Introduction: Considering that obese patients emit greater amounts of scatter radiation during fluoroscopic procedures, it is possible that the growing obesity epidemic could adversely affect the occupational health of physicians performing cardiac catheterization. This study was performed to determine the impact of BMI on physician radiation exposure during cardiac catheterization.
Methods: Real-time radiation exposure data were prospectively collected from dosimeters worn by physicians performing cardiac catheterization. Using data from an outer dosimeter (Hos) and body dosimeter (Hu), the physician effective dose per case (E) was calculated as E = 0.02 (Hos - Hu) + Hos. Patient radiation dose for each case was estimated using the dose-area product (DAP) automatically generated by the fluoroscopy system. Patient BMI was categorized using the NIH classification. DAP and effective dose are reported as median [25th, 75th percentile].
Results: Among 1,068 consecutive cardiac catheterizations, patient BMI was <25.0 in 16.4% of cases, 25.0-29.9 in 33.2%, 30.0-34.9 in 27.7%, 35.0-39.9 in 13.0%, and ≥40 in 9.6%. There was a significant and stepwise increase in both DAP and physician effective dose across increasing BMI categories (Figure). When compared to a BMI <25, a BMI ≥40 was associated with a 2.2-fold increase in DAP (44.4 [25.7, 65.7] Gy x cm2 vs 95.6 [60.8, 149.2] Gy x cm2, p<0.05) and a 7.5-fold increase in physician effective dose (0.2 [0.0, 2.9] μSv vs 1.5 [0.2, 8.2] μSv, p<0.05).
Conclusions: Significant stepwise increases in patient and physician radiation exposures were observed across increasing BMI categories. Compared to a BMI <25, a BMI ≥40 was associated with a doubling in patient irradiation, yet was associated with a nearly 8-fold increase in physician radiation exposure. These observations represent preliminary evidence that obesity could adversely impact the occupational risks of physicians performing cardiac catheterization.