Tomography has now become of considerable clinical importance in nuclear medicine, in particular for use in brain and heart. While positron emission tomography can also be of great clinical value, the most common tomography technique employed is that of single photon tomography (SPECT) using a rotating gamma camera, or sometimes specialised devices such as rings, cylinders and multiple heads. This paper is concerned primarily with the quality assurance required for a single headed gamma camera. A series of tests and protocols are presented, with an indication of action to take when one test fails. Examples of images acquired from different systems in different states of usability, and with typical defects will also be shown. It is hoped that some of this expertise can be encapsulated in the form of an expert system which can be used to assist and advise users in the area of SPECT QC.