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Dose Rate Calculator
Click to use calculator.
This tool calculates a dose rate (DR) at 2 meters (about 6 ft) from the surface of a package containing radioactive material IF you know the dose rate at 1 meter (about 3 ft).
It will also calculate the reverse; DR at 1 meter if you know the DR at 2 meters.
These two distances are used by the Nuclear Regulatory Commission to define acceptable dose rates for packages.
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Dose (Rad)
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Biological Effect
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< 5 rad
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No immediate observable effects
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5 - 50 rad
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Slight blood changes may be detected by medical evaluation
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50 - 150 rad
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Slight blood changes will be noted and likely symptoms of nausea, fatigue, vomiting, etc.
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150 - 1000 rad
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Severe blood changes will be noted and symptoms appear immediately. Approximately 2 weeks later, some of those exposed may die. At 300-500 rad, up to one half of the people exposed will die within 30 days without intensive medical attention. Death is due to the destruction of the blood forming organs. Without white blood cells, infection is likely. At the lower end of the dose range, isolation, antibiotics, and transfusions may provide the bone marrow with time to generate new blood cells, and full
recovery is possible. At the upper end of the dose range, a bone marrow transplant may be required to produce new blood cells.
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1000 - 2000 rad
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The probability of death increases to 100% within one to two weeks of recieving a 2000 rad dose. The initial symptoms appear immediately. A few days later, things get very bad, very quickly since the gastrointestinal system is destroyed. Once the GI system ceases to function, nothing can be done, and medical care is for comfort only.
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> 2000 rad
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Death is a certainty. At doses above 5,000 rad, the central nervous system (brain and muscles) can no longer control the body functions, including breathing and blood circulation. Everything happens very quickly. Death occurs within days or hours. Nothing can be done, and medical care is for comfort only.
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As noted, nothing can be done if the dose is high enough to destroy the gastrointestinal or central nervous systems. That is why bone marrow transplants do not always work.
The information for this table was extracted from National Council on Radiation Protection (NCRP), Report No. 89, "Guidance on Radiation Received in Space Activities," 1989. (this link is only the abstract from the report)
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