Radiation Dose and Risk from Fluoroscopically Guided Percutaneous Transhepatic Biliary Procedures

Abstract

To estimate radiation dose and associated risks after fluoroscopically guided percutaneous transhepatic biliary (PTB) drainage and stent implantation procedures. Organ and effective doses, normalized to dose-area product (DAP), were estimated for PTB procedures with use of a Monte Carlo transport code and an adult mathematical phantom. Exposure parameters from 51 consecutive patients were used to determine average examination parameters for biliary drainage and stent implantation procedures. Thermoluminescent dosimeters were used in an anthropomorphic phantom to verify Monte Carlo calculations. Radiation-induced cancer and genetic risks were estimated. The results consist of doses normalized to DAP so patient dose from any technique and x-ray unit can be easily calculated for left and right biliary access and for separate or combined biliary and metallic stent implantation sessions. A good agreement was found between Monte Carlo-calculated data and data derived from thermoluminescent dosimetry. The average effective dose varied from 1.8 to 5.4 mSv depending on procedure approach (left vs right access) and procedure scheme. A maximum effective dose of 13 mSv was estimated for 30 minutes of fluoroscopy. Doses delivered to patients undergoing PTB procedures are comparable to those that arise from computed tomography protocols. Radiation-induced cancer risk may be considerable for young patients undergoing PTB drainage and stent implantation procedures.