Effects of Respiration-Induced Density Variations on Dose Distributions in Radiotherapy of Lung Cancer

The effect of respiration-induced density variations on the dose accumulated over the respiratory cycle was very small, even in the presence of considerable respiratory motion. A full 4D-dose calculation for treatment planning that takes into account such density variations is therefore not required. Planning using the MidV-CT derived from 4D-CT with an appropriate margin for geometric uncertainties is an accurate and safe method to account for respiration-induced anatomy variations.