Evaluation of fetal, medical and occupational exposure in ERCP procedures using Monte Carlo simulation and virtual anthropomorphic phantoms

Abstract

In this study, computational modeling was applied to evaluate medical and occupational exposure, to ionizing radiation, during the Endoscopic Retrograde Cholangiopancreatography (ERCP) procedure of a pregnant woman in the second gestational trimester. The fetal dose evaluation and the construction of a photon fluence map inside the procedure room were also performed. The medical staff and patient were represented by virtual anthropomorphic phantoms. These phantoms were incorporated to the radiation transport code MCNPX (version 2.7.0). The photon beam was projected on the right lateral lower section of the liver of the patient, producing a FOV of 15×15 cm2. The spectral influence was evaluated using tube voltages of 70 kVp and 80 kVp with a total filtration of 5 mmAl. The influence of the suspended shield, lead curtain and fetal shield were evaluated on the Conversion Coefficients for Equivalent Dose (CC[HT]) and Effective Dose (CC[E]) for the medical staff and patient. The removal of the lead curtain and suspended shield was considered the most critical configuration to the medical staff. In this situation, an increase up to 633% in the CC[HT]eye lens and 900% in CC[E], for the medical staff, was reached. The CC[E]Patient ranged between 0.13 mSv/Gy.cm2 (70 kVp with all protective devices) and 0.15 mSv/Gy.cm2 (80 kVp without fetal shield) and the values obtained are in agreement with the literature. The CC[HT]fetus oscillated between 2.2E-1 mSv/Gy.cm2 (70 kV with fetal shield) and 2.7E-1 mSv/Gy.cm2 (80 kV without fetal shield). The outcomes of this work are useful in the prior monitoring of the radiation doses and risks, and a reduction on these may be reached for the medical team and patient, which is a complicated arrangement in ERCP procedures.