Radiation Therapy For Cancer Treatment

Radiation therapy for cancer treatment:

Radiation therapy (also called radiation oncology) uses special kinds of energy waves or particles to fight cancer. Like surgery, radiation therapy is used in several ways depending on the type and location of the cancer. Certain levels of radiation work to destroy cancer cells or prevent cells from growing or reproducing. This treatment may provide a cure for cancer, control the disease, or help relieve its symptoms.

At Rush University Medical Center, we have specific protocols for radiation therapy, typically beginning with these procedures:

• simulation process
  After a physical examination and a review of your medical history, your treatment team "maps" out the position you will be in for each treatment and the exact location on your body (referred to as treatment field or port) where the radiation will be given (the simulation process). Sometimes, the area on your body that requires treatment will be marked to make sure radiation is given properly. The treatment team may also make molds, headrests, or other devices that help to position you during your treatment. Imaging studies may also be performed during the simulation process to help plan how to direct the radiation during your treatments. 
  
  
• treatment plan
  Once the simulation process is completed, the radiation oncologist will determine your treatment plan, including the type of machine to use, the amount of radiation that is needed, and the number of treatments that will be given. When appropriate, radiation may be used in conjunction with chemotherapy.

What are the different types of radiation therapy?

Radiation therapy is given through different methods, depending on the type of cancer, the location of the cancer, and the patient''s health. Sometimes, radiation therapy is used in combination with other treatments. The following are some of the different types of radiation therapy with brief explanations of their goals: 

• external radiation (external beam therapy)
  With external radiation (external beam therapy), radiation is administered by a large machine that points the energy waves directly at the tumor. The radiation therapist controls the machine. Since radiation is used to kill cancer cells, special shields may be made to protect the tissue surrounding the treatment area. Radiation treatments are painless and usually last a few minutes.
  
  
• internal radiation (brachytherapy, implant radiation)
  With internal radiation (brachytherapy, implant radiation), a high dose of radiation is given inside the body as close to the cancer as possible. The radiation treatment may be swallowed, injected, or implanted directly into the tumor. Some of the radioactive implants are called “seeds” or “capsules”. Internal radiation involves administering a higher dose of radiation in a shorter time span when compared with external radiation. Some internal radiation treatments stay in the body temporarily; other internal treatments stay in the body permanently, although the radioactive substance loses its radiation within a short period of time. In some cases, both internal and external radiation therapies are used.

Promising new therapies involving radiation therapy:

Many new radiation techniques are being used and studied to find more effective treatments for cancer. Some of the more promising therapies are described below.

• intensity modulated radiation therapy (IMRT)
  IMRT is a new technology that allows physicians to modulate the beam or to vary the intensity of the beam according to the size and shape of the tumor. This allows physicians to more accurately target the tumor while sparing normal tissues from the side effects of radiation. This technology is available at Rush.
  
  
• radiation and chemotherapy in combination
  Depending upon the particular type of cancer, physicians may choose to combine radiation with chemotherapy. Radiation may help to shrink tumors before surgery, for example, and chemotherapy may be used afterward to kill cancer cells not removed by surgery. Research is being conducted in this area.
  
  
• endovascular brachytherapy
  The use of interventional procedures such as angioplasty, stents, and other procedures has increased greatly in the past 20 years. Angioplasty and stents are used to open blocked areas in blood vessels. Unfortunately, newly opened areas in blood vessels may close after an angioplasty or stent procedure. However, research studies have shown that the use of radiation at the site of angioplasty or stent decreases the chance of vessel closure following these procedures. Endovascular brachytherapy continues to be studied at this time.
  
  
• stereotactic radiation
  This is an important new development in the treatment of brain cancer. Stereotactic radiation is the use of a single high dose of radiation sent into cancerous tissue with very narrow beams of radiation. This is a precise technique that is painless. An example of this technique is called the “gamma knife."
  
  
• three-dimensional (3D) conformal radiation therapy
  Protocols and techniques for three-dimensional conformal radiation therapy are being developed. This type of therapy may help the cancer care team visualize and treat tumors in a more precise way than ever before.
  
  
• radioimmunotherapy
  This type of radiation therapy involves using antibodies "tagged" with a special substance. These tagged antibodies recognize tumor cells and bind with them. By doing so, the antibodies bring cancer medication in contact with the tumor. Radioimmunotherapy may be helpful in treating cancer that has spread to other parts of the body.

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