Cohen SL, et al. - Th present study was performed to ascertain patient, technologist and CT factors that influence excess scan length for chest CT.Researchers carried out a retrospective evaluation of 1118 consecutive noncontrast chest CT scans, over twelve consecutive months, for assessment of scan length above and below the lung parenchyma.  In this study, 5 mm, 29 mm, and 33 mm were the mean excess scan length of above the lungs, below the lungs, and total.  The outcomes of this research highlights that excess scanning on chest CT is common, varies by patient age and gender and was significantly greater for high volume technologists.