If you’ve ever had a pelvic X-ray, you’ve probably felt comforted by the lead aprons technologists placed around your waist to prevent excess exposure to radiation.
Patients have come to expect this shielding over their reproductive organs as necessary protection during X-rays. Knowing we are being exposed to any level of radiation, even in small amounts, taps into our deeply ingrained fear of its potentially harmful effects.
“For many decades, we’ve thought even a small amount of radiation that reached the testes or ovaries could have a significant effect on heritable defects and could potentially increase risk of developing cancer,” says Yale Medicine radiologist Jay Pahade, MD. But, he adds, there wasn’t a lot of science to support that.
When radiologists and medical physicists at the American Association of Physicists in Medicine (AAPM) and National Counsel on Radiation Protection and Measurement (NCRP) both recently examined this decades-old practice, called gonadal (or pelvic) shielding, they found no evidence that low-dose radiation used during routine X-ray exams currently causes harm to patients’ reproductive organs. And, perhaps surprisingly, the researchers also found that, in this case, a pelvic shield sometimes increases a person’s exposure to radiation (explained below).
In light of these findings, numerous national societies, including the American College of Radiology, now recommend that radiologic technologists and technicians at hospitals and clinics can stop using pelvic shields on patients of all ages, including pregnant women. Dr. Pahade points out that lead shielding policies to protect the patient’s thyroid gland and breasts haven’t changed yet but likely will.
This counterintuitive move to stop pelvic shielding might be confusing to patients who feel comforted by the lead shields, especially expecting mothers.
“People may be thinking in the back of their head, ‘Is this technologist forgetting to cover my pelvis?’” Dr. Pahade says.
To ease any fears about this change, we asked radiology experts at Yale Medicine to explain the reasons behind the change in guidelines.
Why patients don’t need pelvic shielding for X-ray
One reason lead shields aren’t helpful during X-rays is because modern equipment uses far less radiation to capture a high-resolution image. Today’s machines emit just 10% of the radiation that older technology did. When pelvic shielding became required in the 1970s, it was because exposure to radiation was far more extensive, says Adel Mustafa, PhD, a Yale School of Medicine medical physicist.
In one study, researchers noted that a 4-year-old getting a routine X-ray today receives just 0.06 mGy (milligray), compared to 2.5 mGy six decades ago.
In recent years, researchers have also learned more about how X-rays reach parts of the body when they are not directly imaged. And, it turns out, most of this radiation reaches other parts of our body through what’s called “internal scatter.” With internal scatter, if you are getting an X-ray of your chest or abdomen, for example, a tiny amount of radiation may travel a short distance inside your body and reach your pelvis (where your ovaries or testicles are located). Shields placed on top of your skin don’t have any impact on reducing internal scatter, and, thus, don’t reduce the radiation dose to this part of your body.
“When a radiation beam reaches our organs, it breaks apart and bounces around a little,” Dr. Pahade explains. “So, a lot of radiation exposure is from inside the body, and external shields can’t prevent that from happening. But this type of radiation comes with getting an X-ray and is so low that we don’t get concerned.”
How lead shielding might actually lead to more exposure to radiation
In some cases, lead shielding can actually create situations that end up increasing a patient’s radiation exposure. This can happen in several ways.
- Slipped shield: If a patient moves during the exam, there is a danger that the shield could slip and block the part of the body that needs to be imaged. This is especially likely to happen with children or with patients who’ve experienced a traumatic injury who have intense pain that makes it difficult for them to lie still.
- Misplaced shield: A shield could be wrongly placed in certain patients, including infants whose pelvic areas are hard to pinpoint, or people with obesity. If this happens, the X-ray must be repeated, bringing a second exposure to radiation. Dr. Pahade confirms that this happens with some frequency. “The incorrect positioning issue is definitely a challenge for X-ray techs, especially in female patients, as often you can’t really tell where the ovary is,” Dr. Pahade says.
- Blocked beam triggering increased radiation: Modern technology meant to help ensure images are captured can sometimes add complexity. Today’s X-ray machines are designed to automatically use the lowest amount of radiation needed to produce a high-quality image. If a pelvic shield is covering the area that is being X-rayed, the machine senses something is blocking the beam. This automatic calibration benefit becomes problematic because the machine detects the barrier and increases the radiation amount in order to get through it.
“The machine is going to say, ‘I need to get enough radiation through to make the image,’” Dr. Pahade says. “That’s how the detector works.”
Lead shielding still in use
This change affects just gonadal (pelvic) shielding, not other protective lead shielding that covers the thyroid and breasts. “This change in guidelines is purely for the shields that are placed over our pelvis to protect our reproductive organs,” Dr. Pahade says, noting that each organ in the body has a different sensitivity to radiation. “The data available right now supports not using a shield to cover the ovaries/testicles, as they don’t really reduce the radiation dose and could actually make it higher.”
“Radiologists and technologists, who are constantly exposed to radiation every day, still need to be protected. For this reason, the guidelines have not changed for health care workers, who will continue to wear lead aprons,” Dr. Pahade says.
And, patients who prefer to wear a pelvic shield can still do so.
“We will do our best to educate patients. However, if a patient says they would feel a lot better just by having it, then we will provide one,” Dr. Pahade says. “We understand everyone wants to feel at ease when getting an X-ray, and our goal is to provide safe, high-quality care that meets the needs of our patients.”