How are permanent and high-dose-rate brachytherapies for prostate cancer performed?

Permanent brachytherapy
Most radiation oncologists performing permanent brachytherapy for prostate cancer use three-dimensional treatment planning and a template guide to precisely implant radioactive seeds in the prostate and to ensure that radiation is evenly distributed throughout the prostate. Ultrasound, delivered through an ultrasound probe, or transducer, allows them to view the prostate throughout the procedure.

After the patient receives spinal anesthesia, the doctor places an ultrasound probe in the patient's rectum and a catheter in the bladder. Viewing a computerized map of the prostate, the doctor guides the placement of the seeds, using a template and a needle to insert them through the perineum. Doctors leave the seeds, which are smaller than grains of rice, in place permanently. Over time, the seeds emit less and less radiation until they become inert, which takes three months to a year, depending on the type of seeds. The radiation does not affect other people.

High-dose-rate brachytherapy
As with permanent brachytherapy for prostate cancer, the radioactive material in high-dose-rate brachytherapy is inserted into the prostate. But given the high intensity of the material, it cannot be left in the body for long. After a set period of time, a remote-controlled machine pulls the material out. The process is then repeated several times in one day or over multiple days. Catheters remain in place until after the final treatment. Most radiation facilities do not offer high-dose-rate brachytherapy because other treatments are less complicated and usually just as effective.