# US 8,543,180 B2 · Method and apparatus for total hemoglobin measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,543,180 B2 - Document ID: US8543180B2 - Status: Granted - Kind: B2 - Application number: 12/875,983 - Filed: 2010-09-03 - Published: 2011-05-19 - Granted: 2013-09-24 - Earliest claimed: 2006-05-03 - Assignees: Covidien LP - Applicants: Kate Leeann Bechtel; Tobias Funk; Brian Patrick Wilfley; Joseph Anthony Heanue - Inventors: Kate Leeann Bechtel; Tobias Funk; Brian Patrick Wilfley; Joseph Anthony Heanue - Web page: https://patentgrep.com/patent/US8543180B2 ## CPC - A61B 5/1455: using optical sensors, e.g. spectral photometrical oximeters - A61B 5/0059: {using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455)} - A61B 5/0091: {for mammography} - A61B 5/415: {the glands, e.g. tonsils, adenoids or thymus} - A61B 5/418: {lymph vessels, ducts or nodes} - A61B 5/4312: {Breast evaluation or disorder diagnosis (optical mammography A61B5/0091)} - A61B 5/6814: {Head} - A61B 5/6826: {Finger} - A61B 5/6838: {Clamps or clips} - G01J 3/02: Details - G01J 3/0205: {Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows} - G01J 3/0218: {using optical fibers} - G01J 3/10: Arrangements of light sources specially adapted for spectrometry or colorimetry - G01J 3/2823: {Imaging spectrometer} - G01J 3/4406: {Fluorescence spectrometry} - A61B 2562/0233: Special features of optical sensors or probes classified in A61B5/00 - A61B 2562/046: in a matrix array - G01N 2201/0826: Fibre array at source, distributing - G01N 2201/0833: Fibre array at detector, resolving - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The present invention pertains to a method and apparatus for total hemoglobin measurement. A modulated optical signal based on a digital code sequence is transmitted to human tissue. A temporal transfer characteristic is derived from the modulated optical signal. Total hemoglobin is determined based on the temporal transfer characteristic. ## Claims ### Claim 1 A total hemoglobin measurement system for measuring total hemoglobin in human tissue comprising: a signal generator for generating a digital modulation signal representing a code sequence; an optical illumination source coupled to said signal generator for receiving said digital modulation signal and configured for transmitting a modulated optical signal along an optical transmission path to said human tissue in response to said digital modulation signal; a detector configured to be optically coupled to said human tissue for receiving said modulated optical signal after transmission through the optical transmission path through said human tissue; a processor coupled to said detector for deriving a temporal transfer characteristic for said optical signal received by said detector and for determining said total hemoglobin based on said temporal transfer characteristic; a second signal generator for generating a second digital modulation signal representing a second code sequence, wherein said second code sequence and said code sequence have the same ordering of code elements and begin at different code elements; and a second optical illumination source coupled to said second signal generator for receiving said second digital modulation signal and configured for transmitting a second modulated optical signal to said human tissue in response to said second digital modulation signal. ### Claim 2 (depends on 1) The total hemoglobin measurement system of claim 1 further comprising: a delay component optically coupled to said optical illumination source for increasing length of said optical transmission path. ### Claim 3 (depends on 2) The total hemoglobin measurement system of claim 2 wherein said delay component further comprises a reflective surface. ### Claim 4 (depends on 1) The total hemoglobin measurement system of claim 1 wherein said code sequence further comprises multiple identical code sequences of a single code sequence. ### Claim 5 (depends on 1) The total hemoglobin measurement system of claim 1 wherein said code sequence is circular. ### Claim 6 (depends on 1) The total hemoglobin measurement system of claim 1 wherein said code sequence is orthogonal. ### Claim 7 (depends on 1) The total hemoglobin measurement system of claim 1 wherein said code sequence is unipolar. ### Claim 8 (depends on 1) The total hemoglobin measurement system of claim 1 wherein said code sequence is a Galois code. ### Claim 9 (depends on 1) The total hemoglobin measurement system of claim 1 wherein said code sequence is a maximal-length sequence. ### Claim 10 A method for measuring total hemoglobin in a human tissue comprising: generating a digital modulation signal associated with a code sequence; generating a modulated optical signal based on said digital modulation signal; transmitting said modulated optical signal to said human tissue; receiving a modified version of said modulated optical signal after transmission through said human tissue; deriving a temporal transfer characteristic for said modified version of said modulated optical signal; calculating said total hemoglobin based on said temporal transfer characteristic; delaying said code sequence to generate a second code sequence; generating a second digital modulation signal associated with said second code sequence; generating a second modulated optical signal based on said second digital modulation signal; transmitting said second modulated optical signal to said human tissue; receiving a second modified version of said second modulated optical signal after transmission through said human tissue; and deriving a second temporal transfer characteristic for said second modified version of said second modulated optical signal. ### Claim 11 (depends on 10) The method of claim 10 further comprising: delaying said modulated optical signal to reduce noise effects. ### Claim 12 (depends on 10) The method of claim 10 further comprising: determining an absorption coefficient of said human tissue from said temporal transfer characteristic. ### Claim 13 (depends on 10) The method of claim 10 wherein said code sequence is circular. ### Claim 14 (depends on 10) The method of claim 10 further comprising: determining a first absorption coefficient during systole based on said temporal transfer characteristic; and determining a second absorption coefficient during diastole based on said temporal transfer characteristic. ### Claim 15 (depends on 10) The method of claim 10 wherein said code sequence is orthogonal. ### Claim 16 A total hemoglobin measurement system for measuring total hemoglobin in human tissue comprising: means for generating a digital modulation signal associated with a code sequence; means for generating a modulated optical signal based on said digital modulation signal; means for transmitting said modulated optical signal to said human tissue; means for receiving a modified version of said modulated optical signal after transmission through said human tissue; means for deriving a temporal transfer characteristic for said modified version of said modulated optical signal; means for calculating said total hemoglobin based on said temporal transfer characteristic; means for delaying said code sequence to generate a second code sequence; means for generating a second digital modulation signal associated with said second code sequence; means for generating a second modulated optical signal based on said second digital modulation signal; means for transmitting said second modulated optical signal to said human tissue; means for receiving a second modified version of said second modulated optical signal after transmission through said human tissue; and means for deriving a second temporal transfer characteristic for said second modified version of said second modulated optical signal.