Particle accelerators do more than just particle physics research. Suzie Sheehy takes a look at the history and promise of proton therapy: using particle accelerators to fight cancer.
The discovery of X-rays in 1895 was the start of the first breakthrough in modern cancer treatment. Wilhelm Röntgen used a cathode ray tube to generate X-rays. It didn’t take long for the destructive power of these rays to be turned to medicinal benefit. X-rays kill cancer cells through ionization. By stripping electrons from water molecules, the X-ray photons leave a highly chemically reactive wake. The reactive water molecules bind to, and destroy, DNA.
But X-ray beams don’t differentiate between healthy and cancerous cells, so their destructive force is hard to localize to the problem zones alone. One option is to use protons, rather than X-ray photons. Particle accelerators can take protons from inside a Hydrogen atom, form them into high energy beams and more specifically target a tumour.
However, instead of passing through the body like X-ray photons, the protons stop at the tumour, thanks to a phenomenon called the ‘Bragg peak’. By tuning the energy of a proton beam, the dose can be much more carefully controlled.
