Radiation Safety and Protection
Radiation is a kind of energy that comes from unstable atoms in the form of particles or waves.
Atoms are composed of a nucleus and electrons. The nucleus is in the center of the atom, just as the sun is the center of our solar system. The weight of the nucleus is almost equivalent to its atomic weight. Two types of particles, positively charged protons and non-charged neutrons, encompass the nucleus in an orderly way.
Atoms can become unstable when there is any change in the number, position, or energy of these nuclear particles. If it happens, the nucleus becomes radioactive and emits radiation.
Radiation occurs naturally from radioactive elements (uranium, thorium, etc.), and radioactive decay products (radon) in soil, rocks, water, food, and even in human bodies. Radiation from outer space also reaches us through cosmic rays.
About eighty percent of human exposure to radiation comes from these natural sources, and among all these sources, radon gas in our home comprises 55% of all radiation exposure. The remaining twenty percent is from man-made sources, such as medical X-rays (11%), nuclear medicine (4%), consumer products (3%), occupation (0.3%), radioactive fallout (0.3%), nuclear fuel cycle (0.1%), and other sources. (National Council on Radiation Protection and Measurements, Report No.93, 1987)
Radiation (specifically ionizing radiation, such as X-rays, gamma rays, and alpha and beta particles) is capable of penetrating and changing materials chemically and structurally.
When exposed to the human body, X-rays can change the chemical balance of cells, and result in cancer. They are also capable of damaging DNA, which might lead to genetic mutation.
The extent of change depends on the type of radiation source, the total amount of exposure, and the sensitivity of the organ that absorbs radiation.
- Small doses of radiation may have no effect on the human body.
- Large doses of radiation for a short period of time (like an atomic bomb explosion or an accident in a nuclear power plant, etc.) can result in death by causing radiation sickness, loss of body fluid, anemia, hemorrhage, and infection. If the victim survives, he or she can suffer from cataracts, cancer, or genetic effects later.
- Low or moderate doses of radiation over a long period of time can result in skin changes, cataracts, birth defects, cancer or pre-cancerous lesions, and, sometimes, harmful genetic effects. At very low doses of radiation, the estimated risk is very low.
Modern X-ray technology has made it possible to significantly lower the amount of radiation exposure from medical tests and procedures by applying filters, high-speed X-ray film/screens, collimation, CR tube display of fluoroscopy, digital radiography, etc.
In diagnostic X-ray procedures, minimum necessary radiation is exposed to patients by trained radiologists and technologists, and the risk from this small amount of radiation is extremely low.
On the other hand, the benefits from diagnostic X-rays greatly outweigh their potential risk. For example, the detection of skull fractures or tension pneumothorax using X-rays can save lives, while the amount of radiation exposure from such a procedure is equivalent only to what one would normally receive from the environment in 10 days, or from one coast-to-coast round trip flight (In high altitudes, we get more radiation from outer space through cosmic rays).
There is no limit to the number of medically necessary X-ray examinations a person may have, because it is known that risks are not increased from multiple exams.
Considering the fact that no radiation exposure is completely risk free, the decision to take an X-ray should be based on the likelihood of benefits from the exam and the potential risk from radiation.
Generally, fetuses are more sensitive to radiation; so pregnant women should avoid X-rays whenever possible.
But modern diagnostic technology uses well-controlled and regulated X-ray procedures, making the risk of such exams to a fetus minimal.
If medically necessary during pregnancy, one can undergo an X-ray examination, so long as after the abdomen and pelvis are covered with a lead apron to minimize radiation exposure to the fetus.
If you are pregnant or suspect pregnancy, tell your doctor before taking an examination. Special precautions can be taken to minimize radiation exposure. Your doctor may find alternative exams for your medical conditions.
- Time: Reducing the amount of time spent near the source of radiation reduces the amount of radiation exposure you receive. X-rays are produced only when a switch is on, and do not remain after the exam. Most radiopharmaceuticals used in nuclear medicine lose their radioactivity quickly.
- Distance: The more distance there is between you and the source of radiation, the less radiation you will receive. When exposure to radiation is not necessary, stay away from the sources, such as X-ray tubes, CAT scanners, radioactive materials in nuclear medicine, linear accelerators, and nuclear power plant accidents.
- Shielding: Use dense and heavy materials such as concrete walls and lead shields/aprons to protect yourself from radiation.