– Patients have come to expect a technician to drape their torsos with a heavy lead apron when they get an X-ray, but new thinking among radiologists and medical physicists is upending the decades-old practice of shielding patients from radiation.

Some hospitals are ditching the ritual of covering reproductive organs and fetuses during imaging exams after prominent medical and scientific groups have said it’s a feel-good measure that can impair the quality of diagnostic tests and sometimes inadvertently increase a patient’s radiation exposure.

The about-face is intended to improve care, but it will require a major effort to reassure regulators, health care workers and the public that it’s better not to shield.

Fear of radiation is entrenched in the collective psyche, and many people are surprised to learn that shielding can cause problems. The movement also has yet to gain much traction among dentists, whose offices perform more than half of all X-rays.

“There’s this big psychological component, not only with patients but with staff,” said Rebecca Marsh, a medical physicist at the University of Colorado Anschutz Medical Campus in Aurora. “How do you approach something that is so deeply ingrained in the minds of the health care community and the minds of patients?”

Covering testicles and ovaries during X-rays has been recommended since the 1950s, when studies in fruit flies prompted concern that radiation might damage human DNA. Only in the past decade did radiology professionals start to reassess the practice, based on changes in imaging technology and a better understanding of radiation’s effects.

Lead shields are difficult to position accurately, so they often miss the target area they are supposed to protect. Even when in the right place, they can inadvertently obscure areas of the body a doctor needs to see — the location of a swallowed object, say — resulting in a need to repeat the imaging process, according to the American Association of Physicists in Medicine, which represents physicists who work in hospitals.

Shields can also cause automatic exposure controls on an X-ray machine to increase radiation to all parts of the body being examined in an effort to “see through” the lead.

Moreover, shielding doesn’t protect against the greatest radiation effect: “scatter,” which occurs when radiation ricochets inside the body, including under the shield, and eventually deposits its energy in tissues.

Still, Dr. Cynthia Rigsby, a radiologist at Chicago’s Ann & Robert H. Lurie Children’s Hospital, called the move away from shielding a “pretty substantial” change. “I don’t think it’s going to happen overnight.”

The physicists’ association have recommended that shielding of patients be “discontinued as routine practice.” Its statement was endorsed by several groups, including the American College of Radiology and the Image Gently Alliance, which promotes safe pediatric imaging.

Around the same time, the Food and Drug Administration proposed removing from the federal code a 1970s recommendation to use shielding. A final rule is expected in September.

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.