Proton therapy is a type of stereotactic radiosurgery that uses proton beams instead of X-rays. In proton therapy, a beam of protons is used to blast diseased tissue precisely. It extracts positively charged protons from hydrogen gas and accelerates them through a cyclotron, or particle accelerator, up to nearly two-thirds the speed of light. The protons are guided to the tumor site by powerful magnetic and electrical fields, and carry just enough charge to reach a precise point in the tumor.
Conventional radiation therapy uses X-ray, or photon, beams. Photon beams enter the body, depositing significant energy in healthy tissue before and after they pass through the tumor. The photons’ lack of charge and mass means most of their energy is deposited in normal tissues near the body’s surface, as well as areas of the body beyond the site of the cancer.
Both proton therapy and traditional radiation treat tumors in the same way — by either killing cancer cells or inhibiting their growth. The most significant difference between the two is that proton beams travel to a specific depth, stop at the tumor, match its shape and volume or depth, and deposit the bulk of their cancer-fighting energy right at the tumor. This provides a proportionately higher dose in the tumor, and relatively less in surrounding normal tissues resulting in fewer treatments and less long-term side effects.
Proton beam therapy is used to treat cancers of the prostate, lung, head and neck, liver, esophagus and brain, as well as for the treatment of lymphoma, pediatric cancers and other rare tumors.
HIGH FACILITY COST
While proton therapy has been used clinically for more than two decades, the high cost of the technology has limited access to this treatment. Until recently, there were approximately a dozen proton therapy centers operating in the United States. The cost of building a proton therapy center can exceed $200 million and existing facilities occupy a significant amount of square footage with multiple treatment rooms to justify the cost of a 200- to 250-ton cyclotron and the massive infrastructure required for operation.
COMPACT SYSTEMS
Manufacturers are now developing more compact single treatment room systems and cost-effective models. As the price of the technology has dropped, more hospitals are able to offer this treatment — accelerating the “arms race” among cancer centers. The explosive sales growth is largely due to the introduction and proliferation of compact proton therapy systems. This has allowed the price of constructing a new center to drop from nearly a quarter of a billion dollars to around $25 million.
Mevion Medical Systems brought the first compact proton therapy system to market in 2012. At the center of the compact system is a superconducting synchrocyclotron which is significantly smaller than the traditional linear accelerator radiation source. The modular system is designed as a single-room solution, but can be adapted into a multi-room configuration.
Varian entered into the compact proton therapy market in 2014 by releasing a smaller version of its original ProBeam system. The ProBeam Compact offers many of the same benefits of its predecessor, but its 250 MeV cyclotron is more space-efficient than traditional radiation therapy linear accelerators.
IBA (Ion Beam Applications S.A.) introduced the Proteus One compact proton therapy system in 2014. Proteus One is also a single-room system offering several different delivery methods, including intensity-modulated proton therapy (IMPT) and image-guided proton therapy.
RECENT GROWTH
The global proton therapy market reached the billion-dollar mark for sales in 2015 which was more than double the previous year’s total. This boom was evidenced by new proton therapy centers springing up all over the world, including 11 just in the past 12 months — eight in the United States and three abroad in Hong Kong, Belgium, and the Netherlands. The new centers represent numerous vendors, and systems both large and small, underscoring the continuing evolution and spread of the technology.
Source: “Proton Therapy Becomes Billion-Dollar Industry” by Jeff Zagoudis, September 07, 2016. [Retrieved online at www.itnonline.com]