Acute radiation syndrome (ARS), also known as radiation sickness, is a collection of health effects due to exposure to high amounts of ionizing radiation over a short period of time. Within the first days symptoms may include nausea, vomiting, and loss of appetite. This may then be followed by a few hours or weeks with little symptoms. After this, depending on the total dose of radiation, people may develop infections, bleeding, dehydration, and confusion, or there may be a period with few symptoms. This is finally followed by either recovery or death. The symptoms can begin within one hour and may last for several months.
The radiation generally occurs from a source outside the body, is applied over minutes with most of the body being exposed, and involves a total dose of greater than 0.7 Gy (70 rads). It is generally divided into three types: i) bone marrow syndrome (0.7 to 10 Gy); ii) gastrointestinal syndrome (10 to 50 Gy); and iii) neurovascular syndrome (>50 Gy). Sources of such radiation may include nuclear reactors, cyclotrons, and certain devices used in cancer therapy. The cells that are most affected are generally those that are rapidly dividing. Diagnosis is based on a history of exposure and symptoms. Repeated complete blood counts (CBCs) can indicate the severity of exposure.
Treatment of acute radiation syndrome is generally supportive care. This may include blood transfusions, antibiotics, colony stimulating factors, or stem cell transplant. If radioactive material remains on the skin or in the stomach it should be removed. If radioiodine was breathed in or ingested, potassium iodide may be recommended. Complications such as leukemia and other cancers among those who survive are managed as usual. Short term outcomes depend on the exposure dose.
ARS is generally rare. A single event, however, can affect a relatively large number of people. Notable cases occurred following the atomic bombing of Hiroshima and Nagasaki and the Chernobyl nuclear power plant disaster. ARS differs from chronic radiation syndrome, which occurs following prolonged exposures to relatively low doses of radiation.
|Acute radiation syndrome|
|Other names||Radiation poisoning, radiation sickness, radiation toxicity|
|Radiation causes cellular degradation by autophagy.|
|Specialty||Critical care medicine|
|Symptoms||Early: Nausea, vomiting, loss of appetite|
Later: Infections, bleeding, dehydration, confusion
|Usual onset||Within days|
|Types||Bone marrow syndrome, gastrointestinal syndrome, neurovascular syndrome|
|Causes||Large amounts of ionizing radiation over a short period of time|
|Diagnostic method||Based on history of exposure and symptoms|
|Treatment||Supportive care (blood transfusions, antibiotics, colony stimulating factors, stem cell transplant)|
|Prognosis||Depends on the exposure dose|
Classically acute radiation syndrome is divided into three main presentations: hematopoietic, gastrointestinal, and neurological/vascular. These syndromes may or may not be preceded by a prodrome. The speed of onset of symptoms is related to radiation exposure, with greater doses resulting in a shorter delay in symptom onset. These presentations presume whole-body exposure and many of them are markers that are not valid if the entire body has not been exposed. Each syndrome requires that the tissue showing the syndrome itself be exposed. The gastrointestinal syndrome is not seen if the stomach and intestines are not exposed to radiation. Some areas affected are:
Early symptoms of ARS typically includes nausea and vomiting, headaches, fatigue, fever, and a short period of skin reddening. These symptoms may occur at radiation doses as low as 0.35 grays (35 rad). These symptoms are common to many illnesses, and may not, by themselves, indicate acute radiation sickness.
|Phase||Symptom||Whole-body absorbed dose (Gy)|
|1–2 Gy||2–6 Gy||6–8 Gy||8–30 Gy||> 30 Gy|
|Immediate||Nausea and vomiting||5–50%||50–100%||75–100%||90–100%||100%|
|Time of onset||2–6 h||1–2 h||10–60 min||< 10 min||Minutes|
|Duration||< 24 h||24–48 h||< 48 h||< 48 h||N/A (patients die in < 48 h)|
|Diarrhea||None||None to mild (< 10%)||Heavy (> 10%)||Heavy (> 95%)||Heavy (100%)|
|Time of onset||—||3–8 h||1–3 h||< 1 h||< 1 h|
|Headache||Slight||Mild to moderate (50%)||Moderate (80%)||Severe (80–90%)||Severe (100%)|
|Time of onset||—||4–24 h||3–4 h||1–2 h||< 1 h|
|Fever||None||Moderate increase (10–100%)||Moderate to severe (100%)||Severe (100%)||Severe (100%)|
|Time of onset||—||1–3 h||< 1 h||< 1 h||< 1 h|
|CNS function||No impairment||Cognitive impairment 6–20 h||Cognitive impairment > 24 h||Rapid incapacitation||Seizures, tremor, ataxia, lethargy|
|Latent period||28–31 days||7–28 days||< 7 days||None||None|
|Illness||Mild to moderate Leukopenia
|Moderate to severe Leukopenia
Alopecia after 3 Gy
Dizziness and disorientation
|N/A (patients die in < 48h)|
|Death||6–8 weeks||4–6 weeks||2–4 weeks||2 days – 2 weeks||1–2 days|
Cutaneous radiation syndrome (CRS) refers to the skin symptoms of radiation exposure. Within a few hours after irradiation, a transient and inconsistent redness (associated with itching) can occur. Then, a latent phase may occur and last from a few days up to several weeks, when intense reddening, blistering, and ulceration of the irradiated site is visible. In most cases, healing occurs by regenerative means; however, very large skin doses can cause permanent hair loss, damaged sebaceous and sweat glands, atrophy, fibrosis (mostly keloids), decreased or increased skin pigmentation, and ulceration or necrosis of the exposed tissue. Notably, as seen at Chernobyl, when skin is irradiated with high energy beta particles, moist desquamation (peeling of skin) and similar early effects can heal, only to be followed by the collapse of the dermal vascular system after two months, resulting in the loss of the full thickness of the exposed skin. This effect had been demonstrated previously with pig skin using high energy beta sources at the Churchill Hospital Research Institute, in Oxford.
According to the linear no-threshold model, any exposure to ionizing radiation, even at doses too low to produce any symptoms of radiation sickness, can induce cancer due to cellular and genetic damage. Under the assumption, survivors of acute radiation syndrome face an increased risk of developing cancer later in life. The probability of developing cancer is a linear function with respect to the effective radiation dose. In radiation-induced cancer, the speed at which the condition advances, the prognosis, the degree of pain, and every other feature of the disease are not believed to be functions of the radiation dosage.
However, some studies contradict the linear no-threshold model. These studies indicate that some low levels of radiation do not increase cancer risk at all and that there may exist a threshold dosage of ionizing radiation below which exposure should be considered safe. Nonetheless, the 'no safe amount' assumption is the basis of US and most national regulatory policies regarding "man-made" sources of radiation.
Radiation sickness is caused by exposure to a large dose of ionizing radiation (> ~0.1 Gy) over a short period of time. (> ~0.1 Gy/h) This might be the result of a nuclear explosion, a criticality accident, a radiotherapy accident as in Therac-25, a solar flare during interplanetary travel, misplacement of radioactive waste as in the 1987 Goiânia accident, human error in a nuclear reactor, or other possibilities. Acute radiation sickness due to ingestion of radioactive material is possible, but rare; examples include the 1987 contamination of Leide das Neves Ferreira and the 2006 poisoning of Alexander Litvinenko.
Alpha and beta radiation have low penetrating power and are unlikely to affect vital internal organs from outside the body. Any type of ionizing radiation can cause burns, but alpha and beta radiation can only do so if radioactive contamination or nuclear fallout is deposited on the individual's skin or clothing. Gamma and neutron radiation can travel much further distances and penetrate the body easily, so whole-body irradiation generally causes ARS before skin effects are evident. Local gamma irradiation can cause skin effects without any sickness. In the early twentieth century, radiographers would commonly calibrate their machines by irradiating their own hands and measuring the time to onset of erythema.
During spaceflight, particularly flights beyond low Earth orbit (LEO), astronauts are exposed to both galactic cosmic radiation (GCR) and solar particle event (SPE) radiation. Evidence indicates past SPE radiation levels that would have been lethal for unprotected astronauts. One possible such event occurred in 1859, but another occurred during the Space Age, in fact in a few months gap between Apollo missions, in early August 1972. GCR levels that might lead to acute radiation poisoning are less well understood.
The most commonly used predictor of acute radiation symptoms is the whole-body absorbed dose. Several related quantities, such as the equivalent dose, effective dose, and committed dose, are used to gauge long-term stochastic biological effects such as cancer incidence, but they are not designed to evaluate acute radiation syndrome. To help avoid confusion between these quantities, absorbed dose is measured in units of grays (in SI, unit symbol Gy) or rads (in CGS), while the others are measured in sieverts (in SI, unit symbol Sv) or rems (in CGS). 1 rad = 0.01 Gy and 1 rem = 0.01 Sv.
In most of the acute exposure scenarios that lead to radiation sickness, the bulk of the radiation is external whole-body gamma, in which case the absorbed, equivalent and effective doses are all equal. There are exceptions, such as the Therac-25 accidents and the 1958 Cecil Kelley criticality accident, where the absorbed doses in Gy or rad are the only useful quantities, because of the targeted nature of the exposure to the body.
Radiotherapy treatments are typically prescribed in terms of the local absorbed dose, which might be 60 Gy or higher. The dose is fractionated (about 2 Gy per day for curative treatment), which allows for the normal tissues to undergo repair, allowing it to tolerate a higher dose than would otherwise be expected. The dose to the targeted tissue mass must be averaged over the entire body mass, most of which receives negligible radiation, to arrive at a whole-body absorbed dose that can be compared to the table above.
High radiation doses can cause DNA damage. If left unrepaired, this damage can create serious and even lethal chromosomal aberrations. Ionizing radiation can produce reactive oxygen species, which are very damaging to DNA.
Ionizing radiation does direct damage to cells by causing localized ionization events, creating clusters of DNA damage. This damage includes loss of nucleobases and breakage of the sugar-phosphate backbone that binds to the nucleobases. Breakages can happen to one or both of the backbone strands. Single-stranded breakages are easier to repair than double-stranded breakages, because there is still an unbroken complementary strand to use as a template. The DNA organization at the level of histones, nucleosomes, and chromatin also affects its susceptibility to radiation damage.
Clustered damage, defined as at least two lesions within a helical turn, is especially harmful. While DNA damage happens frequently and naturally in the cell from endogenous sources, clustered damage is a unique effect of radiation exposure. Clustered damage takes longer to repair than isolated breakages, and is less likely to be repaired at all. Larger radiation doses are more prone to cause tighter clustering of damage, and closely localized damage is increasingly less likely to be repaired.
Somatic mutations cannot be passed down from parent to offspring, but these mutations can propagate in cell lines within an organism. Radiation damage can also cause chromosome and chromatid aberrations, and their effect depends on what stage of the mitotic cycle the cell is currently in when the irradiation occurs. If the cell is in interphase, while it is still a single strand of chromatin, the damage will be replicated during the S1 phase of cell cycle, and there will be a break on both chromosome arms. Then the damage will be apparent in both daughter cells. If the irradiation occurs after replication, only one arm will bear the damage. This damage will only be apparent in one daughter cell. A damaged chromosome may cyclize, binding to another chromosome, or to itself.
Diagnosis is typically made based on a history of significant radiation exposure and suitable clinical findings. An absolute lymphocyte count can give a rough estimate of radiation exposure. Time from exposure to vomiting can also give estimates of exposure levels if they are less than 10 Gray (1000 rad).
The longer that humans are subjected to radiation the larger the dose will be. The advice in the nuclear war manual entitled Nuclear War Survival Skills published by Cresson Kearny in the U.S. was that if one needed to leave the shelter then this should be done as rapidly as possible to minimize exposure.
In chapter 12, he states that "[q]uickly putting or dumping wastes outside is not hazardous once fallout is no longer being deposited. For example, assume the shelter is in an area of heavy fallout and the dose rate outside is 400 roentgen (R) per hour, enough to give a potentially fatal dose in about an hour to a person exposed in the open. If a person needs to be exposed for only 10 seconds to dump a bucket, in this 1/360 of an hour he will receive a dose of only about 1 R. Under war conditions, an additional 1-R dose is of little concern." In peacetime, radiation workers are taught to work as quickly as possible when performing a task that exposes them to radiation. For instance, the recovery of a radioactive source should be done as quickly as possible.
Increasing distance from the radiation source reduces the dose according to the inverse-square law for a point source. Distance can sometimes be effectively increased by means as simple as handling a source with forceps rather than fingers. This could reduce erythema to the fingers, but the extra few centimeters distance from the body will give little protection from acute radiation syndrome.
Matter attenuates radiation in most cases, so placing any mass (e.g., lead, dirt, sandbags, vehicles) between humans and the source will reduce the radiation dose. This is not always the case, however; care should be taken when constructing shielding for a specific purpose. For example, although high atomic number materials are very effective in shielding photons, using them to shield beta particles may cause higher radiation exposure due to the production of bremsstrahlung x-rays, and hence low atomic number materials are recommended. Also, using material with a high neutron activation cross section to shield neutrons will result in the shielding material itself becoming radioactive and hence more dangerous than if it were not present.
There are many types of shielding strategies that can be used to reduce the effects of radiation exposure. Internal contamination protective equipment such as respirators are used to prevent internal deposition as a result of inhalation and ingestion of radioactive material. Dermal protective equipment, which protects against external contamination, provides shielding to prevent radioactive material from being deposited on external structures. While these protective measures do provide a barrier from radioactive material deposition, they do not shield from externally penetrating gamma radiation. This leaves anyone exposed to penetrating gamma rays at high risk of Acute Radiation Syndrome.
Naturally, shielding the entire body from high energy gamma radiation is optimal, but the required mass to provide adequate attenuation makes functional movement nearly impossible. In the event of a radiation catastrophe, medical and security personnel need mobile protection equipment in order to safely assist in containment, evacuation, and many other necessary public safety objectives.
Research has been done exploring the feasibility of partial body shielding, a radiation protection strategy that provides adequate attenuation to only the most radio-sensitive organs and tissues inside the body. Irreversible stem cell damage in the bone marrow is the first life-threatening effect of intense radiation exposure and therefore one of the most important bodily elements to protect. Due to the regenerative property of hematopoietic stem cells, it is only necessary to protect enough bone marrow to repopulate the exposed areas of the body with the shielded supply. This concept allows for the development of lightweight mobile radiation protection equipment, which provides adequate protection, deferring the onset of Acute Radiation Syndrome to much higher exposure doses. One example of such equipment is the 360 gamma, a radiation protection belt that applies selective shielding to protect the bone marrow stored in the pelvic area as well as other radio sensitive organs in the abdominal region without hindering functional mobility.
More information on bone marrow shielding can be found in the Health Physics Radiation Safety Journal article Selective Shielding of Bone Marrow: An Approach to Protecting Humans from External Gamma Radiation, or in the Organisation for Economic Co-operation and Development (OECD) and the Nuclear Energy Agency (NEA)'s 2015 report: Occupational Radiation Protection in Severe Accident Management.
Where radioactive contamination is present, a gas mask, dust mask, or good hygiene practices may offer protection, depending on the nature of the contaminant. Potassium iodide (KI) tablets can reduce the risk of cancer in some situations due to slower uptake of ambient radioiodine. Although this does not protect any organ other than the thyroid gland, their effectiveness is still highly dependent on the time of ingestion, which would protect the gland for the duration of a twenty-four-hour period. They do not prevent acute radiation syndrome as they provide no shielding from other environmental radionuclides.
If an intentional dose is broken up into a number of smaller doses, with time allowed for recovery between irradiations, the same total dose causes less cell death. Even without interruptions, a reduction in dose rate below 0.1 Gy/h also tends to reduce cell death. This technique is routinely used in radiotherapy.
The human body contains many types of cells and a 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 two important types of cells that are constantly being regenerated causes death. 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) is fatal.
There is a direct relationship between the degree of the neutropenia that emerges after exposure to radiation and the increased risk of developing infection. Since there are no controlled studies of therapeutic intervention in humans, most of the current recommendations are based on animal research.
The treatment of established or suspected infection following exposure to radiation (characterized by neutropenia and fever) is similar to the one used for other febrile neutropenic patients. However, important differences between the two conditions exist. Individuals that develop neutropenia after exposure to radiation are also susceptible to irradiation damage in other tissues, such as the gastrointestinal tract, lungs and central nervous system. These patients may require therapeutic interventions not needed in other types of neutropenic patients. The response of irradiated animals to antimicrobial therapy can be unpredictable, as was evident in experimental studies where metronidazole and pefloxacin therapies were detrimental.
Antimicrobials that reduce the number of the strict anaerobic component of the gut flora (i.e., metronidazole) generally should not be given because they may enhance systemic infection by aerobic or facultative bacteria, thus facilitating mortality after irradiation.
An empirical regimen of antimicrobials should be chosen based on the pattern of bacterial susceptibility and nosocomial infections in the affected area and medical center and the degree of neutropenia. Broad-spectrum empirical therapy (see below for choices) with high doses of one or more antibiotics should be initiated at the onset of fever. These antimicrobials should be directed at the eradication of Gram-negative aerobic bacilli ( i.e., Enterobacteriace, Pseudomonas ) that account for more than three quarters of the isolates causing sepsis. Because aerobic and facultative Gram-positive bacteria (mostly alpha-hemolytic streptococci) cause sepsis in about a quarter of the victims, coverage for these organisms may also be needed.
A standardized management plan for people with neutropenia and fever should be devised. Empirical regimens contain antibiotics broadly active against Gram-negative aerobic bacteria (quinolones: i.e., ciprofloxacin, levofloxacin, a third- or fourth-generation cephalosporin with pseudomonal coverage: e.g., cefepime, ceftazidime, or an aminoglycoside: i.e. gentamicin, amikacin).
Acute effects of ionizing radiation were first observed when Wilhelm Röntgen intentionally subjected his fingers to X-rays in 1895. He published his observations concerning the burns that developed, though he misattributed them to ozone, a free radical produced in air by X-rays. Other free radicals produced within the body are now understood to be more important. His injuries healed later.
Ingestion of radioactive materials caused many radiation-induced cancers in the 1930s, but no one was exposed to high enough doses at high enough rates to bring on acute radiation syndrome. Marie Curie died of aplastic anemia caused by radiation, a possible early incident of acute radiation syndrome.
The Radium Girls were female factory workers who contracted radiation poisoning from painting watch dials with self-luminous paint at the United States Radium factory in Orange, New Jersey, around 1917.
The atomic bombings of Hiroshima and Nagasaki resulted in high acute doses of radiation to a large number of Japanese, allowing for greater insight into its symptoms and dangers. Red Cross Hospital Surgeon Terufumi Sasaki led intensive research into the syndrome in the weeks and months following the Hiroshima bombings. Dr Sasaki and his team were able to monitor the effects of radiation in patients of varying proximities to the blast itself, leading to the establishment of three recorded stages of the syndrome. Within 25–30 days of the explosion, the Red Cross surgeon noticed a sharp drop in white blood cell count and established this drop, along with symptoms of fever, as prognostic standards for Acute Radiation Syndrome. Actress Midori Naka, who was present during the atomic bombing of Hiroshima, was the first incident of radiation poisoning to be extensively studied. Her death on 24 August 1945 was the first death ever to be officially certified as a result of acute radiation syndrome (or "Atomic bomb disease").
There are two major databases that track radiation accidents: The American ORISE REAC/TS and the European IRSN ACCIRAD. REAC/TS shows 417 accidents occurring between 1944 and 2000, causing about 3000 cases of acute radiation syndrome, of which 127 were fatal. ACCIRAD lists 580 accidents with 180 ARS fatalities for an almost identical period. The two deliberate bombings are not included in either database, nor are any possible radiation-induced cancers from low doses. The detailed accounting is difficult because of confounding factors. ARS may be accompanied by conventional injuries such as steam burns, or may occur in someone with a pre-existing condition undergoing radiotherapy. There may be multiple causes for death, and the contribution from radiation may be unclear. Some documents may incorrectly refer to radiation-induced cancers as radiation poisoning, or may count all overexposed individuals as survivors without mentioning if they had any symptoms of ARS. The table below attempts to catalog some cases of ARS. Many of these incidents involved additional fatalities from other causes, such as cancer, which are excluded from this table.
|Year||Type||Incident||ARS fatalities||ARS survivors||Location|
|1945||criticality||Exposure of Harry Daghlian||1||0||Los Alamos, New Mexico, United States|
|1946||criticality||Pajarito accident, including exposure of Louis Slotin||1||2||Los Alamos, New Mexico, United States|
|1957||alleged crime||Nikolay Khokhlov assassination attempt||0||1||Frankfurt, West Germany|
|1958||criticality||Cecil Kelley criticality accident||1||0||Los Alamos, New Mexico, United States|
|1961||reactor||Soviet submarine K-19||8||many||North Atlantic, near Southern Greenland|
|1961||criticality||SL-1 experimental reactor explosion||3||0||NRTS, near Idaho Falls, Idaho, United States|
|1962||orphan source||Radiation accident in Mexico City||4||?||Mexico City, Mexico|
|1968||reactor||Soviet submarine K-27||9||40||near Gremikha Bay, Russia|
|1984||orphan source||Radiation accident in Morocco||8||3||Mohammedia, Morocco|
|1985||reactor||Soviet submarine K-431||10||49||Chazhma Bay naval facility near Vladivostok, USSR|
|1985||radiotherapy||Therac-25 radiation overdose accidents||3||3|
|1986||reactor||Chernobyl disaster||28||206 - 209||Chernobyl Nuclear Power Plant, Ukrainian SSR|
|1987||orphan source||Goiânia accident||4||?||Goiânia, Brazil|
|1990||radiotherapy||Radiotherapy accident in Zaragoza||11||?||Zaragoza, Spain|
|1996||radiotherapy||Radiotherapy accident in Costa Rica||7 to 20||46||San José, Costa Rica|
|1999||criticality||Tokaimura nuclear accident||2||1||Tōkai, Ibaraki, Japan|
|2000||orphan source||Samut Prakan radiation accident||3||7||Samut Prakan Province, Thailand|
|2000||radiotherapy||Instituto Oncologico Nacional accident||3 to 7||?||Panama City, Panama|
|2004||alleged murder||Yasser Arafat's alleged poisoning with Polonium-210||1 (disputed)||0||Palestina (was hospitalized and died in France)|
|2006||homicide||Poisoning of Alexander Litvinenko||1||0||London, United Kingdom|
|2010||orphan source||Mayapuri radiological accident||1||7||Mayapuri, India|
Thousands of scientific experiments have been performed to study acute radiation syndrome in animals. There is a simple guide for predicting survival/death in mammals, including humans, following the acute effects of inhaling radioactive particles.
Chronic radiation syndrome (CRS) is a constellation of health effects of radiation that occur after months or years of chronic exposure to high amounts of radiation. Chronic radiation syndrome develops with a speed and severity proportional to the radiation dose received, i.e., it is a deterministic effect of exposure to ionizing radiation, unlike radiation-induced cancer. It is distinct from acute radiation syndrome in that it occurs at dose rates low enough to permit natural repair mechanisms to compete with the radiation damage during the exposure period. Dose rates high enough to cause the acute form (> ~0.1 Gy/h) are fatal long before onset of the chronic form. The lower threshold for chronic radiation syndrome is between 0.7 and 1.5 Gy, at dose rates above 0.1 Gy/yr. This condition is primarily known from the Kyshtym disaster, where 66 cases were diagnosed. It has received little mention in Western literature; but see the ICRP’s 2012 Statement.In 2013, Alexander V. Akleyev described the chronology of the clinical course of CRS while presenting at ConRad in Munich, Germany. In his presentation, he defined the latent period as being 1-5 years, and the formation coinciding with the period of maximum radiation dose. The recovery period was described as being 3-12 months after exposure ceased. He concluded that "CRS represents a systemic response of the body as a whole to the chronic total body exposure in man." In 2014, Akleyev's book "Comprehensive analysis of chronic radiation syndrome, covering epidemiology, pathogenesis, pathoanatomy, diagnosis and treatment" was published by Springer.Cleveland BioLabs
Cleveland BioLabs, Inc. (Nasdaq: CBLI) is a clinical-stage biotechnology company with a focus on oncology development. It specializes in research and development of products with the potential to treat cancer and protect against death following acute radiation syndrome. The company was founded in 2003 and is headquartered in Buffalo, New York. It has license agreements and collaborations with the Cleveland Clinic, Roswell Park Cancer Institute, the Children's Cancer Institute Australia, and the Armed Forces Radiobiology Research Institute.Daigo Fukuryū Maru
Daigo Fukuryū Maru (第五福龍丸, F/V Lucky Dragon 5) was a Japanese tuna fishing boat with a crew of 23 men which was contaminated by nuclear fallout from the United States Castle Bravo thermonuclear weapon test at Bikini Atoll on March 1, 1954.
The crew suffered acute radiation syndrome (ARS) for a number of weeks after the Bravo test in March. During their ARS treatment, the crew were inadvertently infected with hepatitis through blood transfusions. All recovered except for Aikichi Kuboyama, the boat's chief radioman, who died on September 23, 1954, from an underlying liver cirrhosis compounded by the secondary hepatitis infection. Kuboyama is considered the first victim of the hydrogen bomb and of test shot Castle Bravo.Gray (unit)
The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI). It is defined as the absorption of one joule of radiation energy per kilogram of matter.It is used as a unit of the radiation quantity absorbed dose that measures the energy deposited by ionizing radiation in a unit mass of matter being irradiated, and is used for measuring the delivered dose of ionising radiation in applications such as radiotherapy, food irradiation and radiation sterilization and predicting likely acute effects, such as acute radiation syndrome in radiological protection. As a measure of low levels of absorbed dose, it also forms the basis for the calculation of the radiation protection unit the sievert, which is a measure of the health effect of low levels of ionizing radiation on the human body.
The gray is also used in radiation metrology as a unit of the radiation quantity kerma; defined as the sum of the initial kinetic energies of all the charged particles liberated by uncharged ionizing radiation in a sample of matter per unit mass. The gray is an important unit in ionising radiation measurement and was named after British physicist Louis Harold Gray, a pioneer in the measurement of X-ray and radium radiation and their effects on living tissue.The gray was adopted as part of the International System of Units in 1975. The corresponding cgs unit to the gray is the rad (equivalent to 0.01 Gy), which remains common largely in the United States, though "strongly discouraged" in the style guide for U.S. National Institute of Standards and Technology authors.Monitor unit
A monitor unit (MU) is a measure of machine output from a clinical accelerator for radiation therapy such as a linear accelerator or an orthovoltage unit. Monitor units are measured by monitor chambers, which are ionization chambers that measure the dose delivered by a beam and are built into the treatment head of radiotherapy linear accelerators.Nuclear-powered aircraft
A nuclear-powered aircraft is a concept for an aircraft intended to be powered by nuclear energy. The intention was to produce a jet engine that would heat compressed air with heat from fission, instead of heat from burning fuel. During the Cold War, the United States and Soviet Union researched nuclear-powered bomber aircraft, the greater endurance of which could enhance nuclear deterrence, but neither country created any such operational aircraft.One inadequately solved design problem was the need for heavy shielding to protect the crew and those on the ground from acute radiation syndrome; other potential problems included dealing with crashes.
Some unmanned missile designs included nuclear powered supersonic cruise missiles.
However, the advent of ICBMs, and nuclear submarines in the 1960s greatly diminished the strategic advantage of such aircraft, and respective projects were cancelled; the inherent danger of the technology has prevented its civilian use.Rad (unit)
The rad is a unit of absorbed radiation dose, defined as 1 rad = 0.01 Gy = 0.01 J/kg. It was originally defined in CGS units in 1953 as the dose causing 100 ergs of energy to be absorbed by one gram of matter. The material absorbing the radiation can be human tissue or silicon microchips or any other medium (for example, air, water, lead shielding, etc.).
It has been replaced by the gray (Gy) in SI derived units but is still used in the United States, though "strongly discouraged" in the chapter 5.2 of style guide for U.S. National Institute of Standards and Technology authors. A related unit, the roentgen, is used to quantify the radiation exposure. The F-factor can be used to convert between rad and roentgens.Radiation poisoning (disambiguation)
Radiation poisoning may refer to:
Acute radiation syndrome, the short-term systemic health effects of a large radiation dose.
Chronic radiation syndrome
Electromagnetic hypersensitivity, the false belief that exposure to electromagnetic fields result in adverse medical symptoms
The ingestion of radioactive material, notably in the poisoning of Alexander Litvinenko and Eben Byers
The action of neutron poisons that inhibit nuclear chain reactions
Any of the negative health effects of radiation other than teratogenesis, including
Radiation-induced lung injury
Radiation-induced cognitive declineRadiation protection
Radiation protection, also known as radiological protection, is defined by the International Atomic Energy Agency (IAEA) as "The protection of people from harmful effects of exposure to ionizing radiation, and the means for achieving this". Exposure can be from a source of radiation external to the human body or due to internal irradiation caused by the ingestion of radioactive contamination.
Ionizing radiation is widely used in industry and medicine, and can present a significant health hazard by causing microscopic damage to living tissue. There are two main categories of ionizing radiation health effects. At high exposures, it can cause "tissue" effects, also called "deterministic" effects due the certainty of them happening, conventionally indicated by the unit gray and resulting in acute radiation syndrome. For low level exposures there can be statistically elevated risks of radiation-induced cancer, called "stochastic effects" due to the uncertainty of them happening, conventionally indicated by the unit sievert.
Fundamental to radiation protection is the avoidance or reduction of dose using the simple protective measures of time, distance and shielding. The duration of exposure should be limited to that necessary, the distance from the source of radiation should be maximised, and the source shielded wherever possible. To measure personal dose uptake in occupational or emergency exposure, for external radiation personal dosimeters are used, and for internal dose to due to ingestion of radioactive contamination, bioassay techniques are applied.
For radiation protection and dosimetry assessment the International Commission on Radiation Protection (ICRP) and International Commission on Radiation Units and Measurements (ICRU) publish recommendations and data which is used to calculate the biological effects on the human body of certain levels of radiation, and thereby advise acceptable dose uptake limits.Radiobiology
Radiobiology (also known as radiation biology) is a field of clinical and basic medical sciences that involves the study of the action of ionizing radiation on living things, especially health effects of radiation. Ionizing radiation is generally harmful and potentially lethal to living things but can have health benefits in radiation therapy for the treatment of cancer and thyrotoxicosis. Its most common impact is the induction of cancer with a latent period of years or decades after exposure. High doses can cause visually dramatic radiation burns, and/or rapid fatality through acute radiation syndrome. Controlled doses are used for medical imaging and radiotherapy.Radiophobia
Radiophobia is a fear of ionizing radiation. Given that significant doses of radiation are harmful, even deadly (i.e. radiation-induced cancer, and acute radiation syndrome), every threat of the radiation exposure may cause significant fear. The term is also used to describe the opposition to the use of nuclear technology (i.e. nuclear power) arising from concerns disproportionately greater than actual risks would merit.Radioresistance
Radioresistance is the level of ionizing radiation that organisms are able to withstand.
Ionizing-radiation-resistant organisms (IRRO) were defined as organisms for which the dose of acute ionizing radiation (IR) required to achieve 90% reduction (D10) is greater than 1000 gray (Gy) Radioresistance is surprisingly high in many organisms, in contrast to previously held views. For example, the study of environment, animals and plants around the Chernobyl disaster area has revealed an unexpected survival of many species, despite the high radiation levels. A Brazilian study in a hill in the state of Minas Gerais which has high natural radiation levels from uranium deposits, has also shown many radioresistant insects, worms and plants. Certain extremophiles, such as the bacteria Deinococcus radiodurans and the tardigrades, can withstand large doses of ionizing radiation on the order of 5,000 Gy.Roentgen equivalent man
The roentgen equivalent man (or rem) is an older, CGS unit of equivalent dose, effective dose, and committed dose which are measures of the health effect of low levels of ionizing radiation on the human body.
Quantities measured in rem are designed to represent the stochastic biological risk of ionizing radiation; primarily radiation-induced cancer. These quantities are derived from absorbed dose, which in the CGS system has the unit rad which is also an older unit. There is no universally applicable conversion constant from rad to rem; the conversion depends on relative biological effectiveness (RBE).
The rem has been defined since 1976 as equal to 0.01 sievert, which is the more commonly used SI unit outside the United States. A number of earlier definitions going back to 1945 were derived from the roentgen unit, which was named after Wilhelm Röntgen, a German scientist who discovered X-rays. The acronym is now a misleading historical artifact, since 1 roentgen actually deposits about 0.96 rem in soft biological tissue, when all weighting factors equal unity. Older units of rem following other definitions are up to 17% smaller than the modern rem.
One rem carries with it a 0.05% chance of eventually developing cancer. Doses greater than 100 rem received over a short time period are likely to cause acute radiation syndrome (ARS), possibly leading to death within weeks if left untreated. Note that the quantities that are measured in rem were not designed to be correlated to ARS symptoms. The absorbed dose, measured in rad, is the best indicator of ARS.A rem is a large dose of radiation, so the millirem (mrem), which is one thousandth of a rem, is often used for the dosages commonly encountered, such as the amount of radiation received from medical x-rays and background sources.Sievert
The sievert (symbol: Sv) is a derived unit of ionizing radiation dose in the International System of Units (SI) and is a measure of the health effect of low levels of ionizing radiation on the human body. The sievert is of importance in dosimetry and radiation protection, and is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dose measurement and research into the biological effects of radiation.
The sievert is used for radiation dose quantities such as equivalent dose and effective dose, which represent the risk of external radiation from sources outside the body, and committed dose which represents the risk of internal irradiation due to inhaled or ingested radioactive substances. The sievert is intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of radiation-induced cancer and genetic damage. One sievert carries with it a 5.5% chance of eventually developing cancer based on the linear no-threshold model.To enable consideration of stochastic health risk, calculations are performed to convert the physical quantity absorbed dose into equivalent dose and effective dose, the details of which depend on the radiation type and biological context. For applications in radiation protection and dosimetry assessment the International Commission on Radiological Protection (ICRP) and International Commission on Radiation Units and Measurements (ICRU) have published recommendations and data which are used to calculate these. These are under continual review, and changes are advised in the formal "Reports" of those bodies.
Conventionally, the sievert is not used for high dose rates of radiation that produce deterministic effects, which is the severity of acute tissue damage that is certain to happen, such as acute radiation syndrome; these effects are compared to the physical quantity absorbed dose measured by the unit gray (Gy).One sievert equals 100 rem. The rem is an older, non-SI unit of measurement.StemRad
StemRad is an Israeli-American start-up company that develops and manufactures personal protective equipment (PPE) against ionizing radiation. Its first product was the 360 Gamma, a device that protects the user's pelvic bone marrow from gamma radiation. In July 2015 it signed a working agreement with aerospace company Lockheed Martin to develop personal radiation protection for astronauts.Syndrome X
Syndrome X may refer to:
Groups of symptoms, so called as placeholder name, when newly discovered:
Cardiac syndrome X
Neotenic complex syndrome
Acute radiation syndrome, upon its recognition in 1945Terufumi Sasaki
Terufumi Sasaki (Japanese: 佐々木 輝文, Hepburn: Sasaki Terufumi) was a surgeon at the Red Cross hospital in Hiroshima in 1945 and was personally situated 1,650 yards from the hypocenter of the Little Boy explosion. Twenty five years old that year, out of an initial 30 interviewed, he became one of the six central biopics found in the 1946 book Hiroshima by John Hersey. He lived at his family home in Mukaihara district prior to the detonation and practiced medicine in communities with poor health care without a permit.After the detonation occurred, he was one of the first to observe, document and attempt to treat "atomic bomb sickness", now known as acute radiation syndrome. Terufumi Sasaki led intensive research into the syndrome in the weeks and months post-detonation, leading to the establishment of three recorded stages of the syndrome. Within 25–30 days of the explosion, Sasaki noticed a sharp drop in white blood cell count and established this drop, along with symptoms of fever, as prognostic standards for Acute Radiation Syndrome. In the years afterward he would become one of the leading surgeons continuing to document and treat the Hibakusha (explosion-affected) community, serving as an important source of knowledge for the Atomic Bomb Casualty Commission, and later Radiation Effects Research Foundation, who began and continue the Life Span Study of atomic bomb survivors, respectively.Treatment of infections after exposure to ionizing radiation
Infections caused by exposure to ionizing radiation can be extremely dangerous, and are of public and government concern. Numerous studies have demonstrated that the susceptibility of organisms to systemic infection increased following exposure to ionizing radiation. The risk of systemic infection is higher when the organism has a combined injury, such as a conventional blast, thermal burn, or radiation burn. There is a direct quantitative relationship between the magnitude of the neutropenia that develops after exposure to radiation and the increased risk of developing infection. Because no controlled studies of therapeutic intervention in humans are available, almost all of the current information is based on animal research.Vasily Ignatenko
Vasily Ivanovich Ignatenko (Ukrainian: Василь Іванович Ігнатенко; Belarusian: Васіль Іванавіч Ігнаценка; Russian: Василий Иванович Игнатенко; 13 March 1961 – 13 May 1986) was a Soviet firefighter who was one of the first responders at the site of the Chernobyl Nuclear Power Plant disaster. Having received a fatal dose of radiation, he died from acute radiation syndrome on 13 May 1986.Ignatenko was laid to rest at the Mitinskoe Cemetery in Moscow along with others—first responders and plant personnel—who died in the Chernobyl disaster. In 2006, he was posthumously awarded the title of the Hero of Ukraine, the highest national award in the country.Ignatenko's story was told by his widow, Lyudmila Ignatenko, in Voices from Chernobyl by Svetlana Alexievich. It became an inspiration for the related storyline in the 2019 HBO miniseries Chernobyl. Vasily Ignatenko is portrayed by the British actor Adam Nagaitis, and his wife by the Irish actress Jessie Buckley.
Consequences of external causes (T66–T78, 990–995)
Radiation (physics and health)
quantities & units
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