Proton Beam Brachytherapy
Proton beam therapy is a form of external beam radiation therapy. In many ways proton therapy is much like X-ray treatment. Using powerful magnets and other machines, protons, which are small particles, are accelerated to near the speed of light and aimed at cancerous tissues. The nature of these proton particles allows physicians to aim them more precisely, causing the radiation to dissipate soon after reaching the cancerous cells. This precision, however, has the downside of requiring treatments to take twenty to thirty minutes, which is longer than standard radiation therapy. Like IMRT, proton beam therapy also requires approximately 8 weeks of daily treatments.
Results evaluating the efficacy of proton beam therapy have only recently been reported. Only several thousand prostate cancer patients have been treated with this therapy. Results have been satisfactory; however, they have not shown to be superior to IMRT or brachytherapy for the treatment of prostate cancer. Furthermore, there are no urethral sparing techniques yet developed for proton beam therapy, which can potentially mean more urinary side effects. Finally, when compared to proton beam therapy, brachytherapy has a lower incidence of injury to the bladder and rectum, while still being capable of delivering the ultimate dose of radiation.