As a patient, you may have concerns about the imaging procedures prescribed for you. How much medical radiation is too much? What are the benefits of CT scans? Does my age or gender affect my risk? What are the risks?
Is diagnostic medical radiation(x-ray) safe?
Safety and Risks
What does safe mean?
- Does it mean there is no risk?
- Does it mean the risk is very small?
- Does it mean the benefit exceeds the risk?
If someone tells you the air is safe,
- does it mean the air is free of pollutants?
- does it mean that breathing the air every day is safe?
- does it mean that brief exposure to low levels of pollutants is safe, yet constant exposure may not be safe?
Many activities—even going to the beach or riding a bicycle—carry some kind of risk.
To call something safe usually means that it carries a low risk, not zero risk. Zero risk is almost impossible.
To call something safe usually means that it carries a low risk, not zero risk. Zero risk is almost impossible.
Safety is different for everyone. People with asthma do not tolerate pollution well. What is safe to asthma-free people is not necessarily safe to people with asthma. Peanuts are tasty, but they can be dangerous to those with allergies to nuts.
Everything we do has potentially detrimental aspects. An action or product is deemed safe as long as the risk associated with it is very low. This is true for medical x-rays, medication or any medicine. For example, only patients who need diagnostic imaging should have imaging exams.
Safety and Radiation
Radiation is with us every minute of our lives. Background radiation naturally exists everywhere in our environment. These levels of radiation are clearly safe. If they were not, life on Earth would not flourish. Yet, we know radiation has the potential to cause cancer.
The degree of safety depends on the level of exposure. Ultra-high levels of radiation (levels far above background radiation or in amounts well in excess of those used in diagnostic imaging) may cause cancer to develop later in life. But even most of the individuals who are heavily exposed to radiation do not develop radiation-induced cancer.
Only a percentage of these heavily exposed people develop radiation-induced cancer later in life. These groups include:
- People exposed to radiation from nuclear weapons
- People involved in radiation accidents
- People treated for an existing cancer
The potential for inducing cancer from radiation depends on the amount of radiation exposure and accumulation of exposure over a long time. Lower exposure levels — background radiation, nuclear medicine exams, computed tomography (CT) scans, or diagnostic x-rays — carry low risks.
Nevertheless, a large volume of circumstantial evidence suggests that diagnostic levels of radiation probably are associated with a low level of risk for inducing disease many years after exposure. Such an event would be very infrequent.
Benefits to patients who are sick or injured are so substantial that the radiation risk becomes a minor factor in their healthcare.
Some imaging examinations are used to screen for disease in healthy people. Annual mammogramsfind breast cancer early, when it can be treated more successfully. Early diagnosis and treatment far outweigh any radiation risk. By this definition, the examination is safe.
When used in large quantities or when many examinations are performed, the risk from exposure to x-rays increases. In some instances, the accumulated dose from multiple examinations can reach levels where the risk of induced cancer has been identified. (For the technically-oriented, this is where the cumulative absorbed dose to specific organs exceeds 100 mGy.) This can occur after certain types of computed tomography examinations are repeated five or six times in some adult patients. For some very serious medical conditions, multiple exams are necessary, and the benefits far outweigh the risk.
Safety is a priority. To be safe, medical practitioners should use x-rays only in quantities sufficient for medical care. For example, x-rays for children are scaled down, and multiple examinations are limited to those that are essential. The good news is that babies are small. Diagnostic examinations can use far less radiation to obtain necessary pictures.
After 100 years of research, it has been impossible to prove that single, low-dose diagnostic x-rays cause cancer. It is important to use diagnostic exams only when necessary. Based on the facts and using the previously mentioned definition of safe, a necessary exam is safe.
