Volumetric-modulated arc therapy (VMAT) delivers radiation on a linear accelerator using a cone beam that continuously rotates around the patient. Each rotation is called an arc and one or more arcs might be used. During each rotation, the cone beam is continuously shaped (or modulated) by the multi-leaf collimator. In addition, the dose rate (how much radiation delivered for each second) and gantry speed (how fast the beam rotates) are also optimized to generate highly conformal dose distributions. The radiation is delivered to the intended area only, allowing the radiation oncologist to spare more surrounding healthy tissue. Both VAMT and IMRT are equally effective for normal tissue sparing. However, the treatment time for VMAT is significantly shorter, thus benefits patients who require longer (30 minutes or more) treatment time.