RapidArc® radiotherapy technology advances the standard of care with uncompromised treatment in two minutes or less. Varian researchers have found that RapidArc compares favorably with conventional IMRT and helical IMRT planning for a variety of clinical sites.
In one example, a multitarget cancer of the nasopharynx, RapidArc plans were found to be equivalent or better at target coverage for all targets, and superior in protecting critical structures including the spinal cord, brainstem, eyes, optic nerve and chiasm, parotid glands, and brain. In this test, the RapidArc treatment took only 110 seconds and used only 585 monitor units (MUs).
Other tests showed that even complex RapidArc treatment plans can be delivered in less than two minutes, with fewer than 750 MUs. In comparison, Varian’s best IMRT treatments, delivered one field at a time, require approximately one minute per field to deliver, while the average multislice helical IMRT treatment requires 10 to 15 minutes.
Studies by Cedric Yu, DSc, professor of radiation oncology at the University of Maryland Medical Center into single-arc IMRT has shown it to be equal to or better than multiple-field IMRT in terms of target volume coverage and normal tissue sparing. He found that a single arc can deliver essentially similar dose distributions compared with IMRT plans that incorporate as many as 36 fields.