Physician, Shield Thyself!

Exposure to scatter radiation is an occupational hazard for cardiac catheterization laboratory personnel. Despite attempts to keep radiation as low as reasonably achievable (“ALARA”), both patients and operators are exposed to significant radiation doses during procedures such as percutaneous coronary intervention of chronic total occlusion (CTO-PCI).Although most regulatory efforts and media attention are appropriately focused on the patient, chronic low-level radiation exposure poses potential long-term health risks to the interventional cardiologist.

CTO-PCI requires greater technical expertise and longer procedure times than non-CTO PCI.¹ Since many interventionists are unenthusiastic about performing CTO-PCI, likely due to lower success rate, increased procedural time, and need for advanced training, the majority of procedures are performed by “CTO specialists” who thus bear a potentially significantly higher radiation burden. In addition to relatively long fluoroscopy times, there is often a relatively fixed beam angulation to best visualize the culprit lesion, thus increasing radiation scatter in a particular path. Despite attempts to limit cine acquisition runs, lower fluoro frame rate, optimize collimation, and judiciously use fluoroscopy, the total radiation dose (and the consequent amount of scatter radiation) can still be substantial. Shielding is thus crucial to aid in protecting the operator. 

Most cath labs in the United States are equipped with accessory shielding equipment such as a ceiling-mounted lead-acrylic shield (to protect the operator’s upper body from scatter radiation) and a table-to-floor lead flap (to protect the operator’s lower body). The ceiling-mounted shield needs to be precisely positioned with the patient cutout snug to the patient’s body and the shield itself as close to the operator as possible. Despite such precise positioning, the operator is exposed to a large triangle-shaped area of scatter radiation at the level of the bony pelvis of the patient. Previous attempts to “plug this hole” studied a commercially available pelvic lead shield with cutouts for bilateral femoral areas during femoral access and a transradial radiation protection board that is placed on the patient’s armrest during radial angiography.^2,3 Lead pelvic shields can be uncomfortable for patients during a long procedure and can be cumbersome to remove from under the sterile field if additional aortic or pelvic angiography has to be performed at the end of the procedure.

In the current issue of the Journal of Invasive Cardiology, Shorrock et al report their experience during CTO-PCI with a commercially available disposable sterile radiation drape (Radpad; Worldwide Innovations & Technologies, Inc).⁴ They describe significant reductions in operator radiation doses to levels approaching that of non-CTO PCI (20 [9.5-31] µSv vs 15 [7-23] µSv; P=.07). The drape consists of a disposable lead-free bismuth-barium impregnated pad placed on the sterile field after obtaining vascular access and can be removed easily in case pelvic fluoroscopy is required. The product is relatively cheap ($20 USD at the authors’ institution). In the current presentation, it appears to be relatively effective. Thus, it is a welcome addition for radiation protection in cases of expected long duration. In the current era of cost containment, this simple addition to standard radiation protection appears to be a worthwhile investment to decrease radiation exposure and potentially improve long-term operator wellbeing. We echo the authors’ proposal for a prospective randomized trial to determine if and to what extent the use of the Radpad reduces radiation exposure to both patients and operators. While awaiting the results of such a trial, CTO-PCI operators should plan effective shielding techniques to minimize risk to themselves and their lab personnel, considering the Radpad when a case is expected to require a relatively high radiation dose such as with CTO-PCI.

A truly exciting possibility is that bismuth-barium (or similar) coatings can provide a lightweight, lead-free alternative to currently used lead-based protective devices such as aprons, head caps, gloves, and thyroid collars. The weight and discomfort associated with these garments (especially when poorly fitted or improperly used) can lead to musculoskeletal problems and has been an impediment to the uptake of additional radiation shielding garments such as head caps and gloves. Lead-free protective equipment such as a thyroid collar is already commercially available and promises to be a more comfortable and possibly equally efficacious alternative to lead.⁵

References

1. Grantham JA, Marso SP, Spertus J, House J, Holmes DR Jr, Rutherford BD. Chronic total occlusion angioplasty in the United States. JACC Cardiovasc Interv. 2009;2:479-486.
2. Lange HW, von Boetticher H. Reduction of operator radiation dose by a pelvic lead shield during cardiac catheterization by radial access: comparison with femoral access. JACC Cardiovasc Interv. 2012;5:445-449.
3. Behan M, Haworth P, Colley P, et al. Decreasing operators’ radiation exposure during coronary procedures: the transradial radiation protection board. Catheter Cardiovasc Interv. 2010;76:79-84.
4. Shorrock D, Christopoulos G, Wosik J, et al. Impact of a disposable sterile radiation shield on operator radiation exposure during percutaneous coronary intervention of chronic total occlusions. J Invasive Cardiol. 2015;27:313-316. 
5. Uthoff H, Benenati MJ, Katzen BT, et al. Lightweight bilayer barium sulfate–bismuth oxide composite thyroid collars for superior radiation protection in fluoroscopy-guided interventions: a prospective randomized controlled trial. Radiology. 2014;270:601-606.

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From the Central Arkansas Veterans Health System, University of Arkansas for Medical Sciences, Department of Medicine, Little Rock, Arkansas.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. One or more of the authors have disclosed potential conflicts of interest regarding the content herein.

Address for correspondence: Barry F. Uretsky, MD, 4300 West Seventh Street, Little Rock, AR 72205.