Side Effects of Isotopes Used for Medical Purposes

Radiation flag image by Stasys Eidiejus from

Technology changes on an almost daily basis, and the field of medicine sees these changes almost as frequently. Nuclear medicine has had an impact in treating cancer and conducting the most accurate diagnostic testing available.

The main components of nuclear medicine, isotopes, or radioisotopes, allow cancer to be targeted and images produced that once never were thought possible. There are side effects associated with this technology.

What Is an Isotope?

The Radiochemistry Society defines isotopes as "one of two or more species of atoms of a chemical element with the same atomic number, nearly identical chemical behaviour but with different atomic masses and physical properties." This unique make-up allows these isotopes to be stable (non-radioactive) as well as unstable (radioactive).

According to the Radiochemistry Society, nuclear medicine began in the 1950s and generally used the radioactive isotope iodine-151 to treat thyroid cancer. This branch of medicine now includes many more isotopes to treat and diagnose more forms of cancer. It typically involves unstable isotopes, which can cause an array of side effects.

Isotopes in Diagnostic Testing

Radioactive isotopes used in diagnostic testing are linked to a compound that is concentrated in a specific area of the body. These isotopes emit gamma rays and, in doing so, provide an excellent picture of the specific body part or organ. Side effects of diagnostic testing are minimal and usually involve irritation or swelling at the site. Radioactive isotopes are very short lived and leave the body with no trace after a few days.

Low Cellular Count

It is the side effects of radioisotope therapy that most people commonly refer to when speaking of using radiation treatment. The Mayo Clinic explains that the most dangerous side effect of radiation therapy is low cellular count. Determined by frequent complete blood count (CBC) tests, physicians are able to see how many healthy cells were killed by the attack of isotopes on the cancer cells. Although cancer cells are targeted, some healthy cells die in radiation therapy. When these cells are in low numbers, infection that could become life-threatening is a possibility. Other ailments may include weakness, shortness of breath and fatigue.


According to the Cleveland Clinic, a common and uncomfortable side effect of radioisotope treatment is a condition called esophagitis. The oesophagus, or food pipe, is especially sensitive to radiation. Esophagitis is characterised by inflammation and soreness that in many cases results in pain when swallowing. Pain killers and antacids typically are prescribed so the patient may eat. Two to three weeks after treatment ends, esophagitis will subside.


Esophagitis often is accompanied by another painful, uncomfortable condition referred to as mucositis, in which the lining of your mouth, throat and gums become sore, inflamed and cause sores. The treatment for mucositis in most cases is the same diet as for esophagitis. In severe cases, you may be referred to a dentist to treat the sores. Mucositis disappears typically two to three weeks after ending treatment.

Nausea, Vomiting, Diarrhea and Hair Loss

Treatment with radioactive isotopes can cause some of the side effects common to chemotherapy, including nausea and vomiting. Diarrhoea is also a common side effect and must be dealt with by keeping the body hydrated. The loss of hair prevalent in chemotherapy also occurs in treatments with radioisotopes at high dosages.