The Efficacy of Shielding Systems for Reducing Operator Exposure during Neurointerventional Procedures: A Real-World Prospective Study

BACKGROUND AND PURPOSE

Neurointerventional surgery may expose patients and physician operators to substantial amounts of ionizing radiation. Although strategies for reducing patient exposure have been explored in the medical literature, there has been relatively little published in regards to decreasing operator exposure. The purpose of this study was to evaluate the efficacy of shielding systems in reducing physician exposure in a modern neurointerventional practice.

MATERIALS AND METHODS

Informed consent was obtained from operators for this Health Insurance Portability and Accountability Act-compliant, institutional review board-approved study. Operator radiation exposure was prospectively measured during 60 consecutive neurointerventional procedures from October to November 2013 using a 3-part lead shielding system. Exposure was then evaluated without lead shielding in a second 60-procedure block from April to May 2014. A radiation protection drape was randomly selected for use in half of the cases in each block. Two-way analysis of covariance was performed to test the effect of shielding systems on operator exposure while controlling for other covariates, including procedure dose-area product.

RESULTS

Mean operator procedure dose was 20.6 μSv for the entire cohort and 17.7 μSv when using some type of shielding. Operator exposure significantly correlated with procedure dose-area product, but not with other covariates. After we adjusted for procedure dose-area product, the use of lead shielding or a radiation protection drape significantly reduced operator exposure by 45% (F = 12.54, P < .0001) and 29% (F = 7.02, P = .009), respectively. The difference in protection afforded by these systems was not statistically significant (P = .46), and their adjunctive use did not provide additional protection.

CONCLUSIONS

Extensive lead shielding should be used as much as possible in neurointerventional surgery to reduce operator radiation exposure to acceptable levels. A radiation protection drape is a reasonable alternative when standard lead shielding is unavailable or impractical to use without neglecting strategies to minimize the dose.

VITRAX (sodium hyaluronate) in anterior segment surgery: a review and clinical study summary

Anterior segment ophthalmic surgery has been greatly facilitated by the use of viscoelastic surgical aids containing sodium hyaluronate. VITRAX is a highly purified fraction of sodium hyaluronate dissolved in a physiological balanced salt solution. A multiclinic evaluation was conducted in 440 patients undergoing anterior segment surgery who received VITRAX or other viscoelastic surgical aids (HEALON, VISCOAT, or AMVISC). VITRAX was effective in facilitating complex intraocular surgical procedures and was comparable to HEALON in protecting corneal endothelium during surgery. Overall rates for complications and adverse reactions with VITRAX and the comparative agents were similar, although postoperative elevations in intraocular pressure were observed more frequently with HEALON. Vitrax is an effective and well-tolerated surgical aid for anterior chamber procedures.

Flow-cytometric analysis of chicken red blood cells

Flow-cytometric analysis of acriflavin-Feulgen stained chicken erythrocytes shows a complex distribution of amounts of deoxyribonucleic acid fluorescence, the profile consisting of a main peak and a right hand shoulder. This bimodal distribution, an artifact characteristically seen on analysis of flattened cells using orthogonal flow systems, results from fluorescence emission in preferred directions stemming from the combined effects of refractility and orientation of the cells. The shoulder disappears on analysis of lysed erythrocyte ghosts, also on analysis of cells in a medium whose refractive index approximates that the cells. An orientation effect for matrue erythrocytes was indicated by reanalysis of fractions after sorting on the basis of high and low fluorescence or scatter signals. Both fractions gave the original range of values on reanalysis, although some changes in shape of the profile and in the peak positions for the sorted cells were seen. Sodium dodecyl sulfate treatment of stained cells "loosened" the cells' structure, yielding lowered scatter values, and fluorescence values approaching those of the shoulder. The average fluorescence emission of the erythrocytes was lower than that of reticulocytes and lymphocytes. The values of the latter correspond closely, although coincidently, to that the erythrocyte shoulder values. Dual parameter analysis of forward light scatter, and fluorescence, which was detected at 90 degrees to the laser beam, showed the low fluorescence to be accompanied by low scatter signal, and the high fluorescence among the cells with the high scatter signal. The lowered forward scatter signal is due to a wider scattering of light from cells oriented edge-on to the detector, and loss of signal beyond the acceptance angle of the detector. These results suggest that the preferred directions for fluorescence are in the plane of the cells, and the values are dependent on the cells' orientation in the stream. These interpretations were supported by the results of analysis of partially oriented cells. The approaches used and conclusions arrived at are similar to those of Gledhill et al (16), Van Dilla et al (37), in their analysis of fluorescence of flat sperm cells although the affects in the case of the erythrocytes are less extreme.