The Effects of Additional Filtration on Image Quality and Radiation Dose in Cone Beam CT: An In Vivo Preliminary Investigation

Table 1

Filter settings and effective and relative radiation doses.

Filters	Cu-filter thickness (mm)	Air kerma (μGy)	Relative absorbed dose (%)	Interpolated effective dose (μSv)
F0	0 (no filter/reference)	1255	100	36†
F1	0.2	779	62	22.4
F2	0.4	480	38	13.8
F3	0.7	328	26	9.4
F4	1.0	202	16	5.8
F5	1.3	134	11	3.8
F6	1.5	104	8	3.0
F7	2.0	63	5	1.8

F0 (no filter) was used as the reference dose. Relative absorbed doses were assessed based on ion chamber dosimetric (air kerma) measurements with a repeatability error of <0.03-1%. Interpolated effective doses were calculated as linear interpolation in relation to F0. ^†Taken from Ludlow et al. [29]. Interpolation was calculated based on relative absorbed dose measurements and a real effective dose reference value.