Patents by Inventor Thomas K Lewellen
Thomas K Lewellen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9442198Abstract: A radiation detector is disclosed that includes a scintillation crystal and a plurality of photodetectors positioned to detect low-energy scintillation photons generated within the scintillation crystal. The scintillation crystals are processed using subsurface laser engraving to generate point-like defects within the crystal to alter the path of the scintillation photons. In one embodiment, the defects define a plurality of boundaries within a monolithic crystal to delineate individual detector elements. In another embodiment, the defects define a depth-of-interaction boundary that varies longitudinally to vary the amount of light shared by neighboring portions of the crystal. In another embodiment the defects are evenly distributed to reduce the lateral spread of light from a scintillation event. Two or more of these different aspects may be combined in a single scintillation crystal.Type: GrantFiled: April 21, 2015Date of Patent: September 13, 2016Assignee: University of Washington through its Center for CommercializationInventors: Thomas K. Lewellen, William C. J. Hunter, Robert S. Miyaoka, Lawrence MacDonald
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Publication number: 20150226862Abstract: A radiation detector is disclosed that includes a scintillation crystal and a plurality of photodetectors positioned to detect low-energy scintillation photons generated within the scintillation crystal. The scintillation crystals are processed using subsurface laser engraving to generate point-like defects within the crystal to alter the path of the scintillation photons. In one embodiment, the defects define a plurality of boundaries within a monolithic crystal to delineate individual detector elements. In another embodiment, the defects define a depth-of-interaction boundary that varies longitudinally to vary the amount of light shared by neighboring portions of the crystal. In another embodiment the defects are evenly distributed to reduce the lateral spread of light from a scintillation event. Two or more of these different aspects may be combined in a single scintillation crystal.Type: ApplicationFiled: April 21, 2015Publication date: August 13, 2015Applicant: University of Washington through its Center for CommercializationInventors: Thomas K. Lewellen, William C.J. Hunter, Robert S. Miyaoka, Lawrence MacDonald
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Patent number: 9040924Abstract: A radiation detector is disclosed that includes a scintillation crystal and a plurality of photodetectors positioned to detect low-energy scintillation photons generated within the scintillation crystal. The scintillation crystals are processed using subsurface laser engraving to generate point-like defects within the crystal to alter the path of the scintillation photons. In one embodiment, the defects define a plurality of boundaries within a monolithic crystal to delineate individual detector elements. In another embodiment, the defects define a depth-of-interaction boundary that varies longitudinally to vary the amount of light shared by neighboring portions of the crystal. In another embodiment the defects are evenly distributed to reduce the lateral spread of light from a scintillation event. Two or more of these different aspects may be combined in a single scintillation crystal.Type: GrantFiled: October 27, 2010Date of Patent: May 26, 2015Assignee: University of Washington through its Center for CommercializationInventors: Thomas K. Lewellen, William C. J. Hunter, Robert S. Miyaoka, Lawrence MacDonald
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Patent number: 8716669Abstract: A method for estimating a line or response in a positron emission tomography scanner having depth of interaction estimation capability. The method utilizes information from both detector modules detecting a coincident event. A joint probability density function combining factors accounting for intermediate Compton scattering interactions and/or a final interaction that may be either a Compton scattering interaction or photoelectric absorption is calculated. In a preferred embodiment, a Bayesian estimation scheme is used to integrate the PDF for all permutations of the measured signal pairs, and the permutation with the largest joint probability is selected to construct the estimated line of response.Type: GrantFiled: October 22, 2009Date of Patent: May 6, 2014Assignee: University of WashingtonInventors: Robert S. Miyaoka, Kyle Champley, Lawrence MacDonald, Thomas K. Lewellen
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Publication number: 20140042326Abstract: A method is provided for determining the three-dimensional position of an interaction location within a scintillating crystal at which an high-energy photon produces a plurality of scintillation photons. The method includes the use of a sensor-on-entrance-surface photodetector device to determine a distribution pattern of the scintillation photons in the crystal.Type: ApplicationFiled: January 25, 2013Publication date: February 13, 2014Applicant: UNIVERSITY OF WASHINGTONInventors: Robert S. Miyaoka, Thomas K. Lewellen, Tao Ling
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Patent number: 8431904Abstract: Improved processing electronic hardware are disclosed that facilitate the efficient processing of PET system data, while enhancing accuracy and compatibility of PET systems with other analytical methods (e.g., magnetic resonance imaging). Improvements include the use of an application-specific integrated circuit (ASIC) for summing, by row, column, and diagonal, the output signals from an array of photodetectors in the PET system.Type: GrantFiled: October 26, 2009Date of Patent: April 30, 2013Assignee: University of WashingtonInventors: Thomas K. Lewellen, Robert S. Miyaoka
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Patent number: 8309932Abstract: A method for estimating the start time of an electronic pulse generated in response to a detected event, for example the start time for pulses received in response to photon detection in positron emission tomography, includes providing a detector that detects an external event and generates an electronic analog pulse signal. A composite reference pulse curve is calculated to represent analog pulse signals generated by the detector. Upon receiving an analog pulse signal, it may be filtered, and then digitized, and normalized based on the area of the digital signal. Using at least one point of the normalized digital pulse signal, the composite reference pulse curve shape is used to estimate the pulse start time.Type: GrantFiled: August 18, 2011Date of Patent: November 13, 2012Assignee: University of WashingtonInventors: Michael Haselman, Robert S. Miyaoka, Thomas K. Lewellen, Scott Hauck
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Publication number: 20120235047Abstract: A radiation detector is disclosed that includes a scintillation crystal and a plurality of photodetectors positioned to detect low-energy scintillation photons generated within the scintillation crystal. The scintillation crystals are processed using subsurface laser engraving to generate point-like defects within the crystal to alter the path of the scintillation photons. In one embodiment, the defects define a plurality of boundaries within a monolithic crystal to delineate individual detector elements. In another embodiment, the defects define a depth-of-interaction boundary that varies longitudinally to vary the amount of light shared by neighboring portions of the crystal. In another embodiment the defects are evenly distributed to reduce the lateral spread of light from a scintillation event. Two or more of these different aspects may be combined in a single scintillation crystal.Type: ApplicationFiled: October 27, 2010Publication date: September 20, 2012Applicant: University of Washington through its Center for CommercializationInventors: Thomas K. Lewellen, William C. J. Hunter, Robert S. Miyaoka, Lawrence MacDonald
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Publication number: 20120138804Abstract: A method for estimating a line or response in a positron emission tomography scanner having depth of interaction estimation capability. The method utilizes information from both detector modules detecting a coincident event. A joint probability density function combining factors accounting for intermediate Compton scattering interactions and/or a final interaction that may be either a Compton scattering interaction or photoelectric absorption is calculated. In a preferred embodiment, a Bayesian estimation scheme is used to integrate the PDF for all permutations of the measured signal pairs, and the permutation with the largest joint probability is selected to construct the estimated line of response.Type: ApplicationFiled: October 22, 2009Publication date: June 7, 2012Applicant: UNIVERSITY OF WASHINGTONInventors: Robert S. Miyaoka, Kyle Champley, Lawrence MacDonald, Thomas K. Lewellen
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Publication number: 20110301918Abstract: A method for estimating the start time of an electronic pulse generated in response to a detected event, for example the start time for pulses received in response to photon detection in positron emission tomography, includes providing a detector that detects an external event and generates an electronic analog pulse signal. A composite reference pulse curve is calculated to represent analog pulse signals generated by the detector. Upon receiving an analog pulse signal, it may be filtered, and then digitized, and normalized based on the area of the digital signal. Using at least one point of the normalized digital pulse signal, the composite reference pulse curve shape is used to estimate the pulse start time.Type: ApplicationFiled: August 18, 2011Publication date: December 8, 2011Applicant: WASHINGTON, UNIVERSITY OFInventors: Michael Haselman, Robert S. Miyaoka, Thomas K. Lewellen, Scott Hauck
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Publication number: 20110215248Abstract: Improved processing electronic hardware are disclosed that facilitate the efficient processing of PET system data, while enhancing accuracy and compatibility of PET systems with other analytical methods (e.g., magnetic resonance imaging).Type: ApplicationFiled: October 26, 2009Publication date: September 8, 2011Applicant: UNIVERSITY OF WASHINGTONInventors: Thomas K. Lewellen, Robert S. Miyaoka
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Patent number: 8003948Abstract: A method for estimating the start time of an electronic pulse generated in response to a detected event, for example the start time for pulses received in response to photon detection in positron emission tomography, includes providing a detector that detects an external event and generates an electronic analog pulse signal. A parameterized ideal curve shape is selected to represent analog pulse signals generated by the detector. Upon receiving an analog pulse signal, it may be filtered, and then digitized, and normalized based on the area of the digital signal. Using at least one point of the normalized digital pulse signal, a curve from the parameterized ideal curve shape is selected, that best represents the received analog pulse signal, and the selected curve is used to estimate the pulse start time.Type: GrantFiled: November 3, 2008Date of Patent: August 23, 2011Assignee: University of WashingtonInventors: Michael Haselman, Robert S. Miyaoka, Thomas K. Lewellen, Scott Hauck
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Patent number: 7869860Abstract: A method is disclosed for obtaining linear attenuation coefficients for interpreting a PET scan of a region. The method is suitable for use when high molecular weight materials are present in the region, such as contrast agents or metal objects. The method includes obtaining first and second x-ray CT data sets of the region of interest at two different energies or voltage potentials and differencing corresponding CT numbers. The difference values are used to distinguish portions of the region that are bone from portions of the region that are contrast agent or other high molecular weight material. The obtained CT data set is then used to obtain an attenuation coefficient map of the region at the PET energy of 511 keV, for example, using a linear scaling factor suited to the particular identified material. Difference values at or near zero may be used to identify soft tissue portions of the region.Type: GrantFiled: November 10, 2006Date of Patent: January 11, 2011Assignee: University of WashingtonInventors: Paul E Kinahan, Adam M Alessio, Thomas K Lewellen, Hubert J Vesselle
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Publication number: 20100044571Abstract: A method is provided for determining the three-dimensional position of an interaction location within a scintillating crystal at which an high-energy photon produces a plurality of scintillation photons. The method includes the use of a sensor-on-entrance-surface photodetector device to determine a distribution pattern of the scintillation photons in the crystal.Type: ApplicationFiled: August 19, 2009Publication date: February 25, 2010Applicant: UNIVERSITY OF WASHINGTONInventors: Robert S. Miyaoka, Thomas K. Lewellen, Tao Ling
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Publication number: 20090224158Abstract: A method for estimating the start time of an electronic pulse generated in response to a detected event, for example the start time for pulses received in response to photon detection in positron emission tomography, includes providing a detector that detects an external event and generates an electronic analog pulse signal. A parameterized ideal curve shape is selected to represent analog pulse signals generated by the detector. Upon receiving an analog pulse signal, it may be filtered, and then digitized, and normalized based on the area of the digital signal. Using at least one point of the normalized digital pulse signal, a curve from the parameterized ideal curve shape is selected, that best represents the received analog pulse signal, and the selected curve is used to estimate the pulse start time.Type: ApplicationFiled: November 3, 2008Publication date: September 10, 2009Applicant: WASHINGTON, UNIVERSITY OFInventors: Michael Haselman, Robert S. Miyaoka, Thomas K. Lewellen, Scott Hauck