photons can provide information concerning the position of radioisotope (RI) accumulation and the energy of the photons, it would seem reasonable to vary the position and width of the energy window depending on the type of RI and the energy resolution of the detector to collect as many of the primary photons as possible. We propose a method for determining energy window width and position for scintigraphic imaging to collect as many of the primary photons as possible, and studied the influence on the Triple Energy Window (TEW) scatter compensation method of setting such energy window levels for Tc-99m (single photopeak) and Tl-201 (multiple photopeaks) using detector with different energy resolution through simulation. The Monte Carlo simulations were verified by comparing the regional energy spectrum at the phantom obtained from the simulation against experimental measurements. The energy window with our proposed method for Tc-99m is 20% and 47.3% for Tl-201 using gamma camera, and 9.8% for Tc-99m using a semiconductor detector with a theorized energy resolution of 7.0 keV.