The State University of New York

Sunnybrook Health Sciences Centre

Sunnybrook Hospital

Siemens Medical Solutions USA, Inc.

Noranda Inc.

Ifire Technology Corp.

Thunder Bay Regional Institute

Sunnybrook and Woman's College Health Sciences Center

Sunnybrook and Women's College Health Scinences Centre

John A Rowlands

Wei Zhao

Geordi Gendi Pang

Amirhossein Goldan

Anthony R Lubinsky

Adrian Howansky

Alla Reznik

Pia-Krista M Rieppo

Ali Reza Bani-Hashemi

James Alexander Robert Stiles

Zhong Shou Huang

Naoum Araj

David Waechter

Stephen Germann

Herbert J Davis

Wei Zhou

Peter Oakham

Ivaylo Koprinarov

Christie Ann Webster

Jennifer Ann Segui

Giovanni DeCrescenzo

Matthew M Wronski

Chandra Pokhrel

Giovanni Decrescenzo

Geordi G Pang

Structures operable to detect radiation are described. The structure may two screens with a phosphor layer, respective. The structure may further include a photosensor array disposed between the first screen and the second screen such that the photosensor array directly contacts the first screen or is directly attached to the first screen using an optical adhesive and directly contacts the second screen or is directly attached to the second screen using an optical adhesive.

Dual-screen digital radiography with asymmetric reflective screens

Provided is a detector that includes a scintillator, a common electrode, a pixel electrode, and a plurality of insulating layers, with a plurality of nano-pillars formed in the plurality of insulating layers, a nano-scale well structure between adjacent nano-pillars, with a-Se separating the adjacent nano-pillars, and a method for operation thereof.

Nano-electrode multi-well high-gain avalanche rushing photoconductor

Systems and methods of resetting a blocking-type photoconductive imaging detector are provided. In one embodiment, after having obtained an image, the imaging detector may be reset by applying a reversed bias potential difference and illuminating the imaging radiation detector with photoexcitation radiation. The photoexcitation radiation has a wavelength selected to excite mobile charges within the photoconductive layer and a spatial intensity profile related to the measured image for neutralizing the trapped charges in a spatially compensated manner. In another embodiment, a photoionizing beam is directed onto an x-ray light valve having a liquid crystal layer in contact with a photoconductive layer. The beam passes through an optically transmissive surface of the x-ray light valve and photoionizes a species within the liquid crystal layer, generating mobile charged entities that at least partially neutralize charges trapped at the interface, improving the performance of the x-ray light valve when performing subsequent x-ray imaging.

Systems and methods for resetting photoconductive x-ray imaging detectors

A photodetector/imaging device comprises a layer of photoconductive material converting incident electromagnetic radiation into electrical charges, the layer of photoconductive material being capable of avalanche multiplication when an electric field of sufficient magnitude is applied thereacross; a readout layer detecting the electrical charge; and at least one interface layer between the layer of photoconductive material and the readout layer, the interface layer coupling electrical charge to or from the layer of photoconductive material and being configured to inhibit uncontrolled rises in current in the photoconductive material during avalanche multiplication.

Photodetector/imaging device with avalanche gain

The present invention provides a digital x-ray radiographic imaging system. The system is based on a photoconductive detector and an electro-optic light modulator, where the photoconductive detector layer absorbs x-rays that have passed through an object to form an exposure of the object. The absorbed x-rays create a static optical image, which is stored in the electro-optic light modulator, allowing the capture of the optical image to continue over longer time. The optical image is digitized using a scanning system and an external light source. The image is then processed and stored by a computer. After the optical image is recorded, an erasing mechanism is used to reset the system before a new exposure is made.

X-ray light valve based digital radiographic imaging systems

The present invention is an indirect AMFPI wherein a phosphor such as a structured cesium iodide (CsI) is used to convert x-ray energy to optical photons or a charge, which is then detected by a two-dimensional array of either thin-film transistors (TFTs) such as an amorphous a-Se TFTs or a photodiode array. A scanning control circuit generates pulses to turn on the TFTs one row at a time, and thus the charge in the individual arrays is transferred from the TFT to one or more external charge-sensitive amplifiers. The charge-sensitive amplifiers are shared by all the pixels in the same column. The two-dimensional array can be read in real time.

Flat-panel detector with avalanche gain

The present invention provides a practical design of a megavoltage x-ray detector with both high quantum efficiency (QE) and high resolution. The x-ray detector includes an optical-fiber taper (OFT) made from a large number of optical fibers, each of which is aligned with the incident x-rays from an x-ray source hitting a top surface of the optical fiber taper. The optical-fiber taper is a matrix of optical fibers with the core material made of, e.g., silica and coated with a cladding glass or polymer such that light created within the core of each optical fiber will be guided to the bottom ends of the fiber with the ends of the fibers at the bottom being optically coupled to and optical image read-out device. Each optical fiber in the optical fiber taper is fully aligned with the incident x-ray source so that x-rays entering the top of the fiber travel directly towards the bottom of the same fiber. This alignment (or focusing) of the optical-fiber taper towards the x-ray source can be achieved by an extra coating at the bottoms of the optical fibers so they have a larger diameter than the other top ends of the fibers.

Cerenkov x-ray detector for portal imaging

A 4-dimensional digital tomosynthesis system includes an x-ray source, an x-ray detector and a processor. The x-ray source is suitable for emitting x-ray beams to an object with a periodic motion. The periodic motion is divided into (n+1) time intervals, n being a positive integer. Each of the (n+1) time intervals is associated with a time instance t, i=0, 1, 2, . . . , n. The x-ray detector is coupled to the x-ray source for acquiring projection radiographs of the object at each time instance tfor each scan angle based on the x-ray beams. The processor is communicatively coupled to the x-ray source and the x-ray detector for controlling the x-ray source and processing data received from the x-ray detector such that all projection radiographs acquired from all scan angles for each time instance tare reconstructed and (n+1) sets of cross sections of the object are obtained. The cross section is either a coronal cross section or a sagittal cross section. Each of the (n+1) sets of cross sections is for a different time instance t.

4-dimensional digital tomosynthesis and its applications in radiation therapy

The present invention provides a practical design of a megavoltage x-ray detector with both high quantum efficiency (QE) and high resolution. The x-ray detector disclosed herein has a QE that can be an order of magnitude higher than that of current flat panel systems and yet has a spatial resolution equivalent to that of current flat panel systems used for portal imaging. The x-ray detector includes a large number of micro-structured electrically conducting plates, packed together with thin spacers placed between neighboring plates with the micro-structured plates oriented to be parallel to the incident x-rays in operation. Each plate includes an electrically conductive substrate with a first planar surface, elongate electrically conductive strip electrodes separated from each other with strip spacers placed in between and sitting on an insulating layer interposed between the first planar surface of the electrically conductive substrate and the strip electrodes. A power supply applies a bias voltage between each electrically conductive substrate and the electrically conductive strip electrodes, whereby x-rays absorbed in the conductive substrate generates high energy electrons which produce ions in an ionization medium located in spaces between the conductive substrate and the electrically conductive strips. A detector detects an electrical current generated in the electrically conductive strip electrodes and a 2D active readout matrix is coupled to the detector.

High quantum efficiency x-ray detector for portal imaging

A flat panel detector for radiation imaging includes an array of transistor switches each of which is associated with a pixel electrode. A radiation transducer including a top electrode and a radiation conversion layer is disposed over the array. Inhibiting mechanisms are positioned over dead zones between adjacent pixel electrodes to inhibit the accumulation of charge in the radiation conversion layer at the dead zones when the top electrode is biased and the flat panel detector is exposed to radiation. In one embodiment, the inhibiting mechanism is constituted by islands formed of semiconductor material between the array and the radiation transducer. Each island is positioned over a dead zone between adjacent pixel electrodes and contacts a pixel electrode to allow charges accumulated on the islands to drift to the pixel electrodes.

Flat panel detector for radiation imaging with reduced trapped charges

An x-ray image intensifier includes a photoconductive x-ray detector having an electro-optic light modulator disposed on a photoconductive detector layer. The photoconductive x-ray detector absorbs x-rays passing through an object to be imaged to form an x-ray exposure of the object. An optical image of the x-ray exposure is generated when light passes through the photoconductive x-ray detector. An imager captures optical images of the x-ray exposures. A processor coupled to the imager digitizes and stores the optical images of the x-ray exposure captured by the imager at selected intervals.

Method of generating multiple x-ray images of an object from a single

Active matrix X-ray imaging array

Growing community of inventors

Toronto, Canada

John A Rowlands