Direct Radiography Corp.

Hologic, Inc.

Denny L Y Lee

James E Davis

Andrew P Smith

Kelly P Golden

Lawrence K F Cheung

A flat panel x-ray imager includes a gain layer (charge multiplication layer) that facilitates imaging at low x-ray exposure levels. The gain layer can be a gas chamber or a solid state material operating in an avalanche mode.

Flat panel x-ray imager with gain layer

A shielding grid constructed of a radiation absorbing material for use with an array of discreet, non contiguous radiation sensors to protect such sensors from scattered radiation. The sensors each have a radiation sensitive area with a width and a length. In designing the grid a prototile having a prototile width and a prototile length is developed. The prototile width is equal to the radiation sensitive area width divided by an integer and the prototile length is also equal to the radiation sensitive area length divided by a integer. The prototile contains a motif contained solely within the prototile that forms a pattern when a plurality of prototiles sufficient to cover the array of discreet sensor are arrayed contiguously. The grid is constructed with the radiation absorbing material in this pattern.

Anti scatter radiation grid for a detector having discreet sensing elements

A panel for radiation detection having a plurality of sensors arrayed thereon. Each sensor includes a charge storage capacitor, a radiation sensitive layer over the charge storage capacitor and a dielectric layer over the radiation sensitive layer. The dielectric layer has an adjusted resistivity resulting in a time constant &tgr;&equals;&rgr;&kgr;&egr;,between 0.050 and 20 seconds, wherein &kgr; is the dielectric constant of the dielectric layer, and &egr;,is the permitivity of free space. The radiation detection layer is a photoconductor, and the dielectric layer is, preferably, a linear segmented polyurethane.

Direct radiographic imaging panel having a dielectric layer with an adjusted time constant

A radiation anti-scatter device comprising a grid and a grid driver connected to the grid for unidirectionaly moving the grid with a variable grid velocity along a path between a starting and an end position, and a method of providing such grid motion. The variable grid velocity may have a velocity profile V,&equals;k,t for a first period and then V,&equals;k,t,for a second period, where V,and V,are velocity, k,and k,are constants, t is time, and m is an exponent having a value greater than 0. The anti-scatter device may be a component of a direct radiographic diagnostic imaging system which includes an image-producing element having an array of radiation detectors aligned in rows, and where the anti-scatter device is a grid having vanes oriented at an angle to the detector rows. Radiation emission may be synchronized with the grid motion to optimize a radiograph for a particular grid, radiation source, or examination procedure. The apparatus implements a method for reducing Moir{acute over (e)} patterns in radiographic detectors having an array of sensors by unidirectionaly moving the grid in a single stroke during the radiation exposure with an asymptotically decreasing speed profile such that grid motion is maintained for a plurality of different radiation exposure times.

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West Chester, PA, United States of America

Denny L Y Lee