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- National Center for Biotechnology Information - PubMed Central - Radiation injury (Nov. 01, 2026)
radiation injury
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What is radiation injury?
Radiation injury refers to damage or changes in tissues caused by exposure to ionizing radiation, such as X-rays, gamma rays, and high-energy particles. This type of injury occurs more readily in tissues with rapidly dividing cells, including skin, bone marrow, and the lining of the gastrointestinal tract.
Symptoms of radiation injury can include fatigue, confusion, convulsions, weakness, hair loss, internal bleeding, and skin reddening. Long-term effects can include cancer and cataracts. Radiation injury can be localized or affect the whole body, and its effects depend on the dose, duration, and type of radiation.
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How can people be exposed to harmful radiation?
People can be exposed to harmful radiation from both natural and artificial sources. Natural sources include radioactive decay of elements in rocks, soil, and even the human body, as well as from the sun and stars. Radon gas, which can become trapped in poorly ventilated areas, is a major contributor to background radiation exposure.
Artificial sources include medical X-rays, nuclear weapons fallout, nuclear power plants, and consumer products. While radiation doses from medical and dental X-rays are generally low, they contribute significantly to the average annual exposure in developed countries. Accidents involving nuclear reactors, like Chernobyl, can also release large amounts of radioactivity, leading to severe health consequences. Occupational settings, such as telecommunications, welding, and glassblowing, can lead to radiation exposure as well.
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What parts of the body are most sensitive to radiation injury?
The parts of the body most sensitive to radiation injury are those with rapidly dividing cells, including the skin, the lining of the gastrointestinal tract, and the bone marrow. Radiation injury tends to appear sooner in these areas because the destruction of progenitor cells interferes with the replacement of mature cells, which is essential for maintaining normal tissue structure and function.
Other radiosensitive cells include immature sperm-forming cells and oocytes of intermediate maturity in the reproductive organs. Additionally, the tissues of an embryo are highly radiosensitive because they are composed of rapidly proliferating cells.
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How does radiation damage cells and tissues?
Radiation's harm to cells and tissues arises from its energy, which can disrupt molecular bonds through ionization. This process involves the displacement of electrons, leading to damage of the cell's genetic material. A single radiation track can cause multiple lesions, overwhelming the cell's DNA repair mechanisms.
Whether a cell survives or dies depends on the radiation dose and exposure length. High doses cause rapid cell death, while lower doses may prevent reproduction or cause abnormal reproduction. Tissues with rapid cell turnover, like bone marrow, gastrointestinal lining, and skin, are most vulnerable. Overall, radiation can cause cell depletion, hinder tissue regeneration, weaken immunity, reduce blood cell counts, cause hemorrhages, and release toxins from tissue breakdown, leading to long-term issues such as tumor growth and a shortened lifespan.
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What are the common signs and symptoms of radiation injury?
Radiation injury occurs when high-frequency electromagnetic waves or subatomic particles cause tissue destruction and changes including within cells. Initial symptoms of radiation sickness include appetite loss, nausea, and vomiting.
Other signs and symptoms of radiation exposure include:
* Weakness and fatigue
* Fever
* Hair loss
* Inflammation of the throat
* Central nervous system damage
* Internal bleeding and hemorrhages
* Skin reddening
* Gastrointestinal issuesLong-term effects can include cancer and cataracts.
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How do doctors diagnose and treat radiation injuries?
Radiation injuries are diagnosed based on the type of ionizing radiation involved, the dose received, the duration and body part exposed, and its penetrating ability. The tissues that are most vulnerable to radiation are those with rapidly dividing cells, such as the gastrointestinal tract, skin, and bone marrow.
While there are no practical treatments to protect humans from radiation injury before it occurs, bone marrow transplants have been successful in helping people survive otherwise lethal doses of radiation. These cells migrate to the recipient's marrow, reproduce, and repopulate the blood-forming tissues.
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radiation injury, tissue damage or changes caused by exposure to ionizing radiation—namely, gamma rays, X-rays, and high-energy particles such as neutrons, electrons, and positrons. Sources of ionizing radiation may be natural (e.g., radioactive substances such as the element radium or the radioisotopes potassium-40 and carbon-14) or human-made (X-ray machines, nuclear reactors, particle accelerators, nuclear weapons, etc.).
A brief treatment of radiation injury follows. For further discussion, see radiation: Biological effects of ionizing radiation.
Radiation injury occurs in various forms, with each type dependent on the ionizing radiation involved, its penetrating ability, the portion of the body exposed, the duration of exposure, and the total dose. Radiation injury occurs most readily in tissues and organs consisting of rapidly proliferating cells; examples include the skin, the lining of the gastrointestinal tract, and the bone marrow, where progenitor cells multiply continuously to replace the mature cells that are constantly being lost through normal aging. The effects of radiation on these organs result primarily from the destruction of the progenitor cells and the consequent interference with the replacement of mature cells, which is vital to the maintenance of tissue structure and function.
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Symptoms resulting from the intensive irradiation of a large segment of the gastrointestinal tract or portion of the bone marrow constitute a condition called radiation sickness, or acute radiation syndrome. Early signs of this condition include loss of appetite, nausea, and vomiting within the first few hours after irradiation, followed by a symptom-free period that lasts until the main phase of the illness. In the intestinal form of radiation sickness, the main phase is characterized by abdominal pain, fever, and diarrhea, which lead within several days to dehydration, prostration, and a fatal shocklike state. The main phase of the hemopoietic form (that associated with bone marrow) of the illness begins later (about two to three weeks after irradiation), with typical symptoms including fever, weakness, loss of hair, infection, and hemorrhage. When damage to the bone marrow is severe, death may result from infection and uncontrollable bleeding.
Other manifestations of radiation injury are certain forms of cancer. The survivors of the atomic bomb blasts at Hiroshima and Nagasaki, some patients subjected to multiple fluoroscopic chest examinations, and certain groups of radiation workers (e.g., women who painted radium watch and clock dials) subsequently exhibited dose-dependent increases in the incidence of cancer, most notably leukemia and breast cancer.
Radiation injury also includes abnormalities produced in the embryo. The tissues of the embryo, like others composed of rapidly proliferating cells, are extremely sensitive to ionizing radiation. Organs irradiated during the process of formation thus tend to be malformed. Many kinds of radiation-induced abnormalities have been observed in experimentally irradiated rodents. A large number of these are malformations of the nervous system, such as reduced brain size or the failure of the eyes to develop. Nervous system abnormalities in human infants have been found with higher-than-normal frequency among children born to women who were pregnant and living in Hiroshima and Nagasaki at the time of the atomic bomb explosions. The incidence of intellectual disability and reduced head size in such children increased substantially when exposure occurred between the 8th and 15th weeks of gestation, which has been determined to be the age of greatest susceptibility to ionizing radiation.