Low-Dose and Scatter-Free Cone-Beam CT Imaging Using a Stationary Beam Blocker in a Single Scan: Phantom Studies

Table 1

Comparison of the averaged CT numbers and contrasts inside the contrast rods of the Catphan 600 phantom. The CT number errors are also shown in parentheses. The numbers of the ROIs are marked in Figure 3(d). All unites are in HU.

	ROI	1	2	3	4	5	6	7	RMSE
	Fan-beam CT	−131	−84	−895	248	776	−889	−211
	CBCT with correction	−148	−107	−933	227	780	−921	−234
CT number (HU)		(−17)	(−23)	(−38)	(−21)	(4)	(−32)	(−23)	24
	CBCT without correction	−239	−217	−646	−48	202	−639	−281
		(−108)	(−133)	(249)	(−296)	(−574)	(250)	(−70)	250
	CT number improvement	91	110	211	275	570	218	47
	CBCT with correction	169	118	934	201	753	933	253
Contrast (HU)	CBCT without correction	88	55	452	112	322	456	126
	Contrast improvement	1.93	2.13	2.07	1.79	2.34	2.05	2.02