Automatic delineation of functional lung volumes with 68Ga-ventilation/perfusion PET/CT.

To automatically delineate functional volumes with 68Ga-V/Q PET/CT, the most appropriate cutoff was 15%max for both ventilation and perfusion images. However, using this unique threshold systematically provided unacceptable variability compared to the reference volume and relatively poor correlation with PFT parameters. Accordingly, a visually adapted semi-automatic method is favored, enabling rapid and quantitative delineation of lung functional volumes with 68Ga-V/Q PET/CT.