Medical linear accelerator - proton therapy

Proton Therapy

Proton therapy as cancer treatment method

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. 

Leybold offers both vacuum pumps and a wide range of ancillary equipment

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. Leybold offers oil-free pumps such as the SCROLLVAC plus series and high speed turbomolecular TURBOVAC iR and cryopump combinations to improve vacuum levels by an order of magnitude into the 10-7 mbar range which maximises beam intensity due to fewer collisions with residual gas molecules.

Ion getter pumps and ionization gauges are also utilised. Smaller cyclotron systems can still use diffusion pumps and in some cases oil-sealed rotary vane pumps are still employed. In addition to these products, Leybold offers a wide range of ancillary equipment such as leak detectors PHOENIX 4  and portable pumps systems plus related hardware accessories.