Proton therapy now has a foothold in most parts of the world. Altogether, the global market for proton therapy systems is expected to triple by 2018, and reach $2.5 billion by 2030, according to a new market research report by MEDraysintell.

Though the U.S. retains 28 percent of the world's proton therapy centers, and has 17 more currently in development or construction, the technology has also made inroads in various other corners of the world thanks to government financing and interest in more advanced technology.

In the UK, the state-run health care system announced in August that it would invest $380 million to build two proton-beam therapy centers. Japan is home to some of the first facilities to use carbon ion radiotherapy, the newest form of particle therapy, as well as 23 percent of the world's proton therapy centers. And at least four centers opened in Europe in 2012 and 2013.

Shifting attitudes toward proton therapy are contributing in part to the treatment's growth internationally, along with state-funded financing.

"The value of proton therapy is definitely a worldwide discussion, but there might be less challenge elsewhere in the world," said Jonathan Cohen, principal architect at TK&A Architects.

Less challenge means unique approaches that diverge from the way proton therapy is used in the U.S.

Asia invests in newest technology

Japan has long been at the forefront of proton therapy investment thanks to government support and access to technology. The country is now investing in carbon ion radiotherapy, a powerful but expensive treatment that drives heavy carbon ions to a tumor. Preliminary studies have found that it's most effective against rare and challenging cancers such as spinal tumors. Currently, four of the seven carbon ion therapy treatment facilities are in Japan.

"Japan is really taking the lead in that," Steve Courtney, partner at SCI X Science Studio, told DOTmed News. "It's encouraging when we go to the conferences because they make carbon ion sound doable, and [that] maybe it shouldn't be dismissed as it has been because of budgets."

Around 5,000 patients have been treated with carbon so far. Cohen predicts that it will be some time before carbon ions are seen in the U.S.

"Because the emphasis here is much more on private development, the financing mechanisms might be a huge hurdle," said Cohen. "The lack of a reimbursement policy for carbon would also be a problem."

Meanwhile, in China, private development is driving the creation of at least one new center. There is currently only one other center in China, located in Zibo.

"There are some developers and private entities interested, but it's going to go at a slower pace until the government really embraces it," said John Jessen, managing principal at VOA Associates.

Courtney also has a China project his team is working on, in Guangdong, China. The facility there plans to design its own equipment to save on costs and optimize treatment for a larger population.

"What they're really trying to do is get proton therapy promulgated through the country, and not just for the wealthy," said Courtney.

Taiwan has one center, and Korea has one center with another on the way. A center is also planned in Singapore.

Europe expands its proton therapy reach

In December 2012, the first proton therapy center in Central and Eastern Europe opened in Prague, Czech Republic. The center has treated local patients as well as patients from Russia, Germany, Norway, Switzerland, England and Serbia.

"Prague is less than two hours by plane from London, so it's highly accessible to cancer patients throughout Europe," said Mike Cullen, of Proton Therapy UK Ltd.

Like most centers in Europe, it's a multi-room facility, with five treatment rooms. Cullen estimates the anticipated treatment capacity will be 2,000 to 2,500 patients per year.

In the United States, small, one-room centers have become more popular, but Cohen predicts that trend will not be as prevalent in Europe because centers are less dependent on profit.

"Certainly in terms of the business model, there's less private development overseas, and less pressure to meet minimum thresholds for patient volumes," said Cohen. "Generating revenue quickly to address the financing challenge seems to be less intense than it is in the U.S."

Though government-funded centers have benefits in terms of financing, Cohen has noticed drawbacks in the process as well. Many public facilities have an open bid for proton therapy vendors and begin building the facility before making a vendor selection.

"In our experience, it significantly extends the time frame needed to build these projects," said Cohen. "The open bid process can require us to design with a universal approach, so it becomes a facility that can accommodate a number of vendor systems."

Cohen said the open bid process can also ultimately be more costly than leading with a vendor in mind.

Next up for proton

Besides established markets, proton therapy professionals expect the treatment to continue to expand in more underserved parts of the world. Jessen, for one, is working with his team on a project in the Middle East, where religious requirements have impacted the center's design.

"Islamic architecture is impacted by the religious beliefs, where we have concerns about gender, sharing the same rooms, concerns about which direction is Mecca, and where do you place patients when lying on cots because their feet can't be showing," said Jessen. "The gender based one is significant because you wonder, does this mean we have to have two separate accelerators, two separate facilities? The answer in this particular case is no, but I see how that could be the case."

A center is being planned to open in Saudi Arabia in 2015, according to Proton Therapy Today. There is also talk of centers opening up in India as well as two in Russia, Courtney said.

"In India there's a huge need, so I think you're going to see some dramatic numbers there," said Courtney. "In general, the number of centers has really been escalating. We will have added more than 50 centers just in this decade, and with carbon ion therapy, we're only going to see more."