Phase-contrast breast CT: the effect of propagation distance. (18th December 2018)

• Record Type: Journal Article
• Authors: Brombal, Luca; Donato, Sandro; Dreossi, Diego; Arfelli, Fulvia; Bonazza, Deborah; Contillo, Adriano; Delogu, Pasquale; Di Trapani, Vittorio; Golosio, Bruno; Mettivier, Giovanni; Oliva, Piernicola; Rigon, Luigi; Taibi, Angelo; Longo, Renata
• Is Part Of: Physics in medicine & biology. Volume 63:Number 24(2018:Dec.)
• Publication Date: 2018-12-18
• Subjects: phase contrast imaging -- phase retrieval -- propagation distance -- breast CT -- synchrotron radiation; Biophysics -- Periodicals; Medical physics -- Periodicals; 610.153
• DOI: 10.1088/1361-6560/aaf2e1
• Languages: English
• ISSNs: 0031-9155

Abstract

Abstract: X-ray phase imaging has the potential to dramatically improve soft tissue contrast sensitivity, which is a crucial requirement in many diagnostic applications such as breast imaging. In this context, a program devoted to perform in vivo phase-contrast synchrotron radiation breast computed tomography is ongoing at the Elettra facility (Trieste, Italy). The used phase-contrast technique is the propagation-based configuration, which requires a spatially coherent source and a sufficient object-to-detector distance. In this work the effect of this distance on image quality is quantitatively investigated scanning a large breast surgical specimen at three object-to-detector distances (1.6, 3, 9 m) and comparing the images both before and after applying the phase-retrieval procedure. The sample is imaged at 30 keV with a pixel pitch CdTe single-photon-counting detector, positioned at a fixed distance of 31.6 m from the source. The detector fluence is kept constant for all acquisitions. The study shows that, at the largest distance, a 20-fold SNR increase can be obtained by applying the phase-retrieval procedure. Moreover, it is shown that, for phase-retrieved images, changing the object-to-detector distance does not affect spatial resolution while boosting SNR (four-fold increase going from the shortest to the largest distance). The experimental results are supported by a theoretical model proposed by other authors, whose salient results are presented in this paper.