In order to ensure that the dosimetry simulations performed
for this study were as comparable as possible across
scanner models, all simulations were carried out using a tube
voltage of 120 kVp, the bowtie filter designed for the adult
body, and the widest available collimation setting for each
scanner. Consequently, the selected bowtie filter was kept
constant for each scanner, even when smaller sized patient
models including pediatric were being simulated. While it
is recognized that this may not be how some scanners would
be used in a clinical setting, keeping the bowtie filter selection
constant across patient models allowed the effect of patient
size to be isolated under constant source conditions. The
selected nominal beam width and detector configuration settings
were 40 mm i.e., 640.625 mm for the LightSpeed
VCT, 40 mm i.e., 640.625 mm for the Brilliance CT 64,
28.8 mm i.e., 241.2 mm for the Sensation 64 scanners,
and 32 mm i.e., 640.5 mm for the Aquilion 64. The
simulation package described below models the actual longitudinal
beam width of each scanner defined as the FWHM
of the longitudinal dose profile measured with Optically