A form of radiation therapy involving the use of radioactive seed implants. This is also referred to as internal radiation therapy, or Brachytherapy. For the treatment of prostate cancer we can implant radioactive iodine-225 seeds into the prostate gland. This is done with the help of an ultrasound for guidance and the number and placement are determined by a customized computer-generated treatment plan for each patient. It is common for 40-100 seeds to be implanted.