Since early 1990s, when 18F-FDG PET has emerged as a promising diagnostic imaging tool in nuclear medicine, a large number of studies have been reported without exception that PET is a better staging tool than CT for patients with NSCLC. However, due to the prohibitive cost, PET is not routinely used for the staging of NSCLC in Taiwan. The extra cost accruing from the introduction of this new technology has been the major concerns from the clinical physicians and health policy makers.