The role of the free-response receiver operating characteristic method for dose and image quality optimisation

This thesis describes the value of the free-response receiver operating characteristic (FROC) paradigm for dose and image quality optimisation in a niche area of imaging. The empirical works discussed in this thesis focus on the diagnostic value of the low-resolution computed tomography (CT) images acquired for attenuation correction (AC) – a process primarily used to correct for photon attenuation with images produced merely as a consequence of the exposure. The potential discovery of incidental findings on these images was investigated. The observers taking part in the empirical studies were generally lacking in significant experience of interpreting CT images. As a consequence it was also deemed valuable to investigate the value of the novice observer in free-response studies. A further methodological consideration for studies of this kind is consistent and reliable image display and FROC data collection. Prototype software, ROCView, was designed and developed to make this an easy process and the key functionality and impact is analysed here. In addition to the empirical works, two review papers, aimed at the technologists and radiographers performing low-resolution CT for AC, are summarised. They explain the value of the FROC paradigm and the jackkinfe alternative FROC (JAFROC) analysis method to a wide audience in nuclear medicine