Radiation poisoning

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Radiation poisoning, also called "radiation sickness", is a form of damage to organic tissue due to excessive exposure to ionizing radiation. The term is generally used to refer to acute problems caused by a large dosage of radiation in a short period. Many of the symptoms of radiation poisoning occur as ionizing radiation interferes with cell division. This interference allows for treatment of cancer cells; such cells are among the fastest-dividing in the body, and will be killed by a radiation dose that adjacent normal cells are likely to survive.

Strictly speaking the correct name for "radiation sickness" is acute radiation syndrome. A chronic radiation syndrome does exist but is very uncommon; this has been observed among workers in early radium source production sites and in the early days of the Soviet nuclear program. A short exposure can result in acute radiation syndrome; chronic radiation syndrome requires a prolonged high level of exposure.

The use of radionuclides in science and industry is strictly regulated in most countries (in the U.S. by the Nuclear Regulatory Commission). In the event of an accidental or deliberate release of radioactive material, either evacuation or sheltering in place will be the recommended measures.

Contents

[edit] Measuring radiation dosage

The rad is a unit of absorbed radiation dose defined in terms of the energy actually deposited in the tissue. One rad is an absorbed dose of 0.01 joules of energy per kilogram of tissue. The more recent SI unit is the gray, which is defined as 1 joule of deposited energy per kilogram of tissue. Thus one gray is equal to 100 rad.

To accurately assess the risk of radiation, the absorbed dose energy in rad is multiplied by the relative biological effectiveness (RBE) of the radiation to get the biological dose equivalent in rems. Rem stands for "Röntgen equivalent in man." In SI units, the absorbed dose energy in grays is multiplied by the same RBE to get a biological dose equivalent in sieverts (Sv). The sievert is equal to 100 rem.

The RBE is a "quality factor," often denoted by the letter Q, which assesses the damage to tissue caused by a particular type and energy of radiation. For alpha particles Q may be as high as 20, so that one rad of alpha radiation is equivalent to 20 rem. The Q of neutron radiation depends on their energy. However, for beta particles, x-rays, and gamma rays, Q is taken as one, so that the rad and rem are equivalent for those radiation sources, as are the gray and sievert. See the sievert article for a more complete list of Q values.

[edit] Acute (short-term) vs Chronic (long-term) effects

Radiation sickness is generally associated with acute exposure and has a characteristic set of symptoms that appear in an orderly fashion. The symptoms of radiation sickness become more serious (and the chance of survival decreases) as the dosage of radiation increases. These effects are described as the deterministic effects of radiation.

Longer term exposure to radiation, at doses less than that which produces serious radiation sickness, can induce cancer as cell-cycle genes are mutated. If a cancer is radiation induced then the disease, the speed at which the condition advances, the prognosis, the degree of pain and every other feature of the disease is not a function of the radiation dose which the person was exposed to.

Since tumors grow by abnormally rapid cell division, the ability of radiation to disturb cell division is also used to treat cancer (see radiotherapy), and low levels of ionizing radiation have been claimed to lower one's risk of cancer (see hormesis).

[edit] Exposure

[edit] Nuclear warfare

[edit] Types of exposure

Image:Radiation burns on a Japanese woman after a nuclear explosion in 1945.jpg
Japanese woman suffering burns from thermal radiation after a nuclear explosion in 1945.

Nuclear warfare is made more complex by virtue of the fact that a person can be thus burned by at least three processes. The first (the major cause of burns) is not caused by ionizing radiation.

  • Thermal burns from infrared heat radiation.
  • Beta burns from shallow ionising radition burns to skin from fallout particles.
  • Gamma burns from highly penetrating radiation.

In the picture on the right the normal clothing that the woman was wearing would have been unable to attenuate the gamma radiation and it is likely that any such effect was evenly applied to her entire body. Beta burns would be likely all over the body due to contact with fallout, but thermal burns are often on one side of the body as heat radiation does not penetrate through a human body. In addition the pattern on her clothing has been burnt into the skin, this is due to the fact that white fabric reflects more infra-red light than dark fabric. As a result the skin close to dark fabric is burnt more than the skin covered by white clothing.

Radiation caused illness and death after the bombings of Hiroshima and Nagasaki in about 1% of those exposed who survived the initial explosions. The casualty rate due to radiation was higher in Hiroshima, because although Fat Man (the bomb used at Nagasaki) had a higher yield than Little Boy (the bomb used at Hiroshima), Fat Man was a plutonium weapon, which is actually much less radioactive than a uranium weapon of equal yield (except at the moment of critical mass). Both bombs were airburst, minimizing nuclear fallout (which otherwise would have killed many more).

[edit] Radiation work e.g. industrial radiography

Radiation poisoning can result from accidental exposure to industrial radiation sources. People working with radioactive materials often wear electrometer dosimeters or film "badges" to monitor their total exposure to radiation. These devices are more useful than Geiger counters for determining biological effects, as they measure cumulative exposure over time, and are calibrated to change color or otherwise signal the user before exposure reaches unsafe levels. However, film badge types require the film to be developed, as with photographic film, and are used to measure long-term exposure where brief catastrophic exposures are not expected.

[edit] Nuclear reactor accidents

Radiation poisoning was a major concern after the Chernobyl reactor accident. It is important to note that in humans the acute effects were largely confined to the accident site. Of the 100 million curies (4 exabecquerels) of radioactive material, the short lived radioactive isotopes such as 131I Chernobyl released were initially the most dangerous. Due to their short half-lives of 5 and 8 days they have now decayed, leaving the more long-lived 137Cs (with a half-life of 30.07 years) and 90Sr (with a half-life of 28.78 years) as main dangers. Thirty-one people died as an immediate result of the Chernobyl accident.

[edit] Deliberate poisoning

On the 23rd. of November 2006 Alexander Litvinenko died due to suspected deliberate poisoning with polonium-210. His is the first case of confirmed death due to such a cause, though it is also known that there have been other cases of attempted assassination such as in the cases of KGB defector Nikolay Khokhlov and journalist Yuri Shchekochikhin where radioactive thallium was used. Also, an incident in 1990 at Point Lepreau Nuclear Generating Station where several employees acquired small doses of radiation due to the contamination of water in the office watercooler with tritium contaminated heavy water.

[edit] Prevention

The best prevention for radiation sickness is to minimize the dose suffered by the human, or to reduce the dose rate.

[edit] Time

The longer that the humans are subjected to radiation the larger the dose will be. The advice in the nuclear war manual published in the USA was that if one needed to leave the shelter to dispose of human waste then this should be done as fast as possible. The suggested method is to collect it in a plastic bag, tie it with a small hole to allow gas to escape, then to quickly step out of the shelter, throw it and step back inside.

<math> Dose \propto t </math>

[edit] Distance

The radiation due to any point source will obey the inverse square law: by doubling the distance the dose rate is quartered. This is why radiation workers are always taught to pick up a gamma source with a pair of tongs rather than their hand.

<math> Dose \propto \frac{1}{r^2} </math>

[edit] Shielding

By placing a layer of a material which will absorb the radiation between the source and the human then the dose and the dose rate can be reduced. For instance in the event of a nuclear war it would be a good idea to shelter within a building with thick stone walls (Fallout shelter). During the height of the cold war, fallout shelters were identified in many urban areas. It is interesting to note that, under some conditions, shielding can increase the dose rate. For instance, if the electrons from a high energy beta source (such as 32P) strike a lead surface then X-ray photons will be generated (radiation produced in this way is known as bremsstrahlung). It is best for this reason to cover any high Z materials (such as lead, tungsten or uranium) with a low Z material such as aluminium, wood, plastic. This effect can be significant if a person wearing lead containing gloves picks up a strong beta source. Also gamma photons can induce the emission of electrons from very dense materials by the photoelectric effect, again by covering the high Z material with a low Z material this potential additional source of exposure to humans can be avoided. Furthermore gamma rays can scatter off a dense object, this enables gamma rays to "go around corners" to a small degree. Hence to obtain a very high protection factor the path in/out of the shielded enclosure should have several 90 degree turns rather than just one.

[edit] Reduction of incorporation into the human body

Potassium iodide (KI), administered orally immediately after exposure, may be used to protect the thyroid from ingested radioactive iodine in the event of an accident or terrorist attack at a nuclear power plant, or the detonation of a nuclear explosive. KI would not be effective against a dirty bomb unless the bomb happened to contain radioactive iodine, and even then it would only help to prevent thyroid cancer.

[edit] Fractionation of dose

While Devair Alves Ferreira got a large dose during the Goiânia accident of 7.0 Gy, he lived while his wife got a dose of 5.7 Gy and died. The most likely explanation is that his dose was fractionated into many smaller doses which were absorbed over a length of time, while his wife stayed in the house more and was subjected to continuous irradiation without a break, giving her body less time to repair some of the damage done by the radiation. In the same way, some of the people who worked in the basement of the wrecked Chernobyl plant received doses of 10 Gy, but in small fractions, so the acute effects were avoided.

It has been found in radiation biology experiments that if a group of cells are irradiated, then as the dose increases, the number of cells which survive decreases. It has also been found that if a population of cells is given a dose before being set aside (without being irradiated) for a length of time before being irradiated again, then the radiation causes less cell death. The human body contains many types of cells and the human can be killed by the loss of a single type of cells in a vital organ. For many short term radiation deaths (3 days to 30 days), the loss of cells forming blood cells (bone marrow) and the cells in the digestive system (microvilli which form part of the wall of the intestines are constantly being regenerated in a healthy human) cause death.

In the graph below, dose/survival curves for a hypothetical group of cells have been drawn, with and without a rest time for the cells to recover. Other than the recovery time partway through the irradiation, the cells would have been treated identically.

[edit] Treatment

[edit] Overview of modern medical practice

No effective treatment for the acute radiation syndrome exists which is able to cure it or prevent harm being caused to the body after exposure. But the medical treatment of radiation victims has a great outcome upon the chance of survival. The treatment used for such a case is designed to support the human body and keep it alive so that it can, through self repair processes, recover.

It is common for a contaminated person to be cleaned up as part of the medical care. This is to reduce the dose to medical staff and the person.

Due to the baneful effect upon the immune system one of the key parts of the medical care is to prevent infections through reverse quarantine, antibiotics, antifungals, antivirals and other means designed to prevent infections. As radiation causes damage to the blood forming tissues in the bone marrow it is common to use blood transfusions or in extreme cases a bone marrow transplant to treat the person. In the case of the Chernobyl accident it was found that bone marrow transplants were of limited use in curing the most exposed persons.

For details of the medical treatment and management of irradated persons see [1], [2], [3], [4], [5], and [6] (Warning: the content of these IAEA reports may be disturbing to some readers).

[edit] Whole body vs. part of body exposure

In the case of a person who has had only part of their body irradated then the treatment is easier, as the human body can tolerate very large exposures to the non-vital parts such as hands and feet, without having a global effect on the entire body. In short if the hands get a 100 Sv dose which results in the body receiving a dose (averaged over your entire body of 5 Sv) then the hands may be lost but Radiation poisoning would not occur. The resulting injury would be described as localised radiation burn.

[edit] Experimental treatments designed to mitigate the effect on bone marrow

Neumune® (5-androstenediol) was introduced as a radiation countermeasure by the US Armed Forces Radiobiology Research Institute (AFRRI), and is currently under joint development by Hollis-Eden Pharmaceuticals and AFRRI. Neumune® is in Investigational New Drug (IND) status and Phase I trials are being completed.

[edit] Table of exposure levels and symptoms

Dose-equivalents are presently stated in sieverts:

[edit] 0.05–0.2 Sv (5–20 REM)

No symptoms. Potential for cancer and mutation of genetic material, according to the LNT model: this is disputed (Note: see hormesis). A few researchers contend that low dose radiation may be beneficial. [7] [8] [9] 50 mSv is the yearly federal limit for radiation workers in the United States. In the UK the yearly limit for a classified radiation worker is 20 mSv. In Canada, the single-year maximum is 50 mSv, but the maximum 5-year dose is only 100 mSv. Company limits are usually stricter so as not to violate federal limits. [10]

[edit] 0.2–0.5 Sv (20–50 REM)

No noticeable symptoms. Red blood cell count decreases temporarily.

[edit] 0.5–1 Sv (50–100 REM)

Mild radiation sickness with headache and increased risk of infection due to disruption of immunity cells. Temporary male sterility is possible.

[edit] 1–2 Sv (100–200 REM)

Light radiation poisoning, 10% fatality after 30 days (LD 10/30). Typical symptoms include mild to moderate nausea (50% probability at 2 Sv), with occasional vomiting, beginning 3 to 6 hours after irradiation and lasting for up to one day. This is followed by a 10 to 14 day latent phase, after which light symptoms like general illness and fatigue appear (50% probability at 2 Sv). The immune system is depressed, with convalescence extended and increased risk of infection. Temporary male sterility is common. Spontaneous abortion or stillbirth will occur in pregnant women.

[edit] 2–3 Sv (200–300 REM)

Severe radiation poisoning, 35% fatality after 30 days (LD 35/30). Nausea is common (100% at 3 Sv), with 50% risk of vomiting at 2.8 Sv. Symptoms onset at 1 to 6 hours after irradiation and last for 1 to 2 days. After that, there is a 7 to 14 day latent phase, after which the following symptoms appear: loss of hair all over the body (50% probability at 3 Sv), fatigue and general illness. There is a massive loss of leukocytes (white blood cells), greatly increasing the risk of infection. Permanent female sterility is possible. Convalescence takes one to several months.

[edit] 3–4 Sv (300–400 REM)

Severe radiation poisoning, 50% fatality after 30 days (LD 50/30). Other symptoms are similar to the 2–3 Sv dose, with uncontrollable bleeding in the mouth, under the skin and in the kidneys (50% probability at 4 Sv) after the latent phase.

[edit] 4–6 Sv (400–600 REM)

Acute radiation poisoning, 60% fatality after 30 days (LD 60/30). Fatality increases from 60% at 4.5 Sv to 90% at 6 Sv (unless there is intense medical care). Symptoms start half an hour to two hours after irradiation and last for up to 2 days. After that, there is a 7 to 14 day latent phase, after which generally the same symptoms appear as with 3-4 Sv irradiation, with increased intensity. Female sterility is common at this point. Convalescence takes several months to a year. The primary causes of death (in general 2 to 12 weeks after irradiation) are infections and internal bleeding.

[edit] 6–10 Sv (600–1,000 REM)

Acute radiation poisoning, near 100% fatality after 14 days (LD 100/14). Survival depends on intense medical care. Bone marrow is nearly or completely destroyed, so a bone marrow transplant is required. Gastric and intestinal tissue are severely damaged. Symptoms start 15 to 30 minutes after irradiation and last for up to 2 days. Subsequently, there is a 5 to 10 day latent phase, after which the person dies of infection or internal bleeding. Recovery would take several years and probably would never be complete.

Devair Alves Ferreira received a dose of approximately 7.0 Sv (700 REM) during the Goiânia accident and lived partially due to his fractionated exposure.


[edit] 10–50 Sv (1,000–5,000 REM)

Acute radiation poisoning, 100% fatality after 7 days (LD 100/7). An exposure this high leads to spontaneous symptoms after 5 to 30 minutes. After powerful fatigue and immediate nausea caused by direct activation of chemical receptors in the brain by the irradiation, there is a period of several days of comparative well-being, called the latent (or "walking ghost") phase. After that, cell death in the gastric and intestinal tissue, causing massive diarrhea, intestinal bleeding and loss of water, leads to water-electrolyte imbalance. Death sets in with delirium and coma due to breakdown of circulation. Death is currently inevitable; the only treatment that can be offered is pain therapy.

Louis Slotin was exposed to approximately 21 Sv in a criticality accident on 21 May 1946, and died nine days later on 30 May.

[edit] 50–80 Sv (5,000–8,000 REM)

Immediate disorientation and coma in seconds or minutes. Death occurs after a few hours by total collapse of nervous system.[citation needed]

[edit] More than 80 Sv (>8,000 REM)

U.S. military forces expect immediate death.[citation needed] A worker receiving 100 Sv (10,000 REM) in an accident at Wood River, Rhode Island, USA on 24 July 1964 survived for 49 hours after exposure, and an operator receiving 120 Sv (12,000 REM) to his upper body in an accident at Los Alamos, New Mexico, USA on 30 December 1958 survived for 36 hours; details of this accident can be found on page 16 (page 30 in the PDF version) of Los Alamos' 2000 Review of Criticality Accidents [11].

[edit] Radiation poisoning in fiction

  • On the Beach is a post-apocalyptic end-of-the-world novel written by British (later Australian) author Nevil Shute, made into a movie in 1959 and a television movie in 2000. It depicts the lives of various people in Australia awaiting the arrival of a deadly radioactive cloud from a nuclear war in the northern hemisphere. In the end, everybody dies of radiation sickness or suicide. The length of time that such a fallout cloud would survive is greatly exaggerated for effect. The 1959 movie was a sensation and frightened many people.
  • Alas Babylon is a 1959 novel by Pat Frank taking a what-if look at possible effects of nuclear war on people in the fictional community of Fort Repose, Florida.
  • The 1983 film Testament follows a suburban family coping with radiation sickness after Soviet nuclear attacks on San Francisco and the continental United States.
  • The 1983 film The Day After portrays the aftereffects of a global nuclear war between the US and the USSR, focusing mainly on the residents of Lawrence, Kansas. Various characters are shown dying of radiation poisoning, in particular showing hair loss and baldness. Because actor Jason Robards played the lead role, it popularly got called "Jason Robards' disease."
  • The 1983 film Silkwood portrayed Karen Silkwood, a metallurgy worker at a plutonium processing plant.
  • Mick Jackson's 1984 TV movie Threads follows two Sheffield families and their children through the aftermath of a Soviet nuclear attack. Many characters are shown dying of radiation poisoning, cancers and deformity. Those who survive are shown aging prematurely.
  • The writers of the BBC television drama serial Edge of Darkness (1985) researched the effects of radiation poisoning and made sure that the two main characters in question, Ronald Craven (Bob Peck) and Darius Jedburgh (Joe Don Baker), exhibited realistic symptoms. After being exposed to lethal levels of radiation in a secret underground hot cell, both characters experience fatigue, vomiting and delirium before being able to continue working during a brief latency period. One other character, Emma Craven, was exposed to a lesser dose and is seen checking her hair to see if any of it was falling out. Another character, Jerry Grogan, is exposed to a lethal dose during a criticality accident, and is falling ill as the serial finishes.
  • Shohei Imamura's 1989 movie Black Rain (黒い雨; kuroi ame) deals with the aftermath of the atomic bombing of Hiroshima. The title refers to the "black rain" of radioactive fallout that fell on Hiroshima after the bombing. It is based on the book of the same name by Ibuse Masuji.
  • The events of the 1988 pilot episode of the BBC TV series Red Dwarf (and first few chapters of the 1990 book Infinity Welcomes Careful Drivers) include the entire crew of the vessel being killed in a criticality accident after Rimmer failed to reseal a drive plate correctly. Only Lister (being stored in a penal time stasis field) and his pregnant cat (concealed in the cargo bay) survived. The fallout takes precisely 3,000,000 years to become safe.
  • 1989's Fat Man and Little Boy is the dramatization of American efforts to construct the first nuclear weapon, during World War II. Scientist Michael Merriman, played by John Cusack, was exposed to a lethal dose of ionizing radiation during a criticality accident. Merriman is shown before his death, in graphic scenes. The character of Merriman was based on Louis Slotin, who died after an identical accident at Los Alamos National Laboratory.
  • In the television series 24's second season, major character George Mason inhales a fatal amount of airborne plutonium. The effects on his health are shown on an hour-by-hour basis. He becomes very ill and faces imminent death, and so sacrifices his life by flying a nuclear bomb out into the Mojave Desert, saving Los Angeles.
  • In the graphic novel When the Wind Blows by Raymond Briggs, an elderly couple is exposed to fallout after a nuclear war. Much of the second half of the story deals with the effects of radiation poisoning on them and how they interpret what is happening to them. Oblivious to the true danger they are in, they put most of the symptoms they are suffering from down to shock and stress.
  • In the television series Stargate SG-1, the character Daniel Jackson is exposed to a massive dose of radiation (approximately 12 Sv) while disarming an experimental nuclear weapon on another planet. Allowed to return to his home planet on compassionate grounds, he quickly succumbs to the symptoms of radiation poisoning, eventually only cheating death by ascending to a higher plane of existence.
  • A "twinned" copy of John Crichton, in the scifi series Farscape, suffered fatal radiation exposure during a wormhole activation, dying within a matter of hours. Symptoms included reddened complexion, nausea, pain and lethargy.
  • The 1999 time-travel TV series 7 Days features an episode in the first season involving a radiation leak from a damaged Russian nuclear submarine. When asked to describe the size of the leak, one scientist explains, "The phrase 'radioactive death cloud' comes to mind." Victims are pictured as pale and sickly.
  • The 2002 film K-19: The Widowmaker shows the events of Soviet submarine K-19, where seven crew members experience acute radiation poisoning (spending 10 to 20 minutes repairing the coolant system of the reactor); the film is based on real events. They immediately experience vomiting and nausea, and become extremely ill. Some of the remaining crew members suffer minor symptoms.
  • The German short film Tag 26 portrays the life of two survivors after a non-descript nuclear disaster, one of whom's protective radiation suits is pierced. After sealing the hole it is revealed the very small amount of time he was exposed to the contaminated air was enough to cause a blood test taken immediately after his accident to show that he had radiation poisoning. He decides a slow death in his suit is not preferable to a relatively quick one in the open air and removes the suit.
  • In the first season of War of the Worlds, host bodies to the aliens, who need radiation to negate the presence of bacteria, are often featured with sores to reflect the damage the radiation is doing to the human body (a novelisation of the pilot episode went further with the sickness as their clothes were stained by feces and vomit).
  • In the 2002 film The Sum of All Fears, an Arab man and his son find an atomic bomb in the Sinai desert that was lost when an Israeli bomber was shot down in the early days of the 1973 Arab-Israeli Yom Kippur War. The bomb had been buried there for nearly 30 years. When they uncover it they notice that the side is dented and the interior partially exposed. The man reaches inside and notes that it is warm. Later the man is shown dying from acute radiation poisoning as he is being questioned by a US intelligence agent.
  • The Russian movie Dead Man's Letters describes the life and struggle of survivors in a post-apocalyptic world. While the open end leaves room for speculation, most characters gradually die due to the lethal radiation. The movie dates 1986, the year of the Chernobyl accident.
  • The computer game Fallout deals extensively with radiation effects and treatment. The protagonist travels across post-nuclear California, encountering numerous radiation-induced mutations and highly radioactive zones. Unless special precautions are taken, the player character suffers from increasingly severe syndromes of radiation sickness and eventually dies.
  • In the docu-drama Fallout, shown on RTÉ, people on a fishing trip in the Irish Sea are exposed to a high level of radiation from an accident at Sellafield. The fisherman are shown bleeding from their mouths, ears and noses. Two of them die within a year while another is shown suffering from radiation poisoning in a hospital.
  • In the television series Battlestar Galactica the humans left on Caprica after the Cylon nuclear attack must receive constant injections of anti-radiation doses in order to survive and avoid radiation sickness.
  • Robert C. O'Brien's young adult book Z For Zachariah is set in a small American town after a nuclear holocaust. Anne Burden, a teenage girl, nurses a scientist Dr Loomis back to health after he accidentally contaminates himself by bathing in a river. He becomes sick and delirious with poisoning revealing he committed murder in his delirious state.
  • In the television series Jericho, a mysterious man seemingly coming from Denver arrives in Jericho with serious radiation poisoning and burns, with external injuries obvious. The man ultimately dies after being awakened for questioning by Jericho residents.
  • In the Star Trek: The Next Generation episode "Thine Own Self", the residents of an alien village are infected with radiation poisoning after Data, suffering from amnesia, appears carrying radioactive probe fragments. The theme of this episode parallels the actual events of the Goiânia accident.
  • Wolves Eat Dogs is a novel by Martin Cruz Smith, partially set in the fallout zone around Chernobyl,Ukraine in the year 1996. It deals extensively with radiation and radiation poisoning.
  • In the novel The Stand, by Stephen King, late stage radiation poisoning from exposure to a nuclear weapon is mentioned.

[edit] Further reading

[edit] See also

[edit] External links

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Radiation poisoning

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