Filed at 7:06 p.m. ET
SAN FRANCISCO (Reuters Health) - Using computers to help plan brachytherapy--the placement of radioactive seeds near a prostate tumor--can reduce damage to surrounding healthy tissue and improve control of the cancer, according to preliminary findings presented at the annual meeting of the American Association for the Advancement of Science.
Currently, brachytherapy planning is performed by a medical physicist, who may need 4 to 8 hours to map out where the 50 to 200 rice-sized seeds should be placed in the prostate, explained Dr. Eva K. Lee of the Georgia Institute of Technology and Emory University School of Medicine in Atlanta.
``They work very hard for each special patient,'' Lee said.plan in 5 to 15 minutes. This allows treatment planning to occur immediately before the procedure, using accurate imaging data regarding the shape of the patient's prostate, instead of data that may be several weeks old. Because the prostate is cancerous, its shape tends to change as the disease progresses, Lee noted. And due to scheduling constraints it may take a few weeks before the patient can undergo brachytherapy.
Imaging studies in patients show that the computerized treatment planning system causes many more seeds to be placed in the prostate instead of in surrounding tissue, Lee said. The planning also enables the radiation oncologist to avoid placing seeds in the urethra and rectum, errors that can cause ``hot spots'' that may lead to incontinence, a common side effect of brachytherapy.
Lee based her presentation on results in 10 patients. Clinical trials of her system are ongoing at Memorial Sloan-Kettering Cancer Center in New York City.