A survey of 29 EMI CT machines in Britain

During 1978/79 a survey was made of the performance characteristics of 29 EMI brain and body CT scanners in Britain. Comparative data on such performance parameters as noise, uniformity of CT numbers, low-contrast detectability, resolution, modulation transfer function (MTF) and effective photon energy were measured using a set of regular-geometry and anthropomorphic phantoms. In addition, dose profiles were obtained for a single slice using TLD and film. The results of the survey are presented; the dependence of the performance characteristics on the types of machines surveyed and the operating modes employed is discussed.