Abstract: X-ray image degradation due to scattered radiation is reduced in a system using a planar sensor sheet by providing an X-ray absorbing sheet in front of the sensor sheet, or in back of the sensor sheet, or both. The thickness and material of construction of each X-ray absorbing sheet depends on the X-ray absorptivity of the material used, and whether the absorbing sheet is in front or in back of the sensor sheet. The front absorbing sheet is preferably as close as possible to the sensor sheet. The back absorbing sheet, if used, can be at essentially any distance from the sensor sheet, beyond a certain minimum, consistent with practical space limitations in the overall physical shape and design of the unit.

Abstract: 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 an integer. The prototile contains a pinwheel motif of radiation absorbing material 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.

Abstract: The present invention provides an interactive integrated medical radiographic system comprising in combination a radiation source, an electronic detector including an analog to digital converter, a central control device including a CPU and a user interface a memory and a display device. The radiation source emits on command a radiation beam that is directed to pass through a target and impinge on the electronic radiation detector. The central control device communicates with both the memory, the radiation source, and the electronic detector, and is programmed to interact with an operator through the user interface and in response to input by the operator, and data stored in the memory, to initialize the detector, to set the radiation source for a desired exam, to retrieve from memory a sequence of steps representing actions by the operator required to perform said desired exam, and to sequentially guide the operator through said sequence of actions.

Abstract: A method for displaying on a display medium an image corresponding to detected exposures of a plurality of pixels converted to a matrix having n rows and m columns of digital values. The method comprises creating a weighted, smoothed, subtracted matrix, adding the weighted, smoothed, subtracted matrix to the starting matrix to produce an enhanced matrix; and then using the digital values from the enhanced matrix to display an image. Preferably, a sampled submatrix of digital values having n/I rows and m/I columns is created from the starting matrix from which is compiled a weighted, smoothed, subtracted submatrix that is then extrapolated to create the weighted, smoothed, subtracted matrix. A program storage device for carrying out the method, a digital x-ray image data capture system, and a method of using the system of this invention are also claimed.

Abstract: A method for generating on demand a gray scale transfer curve for use in displaying an image comprised of a plurality of digital values representing pixel gray scale levels with a desired contrast and brightness. This is achieved by using a single sigmoid shaped function Y=f(X, a, b, c) resembling an H&D curve of a photographic film. The Y axis represents digital output values to be used in displaying an image, while the X axis represents input digital values representing captured image information. “a” is a number representing boundary conditions for X and Y, “b” is a first parameter controlling the location of the curve along the X axis and “c” is a second parameter controlling the slope of the curve slope. This function is used to derive a Look-Up-Table (LUT) representing a continuous GST curve having the desired contrast and brightness.

Abstract: 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.

Abstract: An orientation marker for a digital radiogram formed by a plurality of pixels arrayed along a plurality of rows and columns. The pixels have densities which represent the radiogram optical density at each pixel point, and the densities are represented by digital values. The marker is made by a number of marker pixels arrayed along at least one row and one column of the radiogram. Each of the pixels forming the marker, have a marker pixel digital value which has been selected to form an asymmetrical marker pixel pattern on the radiogram, replacing the original radiogram pixel values.

Abstract: A method for developing a set of gain correction coefficients corrected for structural noise to be used in correcting the digital values representing an image captured by a pixelated detector having a plurality of individual sensors. The gain correction coefficients are developed by first obtaining a first set gain correction coefficients using a flat exposure and adjusting the individual sensor gain output so that all sensors produce the same output value, and then applying a smoothing filter to the first set of gain correction coefficients to obtain a new set of corrected gain correction coefficients.

Abstract: A method for optimizing the radiogram image of a subject is provided. The method provides for showing the location of automatic exposure control sensors on the radiograms, along with alignment and targeting projections to optimize the radiation exposure of the subject. By displaying the location of the automatic exposure control sensors on the radiograms along with the image of the subject, the observers can determine whether the radiogram image was taken with appropriate subject alignment. This method also serves as an educational aid in training radiography technicians.

Abstract: A method for automatically identifying the range of useful digital values to be displayed on a display medium and providing an appropriate gray scale transfer to optimize the diagnostic value of the final displayed image. One or more gray scale transfer functions corresponding to desired display media, one or more sets of experimentally determined constants, and one or more sets of algorithms are stored in a computer memory. A smoothed histogram and its histogram integral are constructed representing the frequency of occurrence of the digital values stored in the data bank. A low point and an edge point are identified from the histogram and integral, and based on the type of radiographic examination selected, are used with appropriate constants and algorithms to calculate a maximum and minimum value. Values lower than the minimum are replaced with the minimum, and values higher than the maximum are replaced by the maximum.

Abstract: 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;=&rgr;&kgr;&egr;0 between 0.050 and 20 seconds, wherein &kgr; is the dielectric constant of the dielectric layer, and &egr;0 is the permitivity of free space. The radiation detection layer is a photoconductor, and the dielectric layer is, preferably, a linear segmented polyurethane.

Abstract: 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 V1=k1t for a first period and then V2=k2t−m for a second period, where V1 and V2 are velocity, k1 and k2 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.

Abstract: A method for forming a large imaging panel by assembling a plurality of smaller submodules, the method comprising providing an adhesive filler between two abutting edges of a first and a second submodule, and forming a degassing channel in the adhesive filler extending along the length of the abutting edges. The method may further comprise adhering the submodules onto a top surface of a base plate, beveling the abutting edges of the submodules, and forming the degassing channel in the space between the beveled edges and the base plate.

Abstract: A process and associated apparatus for performing defective pixel correction in a radiation detector having a plurality of radiation sensors arrayed in rows and columns. The process and associated apparatus are specifically directed to correcting defects consisting of a plurality of adjacent pixels arrayed along and connected to a common electrode forming a bad pixel line. The pixel correction is accomplished by identifying the bad pixel line, forming a window of a plurality of pixel lines co-extending along the bad pixel line; identifying a limited number of adjacent pixel lines adjacent to the bad pixel line as also being bad pixel lines; preferably subdividing the window pixels into smaller windows along the bad pixel line, deriving correction coefficients for all bad line pixels in each subdivision from the good pixels in each subdivision and using the correction coefficients to correct the pixels in both the original bad line and in the adjacent bad pixel lines.

Abstract: A method for automatically forming a filtered subset of digital values from a first set of digital values corresponding to a plurality of picture elements representing a radiographic exposure of a subject for use in displaying a radiograph of said subject, the method comprising: (1) generating a first histogram of the first set of digital values; (2) generating an integral curve representing an integral of the first histogram; (3) identifying an inflection point and corresponding digital value V.sub.peak1 on the first histogram integral where the integral curve first changes slope in a direction decreasing from the highest digital value; (4) calculating a parameter V.sub.test =V.sub.

Abstract: An image capture panel including a substrate with a plurality of radiation detection sensors, a plurality of conductors connected one to each radiation detection sensor, a plurality of amplifiers connected to the sensors all on the substrate, and a field electrode having an peripheral edge mounted above the radiation detection sensors and the conductors. A shielding electrode may surround the field electrode peripheral edge or may completely cover the field electrode with a dielectric layer in-between. A shielding electrode may instead surround or completely cover each amplifier. The shielding electrode may be biased to ground via a resistor, and may be constructed of a conductive paint, such as silver paint.

Abstract: A process for selectively removing a dielectric layer from a portion of a panel to create a coated and an uncoated region, the process including (a) applying a laser-termination bead on the panel to separate a first region corresponding to the coated region from a second region corresponding to the uncoated region; (b) applying a dielectric coating over the panel and the laser-termination bead; (c) cutting the dielectric layer along the laser-termination bead with a laser beam; and (d) peeling away the dielectric layer from the second region. The panel may be a direct radiography panel; the dielectric layer may be a polymer such as parylene; the laser-termination bead may be an epoxy; and/or the laser may be an excimer laser.

Abstract: An X-ray image capture radiation detector for use in digital radiography is disclosed. The radiation detector has, in order, a dielectric substrate, a TFT transistor and a capacitor on the surface of the dielectric substrate, an insulating layer, a photoconductive layer over the insulating layer, a top dielectric layer, and a top conducting layer. The insulating layer prevents any direct charge transfer between the photoconductive layer and the capacitor.

Abstract: A method for the elimination of residual image artifacts from prior image exposure in an x-ray image obtained by exposing an x-ray image detector which includes a photoconductor to imaging x-ray radiation, wherein the residual image artifacts are eliminated by a process which includes obtaining and averaging pre and post exposure image data from the detector and subtracting the averaged pre and post exposure data from the image exposure data.

Abstract: A large imaging panel useful for direct radiography is prepared from two or four discrete modules, or tiles, containing arrays of solid state pixels. In preparing the large panels, a protective layer is applied over the array of solid state pixels on each module to protect the modules during subsequent processing steps. One or two edges of each protected module is trimmed and polished to form a polished edge which is within a specified distance from the solid state pixels of the array. The polished edges typically are surface treated (e.g., by etching) to enhance wetting and adherence of applied adhesive material. Protected modules are then assembled on a flat surface to form a two-dimensional mosaic of the modules in a way that each polished edge of each module is placed adjacent to the polished edge of a neighboring module to form a gap and a precise separation between the pixels of neighboring modules which is the same as the separation between adjacent pixels of one of the modules.