The Feasibility of Cylindrical Step-Wedge Phantom for Evaluating Modulation Transfer Function of CT Image : Variation of Field of View

Abstract

This study aims to evaluate the modulation transfer function (MTF) from a cylindrical step-wedge phantom having diameters of 8-32 cm at various field of views (FOVs). In this study, MTF curves were measured based on the edge spread function (ESF) using IndoQCT software. In addition, noises were also measured using IndoQCT software. It was found that the MTF curve decreased as the FOV increases. The difference in the MTF 10% from FOVs of 35-50 cm was 16-20% with a p-value of 0.392. Meanwhile, the difference in MTF 50% was 16-21% with the same p-value of 0.392. It was also found that MTF curve also decreased as the phantom diameter increases. The differences in MTF 10% and 50% from phantom diameter of 8-32 cm were 6-14% and 6-16%. It is resulted that the noise level decreases as the FOV increases and the noise level also decreased as the phantom diameter increases.