Empirical electro-optical and x-ray performance evaluation of CMOS active pixels sensor for low dose, high resolution x-ray medical imaging

The recent availability of a cryotransfer stage, efficient electron energy loss spectrometers (EELS), and ultrathin window energy-dispersive x-ray spectrometers (EDXS) for the VG Microscopes HB501 field-emission STEM now provides this instrument with the potential for high resolution (<20 nm) biological microanalysis. In practice, limits are normally imposed by the sample itself, due to damage in the electron beam and to changes in structure and composition during freezing, sectioning, transfering and freeze-drying. We have therefore investigated what types of useful high-resolution analytical information can be obtained from rapidly frozen samples, including thin tissue cryosections and frozen isolated macromolecules and macromolecular assemblies.Frozen-hydrated samples were cryotransfered at ~-175C into the VG STEM after which a vacuum of ~3x10-9 mbar was maintained. Samples were freeze-dried by warming to ~-90C over 30 min and were then recooled to below ~-160C to minimize radiation damage and contamination during analysis. Digital annular dark-field images were obtained at low dose (~10 e/Å2) with single electron sensitivity, using a probe current of 2 to10 pA and a beam energy of 100 keV.

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Scintillator avalanche photoconductor with high resolution emitter readout for low dose x-ray imaging: Lag

Medical Physics ◽

10.1118/1.3187227 ◽

2009 ◽

Vol 36 (9Part1) ◽

pp. 4047-4058 ◽

Cited By ~ 1

Author(s):

Dan Li ◽

Wei Zhao ◽

Masakazu Nanba ◽

Norifomi Egami

Keyword(s):

High Resolution ◽

Low Dose ◽

X Ray ◽

X Ray Imaging

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High Resolution Electron Microscopy of a Novel Zeolite

Microscopy and Microanalysis ◽

10.1017/s1431927600009090 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 441-442

Author(s):

P.A. Crozier ◽

I.Y. Chan ◽

C.Y. Chen ◽

L.W. Finger ◽

R.C. Medrud ◽

...

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Low Dose ◽

High Resolution Electron Microscopy ◽

X Ray Diffraction ◽

High Adsorption ◽

Structural Units ◽

X Ray ◽

Resolution Electron ◽

Crystal Structural

Low-dose high resolution electron microscopy (HREM) is a useful technique for elucidating the structure of zeolites. In recent years a number of zeolite structures have been solved using combinations of different characterization techniques including adsorption measurements, powder x-ray diffraction and low-dose high resolution electron microscopy (for example see ref. 2). We have used these techniques to study the structure of a novel zeolite material. However, great care must be exercised when interpreting data from these techniques in terms of crystal structural units. In this particular case, the structure was recently determined using single crystal x-ray diffraction and showed some surprises.Details of the synthesis of this zeolite are given elsewhere. The high adsorption capacity suggested that this zeolite possessed two interpenetrating channels (either a 10 and a 12 ring or two 12 ring channels). X-ray powder diffraction showed the material to be monoclinic with a= 18.5Å, b= 13.4 Å, c= 7.6 Å β = 101.5°).

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