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What Is Radioisotope Therapy?

Chemotherapy and radiation therapy are the two most well-known cancer treatments. Just like there are many types of chemotherapy, there are many types of radiation therapy too. Internal radiotherapy is a cancer treatment in which a radioactive material is put inside your body to treat cancer. Radioisotope therapy is a type of internal radiotherapy.

Here at Excel Diagnostics & Nuclear Oncology Center, our compassionate and skilled team,  under the leadership of Dr. Ebrahim Delpassand, offers radioisotope therapy here in Houston, Texas.

In this article, we discuss what radioisotope therapy is and who might benefit from this therapy.

What are radioisotopes?

Radioisotopes are radioactive isotopes of a particular chemical element on the periodic table. Isotopes have a different number of neutrons in the nucleus, which contributes to their instability. Radioisotopes of a particular atom contain an unstable combination of neutrons and protons, which may lead to an excess energy (and instability). 

Every chemical element on the periodic table has at least one isotope, and radioisotopes are identified by that chemical and its atomic weight. For example, an isotope of Iodine is written as Iodine-131, meaning that particular isotope has an atomic weight of 131 neutrons. Normal Iodine atoms have a weight of 127.

Radioisotopes are used for industrial and medical purposes. When radioisotopes are attached to a small molecule (i.e., a peptide), a radiopharmaceutical is created.

What is radioisotope therapy?

Radioisotope therapy uses radioisotopes to destroy cancer cells. Radioisotope therapy can be used to treat several different kinds of cancer, including thyroid cancer, bile duct cancer, liver cancer, bone metastases, and neuroblastoma. Depending on which type of cancer is present, different radioactive isotopes will be used. For example, I-131 radiotherapy is used to treat thyroid cancer, while radium Ra 223 dichloride may be used if you have prostate cancer. Radioisotope therapy can be combined with other cancer treatments.

Radioisotope therapy is a nonsurgical procedure. The radiation is delivered via a liquid in one of two ways: by mouth (i.e., a drink or capsules); or as an injection into your vein. We offer radioisotope therapy for the treatment of several different kinds of cancer, including thyroid cancer, non-Hodgkin’s lymphoma, prostate cancer, and osteoblastic metastatic bone lesions.

How does radioisotope therapy work?

Because radiopharmaceuticals contain a radioisotope and a tracer connected to the pharmaceutical, the radioisotope is able to target a specific tissue or part of the body. As the radioisotope begins to decay, it affects the targeted tissue or tumor because cancer cells absorb more of the radioisotope than noncancer cells do. The higher dose of radiation eventually destroys the cancer cells. The amount of radiopharmaceutical administered is carefully determined based on your specific tumors, their location, etc. 

What happens after radioisotope therapy?

After your therapy, you’ll follow specific instructions to reduce radiation exposure to others in your home. Your body expels small amounts of radiation through urine and bowel movements, saliva, and sweat. As a result, patients must observe certain precautions to minimize radiation exposure to others. For these reasons, you may be instructed to:

To learn more about radioisotope therapy, call our Houston, Texas, office at 713-781-6200. You may also use our online scheduling tool or email our clinical coordinator, Ms. Susan Cork, at for additional registration for this therapy.

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