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What is a Cyclotron?

What is a Cyclotron?

A cyclotron sounds like a weapon out of a James Bond movie, and it kind of looks like one, too. But in this case, it’s a weapon aimed at cancer—a weapon on the good guy’s side.

The cyclotron is basically a particle accelerator, which means it gets particles – in this case protons inside of Hydrogen atoms – moving really, really fast! First a jolt of electricity is applied to hydrogen gas, causing the atoms to spit out protons. The electrons dissipate. The fast-moving protons then travel in the form of beams to the rooms where treatment is given. Since protons are positively charged, we can use magnets to guide them to the tumor. In the treatment rooms, the proton beams are shaped to conform to the patient's tumor. The beam is then delivered with absolute precision to the cancer, where the proton destructive force is concentrated, thereby sparing the surrounding healthy tissue.

A few fun facts about cyclotrons:

  • They can accelerate protons to 223 million miles per hour, or 60% the speed of light.
  • A Nobel Prize was awarded to their inventor, Ernest Lawrence, in 1939. 
  • Ernest Lawrence’s brother, John Lawrence, a doctor, was the first to use a cyclotron in the treatment of cancer. 
  • Protons have been approved to treat cancer by the FDA since 1988, but were used in research since the 1950s.
  • Cyclotrons can also be used for other heavy ions, such as carbon.

 The cyclotron

 The beam line (guided by magnets)

 A compensator (guiding the depth of the beam)

 An aperture (guiding the shape of the beam)

 The gantry (where treatment occurs)