Purpose: Little is known about the variations in image quality (IQ) and radiation dose for paediatric and adult chest radiography (CXR), between and within hospitals. Large variations in IQ could influence the diagnostic accuracy, and variations in radiation dose could affect the risk to patients. This thesis aims to develop, validate and then use a novel method for comparing IQ and radiation dose for paediatric and adult CXR imaging examinations and report variation between a series of public hospitals. Method: A Figure of Merit (FOM) concept was used for the purposes of comparing IQ and radiation dose, between and within hospitals. Low contrast detail (LCD) detectability, using the CDRAD 2.0 phantom, was utilised as the main method for IQ evaluation. The validity of utilising LCD detectability, using CDRAD 2.0 phantom, for evaluating visual IQ, simulated lesion visibility (LV) and CXR optimisation studies, was investigated. This was done by determining the correlation between the LCD detectability and visual measures of IQ and LV for two lesions with different locations and visibility in the Lungman chest phantom. The CDRAD 2.0 phantom and two anthropomorphic phantoms (adult Lungman and the neonatal Gammex phantom) were used to simulate the chest region. Radiographic acquisitions were conducted on 17 X-ray units located in eight United Kingdom (UK) public hospitals within the North-west of England using their existing CXR protocols. The CDRAD 2.0 phantom was combined with different thicknesses of Polymethyl methacrylate (PMMA) slabs to simulate the chest regions of 5 different age groups: neonate, 1, 5, 10 years and … View article