Program Information

Investigating Performance of Spectral Shaping Filters for Contrast-Enhanced Breast CT

S Glick

SJ Glick*, A Makeev , US Food and Drug Administration, Silver Spring, MD

Presentations

WE-G-601-5 (Wednesday, August 2, 2017) 4:30 PM - 6:00 PM Room: 601

Purpose: Contrast-enhanced breast imaging has been evaluated with various modalities including digital mammography, breast tomosynthesis, and dedicated breast CT. Since breast CT does not have certain limitations such as breast structural overlap and breast compression, it is well suited for iodinated contrast-enhanced imaging. However, clinical studies have suggested a relatively high mean glandular dose for breast CT. For breast CT to be considered as a viable screening tool for women at high risk of breast cancer, radiation dose to the breast must be reduced. A number of approaches for reducing breast CT dose have been suggested, one of which is the use of spectral shaping with high Z filters. This study evaluates the use of Gd and Er x-ray filters to shape the breast CT x-ray spectrum.

Methods: Task-based performance in detecting iodine signals is investigated by imaging a cylindrical PMMA phantom containing signals of varying iodine concentration with a benchtop breast CT system that emulates clinical breast CT. To assess detectability, a channelized Hotelling observer is used with LaGuerre-Gauss channels.

Results: With signals of 3 mg/ml iodine concentration, a standard Al x-ray filter provides an SNR-CHO value of 3.0 with mean glandular dose (MGD) of 4.66 mGy, whereas imaging with Gd and Er filters provided substantially higher SNR-CHO values of 5.2 and 5.5 for MGD of 4.6 mGy and 5.0 mGy respectively. It was observed that dose reduction of at least 62.9% and 47.9% can be achieved with Gd and Er filters without sacrificing detectability.

Conclusion: These experimental phantom study results are encouraging for reducing dose of breast CT; however, further studies involving patients are needed.


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