Chapter 21: Technology and Techniques for Treatment: IGRT, SGRT, ART, and Respiratory Management

To deliver external beam radiation treatment as intended, numerous variables must be accounted for and controlled. First, the patient must be aligned with the radiation beams in the way intended during the treatment planning process. Second, if the patient moves during treatment (or if their internal anatomy moves), this must be accommodated in some way. Finally, if the changes in internal anatomy are significant enough compared to the plan that was originally developed, a new plan may have to be created. All of this is made even more challenging since each course of radiation therapy may last many weeks and each individual session (fraction) may last many minutes or even up to an hour or more.