During a RapidArc radiotherapy treatment, the treatment beam is continually shaped by a multi-leaf collimator (MLC), a device with 120 computer-controlled mechanical “leaves” or “fingers” that move to create apertures of different shapes and sizes so that the treatment beam conforms to the shape of the targeted tumor.

A RapidArc radiotherapy treatment is delivered very quickly, in less than two minutes, with just one turn of the machine around the patient. RapidArc shapes and modulates a highly focused treatment beam so that it focuses on the tumor, sparing surrounding healthy tissue. It treats the entire tumor with pinpoint accuracy and is easier on the patient, who does not have to hold still for long periods of time.