For all calculations, animal weights were expressed in kilograms and FDG activity in megabecquerels. For each image series, SUVs for each voxel were calculated using an external filter in PMOD, with the radionuclide half-life set at 6586.2 sec for 18F-FDG. For each pulmonary lesion, an ellipsoid volume of interest (VOI) was generated that encompassed the structure. Then, automatic isocontour detection was used to refit the VOI by setting a threshold of 50-60% of the difference between the maximum and minimum intensity SUVs in the ellipsoid VOI such that 0.5*(SUV max 2SUV min ). In cases where the automated threshold included contiguous structures in the VOI, manual refitting in conjunction with the co-registered CT scan was used to exclude those surrounding structures. For all VOIs, maximum SUV (SUV Max ) and average and standard deviation of all pixels in the volume (SUV Mean 6 SD) were calculated.