what is mSv?
The sievert (symbol: Sv) is the International System of Units (SI) derived unit of dose equivalent radiation. It attempts to quantitatively evaluate the biological effects of ionizing radiation as opposed to just the absorbed dose of radiation energy, which is measured in grays. It is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dosage measurement and research into the biological effects of radiation.
The unit gray measures the absorbed dose of radiation (D), absorbed by any material. The unit sievert measures the equivalent dose of radiation (H), having the same damaging effect as an equal dose of gamma rays.
Although they are not interchangeable, the gray (symbol Gy) and the sievert both have dimensions of energy per unit mass, and are equal to one joule per kilogram
1 Gy = 1 J/kgThis SI unit is named after Rolf Maximilian Sievert. As with every International System of Units (SI) unit whose name is derived from the proper name of a person, the first letter of its symbol is upper case (Sv). When an SI unit is spelled out in English, it should always begin with a lower case letter (sievert), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Note that "degree Celsius" conforms to this rule because the "d" is lowercase. —Based on The International System of Units