When applying for registration of PET/CT products, when CT has obtained a separate registration certificate, the overview material and research data of CT part shall include the following contents: the manufacturer, model and registration certificate number of CT shall be specified in the overview material, and whether there is difference between CT in PET/CT system and CT with registration certificate. If there are differences, the administrative counterparts shall provide the data of difference analysis and submit the research data of the impact of differences on safety and effectiveness. If there is no difference between CT in PET/CT and CT in the original registration certificate, the research data of PET/CT system can be provided and the research data of CT does not need to be provided separately.