Table 2a.

Parameters for multivariate normal distribution used in the regression model of CTDI_w at 120 kVp. These parameters are shared by all across 500 realizations but $\theta$ was only shared by those with the same scan types.

Parameter	Description	Mean	Standard error
$B_0$ (head)	Intercept	3.500	0.060
$B_0$ (body)	Intercept	3.750	0.060
$B_1$	Coefficient on age variable	0.023	0.004
$B_2$	Coefficient on scan year variable	−0.067	0.005
$\theta$ (head)	Full head scans indicator (reference)	0.000	NA
$\theta$ (abdomen)	Abdomen scans indicator	−0.489	0.077
$\theta$ (pelvis)	pelvis scans indicator	−0.602	0.087
$\theta$ (chest)	Chest scans indicator	−0.807	0.058
$\theta$ (extremity)	Extremity scans indicator	−1.073	0.091
$\theta$ (neck)	Neck scans indicator	−0.744	0.086
$\theta$ (partial head)	Partial head scans indicator	−0.396	0.061
$\theta$ (spine)	Spine scans indicator	−0.242	0.153