Although the first suggestions of using energetic protons as a cancer treatment method was made in 1946, proton therapy (or more accurately proton radiotherapy) has been used as a treatment technique only relatively recently, with a significant increase in its use over the last decade.
Key advantage of using protons, versus photons (X-rays) for therapy is that protons are relatively heavier and their energy can be focused at the point of the tumor (the Bragg Peak) with less damage to the patient’s unaffected tissue, in front of and beyond the tumor, that X-ray techniques produce.
Most installed proton therapy systems use isochronous cyclotrons (which can produce much higher proton beam currents than ) which are made more compact by the use of superconducting magnets. Synchrotrons and linear accelerators however can also be used. During treatment, the proton beam is tailored to a certain energy, allowing cancer cells to be targeted specifically.
There are several basic sections to a cyclotron - injection, extraction, transport lines and the main chamber – all of which require vacuum equipment. Some challenges for this equipment include their required use in high magnetic fields and radiation environments, conductance limitations and space-constraints.