Table V.

Registration times for different 3D modalities and kV and MV x-ray images with and without a ROI for the intensity-based method using four different merit functions (CC, RC, CR, and MI) and the gradient-based BGB and RGB methods. The best results are typeset in bold.

3D image	X ray	ROI used	Registration time (s)
			CC	RC	CR	MI	BGB	RGB
CBCT big FOV	kV		2.20	2.27	2.57	2.14	65	67
			5.46	5.85	5.69	5.21	69	207
	MV		1.48	1.52	1.81	1.41	45	63
			2.30	2.31	2.57	2.13	46	129
CBCT small FOV	kV		1.96	2.10	2.31	1.84	50	78
			4.51	4.96	4.93	4.40	67	81.5
	MV		1.29	1.35	1.49	1.21	45	74
			2.00	1.95	2.11	1.68	48	123
CT	kV		2.22	2.39	2.76	2.17	71	79
			8.21	8.01	7.64	5.70	96	199
	MV		1.61	1.64	1.78	1.53	52	73
			2.38	2.46	2.60	2.08	60	133
MR-T1	kV		2.93	2.55	2.71	2.03	100	100
			4.63	5.10	4.99	4.37	77	214
	MV		1.71	1.61	1.76	1.30	73	98
			2.33	2.01	2.60	1.83	60	143