Cobalt is a nonradioactive metal found in nature from which radioactive isotopes can be produced by linear accelerators (for medical and commercial uses) and nuclear reactors (as a waste by-product). Cobalt-60 is the most common isotope and is widely utilized in medicine for the treatment of brain tumors and other central nervous system disorders.
If you are experiencing serious medical symptoms, seek emergency treatment immediately.
Cobalt-60 does emit radiation and must be handled with care. The side effects from exposure to this radioisotope depend largely upon the length of exposure and whether the exposure was internal (i.e. ingested or inhaled) or external (i.e. skin contact). These side effects may develop within hours or days of treatment (acute/subacute) or months and years later (delayed/late onset).
Cobalt-60 is almost exclusively used for Gamma Knife® surgery in the United States. The Gamma Knife® is a nonsurgical approach to the treatment of brain tumors, blood vessel abnormalities and other brain disorders, such as Parkinson’s disease, epilepsy and tremors. Multiple beams of gamma radiation from Cobalt-60 are directed simultaneously at a specific point in the brain. The delivery of a single, large dose of radiation (referred to as stereotactic radiosurgery), is executed with extreme precision and minimizes damage to surrounding healthy tissues.
- Cobalt-60 is almost exclusively used for Gamma Knife® surgery in the United States.
- The delivery of a single, large dose of radiation (referred to as stereotactic radiosurgery), is executed with extreme precision and minimizes damage to surrounding healthy tissues.
Acute/Subacute Side Effects
The Risks of Glycolic Peels
Fatigue is the most common side effect of Cobalt-60 radiation and can last weeks to years. Many patients never regain their full energy, although it is not clear that radiation therapy alone is to blame, according to the American Cancer Society 2.
Cerebral edema, or swelling of brain tissue, occurs in all patients with varying degrees of severity. Some patients experience only a mild headache, while others can experience more significant headache, profound dizziness, nausea, vomiting and even loss of consciousness.
Localized hair loss-if the treated lesion was close to the scalp, skin irritation, scalp numbness/tingling, vision changes and decreased appetite have been reported.
- Fatigue is the most common side effect of Cobalt-60 radiation and can last weeks to years.
- Some patients experience only a mild headache, while others can experience more significant headache, profound dizziness, nausea, vomiting and even loss of consciousness.
Delayed/Late Onset Side Effects
Delayed or late onset symptoms can include slowed thinking, poor memory/recall, personality changes and confusion. The development of a new tumor--oncogenesis--is a rare occurrence from the radiation exposure in the brain.
Radiation necrosis, the death of brain tissue in response to radiation treatment, can also create an inflammatory reaction with symptoms of cerebral edema and can trigger seizures and rarely, death, according to the American Cancer Society 2.
- Delayed or late onset symptoms can include slowed thinking, poor memory/recall, personality changes and confusion.
- Radiation necrosis, the death of brain tissue in response to radiation treatment, can also create an inflammatory reaction with symptoms of cerebral edema and can trigger seizures and rarely, death, according to the American Cancer Society 2.
The Risks of Glycolic Peels
How Long Does It Take for Hair to Grow Back After Radiation?
Uses of the Radioactive Iodine 131
How to Remove Lice From Helmets
Cellphones and Hidden Radiation: Is There Evidence of Harm?
IPL Laser Treatment Side Effects
Harmful Effects of Benzene
A Tumor of the Right Temporal Lobe
Side Effects of Novocain
- U.S. Environmental Protection Agency: Cobalt
- American Cancer Society: Possible Side Effects of Radiation Therapy
- American Society of Clinical Oncology. Long-Term Side Effects of Cancer Treatment. Updated September 2019.
- Krasin MJ, Constine LS, Friedman DL, Marks LB. Radiation-related treatment effects across the age spectrum: differences and similarities or what the old and young can learn from each other. Semin Radiat Oncol. 2010;20(1):21–29. doi:10.1016/j.semradonc.2009.09.001
- Gelband H, Jha P, Sankaranarayanan R, Horton S, Bank W. Disease Control Priorities, Third Edition (Volume 3): Cancer. Washington: World Bank Publications; 2015.
- American Society of Clinical Oncology. Side Effects of Radiation Therapy. Updated December 2018.
- Wolny-Rokicka E, Tukiendorf A, Wydmański J, Roszkowska D, Staniul BS, Zembroń-Łacny A. Thyroid Function after Postoperative Radiation Therapy in Patients with Breast Cancer. Asian Pac J Cancer Prev. 2016;17(10):4577–4581. doi:10.22034/apjcp.2016.17.10.4577
- Chalan P, Di Dalmazi G, Pani F, De Remigis A, Corsello A, Caturegli P. Thyroid dysfunctions secondary to cancer immunotherapy. J Endocrinol Invest. 2018;41(6):625–638. doi:10.1007/s40618-017-0778-8
- Stubblefield MD. Radiation fibrosis syndrome: neuromuscular and musculoskeletal complications in cancer survivors. PM R. 2011;3(11):1041-54. doi:10.1016/j.pmrj.2011.08.535
- Chen Z, Wu Z, Ning W. Advances in Molecular Mechanisms and Treatment of Radiation-Induced Pulmonary Fibrosis. Transl Oncol. 2019;12(1):162–169. doi:10.1016/j.tranon.2018.09.009
- Yusuf SW, Sami S, Daher IN. Radiation-induced heart disease: a clinical update. Cardiol Res Pract. 2011;2011:317659. doi:10.4061/2011/317659
- Sung K, Lee KC, Lee SH, Ahn SH, Lee SH, Choi J. Cardiac dose reduction with breathing adapted radiotherapy using self respiration monitoring system for left-sided breast cancer. Radiat Oncol J. 2014;32(2):84–94. doi:10.3857/roj.2014.32.2.84
- American Cancer Society. How does radiation therapy affect the risk of second cancers? Updated December 11, 2014.
- Schaapveld M, Aleman BM, Van eggermond AM, et al. Second Cancer Risk Up to 40 Years after Treatment for Hodgkin's Lymphoma. N Engl J Med. 2015;373(26):2499-511. doi:10.1056/NEJMoa1505949
- Ng AK, Kenney LB, Gilbert ES, Travis LB. Secondary malignancies across the age spectrum. Semin Radiat Oncol. 2010;20(1):67–78. doi:10.1016/j.semradonc.2009.09.002
- Pendergrass JC, Targum SD, Harrison JE. Cognitive Impairment Associated with Cancer: A Brief Review. Innov Clin Neurosci. 2018;15(1-2):36–44.
- Gegechkori N, Haines L, Lin JJ. Long-Term and Latent Side Effects of Specific Cancer Types. Med Clin North Am. 2017;101(6):1053–1073. doi:10.1016/j.mcna.2017.06.003
- National Cancer Institute. Oral Complications of Chemotherapy and Head/Neck Radiation (PDQ®)–Health Professional Version. Updated December 16, 2016.
- Schover LR, van der Kaaij M, van Dorst E, Creutzberg C, Huyghe E, Kiserud CE. Sexual dysfunction and infertility as late effects of cancer treatment. EJC Suppl. 2014;12(1):41–53. doi:10.1016/j.ejcsup.2014.03.004
Lisa Holbrook has been writing since 2000. She is a family practice physician with more than 10 years' experience and has a strong interest in public health and sports medicine. Her articles have appeared in "Medical Economics." She holds a bachelor's degree in molecular genetics from Purdue University and a Doctorate of Medicine from Indiana University.