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Diagnostic Radiologists || Diagnostiese Radioloë
Reg. No. 1995/003519/21       Pr. No. 3803724
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RADIATION

X-RAYS

X-rays are a type of electromagnetic radiation which pass through the body. Modern techniques use very small doses, approximately 20 milliroentgens per single exposure. Put into perspective, we all receive about 100 milliroentgens radiation exposure each year from natural sources like the sun and trace isotopes in soil.

RADIATION RISKS IN PERSPECTIVE

Just about everything we do in our daily lives carries some level of risk. We tend to regard activities as being “safe” when the risk of something unpleasant happening falls below a certain level. The lower the level of risk, the “safer” the activity becomes. For example, most people would regard activities involving a risk of below 1 in 1,000,000 as exceedingly safe. The radiation risks for simple X-ray examinations of the teeth, chest or limbs, can be seen to fall into this negligible risk category (less than 1 in 1,000,000 risk). More complicated examinations carry a minimal to low risk. Higher dose examinations such as barium enemas, CT body scans or isotope bone scans fall into the low risk category (1 in 10,000 to 1 in 1,000 risk).

As we all have a 1 in 3 chance of getting cancer even if we never have an X-ray, these higher dose examinations still represent a very small addition to this underlying cancer risk from all causes. As long as it is clearly necessary to help make the correct treatment decision for a patient, the benefits from any X-ray examination or isotope scan usually outweigh these small radiation risks. It should be remembered that the higher dose examinations are normally used to diagnose more serious conditions when a greater benefit to the patient is to be expected

RADIATION RISKS FOR OLDER AND YOUNGER PATIENTS

As you get older you are more likely to need an X-ray examination. Fortunately radiation risks for older people are lower than those shown in the table above. This is because there is less time for a radiation-induced cancer to develop, so the chances of it happening are greatly reduced. Children, however, with most of their life still ahead of them, may be at twice the risk of middle-aged people from the same X-ray examination. This is why particular attention is paid to ensuring that there is a clear medical benefit for every child who is X-rayed. The radiation dose is also kept as low as possible without detracting from the information the examination can provide. A baby in the womb may also be more sensitive to radiation than an adult, so we are particularly careful about X-rays during pregnancy. There is no problem with something like an X-ray of the hand or the chest because the radiation does not go anywhere near the baby. However, special precautions are required for examinations where the womb is in, or near, the beam of radiation, or for isotope scans where the radioactive material could reach the baby through the mother’s circulating blood. If you are about to have such an examination and are a woman of childbearing age, the radiographer or radiologist will ask you if there is any chance of your being pregnant.   If this is a possibility, your case will be discussed with the doctors looking after you to decide whether or not to recommend postponing the investigation. There will be occasions when diagnosing and treating your illness is essential for your health and your unborn child. When this health benefit clearly outweighs the small radiation risks, the X-ray or scan may go ahead after discussing all the options with you.

RADIATION RISKS FOR FUTURE GENERATIONS

If the reproductive organs (ovaries or testes) are exposed to radiation there is a possibility that hereditary diseases or abnormalities may be passed on to future generations. Although the effect has never been seen in humans, lead-rubber shields can be placed over the ovaries or testes during some X-ray examinations, as a precaution. They are only necessary for examinations of the lower abdomen and thighs on patients who are young enough to have children. Even then, there are some examinations where it is not practicable to use gonad shields since they will obscure important diagnostic information.

IMPORTANT POINTS TO REMEMBER

  • In radiology departments every effort is made to keep radiation doses as low as possible
  • The radiation doses from X-ray examinations or isotope scans are small in relation to those we receive from natural background radiation
  • The health risks from these doses are very small in relation to the underlying risks of cancer, but are not entirely negligible for some procedures involving fluoroscopy or computed tomography (CT).
  • The risks are much lower for older people and a little higher for children and unborn babies, so extra care is taken with young or pregnant patients.
  • If you are concerned about the possible risks from an investigation using radiation, you should be aware that most of the time the risk to your health from not having the examination is likely to be very much greater than that from the radiation itself.