TomoTherapy (Madison, Wisconsin) reported its participation in a new venture, Compact Particle Acceleration Corp. (CPAC), to develop a compact proton therapy system for the treatment of cancer. The company said the system would feature a dielectric-wall accelerator (DWA).

CPAC conducted the initial closing of phase I of the investment and said it anticipates completing phase I with one or more additional closings over the next several months. Investors will include TomoTherapy, private investors and potential customers.

The company said it expects to raise about $45 million in three phases, linked to key technological milestones.

According to TomoTherapy, the DWA technology, which resulted from defense-related research at Lawrence Livermore National Laboratory (LLNL; Livermore, California), has the potential to bring fixed and rotational intensity-modulated proton therapy to treat cancer into the medical mainstream.

It is distinct from current particle accelerator technology in that it is expected to achieve energies of 200 megavolts within a relatively compact structure that fits in a standard therapy treatment room as compared to other technologies that require significantly more space and weight-bearing capacity, the company said.

DWA technology will form the basis of a compact, high-gradient particle accelerator that is anticipated to be used in medical, security and defense applications, TomoTherapy said.

"We believe, as do the investors who have committed funding to this project, that compact proton therapy systems are the future of particle therapy," said Shawn Guse, VP, secretary and general counsel of TomoTherapy and CEO of CPAC. "The collaboration of TomoTherapy, CPAC and LLNL strengthens our commitment to deliver on the promise of this technology, and increases our capacity to move proton therapy to market more quickly."

Heavier particles such as protons will stop at a given depth that is related directly to the amount of energy they have so they don't deposit nearly as much energy on the way in, Guse told Medical Device Daily.

"Protons hold the promise of better radiotherapy treatment because you can get more radiation to the tumor and less radiation to the healthier tissue," Guse said.

But conventional proton therapy requires heavy equipment weighing into the hundreds of tons for a facility cost somewhere in the range of $100 million to $160 million, Guse said.

"It takes a tremendous amount of energy to get a heavy particle up to a speed to have a sufficient amount of energy to put it into a patient to have a clinical output that you want," Guse said.

Conventional radiotherapy facilities rely on large magnets to move the energy particle in an ellipse, rather than a straight line, until it has enough energy that it can be shot out.

"What we're trying to do at its simplest is to accelerate a particle in a straight line so you don't have to bend it. You don't need those big bending magnets and it can hopefully fit within a conventional therapy-size wall," Guse said.

The compact particle therapy system, if successful, would cost about $20 million, significantly less than conventional radiotherapy facilities.

"The key difference is we are adding much more energy to the particle in a smaller space than cyclotrons and synchrotons," Guse said. "[W]e're looking to add over 100 megavolts per meter to that particle, which is why we do it in a shorter distance and, hopefully, in a straight line."

TomoTherapy said it would contribute intellectual property to CPAC in exchange for its interest in the company. It will co-develop the compact proton therapy system with CPAC and has the option to acquire the medical applications of the DWA from CPAC in the future. CPAC will also continue to collaborate with LLNL to optimize the DWA for particle therapy and other applications.

CPAC also will work with other commercial partners to develop the DWA for non-medical applications.

Guse said TomoTherapy decided to go the new-venture route, rather than develop the technology in-house, to get it on the market sooner. He said conventional facilities are so large that they take at least three to four years to put in place and TomoTherapy realized it could accelerate the project and be able to offer an alternative, low-cost compact proton therapy system in the same amount of time it would take a hospital to put a conventional radiotherapy facility in place.

Guse told MDD that CPAC hopes to have its first commercial system in place sometime in 2012 an "extremely aggressive timeline," he acknowledged, but one the company believes is doable.

Another anticipated benefit to the DWA technology CPAC is developing, Guse said, is that it will expose patients and facility employees to a reduced amount of unwanted radiation than conventional proton therapy systems.

"Not only is the technology we're promoting better, it's more responsible," he said.

"The formation of CPAC will accelerate the development of the DWA," said Fred Robertson, TomoTherapy's CEO. "The new venture is also expected to reduce risk to the company, as it will focus DWA development for applications beyond medical applications and the investors funding this work will pool their resources with TomoTherapy to increase the speed and likelihood of success."

TomoTherapy sells the Hi-Art treatment system, a radiation therapy system for the treatment of a wide variety of cancers. According to the company, the Hi-Art system combines integrated CT imaging with conformal radiation therapy to deliver radiation treatments with speed and precision while reducing radiation exposure to surrounding healthy tissue.