Dose efficiency consideration for volume-of-interest breast imaging using x-ray differential phase-contrast CT

Weixing Cai; Ruola Ning

doi:10.1117/12.813837

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13 March 2009 Dose efficiency consideration for volume-of-interest breast imaging using x-ray differential phase-contrast CT

Weixing Cai, Ruola Ning

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Proceedings Volume 7258, Medical Imaging 2009: Physics of Medical Imaging; 72584D (2009) https://doi.org/10.1117/12.813837
Event: SPIE Medical Imaging, 2009, Lake Buena Vista (Orlando Area), Florida, United States

Abstract

The newly developed differential phase-contrast (DPC) imaging technique has attracted increasing interest among researchers. In a DPC system, the self-imaging effect and the phase-stepping method are implemented through three gratings to manifest phase contrast, and differentiated phase images can be obtained. An important advantage of this technique is that hospital-grade x-ray tubes can be used, allowing much higher x-ray output power and faster image processing than with micro-focus in-line phase-contrast imaging. A DPC-CT system can acquire images from different view angles along a circular orbit, and tomographic images can be reconstructed. However, the principle of DPC imaging requires multiple exposures to compute any differentiated phase image at each view angle, which raises concerns about radiation exposure via x-ray dose. Computer simulations are carried out to study the dose efficiency for DPC-CT for volume-of-interest breast imaging. A conceptual CBCT/DPC-CT hybrid imaging system and a numerical breast phantom are designed for this study. A FBP-type reconstruction algorithm is optimized for the VOI reconstruction. Factors including the x-ray flux and detector pixel size are considered and their effects on reconstruction image quality in terms of noise level and contrast-to-noise ratio are investigated. The results indicate that with a pixel size of 20 microns and a dose level of 5.7mGy, which is equivalent to the patient dose of a two-view mammography screening or a dedicated CBCT breast imaging scan, much better tissue contrast and spatial resolution can be achieved using the DPC-CT technique. It is very promising for possible application at pathology-level in vivo study for human breasts.

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Weixing Cai and Ruola Ning "Dose efficiency consideration for volume-of-interest breast imaging using x-ray differential phase-contrast CT", Proc. SPIE 7258, Medical Imaging 2009: Physics of Medical Imaging, 72584D (13 March 2009); https://doi.org/10.1117/12.813837

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