Predictors of radiation exposure in percutaneous transhepatic cholangiodrainage: a multifactorial analysis integrating fluoroscopy time, cumulative dose, and dose-area product

This study aims to delineate the predictors influencing three complementary radiation metrics—fluoroscopy time (FT), cumulative dose (CD), and dose-area product (DAP)—during percutaneous transhepatic cholangiodrainage (PTCD) to inform targeted radiation safety protocols. We retrospectively analyzed 100 patients who underwent PTCD procedures. Following univariate screening, multivariate Generalized Linear Models (Gamma distribution, log link) were constructed for each outcome. Because CD and DAP are physically related to FT and to each other (CD reflects dose rate integrated over exposure time; DAP reflects CD multiplied by irradiated field area), FT was retained as a covariate in the CD model, and both FT and CD were retained as covariates in the DAP model. This strategy was intended to partition the intrinsic physical contribution of exposure duration and dose intensity, so that the remaining significant covariates could be interpreted as factors associated with each dose component beyond these relationships. For FT, significant predictors included the subxiphoid access route (subxiphoid vs. dual; Exp(B) = 0.364, p = 0.013), obstruction at the hepatic hilum (hepatic hilum vs. common bile duct; Exp(B) = 0.755, p = 0.043), and older age (Exp(B) = 0.986, p = 0.011). After adjusting for FT, significant predictors of CD were higher patient BMI (Exp(B) = 1.092, p < 0.001), longer FT (Exp(B) = 1.002, p < 0.001), female sex (Exp(B) = 0.710, p = 0.010), and less severe intrahepatic ductal dilatation (mild & moderate vs. severe; p = 0.025). For DAP, significant predictors were higher patient BMI (Exp(B) = 1.067, p < 0.001), longer FT (Exp(B) = 1.001, p < 0.001), higher CD (Exp(B) = 1.001, p < 0.001), and older age (Exp(B) = 1.010, p = 0.021). Patient BMI is associated with overall radiation exposure. Procedural complexity, reflected by obstruction level, access route, and ductal dilatation severity, shows significant associations with FT and CD. Evaluating these multidimensional dosimetric metrics may support pre‑procedural awareness of radiation exposure and could inform efforts to optimize patient radiation safety and indirectly reduce scatter radiation. These findings are exploratory and warrant validation in larger, prospective studies.