The sievert is a unit derived from the dose of ionizing radiation in the International System of Units. It is represented by the symbol Sv. It is a measure of the effect that low levels of ionizing radiation on the human body produce on health. Sievert is of fundamental importance in dosimetry. the protection against radiation.
The name of sievert is due to the Swedish medical physicist Rolf Maximilian Sievert for his work in the measurement of radiation dose. the investigation of the biological effects of radiation.
The quantities that are measured in sieverts are destined. represent the stochastic risk to health, which for the evaluation of radiation dose is defined as the probability of induction of a cancer. of producing some genetic damage. A sievert carries a probability of 5.5% of developing cancer eventually based on the linear model without threshold.
A sievert is equivalent. 100 rem. The rem is an old unit of measurement, not recognized in the international measurement system.
The equivalent dose is a measure of the dose of radiation a tissue receives. Attempts have been made to correct the different biological effects of the different types of ionizing radiation. The equivalent dose is, therefore, a less fundamental quantity than the absorbed dose, but it is biologically more relevant.
The equivalent dose is expressed in sievert.
The equivalent dose for a tissue is found by multiplying the absorbed dose by a weighting factor of the radiation, which depends on the type of radiation.
The effective radiation dose for an individual can then be determined by multiplying the equivalent dose in each organ by a tissue weighting factor, which depends on the part of the body that is exposed. the radiation,. adding the results of all the organs.
Effects of radioactivity on people
In some reference countries, those exposed professionally can not exceed 20 mSv (milisievert) per year.
During the Fukushima nuclear accident in Japan in March 2011, according to some reports, the technicians of the plant were exposed. 400 millisievert per hour. These values are within the dose limits described in the Belgian legislation during rescue interventions in case of nuclear emergencies. A continuous exhibition. 400 mSv. h drives. a decrease in white blood cells after a few hours. This causes vomiting. Headaches.
In the Chernobyl nuclear accident in 1986, a large amount of radiation was released in a short time. Workers. Emergency technicians who were in place at that time could also process large doses of radiation. After the nuclear disaster, much experience has been gained about the influence of these irradiations on the human body.
The latest study conducted by the UN organization UNSCEAR concludes that 134 workers. emergency workers suffered from radiation diseases. Of these, 28 people died as a result of the radiation. The 106 survivors left skin damage. waterfalls. the radiation. In addition, hundreds of thousands of people were called to fight the disaster that they were most at risk. Later cases of leukemia appeared. waterfalls.
Last review: August 30, 2017