Real-time estimation of dose reduction for pediatric CT using bismuth shielding

The purpose of this study is to estimate the dose reduction of bismuth shielding for pediatric CT using a real-time CT dose probe. Routine CT examinations of head, chest and abdomen were performed on a 10-year pediatric anthropomorphic phantom, with and without bismuth shield. A solid-state dosimeter was used to obtain real-time dose measurements and to estimate the dose reduction. The maximum dose reduction of eyes using bismuth shield for in-plane CT scanning can achieve 56% during spiral head scanning interval. The average dose reduction is around 25% for in-plane CT scanning, and reaches 62% combining the technique of automatic tube current modulation. The solid-state probe can provide fast and convenient measurements for dose estimation of superficial organs. It is suggested to use Bismuth shielding in routine CT examinations to protect the radiosensitive tissues.