Radiation Therapy

Medically reviewed by Christina Chun, MPH on November 28, 2017Written by Brian Krans

What is radiation therapy?

Radiation therapy is a cancer treatment that uses concentrated radiation beams to kill cancer cells.

The most common type of radiation therapy is external beam radiation. This type involves a machine that directs high-energy beams of radiation at cancer cells. The machine allows radiation to be targeted at specific sites, which is why doctors use external beam radiation for nearly all types of cancer.

According to the , about half of all people with cancer will receive radiation therapy.

Why radiation therapy is done

Radiation therapy is an important tool for treating cancer and is often used in conjunction with other therapies, such as chemotherapy or tumor removal surgery.

The main goals of radiation therapy are to shrink tumors and kill cancer cells. While the therapy also will likely injure healthy cells, the damage isn’t permanent. Your normal, noncancerous cells have the ability to recover from radiation therapy. To minimize the effect radiation has on the body, the radiation is targeted only to specific points in your body.

Radiation therapy can be used during different stages of cancer treatment and for different outcomes. Radiation therapy can be used:

  • to alleviate symptoms in advanced, late-stage cancer
  • as the primary treatment for cancer
  • in conjunction with other cancer treatments
  • to shrink a tumor before surgery
  • to kill any remaining cancer cells after surgery

Risks of radiation therapy

No matter what type of radiation is used, fatigue and hair loss are common side effects. Hair loss only happens on the part of your body being treated.

Radiation also affects skin cells. Skin changes can include:

Other side effects of radiation depend on the area being treated, and can include:

According to the , the majority of these side effects go away within two months after treatment is complete. In rare cases, side effects can linger or even appear six or more months after treatment has finished. Late side effects can include:

These can sometimes appear years after therapy. Talk to your doctor about any concerns you have regarding side effects.

How to prepare for radiation therapy

The first step in radiation treatment is determining that it’s the right form of treatment for you. Your doctor will also determine dosage amounts and the frequency of radiation best suited for your cancer type and stage. Sometimes your doctor may decide that radiation therapy is best suited for use at a later stage, so you may receive other cancer treatments first.

Preparation for radiation therapy involves a radiation simulation. It typically includes the steps seen below.

Radiation simulation

  1. You’ll lie on the same type of table that will be used for your treatment.
  2. Lying still at the proper angle is very important for treatment success, so your healthcare team may use cushions and restraints to position you at the best angle for treatment.
  3. You will then undergo CT scans or X-rays to determine the full extent of your cancer and where the radiation should be focused.
  4. After determining the best location for radiation treatment, your treatment team will then mark the area with a very small tattoo. This tattoo is usually the size of a freckle. In certain cases, a permanent tattoo is not needed.
  5. You’re now ready to begin radiation therapy.

How radiation therapy is performed

Radiation therapy typically takes five days a week for 1 to 10 weeks. The total number of treatments depends on the size and type of cancer. Each session usually takes about 10 to 30 minutes. Often, the individual is given each weekend off from therapy, which helps with the restoration of normal cells.

At each session, you’ll lie on the treatment table, and your team will position you and apply the same types of cushions and restraints used during your initial radiation simulation. Protective covering or shields may also be positioned on or around you to protect other body parts from unnecessary radiation.

Radiation therapy involves the use of a linear accelerator machine, which directs radiation at the appropriate spot. The machine may move around the table in order to direct the radiation at the appropriate angles. The machine may also make a buzzing sound, which is perfectly normal.

You should feel no pain during this test. You’ll also be able to communicate with your team via the room’s intercom, if necessary. Your doctors will be nearby in an adjacent room, monitoring the test.

Following up after radiation therapy

During the weeks of treatment, your healthcare provider will closely monitor your treatment schedule and dosing, and your general health.

You’ll undergo several imaging scans and tests during radiation so your doctors can observe how well you’re responding to treatment. These scans and tests can also tell them if any changes need to be made to your treatment.

If you experience side effects from radiation — even if they’re expected — tell your healthcare provider at your next appointment. Sometimes, even small changes can make a big difference in lessening side effects. At the very least, you may be given advice or a medication to help ease the discomfort.

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