On a dark-field signal generated by micrometer-sized calcifications in phase-contrast mammography.

Abstract

We show that a distribution of micrometer-sized calcifications in the human breast which are not visible in clinical x-ray mammography at diagnostic dose levels can produce a significant dark-field signal in a grating-based x-ray phase-contrast imaging setup with a tungsten anode x-ray tube operated at 40 kVp. A breast specimen with invasive ductal carcinoma was investigated immediately after surgery by Talbot-Lau x-ray interferometry with a design energy of 25 keV. The sample contained two tumors which were visible in ultrasound and contrast-agent enhanced MRI but invisible in clinical x-ray mammography, in specimen radiography and in the attenuation images obtained with the Talbot-Lau interferometer. One of the tumors produced significant dark-field contrast with an exposure of 0.85 mGy air-kerma. Staining of histological slices revealed sparsely distributed grains of calcium phosphate with sizes varying between 1 and 40 μm in the region of this tumor. By combining the histological investigations with an x-ray wave-field simulation we demonstrate that a corresponding distribution of grains of calcium phosphate in the form of hydroxylapatite has the ability to produce a dark-field signal which would-to a substantial degree-explain the measured dark-field image. Thus we have found the appearance of new information (compared to attenuation and differential phase images) in the dark-field image. The second tumor in the same sample did not contain a significant fraction of these very fine calcification grains and was invisible in the dark-field image. We conclude that some tumors which are invisible in x-ray absorption mammography might be detected in the x-ray dark-field image at tolerable dose levels.

• Authors: Thilo Michel, Jens Rieger, Gisela Anton, Florian Bayer, Matthias W Beckmann, Jürgen Durst, Peter A Fasching, Wilhelm Haas, Arndt Hartmann, Georg Pelzer, Marcus Radicke, Claudia Rauh, André Ritter, Peter Sievers, Rüdiger Schulz-Wendtland, Michael Uder, David L Wachter, Thomas Weber, Evelyn Wenkel, Andrea Zang
• Journal: Physics in medicine and biology (Phys Med Biol) Vol. 58 Issue 8 Pg. 2713-32 (Apr 21 2013) ISSN: 1361-6560 [Electronic] England
• PMID: 23552903 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Calcium Phosphates
• calcium phosphate

Topics

• Breast Neoplasms (diagnostic imaging, metabolism, pathology)
• Calcinosis (diagnostic imaging, pathology)
• Calcium Phosphates (metabolism)
• Darkness
• Female
• Humans
• Interferometry
• Mammography (methods)
• Middle Aged