Radiologist Evaluation of an X-ray Tube-Based Diffraction-Enhanced Imaging Prototype Using Full-Thickness Breast Specimens

Received 24 March 2009; accepted 21 May 2009. published online 13 July 2009.

Rationale and Objectives

Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visualization due to density gradients that attenuate radiation without distinction between transmitted, scattered, or refracted x-rays. Diffraction-enhanced imaging (DEI) allows for increased contrast with decreased radiation dose compared to conventional mammographic imaging because of monochromatic x-rays, its unique refraction-based contrast mechanism, and excellent scatter rejection. However, a lingering drawback to the clinical translation of DEI has been the requirement for synchrotron radiation.

Materials and Methods

The authors' laboratory developed a DEI prototype (DEI-PR) using a readily available tungsten x-ray tube source and traditional DEI crystal optics, providing soft tissue images at 60 keV. Images of full-thickness human breast tissue specimens were acquired on synchrotron-based DEI (DEI-SR), DEI-PR, and digital mammographic systems. A panel of expert radiologists evaluated lesion feature visibility and correlation with pathology after receiving training on the interpretation of refraction contrast mammographic images.

Results

For mammographic features (mass, calcification), no significant differences were detected between the DEI-SR and DEI-PR systems. Benign lesions were perceived as better seen by radiologists using the DEI-SR system than the DEI-PR system at the [111] reflectivity, with generalizations limited by small sample size. No significant differences between DEI-SR and DEI-PR were detected for any other lesion type (atypical, cancer) at either crystal reflectivity.

Conclusions

Thus, except for benign lesion characterizations, the DEI-PR system's performance was roughly equivalent to that of the traditional DEI system, demonstrating a significant step toward clinical translation of this modality for breast cancer applications.

Key Words: Diffraction-enhanced imaging, phase contrast, synchrotron, reader study, breast cancer

a Department of Biomedical Engineering, University of North Carolina at Chapel Hill, CB #7000, 4030 Bondurant Hall, Chapel Hill, NC 27599

b Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, CB #7000, 4030 Bondurant Hall, Chapel Hill, NC 27599

c Lineberger Cancer Center, University of North Carolina at Chapel Hill, CB #7000, 4030 Bondurant Hall, Chapel Hill, NC 27599

d Department of Biostatistics, University of North Carolina at Chapel Hill, CB #7000, 4030 Bondurant Hall, Chapel Hill, NC 27599

e Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, CB #7000, 4030 Bondurant Hall, Chapel Hill, NC 27599

f Department of Radiology, University of North Carolina at Chapel Hill, CB #7000, 4030 Bondurant Hall, Chapel Hill, NC 27599

g Department of Radiology, University of California, San Francisco, San Francisco, CA

h National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY

Address correspondence to: E.P.

PII: S1076-6332(09)00303-1

doi:10.1016/j.acra.2009.05.006

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