Effect of radiation on a human body: Effect of radiation on a human body Units of Measurement : Units of Measurement The unit used to measure radiation dosage is the rem, which stands for r oentgen e quivalent in m an. It represents the amount of radiation needed to produce a particular amount of damage to living tissue. The total dose of rems determines how much harm a person suffers. Effects of Radiation Exposure on Human Health: Effects of Radiation Exposure on Human Health Although a dose of just 25 rems causes some detectable changes in blood, doses to near 100 rems usually have no immediate harmful effects. Doses above 100 rems cause the first signs of radiation sickness including: nausea vomiting headache some loss of white blood cells Doses of 300 rems or more cause temporary hair loss, but also more significant internal harm, including damage to nerve cells and the cells that line the digestive tract. Severe loss of white blood cells, which are the body's main defense against infection, makes radiation victims highly vulnerable to disease. Radiation also reduces production of blood platelets, which aid blood clotting, so victims of radiation sickness are also vulnerable to hemorrhaging. Half of all people exposed to 450 rems die, and doses of 800 rems or more are always fatal. Besides the symptoms mentioned above, these people also suffer from fever and diarrhea. As of yet, there is no effective treatment--so death occurs within two to fourteen days. In time, for survivors, diseases such as leukemia (cancer of the blood), lung cancer, thyroid cancer, breast cancer, and cancers of other organs can appear due to the radiation received. Doses of radiation: Doses of radiation Exposure (rem) Health Effect Time to Onset (without treatment) 5-10 changes in blood chemistry 50 nausea hours 55 fatigue 70 vomiting 75 hair loss 2-3 weeks 90 diarrhea 100 hemorrhage 400 possible death within 2 months 1,000 destruction of intestinal lining internal bleeding and death 1-2 weeks 2,000 damage to central nervous system loss of consciousness; minutes and death hours to days Slide 5: What long-term effects can radiation have? The effect of the radiation may not be to kill the cell, but to alter its DNA code in a way that leaves the cell alive but with an error in the DNA blueprint. The effect of this mutation will depend on the nature of the error and when it is read. Since this is a random process, such effects are now called stochastic. Two important stochastic effects of radiation are cancer, which results from mutations in nongerm cells (termed somatic cells ), and heritable changes, which result from mutations in germ cells (eggs and sperm). Slide 6: Cancer is the most notable long-term somatic effect. In contrast, mutations that occur in germ cells (sperm and ova) can be transmitted to future generations and are therefore called genetic or heritable effects. Genetic effects may not appear until many generations later. Genetic mutation due to radiation does not produce the visible monstrosities of science fiction; it simply produces a greater frequency of the same mutations that occur continuously and spontaneously in nature. Like cancers, the genetic effects of radiation are impossible to distinguish from mutations due to other causes. Today at least 1,300 diseases are known to be caused by a mutation.Some mutations may be beneficial; random mutation is the driving force in evolution Body parts affected: Body parts affected Hair The losing of hair quickly and in clumps occurs with radiation exposure at 200 rems or higher. Brain Since brain cells do not reproduce, they won't be damaged directly unless the exposure is 5,000 rems or greater. Like the heart, radiation kills nerve cells and small blood vessels, and can cause seizures and immediate death. Thyroid The certain body parts are more specifically affected by exposure to different types of radiation sources. The thyroid gland is susceptible to radioactive iodine. In sufficient amounts, radioactive iodine can destroy all or part of the thyroid. By taking potassium iodide can reduce the effects of exposure. Blood System When a person is exposed to around 100 rems , the blood's lymphocyte cell count will be reduced, leaving the victim more susceptible to infection. This is often refered to as mild radiation sickness. Early symptoms of radiation sickness mimic those of flu and may go unnoticed unless a blood count is done.According to data from Hiroshima and Nagaski , show that symptoms may persist for up to 10 years and may also have an increased long-term risk for leukemia and lymphoma. Heart Intense exposure to radioactive material at 1,000 to 5,000 rems would do immediate damage to small blood vessels and probably cause heart failure and death directly. Gastrointestinal Tract Radiation damage to the intestinal tract lining will cause nausea, bloody vomiting and diarrhea. This is occurs when the victim's exposure is 200 rems or more. The radiation will begin to destroy the cells in the body that divide rapidly. These including blood, GI tract, reproductive and hair cells, and harms their DNA and RNA of surviving cells. Reproductive Tract Because reproductive tract cells divide rapidly, these areas of the body can be damaged at rem levels as low as 200. Long-term, some radiation sickness victims will become sterile Is any amount of radiation safe?: Is any amount of radiation safe? There is no firm basis for setting a "safe" level of exposure above background for stochastic effects. Many sources emit radiation that is well below natural background levels. This makes it extremely difficult to isolate its stochastic effects. Some scientists assert that low levels of radiation are beneficial to health (this idea is known as hormesis ). However, there do appear to be threshold exposures for the various non-stochastic effects. (Please note that the acute affects in the following table are cumulative. For example, a dose that produces damage to bone marrow will have produced changes in blood chemistry and be accompanied by nausea.) Aren't children more sensitive to radiation than adults? : Aren't children more sensitive to radiation than adults? Yes, because children are growing more rapidly, there are more cells dividing and a greater opportunity for radiation to disrupt the process. EPA's radiation protection standards take into account the differences in the sensitivity due to age and gender. Fetuses are also highly sensitive to radiation. The resulting effects depend on which systems are developing at the time of exposure.