TABLE 3.

Number of Ordered-Subset Expectation Maximization Updates in Individually Optimized Reconstructions

Parameter	Gaussian filter (mm)	No. of OSEM updates for maximized SSR								ME240 (20 kBq/mL), 3-min scan
		HE80 (95 kBq/mL)	HE240 (94 kBq/mL)	ME80 (90 kBq/mL)	ME240 (90 kBq/mL)	HE80 (30 kBq/mL)	HE240 (29 kBq/mL)	ME80 (29 kBq/mL)	ME240 (29 kBq/mL)
AC	9	75	90	120	180	42	48	180	90	12
	12	900	120	240	720	42	90	900	300	12
	16	900	600	900	600	120	120	900	300	16
SC+AC	9	90	42	42	75	34	75	120	360	12
	12	120	30	42	90	20	90	120	60	12
	16	180	34	120	120	24	180	120	42	12

OSEM = ordered-subsets expectation maximization; HE80 = HE collimator with x-ray window; HE240 = HE collimator with γ-ray window; ME80 = ME collimator with x-ray window; ME240 = ME collimator with γ-ray window.

Table shows optimal number of ordered-subset expectation maximization updates, according to SSR, for each acquisition, as well as ²²⁴Ra concentration in phantom at time of imaging. Scan time was 30 min where not otherwise stated.