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ProBeam Proton Therapy SystemPencil Beam Scanning

What is Pencil-Beam Scanning (PBS)?

Varian's ProBeam® system stands apart from other proton-therapy systems because it uses pencil-beam scanning with its unprecedented precision. Clinicians can therefore treat larger and more complex tumours, while at the same time sparing more of the healthy tissue. Only pencil-beam scanning, and not the passive scattering delivery of proton therapy, can deliver intensity-modulated proton therapy (IMPT). For more than a decade, Varian's research and development in proton therapy has focussed exclusively on this advanced form of pencil-beam scanning. The use of proton therapy—partnered with the accuracy of pencil-beam scanning—offers the optimal tumour control.

Benefits of Pencil Beam Scanning

Benefits of Pencil-Beam Scanning (PBS)

Given that clinicians are able to program pencil beam scanning to the precise depth of the tumour, there are a number of advantages to both patients and clinicians:

  • Can deliver high doses of proton radiation therapy
  • Sculpts doses to the complex shape of an individual tumour—and therefore can be
    used for tumours next to critical structures
  • Spares the healthy tissue adjacent to the targeted tumours
  • Compared with passive scattering-proton therapy, produces fewer neutrons, and therefore a
    significantly lower radiation dose, in terms of the normal, healthy tissue
  • Penetrates in a more precisely targeted manner than passive scattering, which aids in
    the treatment of deeply established and/or complex tumours
  • In the vast majority of cases, does not require beam-modification devices, physical compensators
    or apertures
  • Allows for rapid, flexible re-planning without the need to fabricate, and manually insert,
    new beam-shaping devices
  • Can easily deliver differential dosing or simultaneous integrated boost (SIB) plans
Pencil Beam Scanning

Not all pencil-beam scanning is the same. Compared with the other proton systems with pencil-beam scanning, the ProBeam system offers faster layer switching. The average time per layer switch with the Compact unit is less than 1 second. The ProBeam system also delivers proton therapy of 2G/L/min, with a small spot size across the full energy range. This proton therapy is delivered without the need for range shifters, even at 70-100 MeV. In addition, some single-room proton systems only offer scattering technology today, which is not capable of IMPT. It's also important to note that pencil-beam scanning produces significantly fewer neutrons, so the associated risk is also reduced. Conversely, with passive scattering, neutrons—i.e., secondary radiation—are produced when the scattered proton beam contacts the scattering material or beam-modifying devices. This is especially important when treating children, who are at a higher risk of developing neutron-induced secondary cancers later in life.

Learn More About ProBeam

Optimizing Efficiency

Optimising Efficiency

The ProBeam pencil-beam scanning system is integrated with Varian's other products to optimise the efficiency: