Predictive Factors of Radiation Dose in ERCP: A Prospective Study in 2 Tertiary Centers

Background: The use of fluoroscopy to aid endoscopic retrograde cholangiopancreatography (ERCP) places both the patient and the endoscopy staff at the risk of radiation-induced injury. Previous reports have demonstrated a linear relationship between radiation dose and fluoroscopy duration. Aim: To identify predictive factors of fluoroscopy time and radiation exposure to patients undergoing ERCP by using pulsed fluoroscopy. Methods: Four hundred and four consecutive ERCPs performed from January 2010 to November 2010 at 2 tertiary centers in Spain were prospectively studied. Patients and procedural variables were analyzed. Philips BV Pulsera mobile fluoroscopy system was used on the endoscopy unit. Entrance surface dose, dose-area product, and fluoroscopy time were recorded for each patient. Results: A total of 404 ERCPs on 404 consecutive patients were studied (mean age 73 y). The average entrance surface dose and dose-area product were 12.0 mGy and 0.37 mGy/m(2), respectively. Mean fluoroscopy time was 2.31 minutes. The biliary ducts were adequately visualized in 371 (92%) cases. After analysis with a univariable model, the factors found to significantly increase the radiation dose (P75 > 19.6 mGy) were as follows: alkaline phosphatase serum levels (P = 0.047), balloon dilation (P = 0.005), biliary stent placement (P = 0.001), and ERCP diagnosis (P = < 0.0001). In a multivariate analysis, only stent insertion significantly increased the radiation dose (risk ratio 4.75; 95% confidence interval, 1.84-7.63). Conclusions: In this prospective analysis, multiple factors affected the radiation dose. Stent insertion was the only independent predictor significantly associated with prolonged fluoroscopy.