Fig. 6.
Transaxial OSEM SPECT images of 3-D “hot-sphere” phantom without (no bck), (a), (c), and (e), and with background (with bck), (b), (d), and (f), activities at 35 iterations (six subsets) using three different CDR models: Gaussian, GauExp, and GauBspl. CT image (g) and schematic image (h) show the size of the spheres. The GauBspl method increased the image intensity in the spheres compared to the Gaussian and GauExp methods. Note that not all spheres are centered on the same axial plane. (a) Gaussian, no bck. (b) Gaussian, with bck. (c) GauExp, no bck. (d) GauExp, with bck. (e) GauBspl, no bck. (f) GauBspl, with bck. (g) CT. (h) Schematic image.