This part of IEC 61223 applies to those components of CT SCANNERS which influence the image quality, PATIENT dose and positioning. This standard - defines the essential parameters which describe the performance of the CT SCANNERS with regard to image quality, PATIENT dose and positioning; the list of parameters to be tested can be found in section 4.4. - 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.