Mayo Clinic has a Hitachi PROBEAT-V
proton therapy system
Courtesy: Hitachi

New Arizona research may aid proton therapy precision

April 18, 2017
by Thomas Dworetzky, Contributing Reporter
The collaboration between Arizona State University and the Mayo Clinic that gave the state its first proton therapy facility is starting to pay research dividends.

ASU postdoc physics researcher Jason Holmes is designing devices that will help improve beam accuracy and make therapy safer.

Holmes is working on devices that will more accurately identify the location of protons in the patient's body, and also the number that reach their target.

The Mayo Clinic's Martin Bues, head proton physicist for its radiation oncology department, stressed the utility of the postdoc's work.

“The beauty of Jason’s device, if it, in fact, works, is that all uncertainty will be removed because his device will actually measure in real time, in living breathing patients, where the beam stops,” he noted.

“In order to use proton beam therapy to the fullest, we need to know, with the highest possible precision, where the beam will stop,” he advised.

Holmes is working on a prototype range detector that could be more accurate than today's methods, which can determine the range of a proton to about a centimeter. “You can’t really use this to help the patient, to help their outcome, until you get within around a millimeter,” he told The State Press.

He also has a prototype proton counter. This works by first sending the beam through a diamond and then into the patient's body.

“I’m literally talking about ‘there goes one proton, then another, there’s another,’” Holmes noted, advising that, “if you know how much energy is being deposited into a patient, and where it is being deposited, then you know basically everything you need to know,” and adding, “that’s what all of our projects are trying to do.”

His advisor, Ricardo Alarcon, noted that the range detector will mean that, “it'll be the first time we will be doing this therapy and will be actually looking at what is happening while the treatment is being conducted.”

The collaboration between ASU and Mayo Clinic that led to the proton facility began in 2015. Although the center came with a hefty $182 million price tag, the Mayo Clinic has a new business model, relying on private donations rather than loans, that officials say will lower treatment costs to be in line with other modalities for cancer care.

“We have taken all the risk on this,” Dr. Sameer Keole, a radiation oncologist and center director, told The Arizona Daily Star.

“We have voluntarily said, ‘We are going to completely take the cost argument off the table. It is going to be the same cost for the insurance company and for the patient, in terms of his or her copay, whether they get X-ray therapy or whether they get proton therapy. So anybody who says we are doing it for the money, that completely takes the wind out of the sails.”

The facility's officials estimate that 1,200 patients will eventually be treated annually there, according to The Star.

Beyond cost consideration, the new center makes it more convenient to receive this cutting edge treatment for patients in Arizona.

"While it is important for patients to explore all available treatment options with their physician, to determine what approach is best for their unique condition, we are fortunate that patients no longer have to travel out of state to access this remarkable technology, which provides targeted treatment to cancer cells while minimizing damage to healthy tissue,” Tucson Medical Center's chief medical officer, Dr. Rick Anderson, told the paper.

"The whole idea started because Mayo Clinic decided to build a proton therapy clinic in Phoenix, and there are only a few in the country,” Alarcon said.

Alarcan stated that Holmes’ progress on his research has been impressive.

"It's a really unique position for the student to be in ... thinking of the problem, building the apparatus that is going to solve that problem, and then going and doing the experiments,” Alarcon said. “And that's what he's doing."