Stephen J Walker

Address:

510 Humboldt St, Denver, CO 80218

Phone:

3033213935

VIN:

3D4GH57V69T511589

Make:

DODGE

Model:

JOURNEY

Year:

2009

US Patent:

6453183, Sep 17, 2002

Filed:

Apr 10, 2000

Appl. No.:

09/545916

Inventors:

Stephen D. Walker - Boulder CO 80303

International Classification:

A61B 500

US Classification:

600322, 600323, 600338

Abstract:

A method and apparatus for determining oxygenation and hemoglobin parameters in tissue measures light scattering parameters of light directed through the tissue, using an array of VCSELs, for light directed at more than one frequency. This allows for the calculation of Hb, HbO , and other parameters.

US Patent:

6690958, Feb 10, 2004

Filed:

May 7, 2002

Appl. No.:

10/143248

Inventors:

Stephen D. Walker - Boulder CO
Peter E. Nelson - Longmont CO
R. Dale Zellers - Lafayette CO

Assignee:

Nostix LLC - Boulder CO

International Classification:

A61B 500

US Classification:

600323, 600338, 600407, 600309

Abstract:

A diagnostic apparatus includes a near infrared spectrophotometer (NIRS) and an ultrasound transducer that operate in combination to improve diagnostic measurements. The diagnostic apparatus includes a near infrared spectrophotometer that measures an analyte, for example tissue oxygenation, in an optical sample volume and an ultrasound imager to accurately position the optical sample volume in biological tissue or vessels. In one example, the diagnostic apparatus includes an optical source, a linear array of ultrasound transducers, and an optical photodetector arranged in the same plane so that the ultrasound sample volume interrogated by the ultrasound transducers intersects the optical sample volume formed by the optical source and detector.

US Patent:

6802812, Oct 12, 2004

Filed:

Jul 27, 2001

Appl. No.:

09/917414

Inventors:

Stephen D. Walker - Boulder CO
John E. Repine - Englewood CO
Charles W. Henry - Denver CO
Peter E. Nelson - Longmont CO
R. Dale Zellers - Lafayette CO

Assignee:

Nostix LLC - Boulder CO

International Classification:

A61B 500

US Classification:

600309, 600323

Abstract:

An optical sensor includes an optical source capable of being positioned on a tissue and emitting near infrared light into the tissue at a plurality of selected wavelengths, and a photodetector capable of detecting reflected light from the tissue. The photodetector being positioned on the tissue removed from the optical source but sufficiently close in proximity to the optical source to contact the same general tissue. The optical sensor further includes an oscillator coupled to the optical source and capable of activating the optical source to emit the near infrared light, and a modulator coupled to the oscillator and capable of controlling radio frequency modulation of the optical source to emit a radio frequency component that is used to measure the optical path length and absorbance of an analyte of interest within the tissue.

US Patent:

7251516, Jul 31, 2007

Filed:

May 11, 2004

Appl. No.:

10/844230

Inventors:

Stephen D. Walker - Boulder CO, US
Peter E. Nelson - Longmont CO, US
R. Dale Zellers - Lafayette CO, US
Charles W. Henry - Denver CO, US
John E. Repine - Englewood CO, US

Assignee:

Nostix LLC - Boulder CO

International Classification:

A61B 5/00

US Classification:

600316

Abstract:

Glucose concentration is noninvasively measured by measuring a plurality of absorption values using at least one emitter operating at a corresponding plurality of emission wavelengths through a common optical sample volume and deriving glucose concentration from the absorption measurement values.

US Patent:

20080004513, Jan 3, 2008

Filed:

Jun 30, 2006

Appl. No.:

11/428217

Inventors:

Stephen D. Walker - Boulder CO, US
Peter E. Nelson - Longmont CO, US
R. Dale Zellers - Lafayette CO, US
Charles W. Henry - Denver CO, US
John E. Repine - Englewood CO, US

International Classification:

A61B 5/00

US Classification:

600310, 600344, 600316, 600323

Abstract:

In a tissue sensor, a plurality of emitters are configured to emit narrowband light into biological tissue at a plurality of selected wavelengths including one or more wavelengths indicative of a profile for one or more selected analytes and a reference wavelength at which absorbance for the selected analyte is negligible. The sensor further comprises a photo detector configured to detect light at wavelengths that emerge from the biological tissue.

US Patent:

20090018416, Jan 15, 2009

Filed:

Jul 13, 2007

Appl. No.:

11/777940

Inventors:

Stephen D. Walker - Boulder CO, US
Devon J. Dallmann - Boulder CO, US
Charles W. Henry - Boulder CO, US
Peter E. Nelson - Boulder CO, US
R. Dale Zellers - Boulder CO, US
John E. Repine - Boulder CO, US

International Classification:

A61B 5/00

US Classification:

600316

Abstract:

A method for measuring concentration of an analyte in body fluid comprises acquiring a body fluid sample, emitting light into the body fluid sample, and detecting emitted light intensity on a plurality of optical paths through the body fluid sample. A plurality of optical filters are arranged in respective optical paths of the optical path plurality comprising at least a first optical filter with light absorption by an analyte and water and a second optical filter with light absorption to water alone. Light intensity passed through the first optical filter and passed through the second optical filter is measured and analyte concentration is determined based on a ratio of intensities detected at a detector in an optical path intersected by the first optical filter and detected at a detector in an optical path intersected by the second optical filter.

US Patent:

20090018483, Jan 15, 2009

Filed:

Jul 13, 2007

Appl. No.:

11/777961

Inventors:

Stephen D. Walker - Boulder CO, US
Charles W. Henry - Boulder CO, US
Peter E. Nelson - Boulder CO, US
John E. Repine - Boulder CO, US

International Classification:

A61M 37/00

US Classification:

604 608, 600310

Abstract:

A body fluid analysis apparatus comprises a unitary housing containing a single-celled chamber and having an entry portal for communicating body fluid between a patient body and the chamber. A barrier coupled at the entry portal prevents selected components of the body fluid from entering the chamber.

US Patent:

20090047177, Feb 19, 2009

Filed:

Aug 17, 2007

Appl. No.:

11/840528

Inventors:

Stephen D. Walker - Boulder CO, US
Devon J. Dallmann - Boulder CO, US
Charles W. Henry - Boulder CO, US
Peter E. Nelson - Boulder CO, US
R. Dale Zellers - Boulder CO, US
John E. Repine - Boulder CO, US

International Classification:

G01N 21/00
G01N 33/48

US Classification:

422 55, 436 63

Abstract:

A lactate concentration measurement apparatus comprising a housing enclosing a sample chamber configured for holding a body fluid sample and measurement photo-optics that generate light and monitor light intensity along a plurality of optical paths in the sample chamber. The apparatus further comprises a plurality of optical filters aligned in respective optical paths of the optical path plurality comprising at least a first optical filter with light absorption by lactate and water and a second optical filter with light absorption to water alone. A logic determines lactate concentration based on a ratio of intensities detected at a first detector in an optical path intersected by the first optical filter and detected at a second detector in an optical path intersected by the second optical filter.