Phase Contrast Imaging



Phase Contrast Imaging


Liberato De Caro
Cinzia Giannini


Commessa:  PM.P04.011 / Diffrazione e imaging a raggi x per l'ingegneria di materiali nanostrutturati e tessuti biologici e per la biodiagnostica
Modulo:  PM.P04.011.002 / Imaging a raggi X e algoritmi di ricostruzione della fase


Imaging, Phase Retrieval, Phase Contrast

Prof. R. Bellotti, Dipartimento Interateneo di Fisica, Università di Bari
Dr. S. Tangaro, Istituto Nazionale di Fisica nucleare, sezione di Bari
Prof. R. Longo, Dr. L. Rigon, Syrmep-beamline, Sincrotrone Elettra, Trieste

The spread of different types of cancer is under our eyes as fully documented in the recent congress of the European Society of Medical Oncology ( Specific data can be found on two extremely diffused type of diseases for men (lung cancer) and women (breast cancer).
For the survival of patients, the outcomes of any treatment (surgery, radiotherapy or chemiotherapy) are highly improved by an early diagnosis.
One of the most widely applied diagnostic tool in cancer is absorption (contact) x-ray radiography or tomography, also in a digital version. An evolution of the contact x-ray radiography is the so called phase-contrast imaging (PCI), which has been studied for almost 10 years in other fields of research as well as in medicine. Indeed, the x-ray transmitted beam from any material/tissue depends on the complex refractive index (n=1-δ+iβ), where δ is responsible for the phase shift and β for the beam attenuation. For human tissues the δ-cross section is about 1000 times greater than the β ones in the involved x-ray energies (10-150 KeV). This explains why PCI has a certain potential to improve imaging sensitivity while reducing radiation doses. Indeed, a considerable number of PCI data collections have been performed on different kind of tissues and human body parts, such as cartilage and bone, breast, blood vessels, lungs, brain, demonstrating significant improvements in image quality over simple absorption radiography by exploiting phase contrast.
Low-dose X-ray phase-contrast imaging could be a reliable tool in terms of early diagnosis: the screened patients would receive a radiation dose smaller than in clinical contact radiography and cancer lesions smaller in diameter would be more likely to be diagnosed. The technique has the potentiality to become extremely powerful, showing efficiency in terms of lesion morphology detection, especially when used in combination with algorithms, such as phase retrieved radiography. The latter could allow for quantitative map reconstuction of tissues/organs/human body parts refractive index.
For early diagnosis of cancer lesions, the development of new and more performing image screening methods is of primary importance.
The present research activity deals with the development of novel phase retrieval algorithms which can make a phase contrast image a quantitative tissue inspection tool.



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Last Updated (Monday, 06 December 2010 10:37)