ON THE COVER

Visual comparison of ¹⁵O-H₂O PET perfusion images and late ¹⁸F-fluoromisonidazole (FMISO) PET images of patients with glioblastoma showed a large range of tumor perfusion within areas of increased ¹⁸F-FMISO uptake (i.e., hypoxia was present in both hypoperfused and hyperperfused tumor areas). Generally, increased ¹⁸F-FMISO uptake was found in the tumor margin but not in the tumor center. Tumor centers of all glioblastomas showed decreased radioactivity in both ¹⁵O-H₂O and ¹⁸F-FMISO PET images. The perfusion-hypoxia patterns suggested that hypoxia in these tumors may develop irrespective of the magnitude of perfusion.