External Beam Radiation Therapy
VMAT / RapidArc, is an advanced form of IMRT that was introduced in 2007. VMAT, or volumetric arc therapy,uses special software and an advanced linear accelerator to deliver IMRT treatments up to eight times faster than what was previously possible.. Unlike conventional IMRT treatments, during which the machine must rotate several times around the patient or make repeated stops and starts to treat the tumor from a number of different angles, VMAT / RapidArc can deliver the dose to the entire tumor in a single rotation — in less than two minutes.
IMRT, or intensity modulated radiation therapy, uses 3-D scans of your body to guide the beams of radiation to the tumor from many different angles. At each of these angles, the intensity of the radiation is varied (modulated) and the shape of the beam is changed to match the shape of the tumor. These adjustments enable the prescribed amount of radiation to be delivered to each part of the tumor, while minimizing exposure to the surrounding healthy tissue. Treatments are typically given daily for 10 to 20 minutes over a six to eight week period.
IGRT, or image-guided radiation therapy, uses sophisticated computer software to analyze a series of image scans to create a detailed, three-dimensional picture of the target area and surrounding tissue, which enables your team to view the tumor and its position in your body before and during each treatment. The scans typically are produced by computed tomography (CT scan), magnetic resonance imaging (MRI), or positron emission tomography (PET scan).
SRS, or stereotactic radiosurgery, is a technique that is most commonly used for tumors in the brain or spinal column. Unlike IMRT, SRS is typically delivered in a maximum of five sessions using higher doses of radiation with each session. Despite the use of the word “surgery” in its name, SRS does not involve removing the tumor with a surgical blade. Instead, a focused high-intensity beam of radiation is used to target the tumor.
SBRT, or stereotactic body radiation therapy, is a very similar technique to SRS, but is used for targets that are outside the brain and the spine. SBRT is most commonly used for targets in the lung, liver, pancreas and kidney, and is typically delivered in a maximum of five sessions.