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Dental Radiography
Published in Paolo Russo, Handbook of X-ray Imaging, 2017
As for many radiological applications, phase-contrast imaging will determine another revolution in medical and dental X-ray imaging. As this technique is extensively discussed in Chapters 49 to 53 of this book, in this chapter only a brief summarizing paragraph is included. Until now, medical radiography in a clinical context has always only measured attenuation of the beam. Phase-contrast means that the phase-shift the X-rays undergo during their transit through the object is detected and used as a tissue-discriminating signal. Phase-contrast has been a matter of scientific investigation for some decades already. Until quite recently, however, synchroton sources were needed to generate highly parallel and monochromatic X-rays (see Section I, Chapter 8 of this book). Obviously, such sources are not available in a clinical setting and, thus, phase-contrast X-ray imaging has for a long time never left the status of laboratory investigations. In the middle of the first decade of the millennium years, the first papers introducing alternative methods by application of conventional X-ray tubes were published (Peele et al. 2005; Pfeiffer et al. 2006). Particularly the latter method using gratings in the low micrometer-scale to infer the phase-shift is promising, and yields excellent results in a laboratory environment. Preliminary results obtained in a close-to-clinical setting have been published recently for mammography (Scherer et al. 2015). The major advantage of phase-contrast X-ray imaging over conventional absorption radiography lies in its discriminative power within soft tissues. In theory, this additional signal can be acquired without enlarging the dose (Pfeiffer et al. 2006). It will be exciting to see this revolutionary technique entering the clinical stage within the next decade.
Element differentiation with a Hartmann- based X-ray phase imaging system
Published in Nondestructive Testing and Evaluation, 2022
Ombeline de La Rochefoucauld, Ginevra Begani Provinciali, Alessia Cedola, Philip K. Cook, Francesca Di Lillo, Guillaume Dovillaire, Fabrice Harms, Mourad Idir, Xavier Levecq, Laura Oudjedi, Tan-Binh Phan, Martin Piponnier, Giuliana Tromba, Philippe Zeitoun
When absorption properties are very similar between two parts of the same sample, it becomes difficult to distinguish them using X-ray absorption imaging. This problem arises also when using high energy X-rays that make the sample transparent. X-ray phase imaging is a possible solution as it favours the phase over the amplitude contribution. Indeed, whatever the photon energy is, a sample always modifies the phase of an incident wave. This beam’s phase shift caused by the sample can be either measured directly using an X-ray phase imaging system or can be transformed with a phase-contrast X-ray imaging system into variations in intensity that are then recorded by the detector. In the latter case, intrinsically, the phase and the intensity are then merged in a single characteristic requiring advanced data treatment [1].
Review on the use of medical imaging in orthopedic biomechanics: finite element studies
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2021
Abdelwahed Barkaoui, Imane Ait Oumghar, Rabeb Ben Kahla
Synchrotron radiation (SR) is a form of electromagnetic radiation, which, thanks to its powerful inherent light source, has permitted the development of several 3D biomedical imaging modalities (Takeda et al. 2002; Zhu et al. 2011). This technology may be used for traditional X-ray imaging, phase-contrast X-ray imaging, and tomography.