Radon is one of a group of elements known as noble or inert gases. This means that radon, like other noble gases such as helium or neon, does not react easily with other elements. Radon gas is radioactive, and the EPA warns that radon exposure is a common cause of lung cancer. Nonetheless, applications for radon have been found in medicine and geology.
Radiation Therapy for Cancer
Radon seed therapy is a variety of radiation therapy used to treat cancer. A small amount of radiation is encased in a gold "seed," which is then implanted in the tumour. Seed therapy is intended to deliver radiation directly to the tumour without harming healthy tissue.
Some believe that radon exposure helps treat autoimmune conditions such as arthritis. In the medical journal Dose-Response, Barbra Erickson writes that some arthritis sufferers visit so-called "health mines" in Montana, where they are exposed to radon. This practice is considered alternative medicine and is not endorsed by the mainstream medical community. The EPA warns that any exposure to radon gas carries a risk of lung cancer.
Increased levels of radon in groundwater may be a sign of an imminent earthquake. Because radon is an inert gas, it does not combine easily with other elements in the soil. For this reason, radon separates readily from the soil and strain in a fault prior to an earthquake may cause radon to be released into the groundwater. However, Reuters reports that radon levels are unreliable as an earthquake prediction tool.