Early FDG-PET imaging after radical radiotherapy for non-small-cell lung cancer: Inflammatory changes in normal tissues correlate with tumor response and do not confound therapeutic response evaluation

Abstract

Purpose To investigate the relationship between positron emission tomography (PET) detected inflammatory changes in irradiated normal tissues and metabolic response at tumor sites in patients receiving radical radiotherapy for non-small-cell lung cancer. The prognostic significance of these changes was also studied. Methods In 73 consecutive patients, 18F- fluorodeoxyglucose (FDG) PET was performed at a median of 70 days after completion of radical radiotherapy. Radiation-induced inflammatory change was scored for normal tissues within the radiation treatment volume using a 0-3 grading scale. Metabolic tumor response was assessed using a pattern-recognition algorithm comparing pre- and postt..