The Impact of Radiation on Human Health

Planet Earth is full of radiation. Our exposure to low-dose, background radiation is constant. Man-made sources of radiation are increasingly common, such as tv, radio, x-ray machines and nuclear energy. The ability of IR to ionize atoms poses a health risk, as IR can penetrate skin and other tissues, and attack essential components of cells such as lipids, proteins or even DNA (American Cancer Society, 2015). IR can lead to oxidation of cellular components and induce DNA breaks, which are damaging to the cells and are deeply linked to cancer development. The type of damage depends of the IR source, the radiation dose (high versus low), the exposed area, and the duration of the exposure (Streffer & Herrmannn, 2012; U.S. Food and Drug Administration, 2019).

Health effects of IR can be cancer and noncancer related. Radiobiology has clearly shown that cancers from the lungs, skin, breast and thyroid are highly associated with exposure to both high-dose and low dose IR. Acute exposure to high dose IR may lead to the rapid development of cancer, due to extensive DNA damage in the irradiated cells. Similarly, exposure to low-dose IR is associated with development of cancer, namely from the thyroid and skin. However, in the latter case, cancer develops with higher latency periods, due to chronic exposure to low-dose IR (Mu et al., 2018). Noncancer consequences of irradiation include cardiovascular and Alzheimer diseases, cataracts, congenital malformation and sterility (in case of irradiation of reproductive organs) (Hamada et al., 2014). Acute radiation syndrome (ARS) occurs when a part or whole-body is subjected to irradiation, as it happens in cases of nuclear disasters or atomic bombings. ARS can be multisystemic and present with radiation skin burns, gastrointestinal and metabolic effects (such as nausea and diarrhea), central nervous system impairment (damage to the nerves and convulsions), and internal bleeding and premature death (which can occur as fast as 48h post-irradiation in cases of severe acute exposure) (Centers for Disease Control and Prevention, 2018).

So, Why do we Keep Exposing Ourselves to Radiation?

This seems like a reasonable question, after all. Why would we voluntarily keep exposing ourselves to IR? The ability of IR to ionize can be used with enormous benefits for human health, if its use is properly regulated. IR is consistently used in medical practice in the diagnosis and treatment of several diseases including cancer, improving premature diagnosis and survival rates (Boustani et al.,, 2019; Zeman, 20112). The use of radiotherapy is one of the best-known examples of IR use in the medical setting. A fundamental principle of radiotherapy is fractionation, meaning that patients are exposed to a certain amount of radiation, divided by several sessions in which they are exposed to smaller radiation doses. By controlling fractionation, timing and dose, physicians and radiobiologists are able to improve the effectiveness of radiotherapy, maximizing IR-induced damage in cancer cells, and minimizing the damage to healthy cells (Boustani et al., 2019).