Table of Contents
ISRN Radiology
Volume 2013 (2013), Article ID 457396, 6 pages
http://dx.doi.org/10.5402/2013/457396
Research Article

Scan Quality and Entrance Skin Dose in Thoracic CT: A Comparison between Bismuth Breast Shield and Posteriorly Centered Partial CT Scans

1Radiology Department, Penn State Hershey Medical Center, 500 University Drive, Hershey, PA 17033, USA
2Internal Medicine Department, Penn State Hershey Medical Center, 500 University Drive, Hershey, PA 17033, USA

Received 12 October 2012; Accepted 30 October 2012

Academic Editors: H. Akan, J.-B. Dubois, and G. Storto

Copyright © 2013 Rafel Tappouni and Bradley Mathers. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives. To compare the effectiveness of the bismuth breast shield and partial CT scan in reducing entrance skin dose and to evaluate the effect of the breast shield on image quality (IQ). Methods. Nanodots were placed on an adult anthropomorphic phantom. Standard chest CT, CT with shield, and partial CT were performed. Nanodot readings and effective doses were recorded. 50 patients with chest CTs obtained both with and without breast shields were reviewed. IQ was evaluated by two radiologists and by measuring Hounsfield units (HUs) and standard deviation (SD) of HU in anterior subcutaneous region. Results. Breast shield and the partial CT scans reduced radiation to the anterior chest by 38% and 16%, respectively. Partial CT increased dose to the posterior chest by 37% and effective dose by 8%. Change in IQ in shield CT was observed in the anterior chest wall. Significant change in IQ was observed in 5/50 cases. The shield caused an increase of 20 HU ( ) and a 1.86 reduction in SD of HU ( ) in the anterior compared to posterior subcutaneous regions. Summary. Bismuth breast shield is more effective than the partial CT in reducing entrance skin dose while maintaining image quality.