Whole-body hybrid PET with F-18-FDG in the staging of non-Hodgkin's lymphoma

PET with a double-head gamma camera (hybrid PET) is a new approach to tumor imaging with F-18-FDG. This study was conducted to clarify the feasibility of whole-body FDG hybrid PET in the staging of non-Hodgkin's lymphoma (NHL ) in comparison with PET with a dedicated camera (dedicated PET) and to com pare the results of both FDG studies with those of CT and Ga-67 scanning as conventional imaging studies (CIS). Methods: Thirty patients with NHL were prospectively evaluated. The results of the imaging studies regarding dete ction of the sites involved and staging were compared with each other and w ith those of the reference standard based on the final overall clinical eva luation. Results: Of the total of 206 sites, whole-body FDG hybrid PET and dedicated PET detected 159 sites (77.2%) and 179 sites (86.9%), respectivel y. Eighteen of the 20 sites missed by hybrid PET alone consisted of lesions < 1.5 cm, Both FDG studies provided concordant staging results in all but 2 patients. CIS, on the other hand, detected 164 (79.6%) of the 206 sites, 137 of which were also detected by hybrid PET. Hybrid PET detected an addit ional 22 sites not found by CIS, whereas CIS detected 27 additional sites. Hybrid PET and CIS provided concordant staging results in 19 patients. Hybr id PET correctly staged NHL in 5 additional patients, whereas CIS correctly staged NHL in only 1 additional patient. Conclusion: Whole-body FDG hybrid PET appeared to be an accurate method of staging NHL, Despite its poorer i mage quality compared with dedicated PET, hybrid PET provided NHL staging r esults comparable with those of dedicated PET. Hybrid PET also yielded resu lts comparable with those of CIS. However, whole-body FDG hybrid PET is cur rently inadequate as a single modality for staging NHL and is complementary to CT.