Design of Prototype Phantom to Measure Quality Control for Conventional X-ray Machine Using Quantitative Image Parameters

Abstract

A variety of phantoms that measure image quality parameters are commercially expensive and often complicated to use as they measure only one parameter of a particular x-ray machine, which leads to the difficulty of measuring the quality of x-ray image and thus increase the risk of radiation to the patient and society. The main objective of this study was to design a prototype phantom to measure quality control for conventional x-ray machine using quantitative image parameters. In this study, 5 conventional x-ray machines were investigated using wire phantom designed by the researcher, which consisted of variable thicknesses used to test variable exposure factors. This study introduced a more reliable method of measuring the resolution, which is modulation transfer function, which gives a complete description of the resolution instead of using full width at half maximum or the visibility method, which is more qualitative where modulation transfer function is a real quantitative method, by designing a prototype phantom that consisted of 5 wires with different thicknesses and kVp for 5 x-ray units and assessing the diagnostic x-ray machine resolution by the optimum kV found relative to machine type. This study showed that the one with the best machine resolution was Shimadzu (2011) for Khartoum Emergency Hospital, which had a high resolution of 97% at 46 kV for thickness of 1.4 mm compared with Toshiba 2011 for Almotkamil Hospital, which had 92% at 46 kVp. Also, the result showed that for the 2 types of x-ray machines the x-ray tubes do not produce the same exposure, and the output decreased with age of the x-ray unit; also, the resolution reduced when the thickness of the wires decreased.