Radiation Dose Calculator

Calculating REMS, RADS and Sieverts

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Understanding the radiation doses to the public from the Fukushima explosion and other nuclear power plant releases is difficult without a way to convert the various dose measurement units being reported. This calculator converts a dose measurement unit value entered to most of the other units used.

by HawaiiHealthy.com


REM:             REM: milliREM: mREM:
microREM: μREM: Sievert:            Sv: milliSievert: mSv:
microSievert: μSv: RAD:             *RAD: Gray:                Gy:
nanoGray:      nGy:

* If Alpha radiation RAD = 20*RAD

OSHA uses REMs (Roentgen Equivalent Man) to define the maximum allowable amounts of radiation exposures in the work place that nuclear power workers, medical technologists, and airline employees should receive in a year and a lifetime. The whole body maximum exposure is 1.25 REM over any 3 month period or 5 REM per year. Restricted areas are considered to be 200 milliREM per hour.

There are three types of radiation coming from Fukushima – Protons (alpha particles), Electrons (beta particles), and Photons (gamma). These particles travel varying distances catching rides in air currents and clouds. Each type of radiation has a different level of penetration into the body; Alpha for instance can be stopped by clothing, Beta by metal, whereas Gamma is difficult to stop. If the radiation is ingested in water or food, then radiation may be absorbed more directly by the internal organs.

Damage to the body is measured by RAD, a measure of the actual amount of radiation absorbed by the body. Just because a person is exposed to radiation, does not mean that it was fully absorbed. 1 REM creates 1 RAD of damage, except in the case of Alpha particles where 1 REM creates 20 RAD of damage

A Sievert (Sv) is used by the medical industry to measure the dose based on the exposure time, volume and part of the body. Japanese monitoring sites are reporting in Gray (Gy), a measurement of the absorption of one joule of energy in the form of ionizing radiation by one kilogram of matter.

However, the differences between all the radiation dose unit measurements become irrelevant when there is a nuclear disaster like Fukushima because the entire body is exposed and the exposure is constant, not quick zaps from an Xray machine or single injections for a medical procedure. Being able to convert the various units allows an understanding of the dosage from various locations within Japan and around the world.

Effects of Radiation Exposure (in a single day):
0 – 0.25 Sv (0-25 RADs): No observable effects.
0.25 – 0.50 Sv (25-100 RADs): Some nausea and loss of appetite; and blood changes.
0.50 – 1.5 Sv (25-100 RADs): Nausea, vomiting,bone marrow, lymph nodes, spleen damaged.
1.5 – 3 Sv (100-300 REM): Nausea, vomiting, diarrhea, malaise, infection; more severe bone marrow, lymph node, spleen damage; recovery probable, not assured.
3 – 5 Sv (300-600 REM): Above plus hemorrhaging, infection, diarrhea, skin peels, sterility; death if untreated.
5 – 10 Sv (600-1000 REM): Above symptoms plus central nervous system impairment; death expected..
10+ Sv (1000 REM+): Incapacitation and death.

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