Abstract: Sampling methods and systems that shorten readout time and reduce lag in amorphous silicon flat panel x-ray detectors are described. Embodiments comprise: (a) activating a reset switch to discharge any residual signal being held in a feedback capacitor; (b) deactivating the reset switch; (c) activating a field effect transistor; (d) sampling an electrical signal from the amorphous silicon flat panel x-ray detector, while the field effect transistor is activated; (e) activating a reset switch, after the electrical signal has been sampled and while the field effect transistor is still activated, to discharge any residual signal being held in the feedback capacitor; (f) deactivating the field effect transistor, while the reset switch is still activated; (g) deactivating the reset switch; and (h) repeating steps (c)–(g) as necessary to obtain a predetermined radiographic image.

Abstract: A method and system for detecting the potential of an x-ray imaging system to create images with scintillator hysteresis artifacts includes examining an x-ray image to measure two signal levels for two areas of interest, then determining a difference between the two signal levels and comparing the difference to a threshold. The signal levels can be measured by determining an amount of electrical charge discharged in photodiodes of the detector. If the difference in signals is greater than the threshold amount, then the possibility exists that scintillator hysteresis artifacts may be produced in images. In addition, the present invention also provides for the elimination or reduction in magnitude of scintillator hysteresis artifacts in images produced by an x-ray imaging system. After the possibility of scintillator hysteresis artifacts is detected, the detector can be irradiated with an x-ray flux to eliminate or reduce the magnitude of the artifacts in images produced by the x-ray imaging system.

Abstract: A method for processing a fluoroscopic image includes generating a lag prediction model, scanning an object at a first radiation dosage with an imaging system including at least one radiation source and at least one detector array, and periodically updating the lag prediction model during the scan to generate at least one fluoroscopic image of the object.

Abstract: The present invention relates to a method for forming an active area or flat panel in an X-ray detector device. The method comprises forming at least one flat form factor panel in a first size on a substrate of a second size and extending at least one contact of the at least one flat form factor panel. The method further comprises trimming the substrate to the first size forming the at least one flat panel.

Abstract: Spatially patterned light-blocking layers for radiation imaging detectors are described. Embodiments comprise spatially patterned light-blocking layers for an amorphous silicon flat panel x-ray detector, wherein the spatially patterned light-blocking layer blocks light from a predetermined number of switching elements in the detector, wherein the predetermined number comprises less than all of the switching elements in the detector. These light-blocking layers may block light from each switching element in a predetermined arrangement of switching elements that are read out last, or in any other suitable pattern.

Abstract: Sampling methods and systems that shorten readout time and reduce lag in amorphous silicon flat panel x-ray detectors are described. Embodiments comprise: (a) activating a reset switch to discharge any residual signal being held in a feedback capacitor; (b) deactivating the reset switch; (c) activating a field effect transistor; (d) sampling an electrical signal from the amorphous silicon flat panel x-ray detector, while the field effect transistor is activated; (e) activating a reset switch, after the electrical signal has been sampled and while the field effect transistor is still activated, to discharge any residual signal being held in the feedback capacitor; (f) deactivating the field effect transistor, while the reset switch is still activated; (g) deactivating the reset switch; and (h) repeating steps (c)-(g) as necessary to obtain a predetermined radiographic image.

Abstract: A method for processing a fluoroscopic image includes generating a lag prediction model, scanning an object at a first radiation dosage with an imaging system including at least one radiation source and at least one detector array, and periodically updating the lag prediction model during the scan to generate at least one fluoroscopic image of the object.

Abstract: A detector imaging system having an apparatus and method for correcting defective pixels in a current acquired image is disclosed herein. The system performs the correction of defective pixels using image feature information and temporal information. The system includes a correction scheme which includes determining a temporal matrix based on the current acquired image, at least one prior acquired image, and a filter weight; determining a local gradient based in part on the temporal matrix and a gradient kernel; and providing a correction value based on the local gradient to correct the defective pixel. The correction scheme is repeated a plurality of times as desired to correct all the defective pixels in the current acquired image.

Abstract: A method and apparatus for displaying an image generated by at least one detector of an imaging unit are disclosed herein. The method includes creating a pixel map identifying locations of bad pixels in an array of pixels in the image detected by the at least one detector, linking the pixel map to the image, and providing for selective display of the pixel map. Bad pixels behave from a group including pixels which do not respond electrically and pixels which are statistically different from surrounding pixels in the array of pixels. The apparatus includes an imaging unit for generating x-rays which pass through a body of interest, at least one detector unit for detecting the x-rays, and a processing unit for identifying bad pixels within the detected image.

Abstract: A system for automated x-ray system parameter evaluation is provided. A physical model or template is created and stored in the system, one for each desired phantom. The automated system imports a grayscale x-ray image and then processes the image to determine image components. First, a histogram of the image is created, then a threshold in the histogram is determined and the imported image is binarized with respect to the threshold. Next, connected component analysis is used to determine image components. If the components do not match, then the image is rejected. The system next locates landmarks in the imported image corresponding to expected physical structures. The landmarks include a perimeter ring, vertical and horizontal line segments, and fiducials. The system uses the landmarks to predict Regions of Interest (ROIs) where measurement of the x-ray system parameters takes place. Finally, the x-ray system parameters are measured in the identified ROIs.

Abstract: An x-ray system (14) including a source of x-rays (15) and a detector (22) monitors the detector with a control (36) that calibrates the detector during a calibration phase of operation and powers the detector during use phases of operation occurring at different times. A processor (28, 36) reads the data created by the pixel elements, analyzes the data and identifies pixel elements corresponding to data indicating defective pixel elements during the calibration phase of operation and during a predetermined portion of a plurality of the use phases of operation.

Abstract: A method and apparatus for displaying an image generated by at least one detector of an imaging unit are disclosed herein. The method includes creating a pixel map identifying locations of bad pixels in an array of pixels in the image detected by the at least one detector, linking the pixel map to the image, and providing for selective display of the pixel map. Bad pixels behave from a group including pixels which do not respond electrically and pixels which are statistically different from surrounding pixels in the array of pixels. The apparatus includes an imaging unit for generating x-rays which pass through a body of interest, at least one detector unit for detecting the x-rays, and a processing unit for identifying bad pixels within the detected image.

Abstract: An x-ray system used to acquire successive images is provided. The x-ray system includes an x-ray source for generating x-rays which are detected by a detector. The detector comprises detector elements that store levels of charge and are arranged in rows and columns. An image processor is used to sense the levels of charge stored by the detector elements. First and second offset image memories are included in the image processor. The first offset image memory stores offset image data for a first mode of operation and a second offset image memory stores offset image data for a second mode of operation.

Abstract: A method is provided for identifying detector elements in a solid state X-ray detector susceptible to causing line artifacts due to faulty detector elements that leak charge. A portion of the X-ray detector is covered by a radiation occluding material and the detector is exposed to a level of radiation sufficient to reach a predetermined threshold in the exposed portion of the detector. An image representative of the radiation is acquired and further analyzed to determine whether line artifacts exist. Data lines found to exhibit line artifacts are stored in the image processor.

Abstract: An x-ray system (14) including a source of x-rays (15) and a detector (22) monitors the detector with a control (36) that calibrates the detector during a calibration phase of operation and powers the detector during use phases of operation occurring at different times. A processor (28, 36) reads the data created by the pixel elements, analyzes the data and identifies pixel elements corresponding to data indicating defective pixel elements during the calibration phase of operation and during a predetermined portion of a plurality of the use phases of operation.

Abstract: A method is provided for identifying detector elements in a solid state X-ray detector susceptible to causing line artifacts due to faulty detector elements that leak charge. A portion of the X-ray detector is covered by a radiation occluding material and the detector is exposed to a level of radiation sufficient to reach a predetermined threshold in the exposed portion of the detector. An image representative of the radiation is acquired and further analyzed to determine whether line artifacts exist. Data lines found to exhibit line artifacts are stored in the image processor.

Abstract: Automated measurement of changes in detective quantum efficiency (DQE) within an x-ray detector. The calculation of relative DQE changes is limited to the measurement of two quantities, namely MTF(f) and NPS(f). The measurement of MTF is obtained using an image quality phantom technique. The measurement of NPS includes the use of a flat field phantom, and data can be obtained during system calibration. Detector degradation and potential field replacement, are determined by monitoring the ratio of DQE as a function of time.

Abstract: A method and apparatus for calibrating the resolution of a medical imaging system measures unadjusted performance of a digital image detector used in the medical imaging system. The method then determines a weighting coefficient for a spatial frequency band processed by the medical imaging system. The weighting coefficient is based on a desired performance of the digital image detector and the unadjusted performance of the digital image detector. The method stores the weighting coefficient for subsequent application to the spatial frequency band by the medical imaging system. Identical or distinct weighting coefficients may be used at multiple spatial resolution levels. A single weighting coefficient may applied to all pixels at a given spatial resolution, or numerous spatial resolution variation compensation coefficients may be used in different regions of each spatial resolution.

Abstract: Automated measurement of changes in detective quantum efficiency (DQE) within an x-ray detector. The calculation of relative DQE changes is limited to the measurement of two quantities, namely MTF(f) and NPS(f). The measurement of MTF is obtained using an image quality phantom technique. The measurement of NPS includes the use of a flat field phantom, and data can be obtained during system calibration. Detector degradation and potential field replacement, are determined by monitoring the ratio of DQE as a function of time.

Abstract: A neural network prediction has been provided for predicting radiation exposure and/or Air-Kerma at a predefined arbitrary distance during an x-ray exposure; and for predicting radiation exposure and/or Air-Kerma area product for a radiographic x-ray exposure. The Air-Kerma levels are predicted directly from the x-ray exposure parameters. The method or model is provided to predict the radiation exposure or Air-Kerma for an arbitrary radiographic x-ray exposure by providing input variables to identify the spectral characteristics of the x-ray beam, providing a neural net which has been trained to calculate the exposure or Air-Kerma value, and by scaling the neural net output by the calibrated tube efficiency, and the actual current through the x-ray tube and the duration of the exposure. The prediction for exposure/Air-Kerma further applies the actual source-to-object distance, and the prediction for exposure/Air-Kerma area product further applies the actual imaged field area at a source-to-image distance.