Adaptive Autoregressive Model for Reduction of Noise in SPECT

Table 2

Percentage coefficient of variation for different reconstruction techniques.

Method	Count level	RelAct	CF (cycles/cm)	CoV%
AR-OSEM-AR	50000	0	—	6.35
BW-FBP	50000	2	0.83	6.37
OSEM-BW	50000	4	0.84	6.36
AR-OSEM-AR	100000	0	—	4.60
BW-FBP	100000	2	0.80	4.56
OSEM-BW	100000	4	0.84	4.65
AR-OSEM-AR	150000	0	—	4.43
BW-FBP	150000	2	0.89	4.50
OSEM-BW	150000	4	0.86	4.43

AR-OSEM-AR: autoregressive filtering before and after ordered subset expectation maximisation algorithm; BW-FBP: Butterworth prefiltering and filtered back projection; OSEM-BW: ordered subset expectation maximisation algorithm and Butterworth postfiltering; RelAct: activity relative to background activity of 1; CF: cut-off frequency. The order of the filter was 2; —: not definable.