Kirkwood ML, et al. – This work was carried out to assess the efficacy of the RADPAD (WIT, Lenexa, Kan) No Brainer surgical cap (0.06 mm lead equivalent at 90 kVp) in reducing radiation dose to the surgeon and trainee’s head during fluoroscopically guided interventions (FGIs) and to a phantom to determine relative brain–dose reductions. The No Brainer surgical cap reduced direct x–rays at the superficial temporal location; however, the majority of radiation to an interventionalist’s brain originates from scatter radiation from angles not shadowed by the cap as demonstrated by the trivial percentage brain dose reductions measured in the phantom. Findings thus suggested a minimal clinical relevance of radiation protective caps.

Methods

• Researchers used OSL nanoDot detectors (Landauer Inc, Glenwood, Ill) inside and outside of the cap at the left temporal position to measure cap attenuation during FGIs.
• NanoDot detectors were placed in 15 positions within an anthropomorphic head phantom (ATOM model 701,CIRS, Norfolk, Va) to assess relative brain doses.
• They positioned the phantom to represent a primary operator performing femoral access.
• They performed fluorography on a plastic scatter phantom at 80 kVp for an exposure of 5 Gy reference air kerma with/without the hat.
• For each brain location, they calculaterd the percentage dose reduction with the hat.
• Calculation of means and standard errors was performed using a pooled linear mixed model with repeat measurements.
• They combined anatomically similar locations into five groups: upper brain, upper skull, middle brain, eyes, and left temporal position.

Results

• A prospective, single–center study was performed; this study included 29 endovascular aortic aneurysm procedures.
• The average procedure reference air kerma observed was 2.6 Gy.
• Researchers noticed that the hat attenuation at the temporal position was 60% ± 20% for the attending and 33% ± 36% for the fellow.
• In this study, the equivalent phantom measurements indicated an attenuation of 71% ± 2.0% (P < .0001).
• In the interior phantom locations, statistically significant attenuation was observed for the skull (6% ± 1.4%) and upper brain (7.2% ± 1.0%; P < .0001) but it was not observed for the middle brain (1.4% ± 1.0%; P = .15) or the eyes (–1.5% ± 1.4%; P = .28).