Radiation Emergencies. Section Navigation. Facebook Twitter LinkedIn Syndicate. Minus Related Pages. Mild symptoms may be observed with doses as low as 0. The dose usually must be external i. Radioactive materials deposited inside the body have produced some ARS effects only in extremely rare cases.
The radiation must be penetrating i. High energy X-rays, gamma rays, and neutrons are penetrating radiations. The entire body or a significant portion of it must have received the dose 3. Most radiation injuries are local, frequently involving the hands, and these local injuries seldom cause classical signs of ARS.
The dose must have been delivered in a short time usually a matter of minutes. Fractionated doses are often used in radiation therapy. These are large total doses delivered in small daily amounts over a period of time. Fractionated doses are less effective at inducing ARS than a single dose of the same magnitude. The three classic ARS Syndromes are: Bone marrow syndrome sometimes referred to as hematopoietic syndrome the full syndrome will usually occur with a dose between 0.
The survival rate of patients with this syndrome decreases with increasing dose. The primary cause of death is the destruction of the bone marrow, resulting in infection and hemorrhage. Gastrointestinal GI syndrome: the full syndrome will usually occur with a dose greater than approximately 10 Gy rads although some symptoms may occur as low as 6 Gy or rads. Survival is extremely unlikely with this syndrome. Destructive and irreparable changes in the GI tract and bone marrow usually cause infection, dehydration, and electrolyte imbalance.
Death usually occurs within 2 weeks. Death occurs within 3 days. Death likely is due to collapse of the circulatory system as well as increased pressure in the confining cranial vault as the result of increased fluid content caused by edema, vasculitis, and meningitis. The four stages of ARS are: Prodromal stage N-V-D stage : The classic symptoms for this stage are nausea, vomiting, as well as anorexia and possibly diarrhea depending on dose , which occur from minutes to days following exposure.
The symptoms may last episodically for minutes up to several days. This is known as ionizing radiation, and it's where the problems start. There are many types of ionizing radiation. Take your pick from cosmic, alpha, beta, gamma or X- rays, neutrons, or from a handful more. What really matters is how much an organism is exposed to—a concept called absorbed dose. One way to measure absorbed dose is in units of Grays Gy.
Another common unit is the sievert Sv , which takes the Gy measure and multiples it by the type of radiation to calculate the effective dose in living tissue. The average radiation exposure during a couple of seconds of an abdominal X-ray is 0.
When you really get into trouble is with whole-body exposure, like, say, in the Chernobyl control room immediately after the explosion. There, you would soaked up Sv per hour. But you wouldn't last an hour. The dose would be lethal in just minutes. Large doses of ionizing radiation in a short time period lead to Acute Radiation Syndrome ARS , aka radiation poisoning.
The severity of ARS symptoms depends on the level of exposure. A radiation dose as low as 0. If the body is exposed to a higher dose, somewhere between Gy, blood cells begin to die. You could still recover—treatment of this kind of radiation syndrome usually involves blood transfusions and antibiotics—but you could also suffer a weakened immune response due to a drop in white cell count, uncontrollable bleeding due to a lack of platelets, and anemia due to a reduction of red blood cells.
You'll also notice a kind of odd sunburn if exposed to 2 Gy or more of ionizing radiation. Atomic weapons and nuclear accidents like those at Chernobyl and Fukushima have made sure we all know that nuclear radiation can kill. But how exactly does the radiation affect our bodies? 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.
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