Principles of IMRT

Although the goals of intensity-modulated radiation therapy (IMRT) are the same as those of conventional treatments (maximize dose to target structures while minimizing dose to nearby normal tissues), some significant differences are present in the treatment planning and delivery processes. Here, we describe these differences and introduce considerations related to beam configurations, treatment plan objectives, and alternative approaches. Also described are some aspects of quality assurance (QA) that are specific to IMRT implementation (e.g., commissioning, patient-specific QA, and process QA) and potential unanticipated consequences of IMRT that must be addressed if IMRT is to be successfully used in the clinic.