. Author manuscript; available in PMC: 2016 Jul 14.

Published in final edited form as: Phys Med. 2015 May 8;31(5):529–535. doi: 10.1016/j.ejmp.2015.04.010

Table 2.

CBCT image QA and baseline values acquired at 65 kVp and 0.5 mA. CT numbers of solid water, bone, and lung equivalent materials, unifomity, noise, and CBCT image accuracy. For image resolution, the image was acquired at 50 kVp and 0.8 mA.

Tasks	Baselines	QA	QA	QA	QA

		Month1	Month2	Month3	Month4
CT number of solid water equivalent material (HU)	43.86 ± 6	40.12 ± 11	45.62 ± 5	44.56 ± 6	39.56 ± 5
CT number of bone equivalent material (HU)	280.68 ± 12	282.65 ± 8	278.69 ± 13	289.65 ± 12	290.16 ± 9
CT number of lung equivalent material (HU)	−644.07 ± 9	−660.23 ± 1	−638.56 ± 18	−670.15 ± 11	−638.54 ± 6
Uniformity (HU)	19.54 ± 8.7	19.2 ± 1	22.3 ± 7.1	20.1 ± 9	18.75 ± 4.2
Noise (HU)	44.25 ± 14	50.89 ± 9	53.65 ± 6	38.62 ± 8	40.69 ± 11
CBCT image accuracy (mm pixel⁻¹)	0.27 ± 0.01	0.27 ± 0.01	0.26 ± 0.01	0.27 ± 0.01	0.26 ± 0.01
Resolution (mm)	0.5	0.5	0.5	0.5	0.5