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It is widely acknowledged that proton beams have fundamentally superior qualities for radiation therapy than x-rays and that, if properly controlled, hold the promise of superior treatments. The high cost of proton therapy equipment facilities, however, is the reason why only a fraction of one percent of all cancer patients are treated with proton therapy.

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3 June 2011

CPAC Completes Construction of Pre-Commercial Prototype Dielectric Wall Accelerator

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Livermore, Calif. – February 7, 2011 – Compact Particle Acceleration Corporation (CPAC) announced today that it has demonstrated proton acceleration at its facility in Livermore, Calif., using its revolutionary compact particle accelerator technology. With achievement of this milestone, CPAC further enables the development of the world’s most precise and compact accelerator for use in proton therapy systems, which has the potential to advance the boundaries of cancer care.

Livermore, Calif. – June 3, 2011 – Compact Particle Acceleration Corporation (CPAC) announced today that it has completed the construction of the first Dielectric Wall Accelerator (DWA) pre-commercial prototype system. With the achievement of this milestone, CPAC has taken another step towards the development of the first commercial DWA. It will be the world’s most precise and compact accelerator for use in proton therapy systems, and has the potential to advance the boundaries of cancer care.

Radiation therapy has been used in the treatment of cancer for many years, but most of the treatments have been done with X-rays, which are successful in destroying many tumors but can also damage healthy tissue around the tumor. In contrast, protons deposit their energy near the end of their path. As a result, the beam energy can be precisely delivered to the tumor volume without seriously harming surrounding tissues or critical organs.

Proton therapy is a particularly compelling treatment for pediatric patients and some hard-to-treat cancers, such as those requiring high doses of radiation or tumors that are close to sensitive structures. But because of the cost and size of proton therapy systems, this type of therapy has been limited to approximately 30 centers around the world. With its pioneering work on developing a compact proton accelerator, CPAC aims to make this treatment accessible to every cancer center.

CPAC’s accelerator is a highly compact system based on the DWA technology developed by Lawrence Livermore National Laboratory (LLNL). The prototype system was built exclusively with commercially available components of the highest quality and reliability and has been in operation for several months at CPAC’s state-of-the-art facility in Livermore, Calif.

“This is a significant step forward toward commercializing the DWA for proton therapy,” said George Caporaso, Ph.D., LLNL’s lead investigator in the collaboration with CPAC. “It’s the first integrated proton accelerator system consisting of all the essential elements working together: a commercial proton source and injector, and a DWA section with a high gradient insulating beam tube, solid dielectric Blumleins, high quality photoconductive switches and a laser and a fiber optic distribution system.”

Dr. Jose Alonso, formerly of Lawrence Berkeley Laboratory conducted an independent assessment of the DWA technology and its potential for future proton therapy applications at the request of the European Society of Therapeutic Radiation and Oncology (ESTRO) and presented his assessment at the recent ESTRO Anniversary Congress in London. “CPAC has assembled a very strong team, that includes LLNL, with expertise in materials science, beam dynamics, induction linacs and systems development,” Dr. Alonso said. “CPAC’s parent corporation has much experience in the medical device field, as well, and understands the issues and efforts required to develop effective systems. CPAC has developed and is embarking on a realistic plan. I believe CPAC will be successful in developing a commercial system. The technical risk is low and their commitment to success is very clear.”

“This prototype system demonstrates the key differentiating advantages of the DWA,” said Anthony Zografos, Ph.D., CPAC’s vice president and general manager. “Our injection system has demonstrated extremely good beam stability and intensity control and our Dielectric Wall Accelerator demonstrates excellent repeatability. We have demonstrated the capability of adjusting and controlling on a shot-to-shot basis beam energy and dose. In the coming months we will also implement a shot-to-shot beam spot size adjustment and control capability.”

According to Zografos, the acceleration gradients that are obtainable with this system are approximately 20 Million electron Volts per meter (MeV/m), which far exceeds accelerating gradients for existing medical accelerator devices. CPAC has filed for patent protection for designs that will allow it to reach 40 MeV/m in the next nine months and in excess of 50 MeV/m in the near future. The company plans to ship a 150 MeV clinical system that will be approximately 4 meters in length in 2013.

About Compact Particle Acceleration Corporation (CPAC)

Compact Particle Acceleration Corporation (CPAC) is an affiliated subsidiary of TomoTherapy Incorporated. It is developing and commercializing a highly compact proton therapy system powered by the dielectric-wall accelerator (DWA), a revolutionary proton accelerator that has a substantially smaller structure and greater flexibility than other systems. This breakthrough in size and power is made possible by three key inventions: a high-gradient insulator that allows for substantial increases in voltage-holding capacity, and optical switches that can control high-power loads at ultra high speeds in a very compact size, both licensed from Lawrence Livermore National Laboratory (LLNL); and dielectric materials that are embedded with nanoparticles to facilitate the transmission and isolation of extremely high voltages. CPAC believes these platform technologies that combine extreme switching speed and power handling capability will enable the creation of a proton therapy system that accessible to all cancer centers and their patients. For more information, visit