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3 edition of An amorphous selenium X-ray light valve for diagnostic radiography found in the catalog.

An amorphous selenium X-ray light valve for diagnostic radiography

Pia-Krista Marjut Rieppo

An amorphous selenium X-ray light valve for diagnostic radiography

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  • 39 Currently reading

Published by National Library of Canada in Ottawa .
Written in English


Edition Notes

Thesis (M.Sc.) -- University of Toronto, 1996.

SeriesCanadian theses = -- Thèses canadiennes
The Physical Object
FormatMicroform
Pagination2 microfiches : negative. --
ID Numbers
Open LibraryOL17003639M
ISBN 100612193470

Rad Imaging Equpment Fall final part 2. Digital imaging in radiography is the general term used to describe a number of techniques that can be used to enable the digital acquisition of the information contained in the radiation beam after it exits the patient/5. Investigation of the effect of anode/filter materials on the dose and image quality of a digital mammography system based on an amorphous selenium flat panel detector Full Paper The British Institute of RadiologyCited by: An X-ray (or Röntgen ray) is a form of electromagnetic radiation with a wavelength in the range of 10 to nanometers, corresponding to frequencies in the range 30 PHz to 30 EHz.X-rays are primarily used for diagnostic radiography and crystallography.X-rays are a form of ionizing radiation and as such can be dangerous. In many languages it is called Röntgen radiation after one of the.


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An amorphous selenium X-ray light valve for diagnostic radiography by Pia-Krista Marjut Rieppo Download PDF EPUB FB2

X-ray imaging with amorphous selenium: Theoretical feasibility of the liquid crystal light valve for radiography Pia-Krista Rieppo and J. Rowlandsa) Departments of Medical Biophysics and Medical Imaging, University of Toronto, Research Building, Sunnybrook Health Science Centre, Bayview Avenue, North York, Ontario, M4N 3M5 Canada.

An amorphous selenium X-ray light valve for diagnostic radiography book The x-ray light valve (XLV) has been proposed 7, 8 as a novel approach for a low-cost, high image quality digital radiographic imaging system. It is based on well-established and hence inexpensive technologies: Amorphous selenium (a-Se) as an x-ray to charge transducer and a liquid crystal (LC) cell as an analog image by: 7.

For medical imaging applications such as mammography, general radiography, the X-ray image detector must have large sensing area, typically 30 cm × 30 cm, or greater, since it is not practically possible to focus by:   A new amorphous selenium (a- Se) digital radiography detector is introduced.

The proposed detector generates a charge image in the a- Se layer An amorphous selenium X-ray light valve for diagnostic radiography book a conventional manner, which is stored on electrode pixels at the surface of the a- Se layer. The XLV concept combines three well-established and hence lowcost technologies: an amorphous selenium (a -Se) layer to convert x-rays to image charge, a liquid crystal (LC) cell as an analog display, and an optical scanner for image digitization.

Here we investigate the spatial resolution possible with XLV systems. Amorphous selenium (a-Se) is a photoconductor material that has been intensively investigated from its early application in xerography to An amorphous selenium X-ray light valve for diagnostic radiography book present application in flat panel X-ray imagers.

It can. The resulting high resolution image is not strongly dependent on the Selenium thickness. Amorphous Selenium.

A number of photoconductors (e.g. silicon, germanium, thallium bromide and most semiconductors) could be used for X-ray imaging detectors but amorphous Selenium (a-Se) has many features that make it well suited for this task.

Amorphous selenium photodetectors, in both lateral and vertical An amorphous selenium X-ray light valve for diagnostic radiography book, have been investigated for indirect conversion medical imaging applications.

The low dark current, high responsivity for blue light, and possibility for gain are all among the attractive features of these by: 1.

Radiography: Physical Principles and System During the past two decades, digital radiography has supplanted screen-film radiography in many radiology departments. Today, manu-facturers provide a variety of digital imaging solutions based on various amorphous selenium, lead iodide, lead oxide, thallium bromide, and gadolinium compounds.

In the other *digital* radiography (dr) modes, the capture elementphoto-stimulableiography* (CR), the *capture* *element* is the *photo-stimulable* phosphor. In the other digital radiography (dr) modes, the capture element may be cesium iodide (CsI), gadolinium oxysulfide (GdOS), or amorphous selenium (a-Se).

Abstract. This is a theoretical study of the inherent spatial resolution of the latent image on the surface of an amorphous selenium (a ‐Se) plate used for diagnostic x‐ray imaging.

The following effects are considered: (A) ranges of primary photoelectrons; (B) reabsorption of K fluorescence; (C) reabsorption of Compton scattered photons;Cited by: The x-ray light valve (XLV) is a novel, potentially low-cost, x-ray detector that converts an x-ray exposure into an optical image stored in a liquid crystal cell.

Radiography is an excellent tool to generate diagnostic information in cases where either a skeletal lesion or systemic disease with skeletal manifestation is suspected. The fact that radiographic equipment is available in almost all veterinary practices makes it the imaging method most often used initially to detect and characterize lesions of bones and : Eberhard Ludewig, Fintan J.

McEvoy. Our device, the x‐ray light valve (XLV), consists of a photoconductor, used as an x‐ray to charge transducer, and a liquid‐crystal cell, used as an optically‐addressed spatial light modulator. 6,7 This arrangement allows the latent charge image created by the x‐rays absorbed in the photoconductor to be made visible and stored in the liquid‐crystal cell.

The optical image is subsequently digitized by Cited by: 4. Basically, amorphous selenium converts the x-rays that reach the system into small electrical signals. The x-rays arrive at plate coated with a layer of amorphous selenium, where positive and negative charges are created due to the photoelectric properties in.

There has been a rejuvenated interest in amorphous selenium (a-Se) and its alloys as a photoconductive material in the arena of digital direct conversion flat panel X File Size: 1MB.

In large area diagnostic X-ray imaging using flat panel detectors, two detection mechanisms are dominant: direct and indirect X-ray conversion. Direct conversion detectors use thick amorphous selenium (a-Se) vertical multilayer structures coupled to an amorphous silicon (a-Si:H) thin film transistor (TFT) backplane.

This type of. SPIE Digital Library Proceedings. CONFERENCE PROCEEDINGS Papers PresentationsCited by: 1. This paper presents a radiation detector based on X-ray induced light transmittance of liquid crystal (LC) as a function of radiation.

Our detector incorporates a europium-doped gadolinium oxide (Gd 2O 3:Eu) phosphor and an amorphous selenium (a-Se)-coupled LC light by: 2. Zhao W and Rowlands J A X-ray imaging using amorphous selenium: Feasibility of a flat panel self-scanned detector for digital radiology Med.

Phys. 22 Crossref PubMed Google Scholar Export references: BibTeX RISCited by: Abstract: Amorphous selenium (a-Se) film has the potential to fulfill the requirements of a novel x-ray image detector because of its good photo-to-dark impedance ratio, large area coverage, and low temperature deposition.

This increased the diagnostic value of the imaging, while making it possible to reduce the radiation dose compared with that required in the first available digital X-ray imaging Cited by: 9. Direct conversion detectors.

direct system uses (2) amorphous selenium and a thin film transistor (TFT) term used to describe both the indirect amorphous silicon and. The x-ray light valve (XLV) is a novel, potentially low-cost, x-ray detector that converts an x-ray exposure into an optical image stored in a liquid crystal cell.

This optical image is then transferred from the liquid crystal cell to a computer through an optical-to-digital imaging readout by: 3. @article{osti_, title = {The x-ray time of flight method for investigation of ghosting in amorphous selenium-based flat panel medical x-ray imagers}, author = {Rau, A W and Bakueva, L and Rowlands, J A and Imaging Research, Sunnybrook and Women's College Health Sciences Centre, Bayview Avenue, Toronto, Ontario, M4N 3M5 and.

The device, which is based on the amorphous photoconductor a-Se, is scalable (i.e., can be manufactured in large areas), can overcome electronic noise even at the lowest clinical X-ray exposures used in diagnostic imaging and has a low level of dark current.

Flat-panel detectors are a class of solid-state x-ray digital radiography devices similar in principle to the image sensors used in digital photography and video. They are used in both projectional radiography and as an alternative to x-ray image intensifiers (IIs) in fluoroscopy equipment.

W,Rowlands JA.X-ray imaging using amorphous selenium: feasibility ofaflatpanel self-scanned detector fordigital radiology. Med ;l k LE,Boudry J,WangW,-stration ofmegavoltage anddiagnostic x-ray imaging with hydrogenated amorphous silicon arrays. Med Phys ; Amorphous selenium direct detection CMOS digital x-ray imager with 25 micron pixel pitch.

In Medical Imaging Physics of Medical Imaging [G] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. ).Cited by: In this paper, we present the imaging parameters and compare both mercuric iodide (HgI2) and amorphous selenium (a-Se) films. Using MCNPX code, we designed the film structure and its thickness for the optimized detector in the diagnostic x-ray range.

The mercuric iodide film was formed by a wet binder process, while the amorphous selenium film was deposited by physical vapor deposition (PVD).Cited by: 1.

Medical Imaging Technology reveals the physical and materials principles of medical imaging and image processing, from how images are obtained to how they are used. It covers all aspects of image formation in modern imaging modalities and addresses the techniques, instrumentation, and advanced materials used in this rapidly changing field.

The X-Ray Light Valve used in conjunction with a simple optical scanner is the next step in digital radiographic imaging as a cost-effective alternative to the Active Matrix Flat-Panel flat panel imager. It can be used to produce digital images of revolutionary.

The last decade has seen rapid development and clinical adoption of active-matrix flat-panel imagers (AMFPIs) for diagnostic x-ray imaging. AMFPIs provide better image quality than traditional screen films and computed radiography, 1,2 but further improvement is desirable, especially in spatial resolution and low-dose performance.

Existing AMFPIs use a two-dimensional array of thin-film. The x-ray light valve (XLV) is a novel, potentially low-cost, x-ray detector that converts an x-ray exposure into an optical image stored in a liquid crystal cell. This optical image is then transferred from the liquid crystal cell to a computer through an optical-to-digital imaging readout system.

Previously, CCD-based cameras were used for the optical readout, but recently it was proposed. High gain lateral amorphous selenium (a-Se) detector for medical imaging. Shiva Abbaszadeh. Karim S. Karima, Kai Wanga, Nicholas Alleca, Feng Chena, and a University of Waterloo, University Avenue West, Waterloo, Canada ABSTRACT.

Amorphous selenium (a-Se) is a well known photoconductor and has been used in both indirect and direct. : NEW Patent CD for Method for manufacturing photoconductive layer constituting radiation imaging: Other Products: Everything Else. • Amorphous selenium and Thin Film Transistor (TFT) array efficiency of an imaging system in transferring any given spatial frequency from an input to an output Noise power spectrum (NPS) is the relative strength of spatial frequencies in a uniform image • If only source of noise is x-ray quantum mottle, the NPS is inversely.

Our goal is to develop a large area, flat panel, solid-state detector for both digital radiography and fluoroscopy. The proposed detector employs a photoconductive layer of amorphous selenium (a-Se) to convert x rays into by: A complete description of the selenium-based flat-panel detector is presented elsewhere [14,15,16,17,18] and briefly outlined below.

The solid-state selenium detector radiography system is based on thin-film transistor arrays and is constructed by adding amorphous selenium as the photoconductor by: of imaging,wherein the X-rays are absorbed and the electrical signals are created in one step.

Systems using amorphous selenium represent a direct technology for digital mammography. Selenium is an ideal material for a mammography detector because it has high x-ray absorption efficiency, extremely high intrinsic resolution, low noise, and a.

An x-ray light valve (XLV) pdf with an optical scanner has the potential to meet the need for a low-cost, high quality digital imaging system for general radiography.Converts x-rays to light Scintillators used in many X-ray detectors including Image download pdf, linear diode array, x-ray Vidicon, and a-Si flat panels.

Main properties of scintillators influencing in imaging system performance are: a) Conversion Efficiency X-ray quantum efficiency Light conversion per X-ray photon b) MTF / spatial resolutionFile Size: 1MB.X-ray detectors are devices used to measure the flux, spatial distribution, spectrum, ebook other properties of Ebook.

Detectors can be divided into two major categories: imaging detectors (such as photographic plates and X-ray film (photographic film), now mostly replaced by various digitizing devices like image plates or flat panel detectors) and dose measurement devices (such as.