Imaging Pearls ❯ Radiation Dose ❯ Bismuth Shielding
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- “ Breast tissue may receive substantial doses during CT examinations. Bismuth shields effectively reduce breast exposure at the expense of increased noise and artifacts. Because bismuth shields reduce radiation transmission in all directions posterior to anterior irradiation results in wasted exposure of posterior tissues.”
To Shield or Not to Shield: Application of Bismuth Breast Shields
Colletti PM et al
AJR 2013;200:503-507 - “Similar breast radiation reductions can be achieved without shielding by globally reducing tube current. In general more advanced methods of reducing exposure, including dose modulation and iterative reconstruction techniques are superior if available.”
To Shield or Not to Shield: Application of Bismuth Breast Shields
Colletti PM et al
AJR 2013;200:503-507 - “ In particular, a detailed understanding of a few basic CT scan parameters is essential, and knowledge of how to manipulate these parameters to produce diagnostic images at lower doses is critical for safe imaging.”
CT Scan Parameters and Radiation Dose: Practical Advise for Radiologists
Raman SP, Mahesh M, Blasko RV, Fishman EK
J Am Coll Radiol 2013;10:840-846
- “ Breast shields for woman undergoing coronary CT angiography slightly increased noise but did not negatively affect signal, signal to noise ratio, quality, or interpretability. Breast shields use warrants further study.”
Comparison of Coronary CT Angiography Image Quality With and Without Breast Shields
Hulten E et al.
AJR 2013; 200:529-536 - “ In such dosimetry studies measuring radiation precisely at the breast tissue, dose reduction to the breast achieved by breast shields has been reported to be as much as a statistically significant 37.1%.”
Comparison of Coronary CT Angiography Image Quality With and Without Breast Shields
Hulten E et al.
AJR 2013; 200:529-536
- "In conclusion we believe that the ways in which bismuth shielding can hurt outnumber the ways in which it helps. Although their use is well intentioned, and we applaud the imaging community’s efforts toward safe and effective use of CT imaging, bismuth shields waste radiation dose to patients and degrade image quality."
Bismuth Shields for CT Dose Reduction: Do they Help or Hurt?
McCollough CH et al.
J American College of Radiol Dec 2011; Vol 8, No 12 pg 878-879 - "In conclusion we believe that the ways in which bismuth shielding can hurt outnumber the ways in which it helps."
Bismuth Shields for CT Dose Reduction: Do they Help or Hurt?
McCollough CH et al.
J American College of Radiol Dec 2011; Vol 8, No 12 pg 878-879
- “ In conclusion we believe that the ways in which bismuth shielding can hurt outnumber the ways in which it helps. Although their use is well intentioned, and we applaud the imaging community’s efforts toward safe and effective use of CT imaging, bismuth shields waste radiation dose to patients and degrade image quality.”
Bismuth Shields for CT Dose Reduction: Do they Help or Hurt?
McCollough CH et al.
J American College of Radiol Dec 2011; Vol 8, No 12 pg 878-879 - “ In conclusion we believe that the ways in which bismuth shielding can hurt outnumber the ways in which it helps.”
Bismuth Shields for CT Dose Reduction: Do they Help or Hurt?
McCollough CH et al.
J American College of Radiol Dec 2011; Vol 8, No 12 pg 878-879 - “ Clinical studies of bismuth shielding have shown a 29% decrease in radiation dose to the female breast and a 40% decrease to the adult female breast.”
CT Radiation Dose: What Can You Do Right Now in Your Practice?
Coakley FV et al
AJR 2011; 196:619-625 - “ While the role of bismuth shields continues to be debated, we have successfully implemented a policy of routinely using bismuth breast shields on all woman.”
CT Radiation Dose: What Can You Do Right Now in Your Practice?
Coakley FV et al
AJR 2011; 196:619-625 - Bismuth Breast Shields: Facts
- Some suggest placement after the topogram has been done
- Wrap in sheet or blanket to avoid skin contact. Touching the skin creates artifact and image noise
- Wrapping the shield in towel allows multi-use of the shields which makes the process low cost - “ Potential measures include provision of patient information material, review of CT protocols and indications, promotion of alternative studies, use of decision support software, automatic tube current modulation, bismuth shields, improved image reconstruction algorithms, enpowerment of technologists to adjust protocols, and calculation of radiation dose for possible reporting.”
CT Radiation Dose: What Can You Do Right Now in Your Practice?
Coakley FV et al
AJR 2011; 196:619-625 - "Bismuth in-plane shielding for routine thoracic MDCT decreased radiation dose to the breast without qualitative changes in image quality."
Female Breast Radiation Exposure During Thorax Multidetector Computed Tomography and the Effectiveness of Bismuth Breast Shield to Reduce Breast Radiation Dose
Yilmaz MH et al.
J Comput Assist Tomogr 2007; 31:138-142 - "The breast shield enabled a 40.5% decrease in radiation dose to the breast."
Female Breast Radiation Exposure During Thorax Multidetector Computed Tomography and the Effectiveness of Bismuth Breast Shield to Reduce Breast Radiation Dose
Yilmaz MH et al.
J Comput Assist Tomogr 2007; 31:138-142