Reducing Radiation Dose in Rest–Stress Cardiac PET/CT by Single Poststress Cine CT for Attenuation Correction: Quantitative Validation

Cardiac PET/CT is optimized by cine CT with dedicated shift software for manual correction of attenuation–emission misreg-istration. Separate rest and stress CT scans incur greater radia-tion dose to patients than does standard helical PET/CT or ‘‘pure’ ’ PET using rotating rod attenuation sources. To reduce radiation dose, we tested quantitative accuracy of using a sin-gle poststress cine CT attenuation scan for reconstructing rest perfusion images to eliminate resting CT attenuation scans. Methods: A total of 250 consecutive patients underwent diag-nostic rest-dipyridamole myocardial perfusion PET/CT with 82Rb and a 16-slice PET/CT scanner using averaged cine CT attenuation data during breathing at rest and stress. After cor-recting for any attenuation–emission misregistration, we quanti-tatively compared resting perfusion images reconstructed using rest cine CT attenuation data with the same resting emission dat