TABLE III.

Activity Recovery in Images (iteration=25) with uniform back ground activity and matched AC

Phantom density distribution	Sphere Contrast in the Phantom (TBR)	Sphere Number	Image CR Matched AC
			mean	max*
Uniform	2	1	0.90	1.12
		2	0.98	1.15
	4	1	0.98	1.16
		2	1.02	1.15
Anthropomorphic Phantom 1 (‘predominantly fatty’)	2	1	0.92	1.10
		2	0.98	1.15
	4	1	0.97	1.17
		2	1.02	1.18
Anthropomorphic Phantom 2 (‘heterogeneously dense’)	2	1	0.94	1.38
		2	1.02	1.28
	4	1	0.98	1.30
		2	1.05	1.22

^*VOI max values were taken from smoothed images; see text.