Factors Affecting Radiation Exposure

Radiation exposure is a topic that can evoke feelings of fear and anxiety. Movie and television depictions often paint a dark picture but may represent only part of the story. People are subjected to many natural sources of radiation. Although it isn't necessary to fear all radiation, it's important to have respect for its destructive properties. It's also helpful to understand some of the factors affecting radiation exposure. Minimize the amount of time you are exposed to it and increase your distance from its source.

Sources

• People are bombarded with natural radiation from the ground and outer space. Radon gas is emitted from the ground, building materials and water. Another source is cosmic radiation. Man-made radiation includes X-rays, CT scans, nuclear medicine and radiation therapy. U.S. nuclear reactors typically contribute only minute amounts. Nuclear weapons are an infrequent source of man-made radiation.

Types

• A radio wave, a visible light photon and a gamma ray are all types of electromagnetic energy. The energies are often expressed as waves as they move over a distance. Radio transmits large, lumbering waves. Energies on the opposite end of the spectrum, such as X-rays and gamma rays, are highly energetic.

  It is this difference that explains why X-rays and gamma rays are able to penetrate through matter. As the radiation passes through the human body, it can cause changes to occur. The body is resilient, and ordinarily it can repair most of the damage with minimal lasting effects.

Exposure

• The body's ability to quickly mend cells or DNA injured by radiation varies with the type of tissue exposed. Mature, highly specialized cells are less likely to sustain permanent damage. Cells that divide and metabolize rapidly are more vulnerable. This is why radiation is usually inadvisable for pregnant women. Exposure to the lenses of the eyes, thyroid, gonads and breasts should be reduced or prevented. The blood, skin and lymphatic system are also considered more susceptible than other body systems.

Protection

• In medicine, radiation is used to fight cancer and help physicians diagnose patients. However, because of radiation's ability to disrupt normal body function, the goal should be to keep radiation levels as low as possible. Doctors should always weigh the risk versus the benefit of performing a radiological procedure. Usually the risks are low.