Proton treatment is not widely available. Most people who have received this type of radiation therapy since its introduction in the 1950s have been treated in research centers. The equipment required for proton-beam treatment is massive and expensive. Particle accelerators don't come cheap. A synchrotron, the machine that speeds up the protons before they enter the body, typically requires its own building and costs about $100 million. And the treatment itself can cost up to three times more than conventional radiation therapy. (It's considered a mainstream cancer treatment, though, so most insurance companies cover it.)
Currently, there are proton-therapy centers in several countries including Japan, the United Kingdom and the United States, but only one of those centers is located in a hospital. The others are all specialized treatment centers that only do proton therapy, and they have to pick and choose among prospective patients based on need. In general, children are top candidates, because X-ray radiation treatment can be so damaging to a body that's still growing; and children and adults with inoperable tumors in the brain or on the spinal cord are good candidates. More and more proton-therapy centers are springing up, though -- the United States is up to five as of March 2007. Most experts predict that as the technology continues to advance, costs and equipment size will decrease, making it easier for hospitals to start using the treatment on a much larger scale.
For more information on proton-beam therapy and related topics, check out the next page.