IMRT 2018

4DCT%– time%resolved%3D%CT

Most common 4DCT planning procedure: plan in only one scan, and use other scans to determine margins due to motion. Suggested planning scans: • Produce the maximum intensity projection (MIP) of all phases, use this composite scan as the planning scan • Mid-ventilation CT scan, represents tumour in its time-averaged position over the respiratory cycle • Average scan over all the phases