Synchrotron radiation in radiology: radiology techniques based on synchrotron sources

The characteristics of synchrotron X-ray sources—quite different from those of conventional sources—are exploited by several new imaging techniques. These techniques expand the capabilities of conventional radiology and find interesting application in special cases. We briefly review the basic principle, applications and limitations of the most important of them: monochromatic mammography, two-wavelength digital subtraction angiography, phase-contrast/edge-enhancement imaging, diffraction-enhanced imaging and microtomograph

Scanning tunneling microscopy of deoxyribonucleic acid during replication

Scanning tunneling microscopy was used to produce topographic images of uncoated and unlabeled deoxyribonucleic acid (DNA) in air, on a graphite substrate. The images show for the first time a DNA molecule that had been isolated while it was replicating

Gold nanoparticles as high-resolution X-ray imaging contrast agents for the analysis of tumor-related micro-vasculature

<p>Abstract</p> <p>Background</p> <p>Angiogenesis is widely investigated in conjunction with cancer development, in particular because of the possibility of early stage detection and of new therapeutic strategies. However, such studies are negatively affected by the limitations of imaging techniques in the detection of microscopic blood vessels (diameter 3-5 μm) grown under angiogenic stress. We report that synchrotron-based X-ray imaging techniques with very high spatial resolution can overcome this obstacle, provided that suitable contrast agents are used.</p> <p>Results</p> <p>We tested different contrast agents based on gold nanoparticles (AuNPs) for the detection of cancer-related angiogenesis by synchrotron microradiology, microtomography and high resolution X-ray microscopy. Among them only bare-AuNPs in conjunction with heparin injection provided sufficient contrast to allow <it>in vivo </it>detection of small capillary species (the smallest measured lumen diameters were 3-5 μm). The detected vessel density was 3-7 times higher than with other nanoparticles. We also found that bare-AuNPs with heparin allows detecting symptoms of local extravascular nanoparticle diffusion in tumor areas where capillary leakage appeared.</p> <p>Conclusions</p> <p>Although high-Z AuNPs are natural candidates as radiology contrast agents, their success is not guaranteed, in particular when targeting very small blood vessels in tumor-related angiography. We found that AuNPs injected with heparin produced the contrast level needed to reveal--for the first time by X-ray imaging--tumor microvessels with 3-5 μm diameter as well as extravascular diffusion due to basal membrane defenestration. These results open the interesting possibility of functional imaging of the tumor microvasculature, of its development and organization, as well as of the effects of anti-angiogenic drugs.</p

Quantitative analysis of nanoparticle internalization in mammalian cells by high resolution X-ray microscopy

<p>Abstract</p> <p>Background</p> <p>Quantitative analysis of nanoparticle uptake at the cellular level is critical to nanomedicine procedures. In particular, it is required for a realistic evaluation of their effects. Unfortunately, quantitative measurements of nanoparticle uptake still pose a formidable technical challenge. We present here a method to tackle this problem and analyze the number of metal nanoparticles present in different types of cells. The method relies on high-lateral-resolution (better than 30 nm) transmission x-ray microimages with both absorption contrast and phase contrast -- including two-dimensional (2D) projection images and three-dimensional (3D) tomographic reconstructions that directly show the nanoparticles.</p> <p>Results</p> <p>Practical tests were successfully conducted on bare and polyethylene glycol (PEG) coated gold nanoparticles obtained by x-ray irradiation. Using two different cell lines, EMT and HeLa, we obtained the number of nanoparticle clusters uptaken by each cell and the cluster size. Furthermore, the analysis revealed interesting differences between 2D and 3D cultured cells as well as between 2D and 3D data for the same 3D specimen.</p> <p>Conclusions</p> <p>We demonstrated the feasibility and effectiveness of our method, proving that it is accurate enough to measure the nanoparticle uptake differences between cells as well as the sizes of the formed nanoparticle clusters. The differences between 2D and 3D cultures and 2D and 3D images stress the importance of the 3D analysis which is made possible by our approach.</p

Margaritondo Oral History

Oral history with Giorgio Margaritondo, user of the Synchrotron Radiation Center. Conducted by Eric Verbeten

An enlightening procedure to explain the extreme power of synchrotron radiation

A simple approach exploits quantum properties to justify the dependence on gamma(4) of the total synchrotron emitted power. It also clarifies some apparent puzzles and brings to light the underlying, multiple relativistic phenomena