近距離放射治療

Brachytherapy (brak-e-THER-uh-pee) is a procedure used to treat certain types of cancer and other conditions. It involves placing radioactive material inside the body. This is sometimes called internal radiation.

Another type of radiation, called external radiation, is more common than brachytherapy. During external radiation, a machine moves around you and directs beams of radiation to specific points on the body.

Brachytherapy allows your health care team to use higher doses of radiation than would be possible with external radiation. This is because brachytherapy delivers radiation directly to the treatment area. This lowers the risk of hurting healthy tissue that is nearby.

The overall treatment time can be shorter with brachytherapy because a larger dose of radiation can be safely delivered at one time.

Brachytherapy is used to treat many types of cancer. Some examples include:

• Brain cancer
• Breast cancer
• 子宮頸癌
• Endometrial cancer
• Esophageal cancer
• Eye cancer
• Gallbladder cancer
• Head and neck cancer
• Lung cancer
• 攝護腺癌
• Rectal cancer
• Skin cancer
• Soft tissue sarcomas
• Vaginal cancer

Brachytherapy is most often used to treat cancer. Sometimes it’s used to treat other conditions, such as heart problems, in certain situations.

When it’s used to treat cancer, brachytherapy can be used alone or with other cancer treatments. For example, brachytherapy is sometimes used after surgery. With this approach, the radiation is used to destroy any cancer cells that may remain. Brachytherapy also can be used with external radiation.

Side effects of brachytherapy are specific to the area being treated. Because brachytherapy focuses radiation in a small treatment area, only that area is affected.

You might have tenderness and swelling in the treatment area. Ask your health care provider what other side effects to expect.

Before you begin brachytherapy, you may meet with a doctor who specializes in treating cancer with radiation. This doctor is called a radiation oncologist.

You also may have scans done to help plan your treatment. These might include X-rays, 核磁共振成像 或者 CT scans.

Brachytherapy treatment involves putting radioactive material into the body near the cancer.

How and where the radioactive material is placed depends on many factors. This includes the location and extent of the cancer, your overall health and your treatment goals.

Placement may be inside a body cavity or in body tissue:

• Radiation placed inside a body cavity. This is called intracavity brachytherapy. During this treatment, a device containing radioactive material is placed in a body opening. For example, it might be placed in the windpipe or the vagina. The device may be a tube or cylinder made to fit the specific body opening.

  Your radiation therapy team may place the brachytherapy device by hand or use a computerized machine to help place the device.

  Imaging tests may be used to make sure the device is placed in the most effective location. This could be with CT scans or ultrasound images.

• Radiation inserted into body tissue. This is called interstitial brachytherapy. Devices containing radioactive material are placed within body tissue. For example, the devices might be put into the breast or the prostate.

  Devices used for interstitial brachytherapy include wires, balloons, needles and tiny seeds the size of grains of rice.

  A number of techniques are used for inserting the brachytherapy devices into body tissue.

  Your radiation therapy team may use needles or special applicators. These long, hollow tubes are loaded with the brachytherapy devices, such as seeds. The tubes are inserted into the tissue and the seeds are released.

  Sometimes narrow tubes, called catheters, are used. The tubes might be placed during surgery. Later they can be filled with radioactive material during brachytherapy treatment.

  CT scans, ultrasound or other imaging tests may help guide the devices into place. The images help make sure that the treatment is in the right spot.

During brachytherapy

What you experience during brachytherapy depends on your specific treatment.

Radiation can be given in a brief treatment session, or it can be placed in the body permanently.

• Temporary brachytherapy. This is sometimes called high-dose-rate brachytherapy. It’s often done in short sessions.

  The radioactive material might be in your body for a short amount of time. This can range from a few minutes to about 20 minutes. You might have one or two sessions a day over a number of days.

  During high-dose-rate brachytherapy, you lie in a comfortable position. Depending on the treatment, you may receive anesthesia. The radiation therapy team puts the radiation device into place. This may be a simple tube or tubes placed inside a body cavity or small needles inserted into the cancer.

  The radioactive material is inserted into the brachytherapy device with the help of a machine.

  The radiation therapy team leaves the room during the treatment session. The team members observe from a nearby room where they can see and hear you.

  You may feel some discomfort during brachytherapy. If you feel uncomfortable or have any concerns, tell your care team.

  Once the radioactive material is removed from your body, you won’t give off radiation or be radioactive. You aren’t a danger to other people, and you can go on with your usual activities.

• Permanent brachytherapy. Sometimes radioactive material is placed in your body permanently. This is a common treatment for prostate cancer.

  The radioactive material is typically placed by hand. An imaging test, such as ultrasound or CT, might be used to make sure the material is in the right place. You are under anesthesia during the procedure. You shouldn’t feel any discomfort once the radioactive material is in place.

  Your body will emit low doses of radiation from the area being treated at first. Usually the risk to others is low.

  You might need to limit how much time you spend around children and anyone who is pregnant. The amount of radiation in your body will get lower over time. These limits will end.

Your health care provider may recommend scans or physical exams after brachytherapy. They can help show whether treatment was successful. What types of scans and exams you have depends on the type and location of your cancer.