Utility of Four-Dimensional Computed Tomography for Analysis of Intrafractional and Interfractional Variation in Lung Volumes

Four-dimensional CT assesses lung volume with acceptable precision; but the technique was unable to accurately predict interfractional changes in lung volume because wide variations in intra- and interfractional breathing cause high uncertainties in 4D CT data acquisition. The most reproducible breathing phase seems to be at the 30-40% phase (just before end-expiration).