Brachytherapy Treatment for Prostate Cancer
Brachytherapy refers to radiation therapy that involves placing radioactive material directly into or adjacent to the tumor, rather than through external beams. Today, brachytherapy is a standard technique in the treatment of a large number of malignancies and often used in combination with EBRT. Brachytherapy treatments use radioactive materials such as cesium-137, iridium-192, palladium-103, or iodine-125. Radioactive sources that deliver radiation at a high dose rate such as iridium-192 are referred to as HDR (high dose radiation therapy). Through the use of brachytherapy, the radioactive source can be placed next to or directly into the tumor. Because the energy of the radioactive source is low, a high energy is delivered to the tumor, with nearby normal surrounding tissues receiving very little dose. Brachytherapy can be administered using a multitude of techniques- all dependent on the tumor being treated.
Prostate cancer is treated using iridium-192 as the radiation source. The treatment is achieved through the use of hollow needles placed through the skin between the scrotum and anus and into the prostate. These needles are attached to transfer tubes that deliver the iridium-192 from the source's housing unit into the prostate. The radioactive source does not stay in the patient; it retracts back into its housing unit after every treatment. The treatment process usually takes 5 to 15 minutes. Generally, about 4 brief treatments are given; 2 treatments per day (one in the morning and one in the afternoon) about a week apart. The hollow needles are removed from the patient after the afternoon treatment, each day.