Radiation Therapy: The Basics

Author: Courtney Misher, MPH, BS R.T.(T)
Last Reviewed: October 26, 2022

Radiation therapy is the use of high doses of radiation to damage the DNA of cells. This kills the cancer cells or stops them from reproducing and can also damage healthy cells. Radiation therapy is used to treat many types of cancer. Radiation can be used alone or with other treatments like surgery or chemotherapy. Radiation can be used:

  • For primary cancer treatment.
  • For pain management to lessen symptoms that your cancer is causing (palliative treatment).
  • Before other treatments to shrink a large tumor.
  • After other treatments to kill any cancer cells that are left.

How is radiation given?

Radiation is given in three ways. The type of radiation you get will depend on the kind of cancer you have and the stage. The three ways radiation therapy is given are external beam radiation therapy (EBRT), internal radiation therapy, and systemic radiation.

External Beam Radiation Therapy (EBRT)

External beam radiation therapy is a beam of radiation that is directed into your body from a machine. This may also be called x-ray therapy, 3D conformal radiation (3D-CRT), intensity modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT), stereotactic radiation therapy (SRT), cobalt, photon, or proton therapy. You are not radioactive if you are getting external beam radiation therapy. It is safe to be near and close to your friends and family.

Your radiation treatment plan is made specifically for you and depends on several factors. The fractionation, or the number of treatments, you will get is decided by your radiation oncologist.

Internal Radiation Therapy

Internal radiation therapy is when a radioactive source is put into or near your tumor. This is also called brachytherapy or implant therapy. With internal radiation therapy, you may need to stay away from friends and family for some time to protect them from exposure to radiation.

Systemic Radiation

Systemic therapies affect your whole body. They are given by mouth or given directly into a vein (IV, intravenously), where they travel through the blood stream to cancer cells to kill them.

What are the side effects of radiation therapy?

Radiation damages normal cells as well as cancer cells. Each person can have different side effects from radiation therapy. Some side effects depend on the type of cancer and area being treated. It is important to talk to your radiation team about possible side effects and how to manage them.

It is important to talk to your care team about any side effects you are having, whether you are on treatment or years later.

What happens after treatment ends?

After treatment, you will have follow-up imaging tests (CT scans, MRI scans, PET scans), blood tests (tumor marker), and appointments with your care team. If you have any new or worsening health issues, let your care provider know.

Talk with your oncology team about receiving a survivorship care plan, which can help you manage the transition to survivorship and learn about life after cancer. You can create your own survivorship care plan using the OncoLife Survivorship Care Plan.

Resources for More Information

Proton Radiation Therapy Treatment Process

Questions to Ask During Your Radiation Oncology Consultation

Radiation Consultation and Consent

Radiation Therapy Treatment Process

Video: What to Expect During Radiation Therapy

Your Radiation Care Team

Radiation therapy for cancer. National Cancer Institute. (2019, January 8). Retrieved October 21, 2022, from https://www.cancer.gov/about-cancer/treatment/types/radiation-therapy

What is radiation therapy? Cancer.Net. (2022, May 26). Retrieved October 20, 2022, from https://www.cancer.net/navigating-cancer-care/how-cancer-treated/radiation-therapy/what-radiation-therapy

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