Interstitial Radiation Placement
- What is Interstitial Radiation Placement?
- Effects of Interstitial Radiation Placement
- Candidates for Interstitial Radiation Placement
- Your Consultation
- The Interstitial Radiation Placement Procedure
What is Interstitial Radiation Placement?
Interstitial radiation therapy: Radiation treatment given by placing radioactive material directly into the target, often a tumor. Interstitial radiation therapy is also called seed implantation or brachytherapy.
Effects of Interstitial Radiation Placement
Radiation therapy uses very high-energy rays to kill prostate cancer cells, shrink tumors or to prevent cancer cells from dividing and spreading. In early stages of prostate cancer, radiation therapy may cure the disease.
For most types of implants, you will need to be in the hospital and have general or local anesthesia while the doctor places the container for the radioactive material in your body. In many hospitals, the radioactive material is placed in the container after you return to your room so that others are not exposed to radiation.
To get the radiation as close as possible to the cancer, doctors may use implants of radioactive material sealed in wires, seeds, capsules, or needles. The type of implant and the method of placing it depend on the size and location of the cancer. Implants may be put right into the tumor, in special applicators inside a body cavity, on the surface of a tumor, or in the area from which the tumor has been taken.
The Interstitial Radiation Placement Procedure
Permanent or Low-dose brachytherapy – Two types of brachytherapy are available: one is temporary and the other permanent. Permanent brachytherapy involves low-dose radioactive seeds, which may be made of iodine, pallidium, cesium or iridium. While the patient is under spinal or general anesthesia, the seeds are inserted into the prostate through the perineum, the area between the scrotum and the anus. The seeds remain in place permanently and give off low doses of radiation until they are no longer radioactive. Should there be a risk that the cancer has spread outside the prostate, external beam radiation may also be prescribed.
Temporary or High-dose brachytherapy – For more aggressive prostate cancer or cancer that has likely spread outside the prostate, temporary brachytherapy is often used. This is a newer type of brachytherapy that uses high-dose pellets. The pellets are contained inside catheters that are inserted through the perineum into the prostate. The pellets stay inside the prostate for only a few minutes and then are removed. Two or three applications are needed, separated by about six hours. After the last treatment is complete, the catheters are removed.
The seeds give off radiation continuously for weeks, months or up to a year and can remain safely in place for the rest of a person’s life. The amount of time the seeds remain radioactive depends on the dose and what type of radioactive material used.
Radiation therapy can cause a variety of side effects. Most of these are minor and disappear after therapy stops. These side effects include tiredness, skin reactions in the treated areas, frequent and uncomfortable urination, and rectal irritation or bleeding. There is a chance of some permanent side effects. Bowel function may not completely return to normal even after treatment is complete. Development of impotence may occur up to 2 years later in a small percentage of patients.
External beam therapy is inconvenient in that it requires several weeks of brief daily visits to the radiation department.
What is brachytherapy?
Internal radiation implants containing radioactive material are usually placed during surgery or using a needle. Brachytherapy may include placing implants inside a body cavity, such as the vagina (a technique called intracavitary radiation) or by putting radioactive material directly into body tissue (called interstitial radiation). In both instances placement is usually done once, though it may be done up to several times, and is temporary, lasting from a few minutes to several days. In some cases, such as prostate cancer, interstitial radiation may be permanent, though the radioactivity of the radioactive material diminishes over time.
What is the purpose of this procedure?
By using brachytherapy, radiation is placed as close as possible to the cancerous cells, which receive the prescribed dose while surrounding normal tissue are relatively spared
What happens during this procedure?
Radiation is given off by tiny seeds, which are placed directly into the prostate. Brachytherapy may be used by itself or in combination with external radiation therapy. The seeds are too small to be felt by the patient and do not cause any discomfort. They are inserted into the prostate during a day surgery procedure after the patient is sedated using a local or general anesthetic. Specialized equipment like CT scans, ultrasound, and MRI help the surgeon and validation oncologist to place the seeds accurately.
Who is not a good candidate for this procedure?
Because it is designed to target the cancerous cells and not harm the surrounding area, brachytherapy is rarely recommended when the cancer has spread beyond the prostate gland