Beyond 18F-FDG: Characterization of PET/CT and PET/MR Scanners for a Comprehensive Set of Positron Emitters of Growing Application-18F, 11C, 89Zr, 124I, 68Ga, and 90Y

This study aimed to investigate image quality for a comprehensive set of isotopes (F-18, C-11, Zr-89, I-124, Ga-88, and Y-90) on 2 clinical scanners: a PET/CT scanner and a PET/MR scanner. Methods: Image quality and spatial resolution were tested according to NU 2-2007 of the National Electrical Manufacturers Association. An image-quality phantom was used to measure contrast recovery, residual bias in a cold area, and background variability. Reconstruction methods available on the 2 scanners were compared, including point-spread-function correction for both scanners and time of flight for the PET/CT scanner. Spatial resolution was measured using point sources and filtered backprojection reconstruction. Results: With the exception of Y-90, small differences were seen in the hot-sphere contrast recovery of the different isotopes. Cold-sphere contrast recovery was similar across isotopes for all reconstructions, with an improvement seen with time of flight on the PET/CT scanner. The lower-statistic Y-90 scans yielded substantially lower contrast recovery than the other isotopes. When isotopes were compared, there was no difference in measured spatial resolution except for PET/MR axial spatial resolution, which was significantly higher for I-124 and Ga-88. Conclusion: Overall, both scanners produced good images with F-18, C-11, Zr-89, I-124, Ga-88, and Y-90.