Proton Beam Therapy System Enhances Treatment Quality

An innovative treatment system delivers precise intensity modulated proton therapy (IMPT), using pencil beam scanning technology.

The Varian ProBeam proton therapy system generates protons for precision radiotherapy of lesions, tumors, and any other conditions in which radiation treatment is indicated. The IMPT delivers protons that stop at specified depths within the anatomy, thereby reducing exposure of healthy tissue. Scanning beam technology enables IMPT by modulating dose levels on a spot-by-spot basis throughout the treatment area; irradiations from multiple angles are combined in an optimal manner to improve control of dose distributions. The scanning beam technology also eliminates the time-consuming need to insert separate shaping accessories manually for each beam angle in order to match the beam to the shape of the tumor.


The ProBeam system incorporates dynamic peak integrated scanning technology, which paints a precise radiation dose on the target volume, enabling true IMPT. The system utilizes a 250 MeV super-conducting cyclotron, and includes a streamlined treatment console with a modern, graphical, easy-to-use interface that consolidates all controls for imaging, treatment, and motion management. Treatment process and workflows are simplified and easy to learn, with a "follow the light” guidance system that is designed to enhance usability and promote safety by guiding therapists through the steps of even the most complex treatments. The ProBeam IMPT system was developed by Varian Medical Systems (Varian, Palo Alto, CA, USA), and has been approved by the US Food and Drug Administration (FDA).

"ProBeam is the result of decades of leadership in proton therapy research and development and it has been designed from the ground-up to meet the needs of clinicians and patients alike,” said Moataz Karmalawy, PhD, head of Varian's particle therapy group. "This fully integrated system can be used for all forms of advanced proton therapy, including image-guided proton therapy and intensity-modulated proton therapy.”

Due to their relatively large mass, protons have little lateral side scatter in the tissue; the beam does not broaden much, stays focused on the tumor shape and delivers small dose side effects to surrounding tissue. Protons are generated by accelerators in the range of 70 MeV to 250 MeV; by adjusting the energy of the protons during application of treatment, the cell damage due to the proton beam is maximized within the tumor itself. Tissues closer to the surface of the body than the tumor receive reduced radiation, and therefore, reduced damage; tissues deeper within the body receive very few protons, so that the dosage becomes immeasurably small.

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