Tumor Identification of Less Aggressive or Indolent Lymphoma with Whole-Body 11C-Acetate PET/CT

Purpose The aim of this study was to investigate the diagnostic performance of whole-body [11C]acetate PET/CT in less aggressive or indolent lymphomas, wherein [18F]FDG PET/CT would exhibit limited sensitivity. Methods Between September 2016 and May 2018, we prospectively evaluated 17 patients (9 men, 8 women; mean age [range], 71 [45–87] years) with pathologically proven less aggressive or indolent lymphomas according to Non-Hodgkin's Lymphoma Classification Project, using both [18F]FDG PET/CT and [11C]acetate PET/CT (performed on the same day). Detected nodal lesions were recorded according to the Ann Arbor classification. Extranodal (EN) lesions were also evaluated. We compared whole-body lesion detection between [18F] FDG PET/CT and [11C]acetate PET/CT using the McNemar test. Results In all patients, significantly more nodal and EN lesions were detected using [11C]acetate PET/CT than [18F]FDG PET/CT (nodal: 84 vs 64 regions; P < 0.001; EN: 26 vs 19 regions, P = 0.039). Bone lesions were detected in 8 and 5 patients using [11C]acetate PET/CT and [18F]FDG PET/CT, respectively (P = 0.25). Among the 14 patients (82.4%) who underwent bone marrow biopsy, bone marrow involvement was detected with sensitivities of 100% (6/6 patients) and 80% (5/6 patients) using [11C]acetate PET/CT and [18F]FDG PET/CT, respectively. Multiple areas of focal uptake in the spleen of 1 patient were exhibited on [18F]FDG PET/CT but not [11C]acetate PET/CT. Conclusions [11C]acetate PET/CT exhibited greater sensitivity than [18F]FDG PET/CT for lesion detection in patients with less aggressive or indolent lymphomas, thus promising applicability as a physiological tracer in the study of such lesions.