Synchrotron Radiation for Biomedical Imaging

A synchrotron radiation (SR) X-ray source is an extraordinary tool for many applications because of the high intensity, the energy spectrum properties, the peculiar laminar beam geometry and the high degree of coherence. In the past years several experimental studies have proven the suitability of SR in the field of biomedical X-ray imaging and in diagnostic radiography. SR based X-ray imaging techniques to be mentioned are transvenous coronary angiography, bronchography, computed tomography and mammography that have been successfully implemented at different SR laboratories all around the world. Moreover, the high degree of the coherence of the synchrotron source allows the implementation of novel phase-sensitive X-ray imaging modalities. In contrast to conventional X-ray radiography, based on different X-ray absorption properties of details within an object, these phase-based techniques are capable of visualizing structures that have different scattering and refraction properties respect to the surrounding material. Their importance in medical imaging lies in the fact that the diagnosis of several diseases requires the detection of tiny structures, that consist of light elements in a similar background, and that produce very low X-ray absorption, but considerable phase shift in the wave front propagation. Thus, phase-sensitive techniques may improve dramatically the image quality and subsequently the accuracy in diagnosis offering highly enhanced contrast with dose comparable or even lower than required by conventional radiography.