University of Western Ontario - Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Biomedical Engineering

Supervisor

Dr. Ian Cunningham

Abstract

The risks associated with exposure to radiation make it critical that digital imaging systems give the best possible images for a given dose to the patient. The DQE is the most widely accepted measure of performance and dose efficiency for digital radiography systems, however it is not commonly measured in a clinical environment as part of routine quality assurance. The primary reason for this is that the data provided to the user by clinical systems has typically undergone image processing and therefore may have a non-linear characteristic response. This is a problem because the Fourier metrics of the DQE require a linear response. In this thesis a method to measure the DQE using processed image data is presented. The method is based on a novel theoretical approach to the linearization of the system characteristic response. The method was validated on a cesium iodide-based digital radiography at panel detector and the results where within a few percent of a conventional DQE measurement.