Use of digitally reconstructed radiographs in radiotherapy treatment planning and verification.

The authors present 3 years of experience in using digitally reconstructed radiographs (DRR) for radiotherapy planning and verification. Comparison is made with simulation film (SF), to illustrate the advantages of DRR over SF. Emphasis is placed on using the appropriate equipment and applying the correct technique. A brief discourse on the principle of CT imaging is presented to illustrate the operation of CT software and optimization of image display for axial slices and DRR. Emphasis is placed on the application of clinical knowledge to enhance the usefulness, as well as the technical quality, of the DRR. Illustrative examples are given.