For many, the proverbial pendulum has already swung to PET, especially when integrated with computed tomography (CT), as an indispensable test for noninvasive detection of distant metastatic disease in lung cancer. Fortunately, acceptance by clinicians has been increasingly validated by many detailed studies that have served to clarify its clinical role; an example is the admirable study by Maziak and colleagues (4) in this issue. In this study, derived from 5 Canadian academic institutions, Maziak and colleagues randomly assigned 337 patients with non–small cell lung cancer—thought to be stage I, II, or IIIA on the basis of initial chest radiography and CT—to staging with PET-CT or a combination of abdominal CT and radionuclide bone scanning (conventional staging). Three statistically and clinically significant findings emerged. First, PET-CT correctly upstaged disease to unresectable stage IIIB and IV in 13.8% of patients; conventional staging correctly upstaged disease in only 6.8%. Therefore, PET-CT staging resulted in proportionately fewer inappropriate attempts at surgical cure. Second, false-positive PET-CT findings incorrectly upstaged disease in 4.8% of patients, versus 0.6% in the conventionally staged group. In the latter patients, disease was eventually correctly staged by using additional diagnostic procedures (including biopsy when necessary), then treated appropriately. Maziak and colleagues note that subsequent clarifying tests were performed more frequently in the conventionally staged group. Finally, PET-CT incorrectly downstaged disease in fewer patients (15%) than did conventional staging (29.6%), which also helped avoid futile thoracotomies and allowed more stage-appropriate chemotherapy plus radiation.