This page was reviewed under our medical and editorial policy by

Jason Beland, MD, Chair, Department of Radiology, City of Hope Atlanta, Chicago and Phoenix

This page was updated on December 27, 2023.

Theranostics is a term that combines the words “therapy” and “diagnostics.” This revolutionary technique represents an evolving form of cancer care that may improve patients’ experiences and treatment outcomes. Patients receive highly targeted radioactive drugs while doctors use imaging to view their distribution in the body.

What are theranostics?

Theranostics pair diagnostic biomarkers with therapeutic agents to identify and target cancer cells for destruction.

For instance, molecular imaging allows health care providers to trace a radioactive drug circulating through the bloodstream as it binds to specific targets on cancer cells. Imaging, like positron emission tomography (PET), allows doctors to see where the cancer is located and deliver a drug to those cells. Unlike other types of targeted therapy, the drug is used to deliver radiation to destroy cancer cells. Health care providers know where the drug is going based on the imaging. This highly targeted radiation technique poses less risk to healthy tissues in the vicinity.

Theranostic medicines are used to treat specific types of cancer. For example:

  • Prostate cancer: PLUVICTOTM (Lu-PSMA-617) is a U.S. Food and Drug Administration (FDA)-approved medicine to treat advanced prostate-specific membrane antigen-positive metastatic castration-resistant prostate cancer in patients who have received other anticancer treatments.
  • Adult pheochromocytoma and paraganglioma: Azedra (I131-iobenguane/MIBG) is FDA-approved to treat those 12 years and older diagnosed with local, advanced or metastatic pheochromocytomas and paragangliomas.
  • Neuroendocrine cancer: Lutathera (Lu 177 dotatate) is an FDA-approved radioactive drug that attaches to cancer cells, enabling radiation to damage the cells.

How do theranostics work?

The first step in theranostics involves a diagnostic test. A radioactive drug, or “radiotracer” is injected and travels through the bloodstream and binds to cancer cells throughout the body. The radiotracer emits a very low level of radiation, which is detected by the PET/CT scan. It doesn’t damage cells, but allows health care providers to localize the cancer cells and help determine if this type of treatment is an option.

It takes about an hour for the radiotracer to do its work. At this point, a nuclear medicine physician uses a positron emission tomography (PET) scan to view the cancer’s location by seeing where the radiotracer has accumulated. In some cases, the same health care provider will decide whether to proceed to the next step in the theranostics process. Otherwise, he or she forwards the results to the treating physicians for further consideration.

The second or therapeutic phase involves an intravenous injection or infusion of the drug bound to a different radioactive element. This type of radiation destroys cancer cells by damaging their DNA. Because the radiotracers bind specifically to cancer cells, the drug precisely targets the cancer while sparing nearby tissue.

After an observation period, the patient may go home. The body clears the drug within a few hours or days, eliminating the risk of radiation exposure.

Benefits of theranostics

Theranostics offer precise delivery of radiation using the distribution of the drug within the body as confirmed by imaging. Seeing where the cancer is and how it’s responding in this multi-step procedure helps health care providers identify patients who may benefit from further treatment and avoid unnecessary treatments and side effects. It offers health care providers a clear picture of the cancer’s nature and scope in the body, enabling them to target the disease more precisely while reducing the risk of damage to nearby tissues and organs. The technique may also improve monitoring and treatment evaluation.

Side effects of theranostics

Theranostics allow the care team to precisely deliver radiation to abnormal tissues, reducing the risk of radiotherapy-related complications. However, radiation exposure has been linked to other types of cancer. As part of your treatment, you’ll receive instructions about radiation safety and how to protect yourself and others from excessive radiation exposure.

Some patients also experience a decrease in blood cell production because blood cells, which are produced in bone marrow, may absorb some radiation. Blood cell production often returns to normal over time. Kidney function may also be monitored because these radioactive drugs are often cleared through the urine.

Possible side effects of radiation treatment include:

  • Appetite loss
  • Fatigue
  • Nausea
  • Temporary worsening of cancer symptoms
  • Dry mouth

Side effects may vary in severity and duration depending on the treatment location. Side effects from theranostic treatment or other radiotherapies are managed using a variety of supportive care services before and after treatment. To help manage any side effects, patients should consult their health care provider for advice.

Expert cancer care

is one call away.
appointments in as little as 24 hrs.

Show references
  • National Cancer Institute (2019, January 8). Radiation Therapy To Treat Cancer. National Cancer Institute.
  • U.S. National Library of Medicine MedlinePlus (2020, July 3). PET Scan.
  • National Cancer Institute (2022, January 7). Pheochromocytoma and Paraganglioma Treatment (PDQ®)–Patient Version.
  • American Cancer Society (2021, September 20). Radioactive Iodine (Radioiodine) Therapy for Thyroid Cancer.
  • Gomes Marin JF, Nunes RF, Coutinho AM, et al. (2020). Theranostics in Nuclear Medicine: Emerging and Re-emerging Integrated Imaging and Therapies in the Era of Precision Oncology. Radiographics: A Review Publication of the Radiological Society of North America, Inc., 40(6):1715-1740.
  • Shanbhag PP, Jog SV, Chogale MM, Gaikwad SS (2013). Theranostics for Cancer Therapy. Current Drug Delivery, 10(3):357-362.
  • American Cancer Society (2020, February 1). Second Cancers Related to Treatment.
  • National Cancer Institute (2022). Radiation Therapy Side Effects.
  • American Cancer Society (2020). Managing Nausea and Vomiting at Home.
  • National Cancer Institute (2022, June). Acupuncture (PDQ®)–Patient Version - NCI.
  • American Society of Clinical Oncology (2022, June). Exercise During Cancer Treatment.
  • National Institute of Biomedical Imaging and Bioengineering (NIBIB) (2015, May). Theranostics.
  • American Cancer Society. Prostate Cancer.
  • National Cancer Institute (2021, June). For Advanced Prostate Cancer, Radiopharmaceutical Improves Survival.
  • American Cancer Society (2018, August 1). FDA Approves Azedra (lobenguane) for rare Adrenal Tumors.
  • National Cancer Institute. gallium Ga 68-NOTA-3PTATE-RGD.
  • American Cancer Society. About Pancreatic Neuroendocrine Tumors.
  • American Cancer Society (2018, January 29). FDA Approves Lutathera for Certain Digestive Tract Cancers.