Mayo Clinic Proton Beam Therapy Program

Narrator: Mayo Clinic's Cancer Center offers a full range of services and treatment options to meet your individual needs, including the latest innovations in proton beam therapy. Our new proton beam therapy program has the most up-to-date technology called intensity modulated pencil beam scanning. This is a highly targeted and precise way of administering radiation therapy. It allows delivery of higher doses of radiation to tumors while minimizing the damage to nearby healthy tissue and organs. Significant benefits can be achieved by integrating proton beam therapy with other treatment approaches. Children, young adults and healthy older adults with potentially curable cancers located near or within critical organs will receive the greatest benefit. So let's see how it works.

Common sources of protons used in proton beam facilities are hydrogen gas and water. In the case of water, the protons come from removing a hydrogen atom from a water molecule. These tiny particles are then modified so that they carry an electrical charge. The charged protons are accelerated at 2/3 the speed of light in a series of magnets called the synchrotron. This proton beam is then directed by even more magnets down the beam line into the treatment rooms and aimed precisely at the patient's tumor.

In preparation for treatment, a team of experts develops an individualized treatment plan using the patient's previously obtained imaging studies such as CT, MRI and PET scans. The patient is carefully placed on the table in a stable position to prevent movement during treatment and to maintain the same alignment from day to day. X-rays or CT scans will be taken to ensure proper positioning.

During the treatment, the beam is delivered into the tumor where it stops in a burst of energy. The biggest impact is released precisely within the tumor, where the energy from the proton beam breaks the tumor cell's DNA, damaging them beyond repair and rendering the cancer cells unable to reproduce. Unlike conventional x-ray photon therapy, which delivers a steady stream of damaging radiation to normal tissue surrounding the tumor, protons deliver minimal dose outside the tumor. Therefore, proton therapy can avoid damaging and debilitating side effects to the normal surrounding tissues.

Intensity modulated pencil beam scanning will be used at the Mayo Clinic Proton Beam Centers. It is the most advanced form of proton beam therapy and uniquely conforms the radiation dose to the shape of the tumor. The precise proton beam is used like a brush to paint every part of the tumor while sparing surrounding tissue. Its precision allows the targeting of tumors near critical organs, like the esophageal cancer shown here, with much less dose and less risk of potential damage to the nearby spinal cord, heart and lungs. During one treatment session, the proton may be delivered to the tumor from more than one angle. The patient, meanwhile, can't see or feel the proton beam at all. This therapy is also a particular benefit to pediatric patients in that it can provide the same or higher dose to a tumor while delivering less overall radiation exposure to their vulnerable growing organs. This results in less risk of toxicity, growth delays or radiation-induced malignancies. Greater control of radiation doses, more accurate targeting of tumors and reduced side effects. These are just a few of the potential benefits of cancer treatment at the Mayo Clinic Proton Beam Therapy Program.

The Proton Beam Therapy Program is available at two Mayo Clinic locations: Rochester, Minnesota and Phoenix, Arizona. For more information to to the

Nov. 04, 2023