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Guide to Radiation

Guide to Radiation

Here is a guide on how we deal with radiation as a part of life, where it comes from, and how to protect yourself from the health risks.  Radiation is a complex topic, and its characteristics are best broken down bit by bit to be fully understood. Here we will explore how radiation is used and experienced in everyday life, the difference between ionizing and non-ionizing radiation, some of the dangers of radiation, as well as ways you can protect yourself from some of its negative effects.

Radiation Is a Part of Life

Radiation is essentially energy that originates from a source and is traveling through space in waves or particles. Radiation may be able to penetrate certain materials, according to the Health Physics Society. It is both artificial (man-made) and naturally occurring in our everyday environment, coming at us from outer space and from radioactive materials in the earth and living things, making it impossible for us to avoid it entirely. Radiation is present even in everyday sunshine, with the source in this case being the sun.  Sunshine contains a familiar type of radiation. We feel the effects of radiation from the sun as light and heat and take steps to protect ourselves from it with sunscreen, sunglasses and air conditioners. Why? Because sunshine contains many different types of wavelengths including ultraviolet waves, which can be harmful to our skin if we are exposed to it for too long. We have learned that even though radiation produces beneficial light and heat that are essential to life on earth, too much of it can be harmful to people and other living things. In fact, many other types of radiation are downright dangerous, causing cancer, birth defects, nausea and a host of other health problems. At the same time, radiation therapy can also be used in medicine to combat cancer, as when high-energy radiation is used to destroy cancer cells by damaging their DNA. Radiation is also put to use to safely heat food in a microwave.

Radiation Comes from Unstable Atoms

Scientists have discovered that radiation originates from atoms, basic particles which make up the very foundation of matter. Atoms are usually stable, remaining in a certain state forever. However, some atoms collapse into an entirely new atom that is considered radioactive or unstable. These unstable atoms have a great deal of extra internal energy. However, unstable atoms are always seeking to get back to a more stable form in which they are no longer radioactive, a process called radioactive decay.  All elements on your standard periodic table are made up of atoms with many different sizes of nuclei, which are called isotopes. Unstable isotopes are called radioisotopes. Certain elements, such as uranium (an element well-known for its radioactivity), don’t have any stable isotopes. When radioactive decay occurs in the atoms of an element such as this, excess energy is produced and released in waves or particles. Some of this excess energy is released as radiation. Atoms in an unstable, or radioactive, material decay randomly but take a predictable length of time to do so.  Some radioactive atoms, like uranium and thorium, are naturally-occurring, but others, such as phosphate-32, sulfur-35, and iodine-125, are man-made, according to the University of South Florida.

Ionizing Radiation

Ionizing radiation comes in two forms—waves and particles. It is a type of radiation with enough energy that it can actually remove tightly-bound electrons from orbiting around an atom when it interacts with that atom; this causes the atom to become charged, or ionized, according to the World Health Organization (WHO). Ionizing radiation is a type of radiation that has the potential to cause damage to living tissue, even though we all experience it in low doses from space, air and earth. Ionizing radiation is also put to careful use whenever you undergo a medical or dental x-ray for diagnostic purposes.

Types of Ionizing Radiation

Ionizing radiation gets its name from the ions it produces in the materials the radiation hits. It is released in high-frequency rays and particles. There are many different kinds of ionizing radiation, including:

  • X-rays and gamma rays. Both of these can penetrate and pass through the human body, but can be effectively blocked by a thick barrier of concrete, lead or water. They are pure energy, or photons, according to the U.S. Environmental Protection Agency’s (EPA) description of ionizing radiation.
  • Alpha particles. These include two protons and two neutrons, according to the EPA, have little penetrating power and are blocked by a mere sheet of paper or even by human skin. They are positively charged.
  • Beta particles. These are essentially electrons, according to the EPA, smaller than alpha particles and also have little penetrating power. They can be blocked by a sheet of aluminum a few millimeters thick. They are negatively charged.
  • Cosmic radiation. This type of radiation comes from outer space, and is thus most intense at higher altitudes, particularly for people who live high above sea level or for people who frequently fly at high altitudes by plane. According to the EPA, about 8 percent of our annual radiation exposure comes from outer space. The earth’s atmosphere shields us from most of it.
  • Neutrons. These are particles with an exceptional ability to penetrate different materials. Most of the time they originate from splitting atoms in a nuclear reactor. Thick water and concrete barriers are necessary to prevent penetration. Neutrons are the only type of ionizing radiation that has the ability to make objects radioactive, according to the U.S. Nuclear Regulatory Committee.

Commonly-known types of non-ionic radiation include heat waves, radio waves, infrared light, visible light and ultraviolet light. Waves that have longer wavelengths and lower frequencies, such as heat and radio, have less energy than waves with shorter wavelengths and higher frequencies, such as x-rays and gamma rays. It is the higher frequencies that qualify a type of radiation as ionizing, according to the WHO.

Ionizing Radiation Has Health Risks

High doses of ionizing radiation are well-known to up one’s chances of leukemia and other cancers several years after exposure. In fact, cancer, or the uncontrolled growth of cells, is considered the primary health effect resulting from radiation exposure, according to the EPA. Tests on plants and animals have led many scientists to the conclusion that ionizing radiation can cause genetic mutations that are passed on generationally, even though such mutations in humans haven’t been documented. Very high levels of radiation can cause sickness and death in a matter of weeks. Birth defects are also a common side effect of exposure to ionizing radiation, and the developing human fetus is particularly vulnerable—even more so than adults. Pregnant individuals and those who plan on becoming pregnant are encouraged to take extra precautions to protect the developing embryo or fetus. Acute exposure to radiation can cause burns or radiation sickness, according to the EPA.  The immediate signs and symptoms of radiation sickness include nausea and vomiting, and the later symptoms can include dizziness, weakness/fatigue and hair loss, according to Mayo Clinic. Medical patients being treated with radiation therapy for cancers often experience these adverse effects.

The general consensus in the scientific community is that all ionizing radiation, even low doses, poses some health risk to humans, however minimal, even though no ill effects have been documented from very low doses. However, compared to prolonged exposure to bright sunlight, smoking and dietary factors, radiation is considered a weak carcinogen (cancer-causing agent).  Keeping this in mind, remember that radiation isn’t all bad. It is also used to save lives and also for a wide array of practical purposes. For instance, radiation therapy is used to kill cancer cells. Radiation can also be used in high doses to kill bacteria in food, as well as to sterilize medical supplies. It is also used for industrial purposes; for example, it is used to protect food and blood supplies, increase the safety of roads and buildings, find new sources of energy, light up emergency exits and make smoke detectors functional.  Individuals whose careers involve working with radiation are closely monitored and their exposure to radiation is limited as much as possible.

Protecting Yourself from Radiation

No one can protect themselves entirely from radiation. After all, much of it is environmental, coming from the earth, the sun and outer space. Radiation is already present in our very bodies. However, we can certainly do our best to protect ourselves from unnecessary exposure to man-made radiation and effectively block high doses of it. The first step is limiting the amount of time you are around radiation. This reduces your risk of illness. The second step is to put distance between yourself and the source of radiation. This is an effective technique because radiation is always at its most intense the closer you are to its source. Shielding is the third step to protecting yourself from radiation, as the many professionals who work with radiation technology already know. Radiation shields include lead, concrete and water barriers. Finally, if a large amount of radiation is going to be released, containment is imperative to protect people from being negatively impacted by it. This is why nuclear reactors have a number of barriers that keep the radioactivity contained.  A good rule of thumb is that those who work in occupations involving radiation be exposed to no more than 20 millisievert each year, averaged out over five years. This means in no single year should they be exposed to more than 50 millisievert a year.

Nuclear Fission Releases Radiation

Radiation is also released through a process called nuclear fission, where a nucleus is split after absorbing an additional neutron, according to the Nuclear Regulatory Commission. People refer to this process as “splitting an atom,” which releases a significant amount of energy that is used to produce electricity. The element by which this most often occurs is uranium, which is the fuel behind most nuclear power plants. Another element that can be used in the process of nuclear fission is plutonium. You can learn more about nuclear power generated through nuclear fission from the U.S. Energy Information Administration.

Related Links

  • The National Cancer Institute discusses radiation therapy for cancer patients. The information includes a breakdown of radiation therapy is, how it kills cancer cells and how the therapy is delivered to patients.
  • The Occupational Safety & Health Administration (OSHA) discusses radiation in depth, particularly as it pertains to the workplace. Here you can learn more about ionizing, non-ionizing and electromagnetic radiation.
  • The U.S. Environmental Protection Agency (EPA) has a helpful guide to understanding radiation that includes information on ionizing and non-ionizing radiation. You can learn about a variety of other radiation topics by exploring the items on radiation listed in the sidebar.
  • The Centers for Disease Control and Prevention (CDC) has an area designated for addressing radiation emergencies, such as the one that occurred in Japan after the massive earthquake in 2011. The CDC also has information on radiation’s effect on pregnancy and types of radiation emergencies.
  • MedlinePlus, a service of the National Institutes of Health and the U.S. National Library of Medicine, contains some information on radiation exposure. The article also looks at symptoms of radiation sickness.
  • Breastcancer.org has some useful information on radiation therapy and how it is used to destroy cancer cells in the breast. The article includes links to how radiation works, types of radiation, managing side effects and other information.
  • NASA’s Goddard Space Flight Center discusses the electromagnetic spectrum and the different types of radiation that make it up. Here you have a simple scientific breakdown of information on ultraviolet radiation, x-rays, gamma rays and other types of radiation.
  • The U.S. Nuclear Regulatory Commission has a handy fact sheet on the biological effects of radiation. The fact sheet looks at sources of radiation and how it affects the human body in certain doses.
  • Idaho State University’s Physics Department has compiled a list of links to information about radiation called the Radiation Information Network. Hot topics include the use of body scanners, facts about radiation and the hazards of tanning beds.