Medically reviewed by Suzanne Falck, M.D., FACP — By Yvette Brazier on August 15, 2017
Radiation is used in medicine, to generate electricity, to make food last longer, to sterilize equipment, for carbon dating of archeological finds, and many other reasons. Ionizing radiation happens when the atomic nucleus of an unstable atom decays and starts releasing ionizing particles. When these particles come into contact with organic material, such as human tissue, they will damage them if levels are high enough, in a short period of time. This can lead to burns, problems with the blood, gastrointestinal system, cardiovascular and central nervous system, cancer, and sometimes death. Radiation is normally managed safely, but its use also entails a risk. If an accident happens, for example, the earthquake in Fukushima, Japan, in 2011, or the explosion at Chernobyl, Ukraine in 1986, radiation can become dangerous. Here are some key points about radiation sickness. More detail is in the main article.
Share on PinterestRadiation has many uses, but it can be dangerous if it is not managed correctly. Radiation poisoning happens when a radioactive substance gives off particles that get into a person’s body and cause harm. Different radioactive substances have different characteristics. They can harm and help people in different ways, and some are more dangerous than others. Normally, radiation occurs in a safe environment. Whether or not it becomes dangerous depends on:
A dose of radiation from a single x-ray is not normally harmful. Nevertheless, the parts of the body that are not being x-rayed will be shielded with a lead apron to prevent unnecessary exposure. The technician, meanwhile, will leave the room when taking the image. While one small dose is not dangerous, repeated small doses could be. A sudden, short, low dose of radiation is unlikely to cause a problem, but extended, intense, or repeated doses can be. When radiation damages cells, it is irreversible. The more often a person is exposed, the greater their risk of health problems. How much radiation is dangerous?Radiation dosage can measured in various ways. Some of the units used are Grays, Sieverts, rems, and rads. They are used in a similar way, but 1 rad is equivalent to 0.01 Gray.
According to the Centers for Disease Control and Prevention (CDC), radiation sickness, or acute radiation syndrome (ARS) is diagnosed when:
A person who experiences an atomic explosion will receive two doses of radiation, one during the explosion, and another from fallout, when radioactive particles float down after the explosion. Radiation sickness can be acute, happening soon after exposure, or chronic, where symptoms appear over time or after some time, possibly years later. The signs and symptoms of acute radiation poisoning are:
Symptoms depend on the dose, and whether it is a single dose or repeated. A dose of as low as 30 rads can lead to:
A dose of 300 rads dose may result in:
Stages of radiation sicknessSymptoms of severe radiation poisoning will normally go through four stages. Prodomal stage: Nausea, vomiting, and diarrhea, lasting from a few minutes to several days Latent stage: Symptoms seem to disappear, and the person appears to recover Overt stage: Depending on the type of exposure, this can involve problems with the cardiovascular, gastrointestinal, hematopoietic, and central nervous system (CNS) Recovery or death: There may be a slow recovery, or the poisoning will be fatal. Hematopoietic stem cells, or bone marrow cells, are the cells that all other blood cells derive from. Different doses, different effectsThe risk of illness depends on the dose. Very low doses of radiation are all around us all the time, and they do not have any effect. It also depends on the area of the body that is exposed. If the whole body is exposed to, say, 1,000 rads within a short time, this could be fatal. However, far higher doses can be applied to a small area of the body with less risk. After a mild dose, the person may experience symptoms for just a few hours or days. However, a repeated or even a single, relatively low dose that produces few or no visible symptoms around the time of exposure may cause problems later on. A person who is exposed to 3,000 rads will experience nausea and vomiting, and they may experience confusion and a loss of consciousness within a few hours. Tremors and convulsions will occur 5 to 6 hours after exposure. Within 3 days, there will be coma and death. People who experience repeated doses, or who appear to recover, may have long-term effects. These include:
There may also be skin redness, cataracts, and heart problems. Localized exposure may lead to changes in the skin, loss of hair, and possibly skin cancer. Exposure to certain parts of the body is more dangerous than others, for example, the intestines. The effects of radiation are cumulative. Damage to cells is irreversible. Share on PinterestCT scans should only be carried out when necessary, as they expose a person to more radiation than is usual in everyday life. Exposure to radiation can result from workplace exposure or an industrial accident, radiation therapy, or even deliberate poisoning, as in the case of the former Russian spy, Alexander Litvinenko, who was murdered in London by polonium 210 placed in his tea. However, this is extremely rare. Most people are exposed to an average of around 0.62 rads, or 620 Gray each year. Half of this comes from radon in the air, from the Earth, and from cosmic rays. The other half comes from medical, commercial, and industrial sources. Spread over a year, this is not significant in terms of health. Levels of radiation from an x-ray are not high, but they occur at one moment.
Nuclear medicine is used to target the thyroid in people with a thyroid disorder. Other types of medical treatment include radiation therapy for cancer. Living at a higher altitude, for example, in the plateau of New Mexico and Colorado, increase exposure, as does traveling in an airplane. Radon gas in homes also contributes. Food, too, contains small amounts of radiation. The food and water we drink is responsible for exposure to around 0.03 rads in a year. The many activities that can expose people to sources of radiation include:
Smokers have a higher exposure than non-smokers, as tobacco contains a substance that can decay to become polonium 210. Astronauts have the highest exposure of anyone. They may be exposed to 25 rads in one Space Shuttle mission. Damage by radiation is irreversible. Once the cells are damaged, they do not repair themselves. Until now, there is no way for medicine to do this, so it is important for someone who has been exposed to seek medical help as soon as possible. Possible treatments include:
Depending on exposure, radiation can affect the whole body. For cardiovascular, intestinal, and other problems, treatment will target the symptoms. Tips for reducing unnecessary exposure to radiation include:
It is not possible or necessary to avoid all exposure to radiation, and the risk posed to health by most sources is extremely small. Last medically reviewed on August 15, 2017 Medical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.
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