Assessing respiration-induced tumor motion and internal target volume using four-dimensional computed tomography for radiotherapy of lung cancer.

Purpose: To assess three-dimensional tumor motion caused by respiration and internal target volume (ITV) for radiotherapy of lung cancer.

Methods And Materials: Respiration-induced tumor motion was analyzed for 166 tumors from 152 lung cancer patients, 57.2% of whom had Stage III or IV non-small-cell lung cancer.