No Brainer: Cap and Lead Pelvic Drape Reduce Radiation Exposure to Operators in PCI

September 18, 2014

WASHINGTON, DC — Two simple additions to the catheterization lab can help reduce the amount of operator radiation exposure, according to the results of a new study presented this week at TCT 2014 .

A lead drape that fits over the pelvis of the patient, one that is designed to reduce scattering, reduced exposure to radiation by 75% while a novel surgical cap, also known as the No Brainer (Worldwide Innovations and Technologies, Kansas City), reduced radiation exposure to the head of the operator by more than 80%.

"There is an increased recognition about the occupational hazard of radiation, especially with these cases series showing malignancies in the brain," co–principal investigator Dr Sanjit Jolly (McMaster University, Hamilton, ON) told heartwire . "Physicians, for years, have been exposing themselves to doses of radiation, but it's only now that we're becoming more concerned."

Earlier this year, Dr Ariel Roguin (Rambam Medical Center, Haifa, Israel) and colleagues presented data at SOLACI 2014 on head and neck tumors in interventional cardiologists and radiologists. In total, they identified 36 cases, including tumors in 28 interventional cardiologists, two electrophysiologists, and six interventional radiologists. The doctors worked for an average of 23 years in active interventional practices with exposure to ionizing radiation.

With this in mind, Jolly, along with coinvestigator Dr Ashraf Alazzoni (McMaster University, Hamilton, ON), conducted a small study testing the lead pelvic drape and nonlead surgical cap in 230 patients undergoing PCI. Of these, 115 patients were randomized to the pelvic lead-shield group and 115 patients assigned to the control arm. The surgical cap was worn in all the interventional cases.

"The No Brainer is like a paper, surgical disposable cap," said Jolly. "It has an insert that is made of heavy metals like bismuth and barium. It is so lightweight—it essentially weighs about 50 g—that it's not much more than the disposable cap. We were unsure how effective it would be given how lightweight it was."

Previous attempts to reduce radiation exposure to the brain have seen some attempts to wear a lead cap, which can weigh up to 1 kg, but physicians have struggled wearing these heavy caps for an entire day in the lab, said Jolly.

In their study, which was called RADIATION-PROTECT , a probe was inserted inside the No Brainer, just by the left temple where the brain typically receives the most radiation. A probe was also placed outside the cap to determine the radiation dose differential inside and outside the cap. Inside the cap, the radiation dose was 2.99 µSv vs 10.75 µSv outside the cap (p<0.0001).

"We were very impressed," said Jolly. "We saw an 80% reduction in dose related to the material in the cap. There are three versions of cap related to lead equivalency. We tested the thinnest and lightest cap at 0.125 mm of lead equivalency. If that blocks 80%, you're sure going to get more blockage with the highest levels. But we thought we'd test this version, because if it's light people are going to wear it."

The lead pelvic drape, Jolly said, is designed to reduce radiation exposure as the physician moves throughout the case. While the physician is wearing a lead vest and thyroid collar and there are lead screens and skirts to provide protection, radiation can scatter off the patient in multiple directions. This is problematic as the physician leans in over the protective screens and shields. The lead drape is designed to reduce scatter and limit the radiation they are exposed to when doing PCI.

"The beauty of the addition of a lead drape on a patient is that it blocks the radiation we would get [from them]," said Jolly. "It blocks between 75% and 80% of the dose we would get."

Jolly said the cap is commercially available, and he wears it, as do his interventional fellows and most of the interventional cardiologists on staff. He suspects the cap and lead pelvic shield will become standard practice within the next few years, given how simple it is to reduce radiation exposure this way.

In June, Dr Ryan Reeves (University of California, San Diego) presented data from the BRAIN study at the Society of Cardiovascular Angiography and Interventions (SCAI) scientific sessions. Like this study, the BRAIN study investigators showed that a similar cap—this one made of barium and bismuth oxide (BioXR), could significantly reduce the amount of radiation exposure. They conducted a similar study design, with radiation dosimeters inside and outside the cap, and showed that radiation exposure was 55% lower inside the cap than outside it. The BRAIN researchers also showed that radiation exposure was highest on the left side of the head, which had been suspected but never shown in a clinical study.

Jolly reports grant/research support/consulting fees from Medtronic, St Jude Medical, and AstraZeneca.

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