Table 2.

RMSE of different filtering methods on whole image (FOV) and five uniform tumors. The best value is indicated in boldface. Filters are applied to estimated image at 100 iterations if not indicated.

Post-recon. Filter	RMSE (tumor volume)
	FOV	(9 cc)	(16 cc)	(32 cc)	(113 cc)	(177 cc)
None @ 24 iter.	0.335	0.410	0.325	0.312	0.307	0.204
None @ 100 iter.	0.445	0.317	0.342	0.355	0.276	0.236
NLM without CT @ 24 iter.	0.315	0.415	0.327	0.314	0.308	0.202
NLM without CT	0.311	0.375	0.367	0.367	0.264	0.202
Gaussian	0.363	0.342	0.306	0.294	0.249	0.187
NLM w. true weight	0.241	0.297	0.277	0.254	0.197	0.127
NLM CT-B	0.267	0.417	0.366	0.346	0.233	0.167
NLM CT-M	0.288	0.403	0.359	0.321	0.240	0.167
NLM CT-S	0.293	0.291	0.264	0.318	0.191	0.156
NLM CT-H	0.265	0.320	0.280	0.319	0.196	0.151
NLM CT-B w. 3.4mm misreg. CT	0.275	0.416	0.373	0.350	0.238	0.170
NLM CT-M w. 3.4mm misreg. CT	0.290	0.405	0.365	0.322	0.242	0.169
NLM CT-S w. 3.4mm misreg. CT	0.292	0.328	0.279	0.310	0.189	0.155
NLM CT-H w. 3.4mm misreg. CT	0.270	0.347	0.291	0.314	0.192	0.150
NLM CT-B w. 6.8mm misreg. CT	0.290	0.423	0.384	0.362	0.244	0.175
NLM CT-M w. 6.8mm misreg. CT	0.297	0.414	0.375	0.335	0.246	0.176
NLM CT-S w. 6.8mm misreg. CT	0.293	0.443	0.320	0.297	0.191	0.156
NLM CT-H w. 6.8mm misreg. CT	0.282	0.449	0.327	0.305	0.192	0.150