title: Effect of bismuth breast shielding on radiation dose and image quality in coronary CT angiography.
abstract: BACKGROUND
  Coronary computed tomographic angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding offers the potential to significantly reduce dose to the breasts and nearby organs, but the magnitude of this reduction and its impact on image quality and radiation dose have not been evaluated.
  
  
  METHODS
  Radiation doses from CCTA to critical organs were determined using metal-oxide-semiconductor field-effect transistors positioned in a customized anthropomorphic whole-body dosimetry verification phantom. Image noise and signal were measured in regions of interest (ROIs) including the coronary arteries.
  
  
  RESULTS
  With bismuth shielding, breast radiation dose was reduced 46%-57% depending on breast size and scanning technique, with more moderate dose reduction to the heart, lungs, and esophagus. However, shielding significantly decreased image signal (by 14.6 HU) and contrast (by 28.4 HU), modestly but significantly increased image noise in ROIs in locations of coronary arteries, and decreased contrast-to-noise ratio by 20.9%.
  
  
  CONCLUSIONS
  While bismuth breast shielding can significantly decrease radiation dose to critical organs, it is associated with an increase in image noise, decrease in contrast-to-noise, and changes tissue attenuation characteristics in the location of the coronary arteries.
authors: Cardiology Division, Department of Medicine, Columbia University Medical Center/New York-Presbyterian Hospital, 622 West 168th Street PH 10-203A, New York, NY 10032, USA. andrew.einstein@columbia.edu
authors: Andrew J
authors: AJ
authors: Einstein
authors: Carl D
authors: CD
authors: Elliston
authors: Daniel W
authors: DW
authors: Groves
authors: Bin
authors: B
authors: Cheng
authors: Steven D
authors: SD
authors: Wolff
authors: Gregory D N
authors: GD
authors: Pearson
authors: M
authors: M
authors: Robert Peters
authors: Lynne L
authors: LL
authors: Johnson
authors: Sabahat
authors: S
authors: Bokhari
authors: Gary W
authors: GW
authors: Johnson
authors: Ketan
authors: K
authors: Bhatia
authors: Theodore
authors: T
authors: Pozniakoff
authors: David J
authors: DJ
authors: Brenner
mesh_terms: D001729:Bismuth; D001940:Breast / Q000528:radiation effects*; D017023:Coronary Angiography / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D009928:Organ Specificity; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D011835:Radiation Protection / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods
chemical_list: D001729:Bismuth