Table 4:

Conversion factors for cardiac CT scans in 1-year-old phantom, based on dosimetry from 16-17 MOSFETs in the phantom, in three sub-experiments, using both ICRP Publication 103 and ICRP Publication 60 definitions of ED. The percentage difference for each scan is presented, comparing between a conversion factor derived using 50 MOSFETs per measurement (Table 2) vs. a conversion factor derived using 16-17 MOSFETs in three sets of measurements. All scans utilized a rotation time of 0.35 seconds, a small scan field of view (SFOV), scan length of 69.4 mm, and collimation of 64×0.625 mm. The scanner-reported DLP for all scans was based on the 32 cm CTDI phantom; n/a denotes not applicable.

Scan Description	Tube Potential [kVp]	Pitch	Conversion factor ICRP 103 [mSv·mGy−1·cm−1]	% difference from 50 MOSFETs conversion factor (Table 2)	Conversion factor ICRP 60 [mSv·mGy−1·cm−1]	% difference from 50 MOSFETs conversion factor (Table 2)
Axial	80	n/a	0.1001	1.79	0.0765	7.68
Axial	100	n/a	0.1012	3.85	0.0760	6.40
Axial with padding (100 ms)	80	n/a	0.1027	−6.22	0.0776	−1.20
Axial with padding (100 ms)	100	n/a	0.1011	−6.26	0.0755	−1.96
Helical	80	0.24	0.0991	−1.67	0.0787	−1.85
Helical	100	0.24	0.0931	−1.50	0.0745	0.27
Helical TCM *	80	0.24	0.0972	−0.89	0.0780	−0.25
Helical TCM *	100	0.24	0.0955	−0.58	0.0752	1.23

^*TCM denotes tube current modulation