X-ray Health Risks
by Ron Kurtus (revised 21 March 2007)
Many people are concerned about the risks to their health from getting medical and dental x-rays, as well as from working near x-ray machines. Although x-rays have a potential of causing genetic damage and cancer, the chances of being harmed from medical or dental x-rays is extremely small. In fact, natural radiation may pose a greater risk.
A person can safely get up to 300 simple x-rays a year. CAT scans of body areas drastically reduce the safety factor, but they are still within an acceptable range. Yet, it is always good to be on the cautious side and not receive excessive x-rays unless it is medically necessary. Pregnant women should be especially cautious about being x-rayed.
Questions you may have include :
- What are x-ray hazards?
- How much is safe for pregnant women?
- What is the cancer risk from x-rays?
This lesson will answer those questions. Health Disclaimer
An x-ray is high energy electromagnetic radiation that passes through the body. Metal, bone and dense material block some radiation and that shows up as shadows on the x-ray film or digital sensor. Once it pass through your, it is gone. None stays in your body.
Can damage some cells
But what can happen is that the high energy of the radiation can damage a very small amount of your body's cells. In most cases, the cells simply die prematurely. The amount of cell damage from an x-ray is many times less than you get from cosmic radiation you are exposed to when you fly in an airliner.
Some of the cells may not die, but instead they may have genetic damage done to them. In an extremely rare situation, that genetic damage can result in the cell becoming cancerous.
Genetic damage to a reproductive cell
A greater risk than cancer is a genetic damage to a reproductive cells. Damage to an ovum in a woman or sperm cells in a man could result in a deformed baby or a miscarriage. The reason physicians will cover your private parts with a lead shield is to prevent this damage from happening. You can get an x-ray in another part of your body, and your reproductive organs will be protected.
Some conservative physicians recommend that a woman of child-bearing age wait until at least two menstrual cycles after getting x-rayed before having unprotected sex.
Pregnant women and unborn children
Since their cells are growing rapidly, unborn children are most sensitive to radiation. Because of this, U.S. Federal standards state that the dose of radiation to an unborn child throughout the entire pregnancy cannot exceed 0.5 rem or 500 millirems over 9 months.
Note: Radiation units of measurement can be confusing, because several different ones are used. A millirem, mrem, millirad and mrad are all the same thing. Also, 1 mSv = 100 millirem.
Maximum of 10
That equates to a maximum of about 10 medical x-rays that would irradiate the womb area. It is unlikely that a pregnant woman would ever receive that many x-rays in that region of her body, but if she was required to have a large number of x-rays for some serious ailment, the x-ray technician should make sure she is well shielded in the critical areas.
It is unlikely dental x-rays would affect an unborn child, since they are highly focused and about 1/3 of the strength of a medical x-ray. Yet, caution is always wise.
If you are pregnant and need to be x-rayed, verify with your physician that the x-ray is absolutely necessary. If it is necessary, tell the x-ray technician that you are pregnant to make sure you are well shielded.
If have already been x-rayed, realize that the chances of damage to your unborn child are highly unlikely unless you have exceeded the maximum dosage.
The risk of getting cancer from x-rays is very small. Government studies state that receiving 5000 millirem (50 mSv) of radiation in a year will increase the rate of cancer deaths by 0.3%, which is insignificant. That means that if you got 300 medical x-rays in a year, it would increase your chances of getting cancer by only 1%.
Other major risk factors
A major factor in the risk of cancer concerns your genetic makeup. If your family has a history of cancer, you have a much greater chance of getting cancer yourself. In such a situation, you should be cautious about getting x-rayed, unless really necessary. And of course, do not smoke. The risk of cancer from smoking is many times greater than getting numerous x-rays.
No one is sure how much radiation can cause cancer, but it is assumed that the risk is proportional to the absorbed radiation dose. Low doses might possibly cause cancers 5 to 30 years or longer after exposure. But also, it is important to remember that you are exposed to radiation every day from a variety of sources in the natural environment.
Exposure to background radiation, from sources such as radon gas, cosmic rays from outer space, rocks and soil, results in the body absorbing about 5 millirems each week. Thus, in 10 weeks you get about the same dosage from natural radiation as you would from one medical x-ray or three dental x-rays.
A CAT scan is a Computed Axial Tomography x-ray scan of an area of the body. It is also called a CT scan. Typically, they take about 30 minutes to complete, although the patient may be in the machine for much longer due to required preparations. The x-rays are not turned on until the scan is started.
The amount of radiation received in a CAT scan is about 1000 millirems (10 mSv). That means that a you could safely get 5 CAT scans in a year to increase the chances of cancer 1%. That is as much as you would get from natural radiation in 3 years. It is unlikely that another would have 5 CAT scans in a year.
Pregnant women and CAT scan
But note that this is twice the recommended maximum radiation dose that a pregnant woman should get. A pregnant woman should not have a CAT Scan unless absolutely necessary. The physician should have a good argument for prescribing such a scan.
Note that you always should question your physician about the necessity and safety of any type of x-ray.
Although many people are concerned about the risks to their health from x-rays, the chances of being harmed from medical or dental x-rays is extremely small. A person can safely get up to 300 simple x-rays a year. A pregnant woman can get at most 10 x-rays during her pregnancy. A CAT scan is not recommended for a pregnant woman. It is good to be on the cautious side and not receive excessive x-rays unless it is medically necessary.
Monitor your health
Resources and references
Radiation Exposure in X-ray and CT Examinations - RadiologyInfo.org
X-Ray Risks - Mayo Clinic
Are X-Rays Safe During Pregnancy? - FamilyDoctor.org
Radiation, how much is considered safe for humans? - Massachusetts Institute of Technology (MIT) News
Radiation Exposure Limits - Nondestructive Testing Resource Center
Cabinet X-ray Systems - U.S. Food and Drug Administration (FDA)
Health Effects of Radiation - U.S. Environmental Protection Agency (EPA)
X-rays - Succeed in Physics
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