Hybrid reconstruction method at intermediate energy range

3D Pixel CZT detector based Compton imaging is an ideal candidate at energy above 250 keV, mechanical collimation technique must be used at lower energy range where the Compton scattering probability is low. We propose a hybrid imaging method to reconstruct gamma-ray source distribution at intermediate energy range. In this new method, both single and two interaction events are used, and a coded mask is brought into the system to concentrate the possible source direction of single interaction event. The feasibility of this method is verified by the data generated from the Monte Carlo simulation program of a 3D pixel CZT detector system, better imaging resolution and efficiency are reached than a single method.