Prostate cancer continues to be the second most common cancer in North American men, with an estimated 250,000 new cases per year.
Brachytherapy entails permanent implantation of radioactive isotope capsules (a.k.a. seeds) of the size of a rice grain into the prostate to kill cancer with radiation from inside out.
The efficacy of brachytherapy hinges on precise placement of the implanted seeds, however, tissue motion and deformation, bending of the implant needle, implant error, and above all tissue swelling cause deviations from the optimum. Incorrect seed placement often causes insufficient dose to the cancer and/or inadvertent radiation of adjacent healthy tissue. The former causes failure of treatment, while the latter results in adverse side effects like rectal ulceration, impotence, and urinary incontinence.
Brachytherapy, like surgical removal of the prostate and external beam radiation therapy, has emerged as a definitive treatment option for early stage prostate cancer which represents the majority of patients diagnosed. It is performed for about 55,000 patients in North America every year, with an excellent disease-free survival.