The danger of diagnostic x-rays

We know that children are more vulnerable to the bad effects of ionizing radiation and that the effects of exposure are cumulative over a lifetime.

by Mary Budinger — 

A case was recently adjudicated by the Arizona State Board of Dental Examiners concerning a dentist who performed a panoramic dental x-ray on a child without using protective shielding. The dentist did not use a shield because the manufacturer did not require it since “there is so little scatter around the machine.” The case was terminated due to “lack of supporting evidence.”

On one hand, the American Academy of Pediatrics recommends a schedule for children’s dental x-rays. On the other hand, we know that children are more vulnerable to the bad effects of ionizing radiation and that the effects of exposure are cumulative over a lifetime.

The ionizing radiation exposure from a panoramic dental x-ray is equivalent to 2-1/2 to 4-1/2 adult chest x-rays. The radiation is aimed at the jaw and head, not the thyroid or other organs of the body.

An August 27, 2009, ABC World News report stated:“researchers say 4 million Americans a year have so many medical x-rays that they wind up exposed to a high level of radiation.” An article published the next day in Forbes Magazine pointed out that, in a given year, two percent of people received radiation doses that exceeded 20 millisieverts (m Sv). Compare that to the victims of the Nagasaki atomic bomb who received an average exposure of between five and 20 m Sv.

Clearly, patients must carefully determine their own risk versus benefit for a given diagnostic procedure, as well as their own personal cumulative dose. Parents, especially, must be careful about allowing these procedures to be performed on their children. There is no question that diagnostic x-rays can be important when indicated; however, some are prescribed for minimal indications and may not be worth the risk.

A computerized tomography (CT) scan can have a radiation dose equivalent to 500-750 chest x-rays and can cause DNA breaks, which predispose us to cancers of various types, such as leukemia and breast cancer. A recent study published in the Journal of the American Medical Association concluded that the use of the newer and faster type of CT scan can increase a patient’s potential risk of cancer when used to image the heart or the major vessels around it.

The New England Journal of Medicine reported in November 2007, that “compared with plain-film radiography, CT involves much higher doses of radiation, resulting in a marked increase in radiation exposure in the population. The increase in CT use and in the CT-derived radiation dose in the population is occurring just as our understanding of the carcinogenic potential of low doses of x-ray radiation has improved substantially, particularly for children … Perhaps 20 million adults and, crucially, more than 1 million children per year in the US are being irradiated unnecessarily.”

These studies raise the question of how much risk we undertake in the name of prevention. We must educate ourselves and make our own choices as the mounting studies caution us about the dangers of radiation exposure.

 

Mary Budinger is an Emmy award-winning journalist. She is a freelance writer who focuses on alternative and complementary medicine. 602-494-1999.

Reprinted from AzNetNews, Volume 28, Number 6, Dec 2009/Jan 2010.

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