Diffraction enhanced X-ray imaging of mammals crystalline lens

Antunes, Augusto Celso; Hönnicke, Marcelo Gonçalves; Safatle, Angélica Mendonça Vaz; Cusatis, C.; Barros, P S M; Morelhão, Sérgio L.

doi:10.1016/j.nimb.2005.06.013

Cited by 10 publications

(8 citation statements)

References 5 publications

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“…Synchrotron facilities, adapted for diffraction enhanced x-ray imaging, have incident and transmitted beam optics very suitable for probing inhomogeneities in the eye tissues. In a previous attempt, 20,21 low photon flux at the desired wavelength range have allowed only slices ͑about 1 mm thick͒ of the lenses to be imaged. Cutting damages at surfaces and long exposure times do not collaborate for conclusive studies of ocular tissues by x-ray imaging.…”

Section: Methodsmentioning

confidence: 99%

X‐ray imaging in advanced studies of ophthalmic diseases

et al. 2006

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Microscopic characterization of pathological tissues has one major intrinsic limitation, the small sampling areas with respect to the extension of the tissues. Mapping possible changes on vast tissues and correlating them with large ensembles of clinical cases is not a feasible procedure for studying most diseases, as for instance vision loss related diseases and, in particular, the cataract. Although intraocular lens implants are successful treatments, cataract still is a leading public-health issue that grows in importance as the population increases and life expectancy is extended worldwide. In this work we have exploited the radiation-tissue interaction properties of hard x-rays--very low absorption and scattering--to map distinct lesions on entire eye lenses. At the used synchrotron x-ray photon energy of 20 keV (wavelength lambda=0.062 nm), scattering and refraction are angular resolved effects. It allows the employed x-ray image technique to efficiently characterize two types of lesions in eye lenses under cataractogenesis: distributions of tiny scattering centers and extended areas of fiber cell compaction. The data collection procedure is relatively fast; allowing dozens of samples to be totally imaged (scattering, refraction, and mass absorption images) in a single day of synchrotron beam time. More than 60 cases of canine cataract, not correlated to specific causes, were investigated in this first application of x-rays to image entire lenses. Cortical opacity cases, or partial opacity, could be related to the presence of calcificated tissues at the cortical areas, clearly visible in the images, whose elemental contents were verified by micro x-ray fluorescence as very rich in calcium. Calcificated tissues were also observed at nuclear areas in some cases of hypermature cataract. Total opacity cases without distinguishable amount of scattering centers consist in 70% of the analyzed cases, where remarkable fissure marks owing to extended areas of fiber cell compaction are diagnosed.

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Section: Methodsmentioning

confidence: 99%

X‐ray imaging in advanced studies of ophthalmic diseases

et al. 2006

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“…The ABI proved to be useful to identify different structures in healthy and diseased (with cataract) crystalline lenses [30,31]. Also, microcalcifications were found in experiments developed with higher energies [32].…”

Section: Qualitative Studiesmentioning

confidence: 98%

“…Ophthalmologic diseases have been studied by using, among other techniques, the ABI [30][31][32]. The ABI proved to be useful to identify different structures in healthy and diseased (with cataract) crystalline lenses [30,31].…”

Section: Qualitative Studiesmentioning

confidence: 99%

Multiple imaging radiography at LNLS

Hönnicke

Cusatis

Antunes

et al. 2008

Nuclear Instruments and Methods in Physics Research Section A:

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“…Since 1997, the above-described technique has been reported in the literature as diffraction-enhanced imaging (DEI) [20][21][22][23][24][25][26] or analyser-based imaging (ABI) [27,28] for medical investigations of cartilage and tumour cells.…”

Section: Reviewmentioning

confidence: 99%

Synchrotron‐Based Micro‐CT and Refraction‐Enhanced Micro‐CT for Non‐Destructive Materials Characterisation

et al. 2009

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X‐ray computed tomography is an important tool for non‐destructively evaluating the 3‐D microstructure of modern materials. To resolve material structures in the micrometer range and below, high brilliance synchrotron radiation has to be used. The Federal Institute for Materials Research and Testing (BAM) has built up an imaging setup for micro‐tomography and ‐radiography (BAMline) at the Berliner storage ring for synchrotron radiation (BESSY). In computed tomography, the contrast at interfaces within heterogeneous materials can be strongly amplified by effects related to X‐ray refraction. Such effects are especially useful for materials of low absorption or mixed phases showing similar X‐ray absorption properties that produce low contrast. The technique is based on ultra‐small‐angle scattering by microstructural elements causing phase‐related effects, such as refraction and total reflection. The extraordinary contrast of inner surfaces is far beyond absorption effects. Crack orientation and fibre/matrix debonding in plastics, polymers, ceramics and metal‐matrix‐composites after cyclic loading and hydro‐thermal aging can be visualized. In most cases, the investigated inner surface and interface structures correlate to mechanical properties. The technique is an alternative to other attempts on raising the spatial resolution of CT machines.

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Diffraction enhanced X-ray imaging of mammals crystalline lens

Cited by 10 publications

References 5 publications

X‐ray imaging in advanced studies of ophthalmic diseases

X‐ray imaging in advanced studies of ophthalmic diseases

Multiple imaging radiography at LNLS

Synchrotron‐Based Micro‐CT and Refraction‐Enhanced Micro‐CT for Non‐Destructive Materials Characterisation

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