Assessment of Image Quality for Digital Radiography Units using Prototype Phantom

Abstract

The main objective of this study to measure the x-ray machines resolution using Modulation Transfer Function MTF which gives a full description of the machine resolution. this study introduced the a more reliable method of measuring the resolution which is modulation transfer function (MTF) which gives a complete description of the resolution instead of using full width at half maximum (FWHM) or the visibility method which is more qualitative where MTF is a real quantitative method, by designed a prototype phantom consisted of five wires with different thickness and kV for five x-ray units. with three object spatial frequency 0.333, 0.298 and 0.216 cycle/mm, imaging the designed phantoms the thickness from wire showed the best results of 0.333 cycle/mm from all hospitals was 92% for 44 kV at ALS hospital, and for 0.298 cycle/mm the best resolution from all hospitals was 97% for 40 kV at Sudan University hospital, the frequency 0.216 cycle/mm the best resolution was 100% at RO with kV 40, ALS at 44 kV and SHN and ALS at 46 kV. Also, the results showed that as the object spatial frequency increased (thickness of the wire decreased) the resolution values decreased as the results of the Kv increases. This is mainly due to the penetration of the radiation as well as the limitation of the x-ray resolution in picking up finer details where the intensifying screen and the film capabilities limit the infant of the resolution.