Fig. 1.

Comparisons of organ doses^* and effective doses between VirtualDose and CT-Expo: Head CT scan with 120 kVp tube voltage; ET region stands for extrathoracic region (nose, mouth, pharynx, larynx), and ED103 stands for effective dose with ICRP 103 tissue weighting factors [10]. *Note: Organs outside scan range and with dose smaller than 0.5 mGy are not included in Figs. 1, 2, 3, 4, 5 and 6, since the statistical error in the Monte Carlo results for these organs are high and can be as high as the dose itself