DISEASE SITE AND PROCESSING ENGINE AFFECT RADIATION EXPOSURE DOSE DURING ERCP

Recently, demand for minimally invasive procedures is increasing. Therefore, various endoscopic procedures under fluoroscopic guidance such as ERCP, interventional EUS, enteral endoscopy, stenting et al. are rapidly arising. At the other hand, increasing radiation exposure (RE) from medical imaging has led to be major concerns in whole society because of its potential cancer risk. However, there are still less reports from gastroenterology society than other medical societies like radiology or cardiology. The aim of this study is to evaluate the actual RE dose during ERCP and factors affecting the RE. This is a retrospective single center cohort study of consecutive patients who underwent ERCP in the same fluoroscopic unit under EXAVISTA system (including image processing engine FAICE V, Hitachi..co, Japan) between Oct 2012 and Feb 2017. We have introduced novel image processing engine FAICE V new stage 1 (NS1) since Jul 2016, in addition to FAICE V . Data of a total of 1157 patients (average age 73.4±10.8 years, female 43%) were analyzed. Patients were divided into 4 groups depending on baseline disease: common bile duct stones (CBDs, N=579), distal malignant biliary obstruction (distal MBO, N=224), proximal MBO (N=240) and others (n=114). Then, we evaluated 3 groups except for others. Endoscopists were divided into 2 groups: high-volume endoscopist (HVE) and low-volume endoscopist (LVE). We evaluated the patients’ characteristics, procedure time (PT, min), total fluoroscopy time (FT, min), total radiation dose (RD, mGy), processing engine, experience of endoscopist and baseline diseases. And multiple linear regression was calculated to predict RD based on these factors. Median PTs among diseases were 28 minutes in CBDs, 25 in distal MBO, and 30 in proximal MBO, respectively. In a similar fashion, median FTs were 10.3, 8.8 and 13.4 minutes, and median RD were 167, 123, 242 mGy, respectively. Dunn’s multiple comparison test among three diseases revealed that proximal MBO showed significantly longer PT, FT and greater RD than both distal MBO (P=0.0006, <0.0001, <0.0001) and CBDs (P=0.015, <0.0001, <0.0001). CBDs showed significantly longer FT and greater RD than distal MBO (P=0.030, 0.0002), respectively. Multiple linear regression analysis showed distal MBO and NS1 have negative relation with RD (P=0.04,