This standard - defines the essential parameters which describe the performance of the CT scanners with regard to image quality, patient dose and positioning; - defines the methods of testing the essential parameters; - evaluates compliance with the tolerances of the parameters specified by the accompanying documents. These methods rely mainly on non-invasive measurements, using appropriate test equipment, performed during the installation or after it has been completed. Signed statements covering steps in the installation procedure may be used as part of the acceptance test report. This part of IEC 61223 is intended to assist in performing the acceptance tests on a CT scanner. The aim is to verify compliance of the installation with specifications affecting the image quality, patient dose and positioning. The contents of the corrigendum of March 2006 have been included in this copy.