ImPACT is the NHS CT evaluation centre; the site provides information, publications, and advice on all aspects of CT scanning. It is the home of the famous ImPACT teaching presentations[Keywords: ImPACT, impact, CT, computed, computerised, tomography, scanner, scanners, scanning, assessment, PASA, CEP, dosimetry, CTDI, phantom, image, imaging, quality, transfer, medical physics, DICOM, comparison, St, George's, NHS, nhs, helical, medical, evaluation, cep, sghphys, impactscan, ctdosimetry, sghphy.demon.co.uk]

This article provides a review of the basic principles of CT within the context of the evolution of CT[Keywords: CT; CT technology; imaging; reconstruction]

Image Quality and Lower Doses