January 7, 2008

Accelerating Proton Therapy Usage
By Dan Harvey
For The Record
Vol. 20 No. 1 P. 24

Expensive and unwieldy, the cancer-fighting technology has not been widely employed outside large research facilities. However, there is now a concerted effort being made to bring proton therapy to the forefront of care.

Proton beam therapy—better known as proton therapy—is widely recognized as a valuable cancer treatment option, enabling clinicians to increase radiation dosage while reducing harmful side effects. Noninvasive and painless, it can be delivered in 15- to 30-minute sessions and doesn’t require an overnight hospital stay.

Unfortunately, widespread usage has been hindered by its high price. It can cost more than $100 million to purchase the equipment needed to generate and accelerate proton beams and construct a facility large enough to house the complex technology. Typically, a facility includes a cyclotron, enormous magnets, three or four treatment rooms, and three-story-tall gantries weighing more than 100 tons.

As a result, proton therapy has been confined to larger research facilities. However, the Proton Treatment Center at Loma Linda University Medical Center in California demonstrates that proton therapy could be successfully implemented in a hospital setting. “That was the first high-throughput clinical proton therapy facility,” says Stuart Klein, MHA, executive director of the University of Florida Proton Therapy Institute in Jacksonville.

Now, it’s anticipated that recent developments can increase proton therapy’s viability in more hospitals and cancer centers. These developments include innovative business models, as well as advancements that reduce the size of the technology, the necessary facilities, and, in turn, associated costs.

Proton Therapy Advantage
Proton therapy directs a highly focused beam at cancerous tumors with remarkable accuracy. As its name indicates, it attacks tumors with protons instead of photons, unlike other radiation therapy treatments. The proton’s mass allows radiation therapists to essentially stop the protons in the tumor where they release nearly all their energy, unlike photons, which pass through a tumor and out the other side of the patient. This provides a unique advantage: It arms clinicians with a deadly radiation beam that deposits most of its energy right where they want it, reducing damage to healthy tissue surrounding the targeted tumors.

As such, proton therapy, a Medicare-approved modality, is highly suited for treating tumors close to critical structures. Currently, it’s being used to treat cancers of the prostate, eye, brain, head and neck, spine, breast, and esophagus. Further, because proton therapy minimizes long-lasting tissue damage, it’s particularly useful in treating pediatric patients.

In addition to the proton therapy treatment centers in Florida and California, there are three others in the United States: the Northeast Proton Center at Massachusetts General Hospital in Boston (affiliated with Harvard Medical School), the University of Texas M. D. Anderson Cancer Center in Houston, and the Midwest Proton Radiotherapy Institute at Indiana University in Bloomington.

Addressing Costs
The Florida Proton Therapy Institute’s history illustrates the complexities involved with establishing a proton therapy facility and helps explain why only a handful of sites have been established.

The Florida facility was first envisioned in 1998, but construction didn’t begin until 2003. The first patient was treated in August 2006. “Obviously, it took a number of years to bring it to fruition, and much of that had to do with financing,” says Klein. “A proton therapy project is capital-intensive in terms of equipment purchase and facility construction, but costs also involve the high level of expertise required to get a project off of the ground, both on the clinical and physics side.”

Obviously, costs must be justified, which can be accomplished by the strongly worded communication of proton therapy’s substantial clinical benefits. “In some patients, there are simply no other treatment options,” Klein says. “Their cancers are inoperable, and they can’t be treated with traditional radiation therapy.”

Once justified, costs are generally handled through funding from public and/or private sectors. Klein reports that state funding was initially required for the construction of the Florida Proton Therapy Institute. “But most of the funding was raised through the sale of municipal bonds, as well as some direct financial involvement from the city of Jacksonville,” he adds.

But Klein points out that new avenues have become available to help address the cost issue. “Recently, for-profit ventures have been established that are bringing more projects forward around the country,” he says.

Turnkey Solution Provider
One such for-profit company is ProCure Treatment Centers, Inc., a Bloomington, Ind.-based solutions provider. Established in 2005 with a mission to increase the availability of proton therapy, ProCure provides a turnkey solution for the design, construction, operation, and maintenance of proton therapy facilities. In addition, it helps with financing and reduces costs by investing its own resources. “We not only arrange all of the financing, but we also put our own money into the project,” says Hadley Ford, the company’s CEO and director.

Of course, this involves a trade-off. “We have the majority ownership,” explains Ford. “But if a client is comfortable with a minority ownership position, we can get them off of the ground tomorrow.”

ProCure accomplishes this rapid project initiation through its turnkey solution, a standardized model that provides diagnostics, treatment planning, facility management, and imaging integration systems and software. “We oversee all of the construction, implementation, and equipment installation,” says Ford. “In this way, we take months off of the planning and commissioning time.”

ProCure’s solution reduces capital and operating costs. “Our optimized building design has a significantly smaller footprint than a typical proton therapy facility, and our equipment costs run 20% to 40% less because of our proprietary technology and our relationships with equipment providers,” says Ford.

ProCure reduces the footprint by decreasing the number of rotating gantries to a single unit. A standard ProCure facility includes the following:

• a 230- to 250-megaelectron volt, fixed-energy, isochronous cyclotron that provides a continuous proton beam;

• four treatment rooms (two dual inclined-beam rooms, one fixed horizontal-beam room, and one gantry treatment room); and

• a therapy control system that provides the interface to control and monitor equipment to deliver safe and effective treatment.

Treatment rooms feature advanced inclined-beam lines and robotic positioning equipment fully integrated with the oncology information system and the patient alignment software to ensure rapid and precise patient positioning, verification, and treatment for pinpoint accuracy, as well as safety and comfort.

ProCure was founded by John M. Cameron, PhD, a particle physics pioneer at Indiana University who played a major role in the creation of the Midwest Proton Radiotherapy Institute. Cameron and his team have been involved in the development of five of the seven proton therapy centers operating or under construction in the United States. ProCure is involved in a project in Oklahoma City, where it has partnered with local radiation oncologists and a healthcare system to build the state’s first proton therapy center scheduled to open in 2009. Also, in Illinois, the company is working with local radiation oncologists and the Central DuPage Hospital to establish that state’s first proton therapy center, set to debut in 2010.

The company recognizes the need for increased proton therapy availability. As it points out, 250,000 U.S. cancer patients could benefit from the therapy, but only 3,000 treatment slots are currently available in the country’s five proton therapy centers. The company is meeting its mission by developing a network of proton therapy centers across the United States. Essentially, the company identifies and forms partnerships with physician groups and hospitals in communities with need and leadership.

“As a proton therapy project is an exceptionally complex, expensive, and long lead-time project, community hospitals and doctor groups don’t have the wherewithal to enter into it by themselves,” says Ford. “Conversely, major academic centers such as M. D. Anderson have the resources, the expertise, the time, and patience to do it.”

Compact Technology
Along with innovative business approaches, new technological advancements should also make proton therapy more readily available and less expensive by reducing the size of the technological elements. This is evident in Seattle, where the Swedish Cancer Institute (SCI) is developing a proton therapy facility—the first in the Pacific Northwest—that will cost “only” $22 million to build, thanks to the implementation of a compact proton therapy system scaled for use in cancer centers.

Developed by Still River Systems of Littleton, Mass., the system—the investigational Clinatron 250—is designed to fit in a much smaller space via the application of a super-cooled, super-conducting, high-field magnet developed in collaboration with scientists at the Massachusetts Institute of Technology’s Plasma Science & Fusion Center. “By using such magnets, they’ve been able to reduce the size of the cyclotron and fit it onto a gantry,” says Albert B. Einstein, Jr, MD, SCI’s executive director. “Thus, the cyclotron actually rotates around the patient as it gives off the proton beam.”

In essence, it’s a single-vault, single-cyclotron, single-treatment room version of proton therapy, describes Einstein. “Therefore, it costs much less,” he adds.

Clinatron 250 implementation is designed to require less than 2,700 square feet compared with the 55,000 square feet usually required for previous generations of proton therapy. “Large proton therapy equipment basically consists of a cyclotron running at room temperature, which requires a large room, as well as four treatment vaults attached to the cyclotron room,” Einstein points out.

SCI felt it would be difficult to justify the costs of the traditional arrangement. “It’s difficult to determine if you’re going to have enough patients to generate a return on investment,” explains Einstein. “So, we looked at alternatives and decided to go with the Still River technology. We figured that, from a financial perspective, we could get enough patients to support that kind of facility.”

SCI is seeking local medical providers and other organizations interested in partnering to employ the technology. “While the system enables proton therapy in a smaller facility, it’s still not cheap. After all, you’re talking about $22 million. You need sufficient patient throughput to break even. We think the partnerships will help us identify the most appropriate patients,” says Einstein.

Still River Systems is working toward obtaining FDA marketing approval and hopes to open its first unit in the fall of 2008 at the Barnes-Jewish Hospital in St. Louis. The system will eventually include the cyclotron, the proton beam delivery system, a treatment couch with pendant control, a radiographic patient positioning system, proton beam treatment planning, and a link to a treatment record and verification system.

Proton therapy technology has been around for more than 50 years. But it has now quickly accelerated into an exciting time, thanks to increased financial options and new technology. Within the next 10 years, it should become a more widespread method for treating cancer patients.

— Dan Harvey is a freelance writer based in Wilmington, Del.

Proton Therapy Miniaturized
Potentially, proton therapy technology and costs can be further reduced if all goes well with a system design based on a small device called the dielectric wall accelerator (DWA), which essentially miniaturizes proton therapy.

The DWA, which is currently being built as a prototype at Lawrence Livermore National Laboratory in California, can accelerate protons to up to 100 million electron volts in just 1 meter. A 2-meter DWA could fit into a conventional radiation treatment room and potentially supply protons of sufficiently high energy to treat all tumors, including those buried deep in the body.

“Researchers at Livermore invented the technology for defense purposes,” explains Thomas Mackie, PhD, a professor at the University of Wisconsin and cofounder of TomoTherapy, the Madison, Wis.-based company that would exclusively license the technology from Livermore. “Originally, it was designed for accelerating electrons, but the researchers realized they could use it for making protons and potentially miniaturize the technology.”

The DWA is a hollow tube with walls comprised of an effective insulator. When air is removed to create a vacuum, the tube can withstand the high electric field gradations necessary to accelerate protons at high energies in short distances. However, Mackie points out that it’s still in the research stage and clinical trials are at least five years down the road. “They’ve yet to accelerate any protons, but detailed simulations indicate that it will work,” he reports.

For it to be viable, two hurdles must be overcome, Mackie says. “First, you need a high-gradient insulator of 100 mega volts per meter. Second, you have to create an electrical field that moves down the insulator.”

That’s accomplished through a series of blumleins firing in sequence, he explains. “A blumlein is a storage device, like a long linear capacitor, and when it’s switched on in a sequence, you get an electric field on the dielectric wall that starts accelerating protons. Further, you need to move that electric field down the wall at the same rate as the protons in order to keep ahead of the protons.”

Thus, the switching technology needs to be fast and accurate. To meet that need, Livermore is developing an optical switch fired with a laser, which enables more precise sequencing.

“If it works, it will allow you to have a linear accelerator that is only a couple of meters long and that can accelerate protons to the point where they would have sufficient energy for proton therapy,” says Mackie. “It will also allow you to put the accelerator right onto the beam line.”

In addition to its smaller size, a DWA-based proton therapy system would have another significant benefit: It could vary both proton energy and proton beam intensity, two variables that cannot be adjusted at the same time in existing proton-treatment facilities.

— DH