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Protons: The Ultimate in Radiation Therapy




Radiation treatment has come a long way since 1896 when X-rays were first used to shrink tumors and kill cancer cells.

So, too, have methods of delivering radiation, whether internally through the placement of ‘seeds’ or externally via photon beams (x-rays or gamma rays). Recently, a more advanced form of external radiotherapy which utilizes proton beams (charged particles) has been developed. And it will be available at University Hospitals Case Medical Center in 2014, when construction of UH’s $30 million Proton Therapy Center is expected to be completed.

“Protons are the ultimate means of reaching certain tumors and protecting critical vital organs that are located right behind or adjacent to those tumors,” explains Mitchell Machtay, MD, professor and chairman, Department of Radiation Oncology at UH Case Medical Center and Case Western Reserve University School of Medicine. “It will be an important addition to our existing photon-beam based radiation therapy services which include Synergy-S Hexapod, Cyberknife, TomoTherapy and Perfexion Gamma Knife.”

According to information provided by the National Cancer Institute (NCI), proton beams differ from photon beams mainly in the way they deposit energy in living tissue. Whereas photons deposit energy in small packets all along their path through tissue to the targeted site, protons deposit much of their energy at the end of their path to the site (called the Bragg peak) and deposit less energy along the way. As a result, treatment can be targeted and conformed to the shape of the tumor with incredible accuracy, reducing the exposure of normal tissue to radiation and possibly allowing the delivery of higher doses of radiation to a tumor.

“The goal of radiation is always to deliver a very high dose radiation to sterilize or destroy a tumor, but without causing unacceptable side effects related to the tissues and organs near the tumor we’re treating. And the new proton technology is another way to help us do that,” says 
Dr. Machtay.

According to 
Dr. Machtay, the best candidates for proton therapy are patients with tumors that are located very close to critically sensitive parts of the body such as the brain and spinal cord or in hard-to-reach areas in the pelvis, head and neck. It is especially valuable for children and young adults, who seem to be more prone to both short-term and long-term complications 
from radiation.

He points out that proton therapy is still very new. (The first hospital-based proton treatment facility didn’t open until 1991, and currently there are only nine hospital-based centers in the nation. University Hospitals’ is expected to be the first in Ohio.) As a result, proton therapy has not yet been rigorously compared with standard photon therapy in clinical trials. Once the UH Proton Therapy Center is completed, Dr. Machtay hopes to remedy that situation.

“We want to be at the forefront of studying proton beams, what they can do, what they’re capable of, how can we improve proton beam therapy, because the proton beam therapy that is available today is not what will be available in proton beam therapy 5-10 years from now,” he says. “Our new proton center will be a great complement to the existing state-of-the-art radiation oncology equipment we already have at the UH Seidman Cancer Center. It is a natural evolution of our mission, which is to use radiation in the most effective and safest way to treat and hopefully cure cancers.”

MD News Fall 2011, Cleveland/Akron/Canton


COMMENT ON THIS ARTICLE


1 comment for “Protons: The Ultimate in Radiation Therapy”

  1. Gravatar of Jim SmittsJim Smitts
    Posted Wednesday, September 28, 2011 at 2:41:23 PM

    <a href="http://iuhealthprotontherapy.org">IU Health Proton Therapy</a> is another Midwest center. They've been treating patients since 2004, though the cyclotron there dates back to several decades earlier, as it was initially installed for (non-medical) research. I'm glad to see this type of treatment continuing to receive more notoriety!