Results of screening (for T0, T1, and T2 exams): Official result of the screening exam, after comparing the current image(s) with prior screening images or other available prior images.  Participants with positive screens (scr_resX = 4, 5, or 6) were advised to receive a diagnostic evaluation for lung cancer with their personal physician.Contains information on either the spiral CT or the chest x-ray screening exam, depending on which study arm the participant was randomized to (see rndgroup).