Fig. 5.
Contrast vs. noise trade-off curves for DIRECT and list-mode (TOF and non-TOF) approaches using the same reconstruction algorithm (RAMLA) and (blob) basis function model (10 mm lesions, central slice, 27-cm phantom, 30M counts, 300-ps TOF resolution). DIRECT with blob model is able to match the contrast vs. noise trade-offs and overall image quality of the list-mode TOF reconstruction, but with an order of magnitude shorter time (see Table I). We illustrate also the trade-off curve for DIRECT reconstruction with additional resolution modeling (blob + res. model) as given by the intrinsic resolution of the simulated data. Gray ellipses mark iterations for which we show example images and corresponding profiles in Figs. 6 and 7.