PURPOSE: To review the state of the art in image-guided precision conformal radiotherapy
and to describe how helical tomotherapy compares with the image-guided practices being
developed for conventional radiotherapy. METHODS AND MATERIALS: Image guidance is
beginning to be the fundamental basis for radiotherapy planning, delivery, and verification.
Radiotherapy planning requires more precision in the extension and localization of disease.
When greater precision is not possible, conformal avoidance methodology may be indicated …