Effect of energy resolution in Compton scattered radiation imaging

Recently emission imaging exploiting Compton scattered radiation has been shown to be a feasible three-dimensional imaging modality, in particular for medical imaging. It exhibits several advantageous features among which the possibility of acquiring data using a stationary detector, instead of a moving one as in standard emission tomography imaging modalities. But measurements of scattered photons require high energy resolution detectors. Nowadays progress in detector technology allows to reach higher and higher energy resolution [1]–[3]. In this work, we consider the effect on image reconstruction of the finite energy resolution ΔE of a realistic collimated gamma camera. Approximate reconstruction methods are used to evaluate the image quality of the reconstructed object. It was observed that when ΔE is very small, the relative mean quadratic error is rather stable with respect to increasing values of n, the number of energy channels detected, but it becomes fluctuating as ΔE gets larger and larger. Conversely for given n, the relative mean quadratic error increases with ΔE. Results obtained using a simple phantom are also presented for various values of n and ΔE.