Abstract: A high spatial resolution X-ray computed tomography (CT) system is provided. The system includes a support structure including a gantry mounted to rotate about a vertical axis of rotation. The system further includes a first assembly including an X-ray source mounted on the gantry to rotate therewith for generating a cone X-ray beam and a second assembly including a planar X-ray detector mounted on the gantry to rotate therewith. The detector is spaced from the source on the gantry for enabling a human or other animal body part to be interposed therebetween so as to be scanned by the X-ray beam to obtain a complete CT scan and generating output data representative thereof. The output data is a two-dimensional electronic representation of an area of the detector on which an X-ray beam impinges. A data processor processes the output data to obtain an image of the body part.

Abstract: A high spatial resolution X-ray computed tomography (CT) system is provided. The system includes a support structure including a gantry mounted to rotate about a vertical axis of rotation. The system further includes a first assembly including an X-ray source mounted on the gantry to rotate therewith for generating a cone X-ray beam and a second assembly including a planar X-ray detector mounted on the gantry to rotate therewith. The detector is spaced from the source on the gantry for enabling a human or other animal body part to be interposed therebetween so as to be scanned by the X-ray beam to obtain a complete CT scan and generating output data representative thereof. The output data is a two-dimensional electronic representation of an area of the detector on which an X-ray beam impinges. A data processor processes the output data to obtain an image of the body part.

Abstract: Method and system for generating an image of the radiation density of a source of photons located in an object wherein Compton scattering and non-Compton scattering events are detected and contained within data used for image reconstruction. The system includes a multiple pinhole collimator, a position sensitive scintillation detector as used in standard Gamma cameras, and a silicon pad detector array inserted between the collimator and the scintillation detector. The problem of multiplexing, normally associated with multiple pinhole systems, is reduced by using the extra information from the detected Compton scattering events. For properly selected pinhole spacing, this leads to a significantly improved image quality. A valuable enhancement can be achieved when adding only a small fraction of gamma rays with reduced angular ambiguity. The system does not require a highly optimized Compton camera behind the collimator.

Abstract: A method, processor and computed tomography (CT) machine for generating images utilizing high and low sensitivity data collected from a flat panel detector having an extended dynamic range. Hardware modifications for extending the dynamic range include grouping pixel rows and pixel columns into clusters of two. The sensitivity of the rows/columns is modified by positioning optical masks that have different transparencies for different rows/columns. Software modifications for extending the dynamic range include taking two correlated exposure scan measurements at each angle and combining the two data sets into one scan prior to image reconstruction. This method uses a spatially varying pixel exposure method where several adjacent pixels are clustered and each cluster has a different sensitivity. The signals of these clusters are combined to form one image effectively producing an increased dynamic range.

Abstract: Method and system for generating an image of the radiation density of a source of photons located in an object wherein Compton scattering and non-Compton scattering events are detected and contained within data used for image reconstruction. The system includes a multiple pinhole collimator, a position sensitive scintillation detector as used in standard Gamma cameras, and a silicon pad detector array inserted between the collimator and the scintillation detector. The problem of multiplexing, normally associated with multiple pinhole systems, is reduced by using the extra information from the detected Compton scattering events. For properly selected pinhole spacing, this leads to a significantly improved image quality. A valuable enhancement can be achieved when adding only a small fraction of gamma rays with reduced angular ambiguity. The system does not require a highly optimized Compton camera behind the collimator.

Abstract: A high spatial resolution X-ray computed tomography (CT) system is provided. The system includes a support structure including a gantry mounted to rotate about a vertical axis of rotation. The system further includes a first assembly including an X-ray source mounted on the gantry to rotate therewith for generating a cone X-ray beam and a second assembly including a planar X-ray detector mounted on the gantry to rotate therewith. The detector is spaced from the source on the gantry for enabling a human or other animal body part to be interposed therebetween so as to be scanned by the X-ray beam to obtain a complete CT scan and generating output data representative thereof. The output data is a two-dimensional electronic representation of an area of the detector on which an X-ray beam impinges. A data processor processes the output data to obtain an image of the body part.

Abstract: A method, processor and computed tomography (CT) machine for generating images utilizing high and low sensitivity data collected from a flat panel detector having an extended dynamic range. Hardware modifications for extending the dynamic range include grouping pixel rows and pixel columns into clusters of two. The sensitivity of the rows/columns is modified by positioning optical masks that have different transparencies for different rows/columns. Software modifications for extending the dynamic range include taking two correlated exposure scan measurements at each angle and combining the two data sets into one scan prior to image reconstruction. This method uses a spatially varying pixel exposure method where several adjacent pixels are clustered and each cluster has a different sensitivity. The signals of these clusters are combined to form one image effectively producing an increased dynamic range.

Abstract: An apparatus for identifying the location of a photon source within an imaging area and which generates photons having energies within a known energy range, the apparatus including two oppositely facing cameras disposed on opposite sides of the imaging area, each camera including a first detector unit which causes scattering when a photon enters the unit and generates signals indicative of the scattering event location, energy and time and a second detector unit which absorbs the scattered photon and generates signals indicative of the absorption event energy and time, the generated signals are then mathematically combined to determine the location of the source. Also a Compton camera including a first detector unit which is anatomically configured to generally mirror the external surface of a portion of a patient including an object to be imaged, a second detector unit positioned outside an imaging area to receive scattered photons from the first unit.

Abstract: A Compton camera has two detectors which each sense the location, energy and time of photon collisions. Compton events are detected in which a photon emanating from the subject collides with one detector at energy (E1) and then the second detector at (E2), both energies E1 and E2 are measured and used in conjunction with an initial photon energy E0 to increase the resolution of the camera.

Abstract: Spatial resolution in imaging-type scintillation detectors, such as gamma ray cameras used in nuclear medicine, is improved by providing an array of multi-faceted corner-cube reflectors on the back surface of the scintillator crystal. The reflectors modify the light spread function of the scintillator in accordance with any number of different applications, by appropriate adjustment of the orientation angle between facets.

Abstract: A method of reducing the effects of Compton scattered photons detected in a gamma ray detection arrangement includes the steps of receiving data responsive to energy states of the detected photons and storing the data in memory locations corresponding to predetermined image grid points, grouping the stored data, whereby a coarser grid having fewer image grid points is produced, calibrating the gamma ray detection arrangement by utilizing a spectral shape corresponding to a calibration function which is expected to correspond to a first data set corresponding to unscattered ones of the detected photons, processing the stored data for at least selected ones of the predetermined grid points employing minimization of a function which includes a product of an energy regularization term times an energy regularization parameter, as well as a spatial regularization term times a spatial regularization parameter, for separating the stored data into the first data set corresponding to unscattered ones of the detected ph

Abstract: A system for removing the effects of Compton scattering in systems such as tomographic scanning and radioisotope imaging arrangements, which detect gamma rays, utilizes the smoothness of the Compton component over the image to reduce computing time. Data responsive to energy states of the photons which are detected are received and values corresponding thereto are stored in at least one memory location. In some embodiments, where imaging is the ultimate function of the gamma ray detection system, the data correspond to predetermined image grid points. Also, the data which is stored is processed so as to be separated into a first data set corresponding to unscattered ones of the detected photons and a second data set corresponding to scattered ones of the detected photons. The gamma ray detection arrangement is calibrated by acquiring a spectral shape corresponding to unscattered photons. The processing utilizes non-linear least squares fitting analysis.

Abstract: A system for locating the position of a source of a detectable emittance is particularly adapted for locating the position of a scintillation event in a scintillation crystal which has arranged adjacent thereto a plurality of photomultiplier tubes arranged in a predetermined configuration for detecting the scintillation event. In a single photon emission computer tomography (SPECT) embodiment, a system which utilizes the present invention is initialized by storing weighting factors which are derived from placing a source of radiation in a plurality of known locations. The output values of the photomultiplier tubes are stored in a calibration file and subjected to a mathematical process to produce the weighting factors which are subsequently stored in a memory. During operation of the system, the signal values from the photomultiplier tubes are combined with the weighting factors to produce weighted signals which are then summed together to produce a composite weighted signal.

Abstract: A system for locating the position of a source of a detectable emittance is particularly adapted for locating the position of a scintillation event in a scintillation crystal which has arranged adjacent thereto a plurality of photomultiplier tubes arranged in a predetermined configuration for detecting the scintillation event. In a single photon emission computer tomography (SPECT) embodiment, a system which utilizes the present invention is initialized by storing weighting factors which are derived from placing a source of radiation in a plurality of known locations. The output values of the photomultiplier tubes are stored in a calibration file and subjected to a mathematical process to produce the weighting factors which are subsequently stored in a memory. During operation of the system, the signal values from the photomultiplier tubes are combined with the weighting factors to produce weighting signals which are then summed together to produce a composite weighted signal.

Abstract: An arrangement for determing the most likely interaction time corresponding to an observed pulse in a system having statistical processes is provided with a timing arrangement for producing a plurality of timing signals, the timing signals having a predetermined time relationship with respect to one another. A plurality of sampling elements, each having an input for receiving a respectively associated signal vector to be sampled in accordance with at least one of the timing signals, and an output for producing an associated portion of an analog vector signal are additionally provided. A digital memory stores data corresponding to a plurality of weighting coefficient vectors, the weighting coefficient vectors being formed of values corresponding to a predetermined characteristic of the shape of the pulse event and at least one of the statistical processes.

Abstract: A system for locating the position of a source of a detachable emittance is particularly adapted for locating the position of a scintillation event in a scintillation crystal which has arranged adjacent thereto a plurality of photomultiplier tubes arranged in a predetermined configuration for detecting the scintillation event. In a single photon emission computer tomography (SPECT) embodiment, a system which utilizes the present invention is initialized by storing weighting factors which are derived from placing a source of radiation in a plurality of known locations. The output values of the photomultiplier tubes are stored in a calibration file and subjected to a mathematical process to produce the weighting factors which are subsequently stored in a memory. During operation of the system, the signal values from the photomultiplier tubes are combined with the weighting factors to produce weighted signals which are then summed together to produce a composite weighted signal.

Abstract: A system for removing the effects of Compton scattering in systems such as tomographic scanning and radioisotope imaging arrangements, which detect gamma rays, utilizes the smoothness of the Compton component over the image to reduce computing time. Data responsive to energy states of the photons which are detected are received and values corresponding thereto are stored in at least one memory location. In some embodiments, where imaging is the ultimate function of the gamma ray detection system, the data correspond to predetermined image grid points. Also, the data which is stored is processed so as to be separated into a first data set corresponding to unscattered ones of the detected photons and a second data set corresponding to scattered ones of the detected photons. Such processing utilizes least squares fitting analysis, such as the known Golub method. The first data set is summed within specified limits, for determining a number of the unscattered ones of the detected photons.