Presumably, the makers of the RADPAD No Brainer surgical cap didn't name it "No Brainer" because it offers no brain protection, but a new study indicates just that.
Dosimetry monitoring and simulation measurements in five electrophysiologists wearing the cranial protective caps over a 2-month period showed that the headgear had no impact on brain dose distribution.
As expected, the right side of the operator's head was the most exposed region during left subpectoral device implantation.
The results were not a surprise to the investigators, led by Etienne Pruvot, MD, and Camille Lemesre, MScA, both from the University Hospital Centre Vaudois, Lausanne, Switzerland. Their findings were published online in JACC: Clinical Electrophysiology.
"It did not make sense to us to wear a cap to protect the brain when the radiation scatters upward from the X-ray tube located below the patient," said Pruvot in an email exchange.
He added that most of his colleagues are using these caps and he thinks interventionalists "believe it works as stated by the company, offering a reduction factor of four."
The researchers found that the cap did reduce the amount of radiation exposure to the skin at the front of the head, as expected, but that the skull did most of the work of decreasing exposure to the brain. Exposure to the anterior brain was decreased by a factor of 4.5, compared with the front-head skin value, "thanks to the skull," say the authors.
Pruvot suggested the skin finding is of little consequence. "One may state that it might decrease the risk of developing skin cancers at the front of the head, but I have never heard about this as a significant complication of repeated radiation exposure in contrast to left-sided brain tumors," he said.
The issue is an important one to those working in the cath lab. There have been several reports of malignant tumors affecting the brain, head, or neck, with a predominance seen for left-sided lesions for interventionalists practicing with the X-ray tube on their left side.
"Most left-sided brain tumors have been reported after 10 to 15 years of practice in interventionalists, so years of exposure is the key factor and any protective gear that interposes itself between the scattered radiation emitted by the patients and the physicians head should be used to reduce brain exposure," say Pruvot et al.
"This is a good reality check for electrophysiologists to see whether or not these marketing claims really apply to us. And I think it's really good how the authors went beyond just skin exposure to look at brain exposure," said Stephen Gaeta, MD, PhD.
No-Brainer caps are available in the electrophysiology suites at INOVA Medical Group in Northern Virginia, where Gaeta works. He thinks many clinicians wear them and "probably assume they work," whereas others wear them thinking more along the lines of, "why not?"
"Electrophysiologists are among the most exposed in all of medicine, so people are eager for any solution that can help mitigate the risk of these glioblastomas and head and neck cancers that we've seen in operators. The allure of these caps is that they just sort of replace something you're wearing anyway with something that might be more protective, so there would appear to be limited downside," Gaeta said in an interview.
"That doesn't mean they shouldn't be evaluated to see whether there really is any benefit, and this paper did a good job of this and suggests that there may not be as much as thought," he added.
As for the cost, he doesn't know the exact numbers, but said that any specialty product like this is likely "a lot more expensive than the paper hats we traditionally wear."
Maybe Tucked Under the Chin?
To further test their hypothesis that scatter from below is the issue, Purvot's team tested the effectiveness of the cap worn "as a protruding horizontal plane," meaning fastened below the chin. Positioned there, it reduced brain exposure by a factor of 1.7.
Because the cap itself is too stiff to repurpose in this way, they used phantom measurements to determine exposure to the brain.
"Our purpose in testing this setup was not to propose a new solution for how to wear this cap, but to demonstrate that the radiation comes from an upward angulated direction," said Pruvot.
"I think it's actually a great proof of principle to test the cap in this way. They hypothesized that the actual area that you need to be blocking is from down below, and this answers that question very nicely," said Gaeta.
Both Pruvot and Gaeta said current thinking focuses more on reducing the use of radiation than trying to find better ways to block it.
"The best way to mitigate your radiation exposure is to use less radiation, and that's where the field is really going," said Gaeta. "Radiation minimization techniques, both technological and on the operator side, are where we should be looking."
Asked about what might reduce radiation exposure to the brain, given that the No-Brainer appears not to, Pruvot said one good strategy is to reduce the frames per second (fps) to the lowest allowed by your system to reduce scatter. "We always work with 3 fps," he said.
This was an investigator-initiated and funded study. The authors disclosed no relationships relevant to the content of this study.
J Am Coll Cardiol EP. Published online September 30, 2020. Abstract
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Cite this: RADPAD 'No-Brainer' Surgical Caps Offer No Protection for the Brain - Medscape - Oct 13, 2020.