A Compton camera is a device for imaging a radio-source distribution without using a mechanical collimator. Ordered-subset Expectation-Maximization (OS-EM) is widely used to reconstruct Compton images. However, the OS-EM algorithms tend to over-concentrate and amplify noise in the reconstructed image. It is necessary to optimize the number of iterations to develop high-quality images, but it is difficult. Thus, we introduce a median root prior expectation-maximization (MRP-EM) algorithm to overcome this problem. We evaluated the quality of images reconstructed by the proposed method and compared it with that by conventional algorithms using mathematical phantoms. The spatial resolution was estimated using the images of two point sources. In addition, reproducibility was evaluated on an ellipsoidal phantom. MRP-EM reduces the generated noise and is robust with respect to the number of iterations. An evaluation of the reconstructed image quality using some statistical indices shows that our proposed method delivers better results than conventional techniques.2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (2019 IEEE-NSS-MIC
