Other Early Designs of Micropattern Detectors Developed Between 1998 and 2003

2014 ◽  
pp. 114-128
Keyword(s):  
Radiation Dose ◽  
Plasma Diagnostics ◽  
Parallel Plate ◽  
Leak Detector ◽  
High Quality ◽  
X Ray ◽  
3 Dimensional ◽  
Micro Hole ◽  
Strip Plate

This chapter focuses on the intense developments of micropattern detectors that happened between 1998 and 2003. In this period, many new designs were invented and manufactured by means of a photolithographic technology. These detectors include microwire detectors, microslit detectors, LEAK multiplication structures, microgap parallel-plate chambers, micro-hole strip plate gaseous detectors, etc. Some of them remain simply as interesting exercises demonstrating the great capability of microelectronic technique. Some of them are used in practice, for example in 2 dimensional and 3 dimensional mammographic scanners. These scanners are based on microgap parallel-plate chambers and give high quality X-ray images at a reduced radiation dose delivered to the patients. Early versions of the LEAK detector were intensively used in plasma diagnostics. Micro-hole strip plate gaseous detectors are currently used in some prototypes of photodetectors. This chapter also describes an MSGC type MWPC invented by Charpak et al. in an attempt to overcome the problems associate with the MSGC (i.e. charging up effects and poor rate characteristics).

scholarly journals Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4554
Author(s):  
Ralph-Alexandru Erdelyi ◽  
Virgil-Florin Duma ◽  
Cosmin Sinescu ◽  
George Mihai Dobre ◽  
Adrian Bradu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Radiation Dose ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Optical Coherence ◽  
X Rays ◽  
High Quality ◽  
X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

scholarly journals Recent advances in X-ray detection with micro-hole and strip plate detector

2004 ◽  
Vol 524 (1-3) ◽  
pp. 124-129 ◽  
Author(s):  
J.F.C.A. Veloso ◽  
J.M. Maia ◽  
L.F. Requicha Ferreira ◽  
J.M.F. dos Santos ◽  
A. Breskin ◽  
...  
Keyword(s):  
X Ray ◽  
Recent Advances ◽  
Micro Hole ◽  
Strip Plate

Quantum X-Ray Imaging with the 2D - Micro Hole and Strip Plate

2009 ◽  
pp. 890-893
Author(s):  
A. L. Gouvêa ◽  
H. Natal da Luz ◽  
C. A. Santos ◽  
C. A. B. Oliveira ◽  
A. L. M. Silva ◽  
...  
Keyword(s):  
X Ray ◽  
X Ray Imaging ◽  
Micro Hole ◽  
Strip Plate

Single photon counting x-ray imaging system using a micro hole and strip plate

2007 ◽  
Author(s):  
Hugo Natal da Luz ◽  
Carlos A. B. Oliveira ◽  
Carlos D. R. Azevedo ◽  
Jamil A. Mir ◽  
Joaquim M. F. dos Santos ◽  
...  
Keyword(s):  
Imaging System ◽  
Single Photon ◽  
Photon Counting ◽  
Single Photon Counting ◽  
X Ray ◽  
X Ray Imaging ◽  
Micro Hole ◽  
Strip Plate

scholarly journals Optimization of the non-normal incidence, transient pumped plasma X-ray laser for laser spectroscopy and plasma diagnostics at the facility for antiproton and ion research (FAIR)

2007 ◽  
Vol 25 (1) ◽  
pp. 93-97 ◽  
Author(s):  
TH. KUEHL ◽  
D. URSESCU ◽  
V. BAGNOUD ◽  
D. JAVORKOVA ◽  
O. ROSMEJ ◽  
...  
Keyword(s):  
Long Range ◽  
Plasma Diagnostics ◽  
Normal Incidence ◽  
Radioactive Isotopes ◽  
Laser Operation ◽  
Scientific Program ◽  
High Quality ◽  
X Ray ◽  
Charged Ions ◽  
Stable Laser

Intense and stable laser operation with Ni-like Zr and Ag was demonstrated at pump energies between 2 J and 5 J energy from the PHELIX pre-amplifier section. A novel single mirror focusing scheme for the TCE x-ray laser (XRL) has been successfully implemented by the LIXAM/MBI/GSI collaboration under different pump geometries. This shows potential for an extension to shorter XRL wavelength. Generation of high quality XRL beams for XRL spectroscopy of highly charged ions is an important issue within the scientific program of PHELIX. Long range perspective is the study of nuclear properties of radioactive isotopes within the FAIR project.

X-ray and UV detection with the Micro-Hole & Strip Plate gaseous detector

2005 ◽  
Author(s):  
J. F. C. A. Veloso ◽  
J. M. F. Dos Santos ◽  
A. Breskin ◽  
R. Chechik
Keyword(s):  
Uv Detection ◽  
X Ray ◽  
Micro Hole ◽  
Strip Plate

Sensitivity of HEMATEG Induced by Radiation Dose in the Diagnostic X-Ray Energy Range

2015 ◽  
Vol 1087 ◽  
pp. 267-271
Author(s):  
Siti Atiqah Ishak ◽  
S.M. Iskandar ◽  
Azhar Abdul Rahman
Keyword(s):  
Radiation Dose ◽  
Urbach Energy ◽  
Visible Region ◽  
Band Gap Energy ◽  
Exposure Dose ◽  
Polymer Gel ◽  
Indirect Transition ◽  
X Ray ◽  
3 Dimensional ◽  
Uv Visible

The aim of this study is to determine sensitivity of new recipes polymer gel HEMATEG with varied x-ray exposure by using UV-visible spectrophotometer as an evaluation technique. The gels were irradiated by x-ray radiation and the polymerization of HEMATEG were followed. Polymerization was read based on absorption spectra in the range wavelength UV 300 nm to 700 nm. The dependency of polymerization with increasing of exposure dose was determined by changes in the band gap energy (Eg) and Urbach energy (∆E). In the UV-visible region,Egwith indirect transition of HEMATEG were decreased with increasing radiation dose while,∆Ewere increased with increasing radiation dose. This observation supported the increase of structured disorder of the polymer with increasing radiation dose. This study proved that HEMATEG had a high potential to be used as a 3-dimensional dosimeter in the diagnostic x-ray.

Deformable registration and region-of-interest image reconstruction in sparse repeat CT scanning

2020 ◽  
Vol 28 (6) ◽  
pp. 1069-1089
Author(s):  
Zeev Adelman ◽  
Leo Joskowicz
Keyword(s):  
Image Reconstruction ◽  
Radiation Dose ◽  
Region Of Interest ◽  
Ct Scanning ◽  
Deformable Registration ◽  
Ct Scans ◽  
High Quality ◽  
X Ray ◽  
Radon Space ◽  
A Minor

BACKGROUND: Repeat CT scanning is ubiquitous in many clinical situations, e.g. to follow disease progression, to evaluate treatment efficacy, and to monitor interventional CT procedures. However, it incurs in cumulative radiation to the patient which can be significantly reduced by using a region of interest (ROI) and the existing baseline scan. OBJECTIVE: To obtain a high-quality reconstruction of a ROI with a significantly reduced X-ray radiation dosage that accounts for deformations. METHODS: We present a new method for deformable registration and image reconstruction inside an ROI in repeat CT scans with a highly reduced X-ray radiation dose based on sparse scanning. Our method uses the existing baseline scan data, a user-defined ROI, and a new sparse repeat scan to compute a high-quality repeat scan ROI image with a significantly reduced radiation dose. Our method first performs rigid registration between the densely scanned baseline and the sparsely scanned repeat CT scans followed by deformable registration with a low-order parametric model, both in 3D Radon space and without reconstructing the repeat scan image. It then reconstructs the repeat scan ROI without computing the entire repeat scan image. RESULTS: Our experimental results on clinical lung and liver CT scans yield a mean × 14 computation speedup and a × 7.6-12.5 radiation dose reduction, with a minor image quality loss of 0.0157 in the NRMSE metric. CONCLUSION: Our method is considerably faster than existing methods, thereby enabling intraoperative online repeat scanning that it is accurate and accounts for position, deformation, and structure changes at a fraction of the radiation dose required by existing methods.

Single Photon Counting X-Ray Imaging System Using a Micro Hole and Strip Plate

2008 ◽  
Vol 55 (4) ◽  
pp. 2341-2345 ◽  
Author(s):  
Hugo Natal da Luz ◽  
Carlos A. B. Oliveira ◽  
Carlos D. R. Azevedo ◽  
Jamil A. Mir ◽  
Rui de Oliveira ◽  
...  
Keyword(s):  
Imaging System ◽  
Single Photon ◽  
Photon Counting ◽  
Single Photon Counting ◽  
X Ray ◽  
X Ray Imaging ◽  
Micro Hole ◽  
Strip Plate

The 3-Dimensional Molecular Structure of the Actin Filament Revisited

1985 ◽  
Vol 43 ◽  
pp. 480-481
Author(s):  
U. Aebi ◽  
R. Millonig ◽  
H. Salvo
Keyword(s):  
Actin Filament ◽  
Supramolecular Assembly ◽  
Specimen Preparation ◽  
X Ray Diffraction ◽  
Single Filament ◽  
X Ray ◽  
3 Dimensional ◽  
Filament Diameter ◽  
Preparation Conditions ◽  
Apparent Diameter

To date, most 3-D reconstructions of undecorated actin filaments have been obtained from actin filament paracrystal data (for refs, see 1,2). However, due to the fact that (a) the paracrystals may be several filament layers thick, and (b) adjacent filaments may sustantially interdigitate, these reconstructions may be subject to significant artifacts. None of these reconstructions has permitted unambiguous tracing or orientation of the actin subunits within the filament. Furthermore, measured values for the maximal filament diameter both determined by EM and by X-ray diffraction analysis, vary between 6 and 10 nm. Obviously, the apparent diameter of the actin filament revealed in the EM will critically depend on specimen preparation, since it is a rather flexible supramolecular assembly which can easily be bent or distorted. To resolve some of these ambiguities, we have explored specimen preparation conditions which may preserve single filaments sufficiently straight and helically ordered to be suitable for single filament 3-D reconstructions, possibly revealing molecular detail.

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