Radiation is a powerful energy that can be used to kill germs, sterilize medical equipment and other substances and to destroy harmful cancer cells. It also can be used to help diagnose and treat certain types of cancers, but the effects on the human body from radiation vary widely depending on the application and the amount of exposure.
Health Effects from High Doses of Ionizing Radiation
Ionizing radiation can damage cells, or atoms in the cells, by breaking chemical bonds that hold them together. This can cause a cell to die or to change its DNA, the genetic information that controls the chemical and physical functions of the cell.
People are exposed to ionizing radiation in many ways, including from medical tests and treatments, nuclear power plants and radioactive materials that can be found in nature. It can also be absorbed by the body, either through ingestion (from food or water) or breathing. The body metabolizes (processes) the ionizing radiation to eliminate it from the body.
Some people are very sensitive to radiation and can have serious health effects when they are exposed to it. These people are usually babies, children, pregnant women and those with weakened immune systems.
The health effects from high doses of radiation can include acute radiation syndrome (ARS), skin burns and cancer. ARS is sometimes called “radiation sickness” and may cause symptoms such as headache, vomiting, dizziness and diarrhea that start within hours of being exposed to radiation. In some cases, ARS can cause death within days or weeks.
Acute health effects from low doses of ionizing radiation are less well understood. There is no known threshold below which there is no risk, and the effects of exposure to low doses of radiation are more uncertain than those from high doses of radiation.
In determining the risk of cancer from exposure to low doses of radiation, it is important to consider factors such as age, gender, other exposures and genetic factors. For example, infants who have been exposed to excessive radiation doses before they are born can develop chromosome abnormalities that lead to cancer.
Ionizing radiation can also cause other health problems. For example, ionizing radiation can break chemical bonds that hold the chromosomes of cells together and change the genes inside the cells. These changes can lead to genetic damage that affects how the cells work and how they reproduce.
Survivors of atomic bombings and other high doses of radiation have an excess risk of some types of cancer. In these cases, it is important to follow up on survivors throughout their lives.
It is also important to take into account the effects of ionizing radiation on cells and tissues that are exposed for long periods of time, such as workers at the Chernobyl nuclear power plant in 1986. A study of these workers showed that the risk of cancer from exposure to this radiation increased over time.
Despite the fact that high doses of radiation can cause health problems, it is clear that the benefits to mankind outweigh the risks in most applications. The use of radiation has been a lifesaver in medicine, industry and agriculture; it is also a critical tool for the detection and treatment of some cancers.