Study on Relationships Between CT Dose and CT Image Quality in PET/CT

Objective: The aim of the study was to examine how to decrease of radiation dose caused by CT in PET/CT while ensuring quality of CT image.Methods: PET/CT(GE Discovery ST16),Catphan 500,different scan conditions,total 30 groups.The image quality was evaluated by high resolution、low contrast、uniformity、noise.CTDIw and CTDIvol were calculated.The relationship between CT image quantity and CT dose was analyzed.Results: CT dose was related to uniformity,but not to high resolution.The low contrast of CT image improved with the increasing of CT dose.And the decrease of noise with the increase of CT dose was showed with an expression.Conclusions: The radiation dose by CT in PET/CT could be decreased appropriately under the guarantee of the quality of the CT image.