Prostate brachytherapy is the implantation of radioactive “seeds” into the prostate. The seeds deliver a high dose of radiation to the tumor while sparing the surrounding non-cancerous tissues.
Physicians at Virginia Mason use an advanced technique known as real-time dosimetry prostate brachytherapy to precisely place radioactive seeds directly into the prostate with millimeter accuracy.
This system employs a computer system that can be used in the operating room and gives the physician the ability to precisely track the position of each seed as it is placed, ensuring proper radiation dose within the prostate. Equally important is its ability to help physicians avoid the placement of seeds near normal tissues such as the bladder, urethra and rectum, thus minimizing toxicity.
Patients generally undergo spinal anesthesia for this procedure, although general anesthesia also can be used. Needles are placed through the skin of the perineum (the space between the anus and scrotum) and into the prostate. An ultrasound probe in the rectum helps guide the needles into their proper position. The seeds are then placed into the prostate through each needle. As each needle is withdrawn, it leaves behind a row of seeds.
The Iodine-125 radioactive seeds have a half-life of 2 months. The Palladium-103 radioactive seeds have a half-life of 17 days. After about five half-lives, all radioactivity is gone. The amount of radioactivity that escapes the body is exceedingly small. As a safety precaution, however, we recommend that small children and pregnant women do not sit on or next to the patient for 2 months. Patients often experience temporary difficulty with urination after brachytherapy. Medications (Flomax®, Hytrin®, Cardura®) are provided to alleviate symptoms.
If you would like to learn more about brachytherapy at Virginia Mason, call our specialists at (206) 583-2282.
Patients may have some discomfort in the perineal area for a few days after the procedure. They also may develop some mild urinary obstructive symptoms (mainly frequency and urgency) for which they can be given medication. These symptoms could last four to six weeks. Lasting problems such as urinary incontinence or proctitis (inflammation of the rectum) are rare. Impotence can develop in patients, although there are medications that are often helpful in this situation.
Sexual Function After Radiation Therapy
Because radiation therapy is non-surgical, it does not cause immediate damage to erectile function. Erectile function can, however, be damaged by slow narrowing of the blood vessels responsible for erections. Radiation therapy can narrow these small vessels and thus lead to impotence. Co-existing conditions, such as diabetes, hypertension or high cholesterol, will likely exacerbate this process, while medications like Viagra®, Levitra® or Cialis® will be helpful. Data on the impact of radiation therapy on sexual function are scant but indicate that often men preserve erectile function right after radiation therapy. But, over the next one to three years, sexual function gradually deteriorates.