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| Fig. 1: The Explosure of Hiroshima (left) and Nagasaki (right). (Courtesy of the DOE. Source: Wikimedia Commons) |
There are two types of radiation. The first type is radiation that we interact regularly and are familiar with. We experience it as sound waves, heat waves and visible light. [1] The second type is called ionizing radiation. This radiation has enough energy to remove tightly bound electrons from their orbits during an interaction with an atom. [1] This means that when your body is exposed to ionizing rays, your DNA gets damaged. This can cause potentially life-threatening illness.
There are two ways that people can be exposed to radiation: they can be exposed externally to a close source of radiation or they can be exposed internally with radioactive materials that have entered the body through ingestion, inhalation or transdermal absorption. [2] Earth has background radiation because of the naturally radioactive elements found in its crust and cosmic rays. Because of this, every person is exposed, on average, to 2.4 mSv/yr of ionizing radiation from natural sources every year. This can vary slightly depending on the person's lifestyle, liiving area and area of work. [1] In addition, human technologies such as nuclear reactors, nuclear bombs, medicine, and the nuclear industry are important radiation in the environment. [1] Example of nuclear pollution include the two nuclear bombs dropped on Hiroshima and Nagasaki (see Fig. 1) and the Chernobyl and Fukushima nuclear power plant failures. We need to consider that nuclear explosions emit radiation, heart and shock waves. Because of this, people caught closer to the explosion suffer different radiation dangers than people further from the explosion.
The damage that a person will receive from radiation depends on the time length of exposure and the strength of the exposure. If a person is caught near the detonation of a nuclear bomb, the person will be exposed to a large amount of heat and light and this can lead to thermal injuries such like flash burns, variable degree skin burns, flash blinding and others. The shock wave can lead to broken or fractured bones, lacerations, and ruptures. [3] Avoiding the physical traumas of the blast is just half of the battle, however. If a person's whole body or a major part of it is exposed to a greater dose then 1 Gy delivered at a high-dose-rate, the will develop acute radiation syndrome (ARS). [4] Depending on the dose of radiation, the person can experience long-term risk for infertility, cancer and fetal abnormalities. The rapidly replicating cells like hair follicles, bone marrow, and others have the highest sensitivity to the effect of radiation. If a person is exposed to 5-6 Gy of ionizing radiation during a short amount of time, the person has a low chance of survival. However, if the same amount of exposure is over a longer amount of time the person has a chance of recovery. [2]
Treatments are scarce and dependant of the severity of ARS. For people with low exposure, treatments can be simple protein supplements which attempt to counteract the dramatic decrease in white blood cells. [5] If the exposure is more severe, the person might require a bone marrow transplant. People who experienced skin burns might require a skin transplant or skin grafting. Unfortunately for people with high exposure, there is no treatment.
© Lukas Kisunas. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] J. B. Reitan, "Radiation Accidents and Radiation Disasters," Tidsskr. Nor. Laegeforen. 113 1583 (1983).
[2] J. K. Waselenko et al., "Medical Management of the Acute Radiation Syndrome: Recommendations of the Strategic National Stockpile Radiation Working Group," Ann. Intern. Med. 140, 1037 (2004).
[3] E. R. Goans et al., "Early Dose Assessment Following Severe Radiation Accidents," Health Phys. 72, 513 (1997).
[4] S. C. Finch, "Acute Radiation Syndrome," J. Am. Med. Assoc. 258, 664 (1987).
[5] M. Galla, "Efforts to Cure Radiation Sickness," Physics 241, Stanford University, Winter 2016.
