Pulsed Fluoroscopy to Reduce Radiation Exposure During ERCP: A Prospective Randomized Trial

摘要

Background: Endoscopic retrograde cholangiopancreatography (ERCP) exposes patients and staff to potentially harmful ionizing radiation. Measures should be employed to limit the dose to the minimum required to perform the procedure.Aim: To determine whether "pulsed" fluoroscopy reduces radiation exposure and fluoroscopy time compared to continuous fluoroscopy. Methods: Subjects: Adult patients presenting to a single, university-based endoscopy unit for ERCP. Subjects were randomized into two groups: 1) Pulsed fluoroscopy, where a timer terminates x-ray exposure 3 seconds after the foot-operated switch is depressed; 2) Continuous setting, where x-ray exposure continues for as long as the switch is depressed. All procedures were performed by one of two attending gastroenterologists. Following each procedure, fluoroscopy time (FT) and patient and procedure-related data were recorded. A scoring system rated duct cannulation as easy (<5 touches), moderate (6-15 touches), or difficult (>15 touches). Radiationdosimetry badges were also positioned during each case to estimate exposure to 1) patients, 2) sedation nurse, and 3) endoscopist. These were analyzed in a blinded fashion by the university radiation safety department. Results: A sample size of 99 ERCPs in each group was calculated prior to initiation of the study. A total of 199 procedures were performed: 99 in the pulsed group and 10" using continuous fluoroscopy. By simple linear regression, longer FT was predicted by moderate or difficult cannulations (p = 0.008), lithotripsy (p < 0.001), stent placement (p = 0.007), sphincterotomy (p < 0.001), and longer overall procedure length (p < 0.001). Procedures by one endoscopist also had significantly longer FT (p = 0.04). The difference in mean FT between groups was not statistically significant (314 versus 284 seconds for continuous and pulsed fluoroscopy, respectively; p = 0.34). The difference in radiation dose between groups was also not significant. However, when controlling, for the above factors using a multiple linear regression model, a strong associationbetween lower FT and the pulsed setting was found (p = 0.019). DiscussionFluoroscopy time and radiation exposure are dependent on numerous patient, operator, and procedure-related factors. This study found that, after controlling for the impact of certain significant factors, pulsed fluoroscopy significantly decreases fluoroscopy times. A possible mechanism of this effect is that the pulsed setting serves as a constant reminder to the endoscopist to limit fluoroscopy.