And why does radiation sometimes cause cancer, and other times cure it? Nuclear radiation is the energy given off by all radioactive elements when they break down into more stable atoms. And it is being produced in and around you right now. Radioactive atoms in everything — from rocks to bananas and even our bodies — give off energy as they decay to more stable forms. Our cells can easily clean up any damage done by this low-level background radiation — on average Australians are exposed to about 1.
The combination of how much radiation you are exposed to, what type, and how often will determine the effect on your cells and tissues. Low doses of nuclear radiation are more likely to change cells by modifying DNA, while high doses tend to kill cells.
So long-term exposure to low doses of radiation increase the odds of getting cancer, while a single high dose will quickly cause immediate damage to cells and tissues — a process used effectively to kill tumour cells in radiation therapy. Very high doses like those experienced by workers at the site of nuclear accidents several thousand times higher than the background radiation level cause extensive damage, resulting in a range of symptoms known collectively as radiation sickness.
Extremely high doses can kill in days or weeks. The high-energy radiation given off by radioactive decay can take the form of very high speed particles electrons in the case of beta radiation; two protons and two neutrons in alpha radiation or waves gamma or X-rays. Regardless of the form it takes, all nuclear radiation has enough energy to strip electrons off atoms and molecules that it interacts with, earning it the name ionising radiation.
It is this electron-stripping ionising property that does the damage to our cells and tissues. As well as generating heat, the removal of electrons can break chemical bonds. When that happens in a molecule of DNA it can cause mutations, which can lead to cancer down the track. And ionising a protein can mess with its shape and function — not something you want in the molecules that coordinate most of the chemistry in our cells. Our bodies are full of water, and almost all cells have DNA, but some cells and tissues are more susceptible to damage from nuclear radiation than others.
The cells and organs that are most affected by nuclear radiation are the ones that are actively reproducing, because the DNA is more exposed when the cell is in the process of dividing. Blood cells have the highest turnover rate in our bodies, so the tissue where they are produced — the rapidly dividing cells of the bone marrow — is the most susceptible to radiation damage.
The damage to bone marrow in high doses — and complete destruction of it in very high doses — impairs our immune system by not replacing our white blood cells. Long-term exposure to lower doses can lead to cancerous DNA mutations in the marrow, which can lead to the blood cancer leukaemia in people exposed through work or location.
The cells lining the digestive system are also fast-dividing, so they can cope with the physical and chemical assault of digesting our food. Gastrointestinal damage contributes to the symptoms of acute radiation syndrome in people who are exposed to high doses.
These tablets help protect your thyroid gland from the harmful effects of radioactive iodine, which can be released as a result of a nuclear explosion. They don't protect against any other radioactive substances. KI tablets can be harmful if you don't take them properly, are allergic to iodine, or have certain skin or other health problems.
Some common side effects include upset stomach, skin rash, swollen salivary glands, and a metallic taste in your mouth. In rare cases, a person may have a severe allergic reaction. The reaction may cause breathing problems, hives, or swelling around the lips, tongue, or face. References Citations National Cancer Institute Radiation risks and pediatric computed tomography CT : A guide for health care providers. Patient safety: Radiation dose in X-ray and CT exams. American Nuclear Society Estimate your personal annual radiation dose.
Radiation injuries. In JE Tintinalli, ed. New York: McGraw-Hill. Centers for Disease Control and Prevention Airport Security Scanning and Human Health. Emergency preparedness and response: Potassium iodide KI. Environmental Protection Agency Radiation doses in perspective.
Radiation protection: Health effects. Radiation: Facts, Risks and Realities. Radiation: Non-ionizing and ionizing. Sources of radiation exposure. Mehta P, Smith-Bindman R Airport full-body screening: What is the risk?
Archives of Internal Medicine. Published online March 28, doi National Cancer Institute Schauer DA Report No. World Nuclear Association Certain body parts are more affected by exposure to different types of radiation sources than others. The thyroid gland is susceptible to radioactive iodine. In sufficient amounts, radioactive iodine can destroy all or part of the thyroid.
Taking potassium iodide can reduce the effects of exposure. When a person is exposed to around rems, the blood's lymphocyte cell count will be reduced, leaving the victim more susceptible to infection. This is often referred to as mild radiation sickness. Early symptoms of radiation sickness mimic those of flu and may go unnoticed unless a blood count is done.
According to data from Hiroshima and Nagasaki, symptoms may persist for up to 10 years and may also have an increased long-term risk for leukemia and lymphoma. For more information, visit Radiation Effects Research Foundation. Intense exposure to radioactive material at 1, to 5, rems would do immediate damage to small blood vessels and probably cause heart failure and death directly.
Radiation damage to the intestinal tract lining will cause nausea, bloody vomiting and diarrhea. This occurs when the victim's exposure is rems or more. The radiation will begin to destroy the cells in the body that divide rapidly.
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