Plan studies comparing fixed-beam and helical IMRT with RapidArc show that RapidArc can reduce the amount of non-therapeutic radiation reaching healthy tissues during treatment. For example, in the case of head and neck cancer treatments, RapidArc plans are better at protecting critical structures like the spinal cord, brain stem, eyes, optic nerve and chiasm, parotid (salivary) glands, and brain. Moreover, with RapidArc's highly efficient use of the primary beam, secondary stray radiation caused by scatter and leakage are reduced by over 50 percent on average compared with fixed field IMRT.
RapidArc technology utilizes a sophisticated, proprietary algorithm that creates a finely-shaped IMRT dose distribution that closely matches the size and shape of the tumor. It works by varying three parameters simultaneously: 1) the speed with which the treatment machine rotates around the patient, 2) the dimensions of the beam-shaping aperture, which change continually during the treatment based on the patient's unique anatomy, and 3) the rate at which the dose is delivered. These technologies work together to make RA the most revolutionary advance in radiation therapy in terms of speed, efficiency, and conformality.
"The RapidArc planning algorithm exploits the unique characteristics of
Varian's most advanced medical linear accelerators, which can deliver dose
at different rates, and the multileaf collimator, which is used to shape
the beam so it conforms to the shape of the tumor," said Corey Zankowski,
|SOURCE Varian Medical Systems|
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