Fisher information analysis of list-mode SPECT emission data for joint estimation of activity and attenuation distribution

A list-mode OSEM-based attenuation and scatter compensation method for SPECT

“…Prior work in PET imaging has shown that using LM data and incorporating energy information led to improved ASC [11,12]. More recently, we observed that SPECT LM emission data containing the energy attribute contains information to jointly estimate the activity and attenuation distributions [13]. Also, several studies have shown that LM data can yield improved reconstruction and quantification compared to binned data in SPECT imaging [14,15,16,17,18,19].…”

“…To address this issue, we use the fact that each detected photon traverses through a specific discrete sub-unit of space after being emitted. We refer to this sub-unit as a path [13,22]. For example, in Fig.…”

“…The term Pr(P|f ) represents the radiation that is transmitted through the path P. The expression for this term is given by [13] pr(P|f ) = f (P)s ef f (P)…”

“…There is much interest in exploring whether uptakes in these regions can help with improved diagnosis of Parkinson's disease. A 2D clinical SPECT scanner with a geometry similar to the Optima 640 parallel-hole collimator and imaging uptake of Ioflupane (I-131) tracer within the brain was simulated [13]. Patient anatomy and physiology were modeled using the Zubal digital brain phantom [24].…”

“…Existing SPECT reconstruction methods also typically use only the photo-peak (PP) window data for estimating the activity. In this context, recent studies have shown that addition of data from scatter window can provide more information to estimate the activity uptake compared to using data from only the PP window [13,20]. Using data from PP and scatter windows for activity estimation also increases the effective sensitivity of SPECT systems, that otherwise, is typically very low (< 100 counts/million emitted counts).…”