Interobserver Agreement of Qualitative Analysis and Tumor Delineation of ¹⁸F-Fluoromisonidazole and 3′-Deoxy-3′-¹⁸F-Fluorothymidine PET Images in Lung Cancer

Abstract

The reproducibility of the visual analyses of (18)F-FMISO and (18)F-FLT PET/CT images was demonstrated using a 2-level scale across 18 centers, but the interobserver agreement was low for the (18)F-FMISO and (18)F-FLT volume measurements. Our data support the use of a fixed threshold (1.4) or an adaptive threshold using the aorta background to delineate the volume of increased (18)F-FMISO or (18)F-FLT uptake. With respect to the low tumor-on-background ratio of these tracers, we suggest the use of a fixed threshold (1.4).