The Potential of Proton Therapy

Protontherapy is a type of radiotherapy. The first human was treated with proton beams at the Lawrence Berkeley Laboratory in 1954. In 1962, specialised radiosurgical proton treatments commenced at the Harvard Cyclotron Laboratory, followed in the mid-1970s by treatments for ocular cancers and larger tumours. Proton therapy has been FDA approved for cancer care since 1988.

What is the difference between protons and X-rays?

Protons can be much more precise than X-rays thanks to a property identified by Robert Wilson in 1946 when he was involved in the design of the Harvard Cyclotron Laboratory:

  • Photons (x-rays) are electromagnetic waves that have no mass or charge and can enter the patient on one side of the body and travel straight through, exiting out the other side, with the radiation dose gradually decreasing as it travels through the tissues.
  • Protons are large particles with a positive charge that penetrate matter to a limited depth, the depth of penetration being based on the energy of the beam. they deposit most of their energy at this depth of penetration which effectively defines an end point to the beam. The beam essentially stops at this point, resulting in no radiation to the tissue beyond the target. When dose to tissue is plotted against distance into tissue we see a sudden peak of dose at a depth corresponding to the maximum energy of the protons. This peak is called the Bragg Peak. As a result of this Bragg Peak, and the resultant dose distribution, the side effects of proton therapy occurring from radiotherapy are reduced to a minimum.

When is proton therapy better?

Currently there is clinical evidence to assume that at least 10%-15% of patients who undergo radiotherapy would benefit from proton therapy.This could be significantly more if the price of delivering proton therapy was to reduce.

"If the costs were the same, there would be no debate. Less radiation to healthy tissue is always better for the patient."

Leonard Arzt, Executive Director of the National Association for Proton Therapy

Key indications for proton beam treatment include tumours adjacent to critical normal structures (liver, lung, head and neck, prostate, breast), paediatric tumours, and tumours in patients treated with chemoradiation. Furthermore, to reduce the burden of treatment-related complications on patients and the healthcare system, there is an increasing interest in exploiting the tissue-sparing capabilities inherent to proton therapy.

The cost of proton accelerators has been an obstacle to their more widespread use

Proton therapy centres have been historically expensive to develop due to:

  • the size and weight of the accelerators
  • the size and weight of the rotatable gantries
  • the footprint dedicated to shielding
  • the facility required to house the accelerator
  • the high maintenance and decommissioning costs

Advanced Oncotherapy believes that the LIGHT technology can address those issues and become a game changer for the market of proton therapy systems.