table I.

The Monte Carlo simulation details.

Item name	Description	References
Code	PENELOPE (2006)	13
Validation	The Monte Carlo code was previously validated for full rotation CT (for both axial and helical scans, see references). In the present study, the localizer validation is described in Section 2.B	10,11
Source Description	Particle type: x-ray Prebowtie: The source is modeled as a point source with an effective beam width to account for the penumbra of the beam. Prebowtie spectra are provided by the manufacturer in 0.5-keV bin increments for a 120-kVp tube potential. Postbowtie: The prebowtie spectrum is filtered by the bowtie using a method described in Section 2.A of the present paper, originally described by Li et al. (2014)	14,15
Cross sections	Cross sections are generated using the default material.f provided with PENELOPE, which has a large database of predefined common materials
Transport parameters	Transport of secondary electrons is not included
VRT or AEIT	Variance reduction was performed using the particle-splitting technique	10
Scored Quantities	The Monte Carlo scored quantity is Kerma (eV) in each organ per number of starting (prebowtie) photons
Number of histories	8.00E+07
Postprocessing	The postprocessing for the present study is described in Section 2.A