Getting Oral or Systemic Radiation Therapy
Systemic radiation therapy is treatment that travels through your entire body instead of being aimed at one area (local treatment). It uses radioactive drugs to treat certain types of cancer, including thyroid, bone, and prostate cancer.
Learn more about how systemic radiation therapy works and what to expect from this type of treatment.
What is systemic radiation therapy?
Systemic radiation therapy uses radioactive drugs to treat certain types of cancer.
These medicines are called radiopharmaceuticals or radionuclides. They are liquid and made up of a radioactive substance that travels through your entire body. They are given by mouth or put into a vein.
Even though these drugs travel through your whole body, they can find cancer cells and collect in those places. This helps deliver radiation doses exactly to the tumor or cancer cells.
Sometimes, radioactive medicines are used to help find cancer, such as bone metastasis (when cancer spreads to the bone). There are also radioactive medicines used to help diagnose other non-cancer health problems.
What types of medicines are used?
There are two types of radiopharmaceuticals (medicines) used for systemic radiation therapy:
- Radioimmunotherapy
- Peptide receptor radionuclide therapy (PRRT)
Radioimmunotherapy
Radioimmunotherapy combines a small amount of radioactive material with a special medicine called a monoclonal antibody. The radioactive material acts as a tracer that finds and attaches to cancer cells. The monoclonal antibody is then delivered directly to those cells. Learn more about monoclonal antibodies.
Radioimmunotherapy may be used to treat:
- Prostate cancer
- Neuroendocrine tumors
- Certain lymphomas, such as non-Hodgkin B-cell
It might also be used to treat other types of cancer. Experts continue studying and developing new drugs to treat more cancers this way.
Peptide receptor radionuclide therapy (PRRT)
Peptide receptor radionuclide therapy (PRRT) combines radioactive material with a special protein called a peptide to make a radiopeptide.
The radiopeptide finds and attaches to certain types of cancer cells, then delivers a high dose of radiation directly to those cells.
PRRT may be used to treat:
- Neuroendocrine cancer
Will I be radioactive during or after systemic radiation treatment?
Some radiation stays in your body for a few days after systemic radiation.
This is because systemic radiation uses an unsealed radioactive substance that goes through your whole body. It takes a few days for your body to get rid of it. You may need to stay in the hospital for 1 or 2 days and take special safety measures at home.
Safety during treatment
The drugs used for systemic radiation treatment are kept in special containers that hold the radiation inside. You’ll also be treated in a shielded room that keeps the radiation contained.
When they give you the radioactive drug, the cancer care team will wear safety gear that protects them from harm.
Safety after treatment
You might need to take safety measures to protect the people around you from the systemic radiation in your body.
Radioactive materials can leave your body through:
- Saliva
- Sweat
- Blood
- Urine
These fluids are radioactive when they leave your body. It's very important to limit how much you expose the people around you to radiation.
Following your safety measures
You may know other people who had radiation therapy, but your safety measures might be different from theirs. Every person with cancer is different. What you need to do to stay safe will depend on your specific treatment and how much of it you get.
Your cancer care team will tell you exactly what safety instructions to follow and how long to follow them. You should follow their instructions exactly.
Learn more
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
American College of Radiology and the Radiological Society of North America. Radiation therapy. Accessed at https://www.radiologyinfo.org/en/info/intro_onco on April 4, 2025.
American College of Radiology and the Radiological Society of North America. Radioimmunotherapy (RIT). Accessed at https://www.radiologyinfo.org/en/info/radio-immuno on April 8, 2025.
American Society of Clinical Oncology (ASCO). Side effects of radiation therapy. Accessed at cancer.net. Content is no longer available.
American Society of Clinical Oncology (ASCO). What is radiation therapy? Accessed at cancer.net. Content is no longer available.
American Society of Clinical Oncology (ASCO). What to expect when having radiation therapy. Accessed at cancer.net. Content is no longer available.
Chan, JA, Kulke, M. Systemic therapy of metastatic well-differentiated pancreatic neuroendocrine tumors. UpToDate. 2024. Accessed at https://www.uptodate.com/contents/systemic-therapy-of-metastatic-well-differentiated-pancreatic-neuroendocrine-tumors on April 8, 2025.
Fournier, DM. Radiation therapy. In: Maloney-Newton S, Hickey M, Brant JM, eds. Mosby’s Oncology Nursing Advisor: A Comprehensive Guide to Clinical Practice. 3rd ed. St. Louis: Elsevier; 2023: 322-338.
Galinodo, A. What are Radiopharmaceuticals? International Atomic Energy Agency. February 2, 2024. Accessed at https://www.iaea.org/newscenter/news/what-are-radiopharmaceuticals on April 8, 2025.
Last Revised: June 9, 2025
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