Variation of Time of Flight versus Non-time of Flight PET SUVmax in Lung Cancer Patients

Abstract

Background: To investigate SUVmax of same lung cancer patients who underwent PET-CT with both TOF and non-TOF iterative reconstructions using the same machine.Methods: We performed list mode PET-CT scan of the chest at 1 hr post injection of 370 MBq (10 mCi) ofF-18 FDG under fasting condition. The SUVmax was measured in lung cancer during radiation therapy on ungated PET-CT images using TOF and nonTOF iterative reconstructions in a Philips Big Bore PET-CT system. We measured 94 pairs of SUVmax in TOF and non-TOF PET images from the same patient.Results: The paired t-test showed significant variability of SUVmax between TOF and non-TOF images at I hr post injection (P＜0.0001).Conclusion: While image quality may be improved with PET scanners having TOF options, the SUVmax is in general higher in non-TOF reconstruction. Recognition of such differences is important when patients are scanned multiple times during the course of their disease.