Those of us in the field have always known that draping that lead apron over you when getting an X-ray at the hospital or the dentist was not necessary, that it didn’t protect you or lower your risk of cancer, because those extremely low levels of radiation used in diagnostic exams aren’t high enough to pose any risk in the first place.
But I never considered that it might be harmful to use these aprons.
A radiology room table for obtaining X-Ray images. Lead aprons, like the one in the sketch, have … [+]
It turns out that many radiologists do. A number of radiology organizations are trying to end the historic practice of shielding patients from radiation with lead aprons and some hospitals are ditching the practice completely, especially of covering reproductive organs and fetuses during imaging exams.
That’s because the presence of the lead apron can impair the quality of diagnostic tests and sometimes inadvertently increase a patient’s radiation exposure, according to prominent medical and scientific groups including the American Association of Physicists in Medicine, the American College of Radiology, the Image Gently Alliance which promotes safe pediatric imaging, and Dr. Rebecca Marsh, a member of the Radiological Society of North America.
Ever since the 1950s, it has been the practice to cover the testicles and ovaries during X-ray imaging, based on studies in fruit flies in the 1940s that showed effects on DNA. However, those studies were found to be irrelevant to humans as the doses were extraordinarily high and no such effects have ever been observed in humans at any dose. According to the 2007 Publication 103 of the International Commission on Radiological Protection (ICRP), “no human studies provide direct evidence of a radiation-associated excess of heritable disease.”
Since then, studies have shown that use of these aprons and shields during X-ray imaging may actually obscure anatomic information or interfere with the automatic exposure control of the imaging system. Not only can this effect compromise the diagnostic efficacy of the exam, but often requires more imaging, resulting in an increase in the patient’s radiation dose.
The Food and Drug Administration has proposed removing the recommendation to use shielding that appears in the federal code from the 1970s. A final ruling is expected towards the end of this year. This is critical because state regulations are based on this ruling and at least 46 states require shielding of reproductive organs under many circumstances.
Like most of our actions involving radiation, this practice arose from an exaggerated fear of radiation, especially low levels of radiation. This fear originated after WWII, and was formalized in 1959 when the world adopted a singularly foolish hypothesis for the negative biological effects of radiation, called the Linear No-Threshold hypothesis, or LNT.
In contrast to almost all data on living organisms, LNT assumes that any radiation is bad and there is no threshold of radioactivity below which there is no risk, even at Earth background radiation levels. This is wrong. Background levels of radiation, which can get up to 10 rem/yr (0.1 Sv/yr), have never been correlated with health effects or cancer. A chest X-Ray is about 0.01 rem (0.0001 Sv). Dental X-Rays are orders of magnitude lower than that and provide less dose than eating a lot of potato chips.
Besides, LNT purposefully ignores the immune system which is pretty good at repairing damage from low levels of radiation.
In the coming year, the National Council on Radiation Protection and Measurements, which gives guidance to regulatory bodies, is expected to release a statement supporting a halt to patient shielding.
However, experts continue to recommend that health care workers in the imaging area protect themselves with leaded barriers as a matter of occupational safety, even though that also is probably unnecessary.
Groups in Canada and Australia have endorsed the change, and a movement to abandon lead shields is underway in Britain, according to Dr. Marsh, a medical physicist at the University of Colorado Anschutz Medical Campus in Aurora, Colorado.
So, no benefits from using these aprons and shields – but possible harm.
Sounds like a no-brainer to me.
