Data and methods to estimate fetal dose from fluoroscopically guided prophylactic hypogastric artery balloon occlusion.

Abstract

To provide data for estimation of fetal radiation dose (DF) from prophylactic hypogastric artery balloon occlusion (HABO) procedures. The Monte-Carlo-N-particle (MCNP) transport code and mathematical phantoms representing a pregnant patient at the ninth month of gestation were employed. PA, RAO 20° and LAO 20° fluoroscopy projections of left and right internal iliac arteries were simulated. Projection-specific normalized fetal dose (NFD) data were produced for various beam qualities. The effects of projection angle, x-ray field location relative to the fetus, field size, maternal body size, and fetal size on NFD were investigated. Presented NFD values were compared to corresponding values derived using a physical anthropomorphic phantom simulating pregnancy at the third trimester and thermoluminescence dosimeters. NFD did not considerably vary when projection angle was altered by ±5°, whereas it was found to markedly depend on tube voltage, filtration, x-ray field location and size, and maternal body size. Differences in NFD < 7.5% were observed for naturally expected variations in fetal size. A difference of less than 13.5% was observed between NFD values estimated by MCNP and direct measurements. Data and methods provided allow for reliable estimation of radiation burden to the fetus from HABO.