Naama R. Bogot MD, Presenter: Research Consultant, Siemens AG

Dorith Shaham MD, Abstract Co-Author: Research Consultant, Siemens AG

Eugene Libson MD, Abstract Co-Author: Nothing to Disclose

Jacob Sosna MD, Abstract Co-Author: Research grant, Koninklijke Philips Electronics NV

Benjamin Ze'Ev Koplewitz MD, Abstract Co-Author: Nothing to Disclose

Issac Leichter, Abstract Co-Author: Employee, Siemens AG

Female breasts are subject to significant radiation exposure during CT pulmonary angiography (CTPA). In-plane bismuth radiation shields can protect the breast tissue when used. Our purpose was to measure the dose reduction from breast shielding and to evaluate the effect on image quality and diagnostic capability.

This prospective study was performed in accordance with IRB requirements. Radiation reduction with breast shields was measured using a water phantom. Fifty-four consecutive female patients (21-91 years) with suspected PE underwent CTPA with bismuth breast radiation shields (F&L Medical Products, Vandergrift, PA) using 16-slice MDCT. Study parameters were as follows: 2 mm slice thickness, pitch 1.238; 1 mm slice thickness, pitch 0.66 (28 and 26 exams respectively); 120 kVp, 153-285 mAs. Two thoracic radiologists graded examinations by consensus for the following predetermined parameters: image quality, beam hardening artifacts severity and distribution, shields position and shield smoothness, and diagnostic capability. Non-parametric statistics were computed.

Phantom measured dose reduction was 16.2%. Image quality was very good to moderate in 51 (95%). There were no artifacts in 8 (5%) of exams, mild artifacts in 28 (52%) and moderate to marked in 18 (33%). Artifacts were confined to the anterior chest wall or lung periphery in 38 (70%) of exams. Shields were positioned on breasts in 41 (76%); were smooth in 12 (22%), had small folds in 32 (59%) and large folds in 10 (19%). There was statistical significant correlation between artifact severity and both shield position (p= 0.024) and shield smoothness (p< 0.01) and between artifact distribution and both shield position (p=0.03) and shield smoothness (p=0.04). One exam (1.7%) was determined non diagnostic due to shield related artifacts.

Use of bismuth radiation shields during CTPA reduces breast radiation dose and results in mild to moderate artifacts in the peripheral and anterior lungs, particularly when shields are smoothly positioned on breast.

Smoothly positioned shields on the breasts do not adversely affect CT diagnostic capability and result in decrease in breast radiation exposure.

Bogot, N, Shaham, D, Libson, E, Sosna, J, Koplewitz, B, Leichter, I, Use of Bismuth Breast Radiation Shields during CT Pulmonary Angiography: Dose Reduction and Effect on Image Quality and Interpretation.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5009582.html