Mayo’s proton beam facility on track for 2015 opening

Crews have finished construction of Mayo Clinic's Richard O. Jacobson Building in Rochester that will house one of the clinic's two new proton beam cancer therapy centers. A second facility is also under construction in Phoenix.

Mayo doctors and scientists will spend the next year and a half testing equipment and calibrating the pencil beam scanner before opening in the summer of 2015.

Dr. Michael Herman, chair of the Division of Medical Physics, gave reporters a behind-the-scenes tour of the building on Tuesday.

Here, Herman shows the synchrotron, a particle accelerator that will accelerate protons to 60 percent speed of light. That means with about two seconds of acceleration, the protons will travel the distance of going around the earth 10 times. After two seconds, the protons will be used to treat patients, Herman said.

As the name implies, pencil beam scanning is a more precise form of radiation therapy that allows for greater control over the doses a patient receives. The treatment times are shorter and there are fewer side effects than conventional radiation therapy for cancer patients.

All eight treatment rooms at Mayo Clinic's two new proton beam facilities will feature pencil beam treatment.

Mayo will use the technology primarily for head and neck, breast, gastrointestinal, lung, spine and prostate cancers. Doctors also will use it to treat tumors in or near the eye.

An advancement to traditional radiation therapy, pencil beam scanning targets only the tumor, sparing the surrounding tissue, said Dr. Robert Foote, chair of Mayo's Department of Radiation Oncology in Rochester.

"It’s a lower dose of radiation to normal organs, so it’s a safer way of administering radiation treatments," Foote said. "Much lower entrance dose as the beam enters the body and it stops at the tumor and there’s no exit dose. So there’s less harm to the normal organs that surround the cancer."

Because of this, the benefit of pencil beam scanning for children is especially clear, he said.

Proton therapy can be considerably more expensive than traditional radiation, in part because of the cost of the equipment and facility. The four-room Rochester location will cost approximately $188 million. The center in Arizona is expected to cost $182 million. Funding for the projects will come from Mayo's capital budget and benefactor support, according to Mayo officials.

To understand how pencil beam scanning works, check out this video from Mayo Clinic's Medical Edge:

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