SIMPLE METHOD OF SIZE-SPECIFIC DOSE ESTIMATES CALCULATION FROM PATIENT WEIGHT ON COMPUTED TOMOGRAPHY

摘要

The purpose of this study is to develop a new and simple methodology for calculating mean size-specific dose estimates (SSDE) over the entire scan range (mSSDE) from weight and volume CT dose index (CTDI_(vol)). We retrospectively analyzed data from a dose index registry. Scan areas were divided into two regions: chest and abdomen-pelvis. The original mSSDE was calculated by a commercially available software. The conversion formulas for mSSDE were estimated from weight and CTDI_(vol) (SSDE_(weight)) in each region. SSDE_(weight) were compared with the original mSSDE using Bland-Altman analysis. Root mean square differences were 1.4 mGy for chest and 1.5 mGy for abdomen-pelvis. Our method using formulae can calculate SSDE_(weight) using weight and CTDI_(vol) without a dedicated software, and can be used to calculate DRL to optimize CT exposure doses.