The computed-tomography scanner is a new tool for the medical profession in which a narrow, moving x-ray beam, controlled and measured by a computer, is used to image transverse planes in patients. Because scanners have several unique features, commissioning tests performed during installation can be only partially accomplished by using equipment and procedures designed for conventional x-ray devices. Additional equipment and procedures are required to commission scanners. This paper identifies 21 parameters that should be considered for testing in a scanner commissioning program. Generalized descriptions as to how such tests may be accomplished are outlined and difficulties in testing are cited.