3-D imaging of complex source fields with a Compton Camera Imager

Many practical applications of Compton Camera Imager (CCI) systems require imaging of extended sources in diffuse backgrounds. This paper presents image reconstructions of simulated CCI system data from extended source distributions with and without a diffuse background. The simulations were performed using a biased photon transport Monte Carlo code which was validated with MCNP results. The reconstruction code used an iterative back-projection technique based upon the expectation maximization maximum likelihood method. Examples are shown of two clearly resolved cylindrical sources, an extended source both with and without background, and extended sources at multiple depths within the volume. The results demonstrate the ability to image extended sources in high backgrounds with a limited number of events.