Image-guided 3D Conformal or Intensity Modu- by the various classifcation systems, which might lated Radiation Terapy aims to deliver high doses be hard to fnd in scans performed without contrast of radiation to the tumor, while trying to maintain medium. dose levels to healthy tissue within tolerable limits. Together with experienced radiologists for each Terefore, it is of key importance to defne the dif- anatomical region, we have developed a set of st- ferent target volumes, gross tumor volume (GTV), dards for the acquisition of planning CT images, clinical target volume (CTV), planning...