Sarno, Antonio (2017) Dose and image quality in X-ray phase contrast breast imaging. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Lingua: English
Title: Dose and image quality in X-ray phase contrast breast imaging
Date: 7 April 2017
Number of Pages: 136
Institution: Università degli Studi di Napoli Federico II
Department: Fisica
Scuola di dottorato: Scienze fisiche
Dottorato: Fisica
Ciclo di dottorato: 29
Coordinatore del Corso di dottorato:
Mettivier, GiovanniUNSPECIFIED
Date: 7 April 2017
Number of Pages: 136
Uncontrolled Keywords: X-ray breast imaging; phase-contrast; Monte Carlo; GEANT4; mean glandular dose
Settori scientifico-disciplinari del MIUR: Area 02 - Scienze fisiche > FIS/07 - Fisica applicata (a beni culturali, ambientali, biologia e medicina)
Date Deposited: 03 May 2017 15:04
Last Modified: 08 Mar 2018 11:14
DOI: 10.6093/UNINA/FEDOA/11495


Nowadays, mammographic examination is the gold standard technique for detecting breast cancer in asymptomatic women. However, it presents some limitations, mainly due to the superimposition of the tissues in the 2D mammograms, which may hide tumor lesions. Partially (digital breast tomosynthesis) and fully (CT dedicated to the breast) 3D breast imaging techniques have been developed in order to have a better tissues separation and to overcome such a limitation. Along with 3D breast imaging, the use of the X-ray beam phase shift, via so-called phase-contrast imaging techniques, has been shown to be a promising method in order to increase the image contrast between glandular tissue and tumor lesions. Indeed, in phase-contrast the image contrast is due to the X-ray wave phase-shift between different imaged materials, while in conventional imaging the image contrast arises from the different attenuation they introduce. Among all phase-contrast techniques, propagation based phase-contrast imaging does not need any special optical elements in the beam path, but only an X-ray beam with a certain degree of coherence and enough distance between imaged object and detector. It can be implemented either with synchrotron radiation source or with a compact X-ray tube. The 3D propagation based phase-contrast breast imaging devices are not yet employed in the routine clinical exams but they are available only at experimental level, and appropriate evaluations of image quality and dose are necessary. This is needed in order to optimize the various techniques and to understand the corresponding dose limitations. In this thesis, the dose paradigms in X-ray breast imaging are revisited and specific Monte Carlo simulation codes have been developed. A part of this work focuses on the breast dose aiming at studying the adopted breast models and the effects of the breast partial irradiation on the dose estimates, as occurs in 2D spot mammography clinical examinations as well as by adopting a narrow beam produced via synchrotron radiation. The second part of this work focuses on the image quality obtainable in 3D images of the breast by adopting propagation based phase-contrast imaging. We present the CT scanner dedicated to the breast developed within the SYRMA-CT project at Elettra synchrotron radiation facility. We evaluate its imaging performance in terms of spatial resolution, image noise properties and capability of showing breast lesions and microcalcification clusters. Finally, the CT scanner dedicated to the breast, developed at the University of Naples, which relies on compact X-ray source with a 7-μm focal spot is presented and its image performance at dose comparable to that adopted in two-view digital mammography is explored together with its capability of producing phase-contrast effects. This scanner was developed and studied in order to compare a scanner which is clinical feasible in terms of cost, setup dimension and scan time to the results obtainable via the high flux and monochromatic X-ray beam synchrotron based experimental scanner.


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