Respiratory gating for 3-dimensional PET of the thorax: Feasibility and initial results

Respiratory motion may reduce the sensitivity of 18F-FDG PET for the detection of small pulmonary nodules close to the base of the lungs. This motion also interferes with attempts to use fused PET/CT images through software or combined PET/CT devices. This study was undertaken to assess the feasibility of respiratory gating for PET of the chest and the impact of respi-ratory motion on quantitative analysis. Methods: Ten healthy subjects were enrolled in this study. Three-dimensional studies were acquired with 8 gates per respiratory cycle on a commer-cial PET scanner with a temperature-sensitive respiratory gating device built in-house. All scans were obtained over 42 cm of body length with 3 bed positions of 10 min each after injection of 18F-FDG at 4.5 MBq/kg. The reconstructed images were assembled to produce gated whole-body volumes and maxi-mum-intensity projections. The amplitude of respiratory motio