Reusable Radiation Shield Cuts Operator Exposure by More Than 80%

A flexible and reusable radiation shield that lays across the patient like a blanket can reduce scatter radiation to operators in the cath lab by as much as 84% compared with routine protection strategies, according to a small Norwegian study.

The reductions in the radiation dose to the operators were similar for PCI and diagnostic angiography and similar in male and female operators, the researchers report in Circulation: Cardiovascular Interventions. They say the novel device they developed and tested—a flexible multiconfiguration X-ray shield (FMX)—offers protection against scatter that table- and ceiling-mounted shields can miss.

“The FMX was designed to maintain protection and ease of use across a variety of patients, access sites, and procedure types,” write Cedric Davidsen, MD (Haukeland University Hospital, Bergen, Norway), and colleagues. “The system can be immediately and fully removed or repositioned in seconds according to clinical need.”

Commenting for TCTMD, Ryan D. Madder, MD (Frederik Meijer Heart & Vascular Institute, Spectrum Health, Grand Rapids, MI), said the FMX seems easy and straightforward to use, but he was most impressed that it can be reused.

“I think that's really important because some of the newer technologies that are coming out with a focus on radiation safety are very expensive,” he said. “In this day and age when hospital finances are so tight and often hospital administrators don't want to spend money, or can't spend money, on technologies to enhance operator and cath lab radiation safety, having something like they've presented in this paper that's reusable may be more attractive to some cath labs.”

Testing the FMX

Davidsen and colleagues assessed the efficacy of the radiation shield in 103 consecutive procedures at their institution over a 2-week period. Of these, routine radiation protection, which included ceiling-mounted and table-side rail shields, was used in 51 procedures and the FMX in 52 procedures. Mean patient age was 68.8 years in the routine protection group and 65 years in the FMX group, with similar mean body mass index (BMI), height, and weight in both groups. The percentage of female patients was 24% in the routine group and 30% in the FMX group.

Procedures were planned in 51%, semiurgent in 46%, and urgent in 3%. Slightly more than half of all procedures were PCI, with chronic total occlusion (CTO) accounting for 6.8% and bifurcation for 3.9%. Ten operators participated in the study (six male, four female), wearing dosimeters attached to a thyroid collar to record radiation exposure.

The median relative operator dose in the routine protection group was 3.63 μSv versus 0.57 μSv in the FMX group (P < 0.001), corresponding to an 84.4% reduction in exposure. The mean reduction was 81.6% for PCI procedures and 86.4% for angiography.

The relative operator dose varied to a greater extent in the standard-protection group, with a high of 16.45 mSv in a complex PCI of the right coronary artery and a low of 0.31 mSv in a planned PCI of a left anterior descending artery.

The ultimate goal would be to eventually get to a state where we nearly eliminate the radiation exposure to operators and staff members. Ryan Madder

To assess the potential reduction for high-volume operators, the researchers calculated the impact of using FMX for 500 procedures, concluding that the yearly dose reduction would drop from 3.6 mSv with standard protection measures to 0.7 mSv.

In user feedback, the operators were generally positive about the FMX, with 86% saying it was optimal, 13% calling it adequate, and 1% saying they thought the size could be improved. Of the 10 operators, nine said it did not increase procedural time and eight considered it to be better than existing shielding approaches. All of the participating operators reported that they would use the FMX in their daily practice if it were available, Davidsen and colleagues say.

Getting the Lead Out (of the Lab)

In an editorial accompanying the study, Jay Khambhati, MD and Jane A. Leopold, MD (both Brigham and Women’s Hospital, Boston, MA), note that the single-center study did not include a sham arm to account for operator behavior, and point out that it is unclear if the FMX in its current form is applicable to patients at extremes of BMI and height.

Nevertheless, Khambhati and Leopold say the shield has the potential to significantly reduce the amount of radiation operators are exposed to over decades in a similar fashion to what has been demonstrated with the disposable RADPAD (Worldwide Innovations and Technologies) radiation shield, which like the FMX is placed on the patient’s midsection to intercept scatter.

“The obvious question is whether the FMX shield improves upon the radioprotection offered by the RADPAD? The per-procedure median operator dose with RADPAD was 7 μSv, which translates to an annual dose of 3.5 mSv for operators who perform 500 procedures using a RADPAD,” Khambhati and Leopold write.

While the difference between that and the estimated annual exposure of 0.7 mSv for high-volume operators using the FMX appears fairly large, they say a head-to-head comparison to account for differences like operator radioprotection practices, cath lab differences, and case types is needed for confirmation.

“Nonetheless, the radioprotection offered by the FMX shield appears favorable,” Khambhati and Leopold conclude.

To TCTMD, Madder said the study is another reminder to operators and cath lab staff to do frequent critical reappraisals of their radiation safety culture.

“With more and more of these new technologies coming out, the ultimate goal would be to eventually get to a state where we nearly eliminate the radiation exposure to operators and staff members,” he said. “We know that lead garments are associated with orthopedic injury  . . . so optimal solutions would [include] getting the dose down to levels that you could safely take off your lead. It ultimately may be a combination of technologies that are required to get us to that level of protection.”