Development and tuning of models for accurate simulation of CT spatial resolution using CatSim.

. We sought to systematically evaluate CatSim's ability to accurately simulate the spatial resolution produced by a typical 64-detector-row clinical CT scanner in the projection and image domains, over the range of clinically used x-ray techniques.Using a 64-detector-row clinical scanner, we scanned two phantoms designed to evaluate spatial resolution in the projection and image domains.

Semiempirical, parameterized spectrum estimation for x-ray computed tomography.

Purpose: To develop a tool to produce accurate, well-validated x-ray spectra for standalone use or for use in an open-access x-ray/CT simulation tool. Spectrum models will be developed for tube voltages in the range of 80 kVp through 140 kVp and for anode takeoff angles in the range of 5° to 9°.

Methods: Spectra were initialized based on physics models, then refined using empirical measurements, as follows.