  We study the image reconstruction problem of a Compton camera which consists
of semiconductor detectors. The image reconstruction is formulated as a
statistical estimation problem. We employ a bin-mode estimation (BME) and
extend an existing framework to a Compton camera with multiple scatterers and
absorbers. Two estimation algorithms are proposed: an accelerated EM algorithm
for the maximum likelihood estimation (MLE) and a modified EM algorithm for the
maximum a posteriori (MAP) estimation. Numerical simulations demonstrate the
potential of the proposed methods.
