Systems and methods for spectroscopic measurement of a characteristic of biological tissue

• US 9,714,969 B2
• Filed: 09/30/2013
• Issued: 07/25/2017
• Est. Priority Date: 09/28/2012
• Status: Active Grant

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Cas Medical Systems Incorporated (Edwards Lifesciences Corporation)
• Inventors: Kosturko, William
• Primary Examiner(s): BHAT, ADITYA S
• Application Number:
  US14/041,733
• Publication Number:
  US 20140100823A1
• Time in Patent Office: 1,394 Days
• Field of Search: 702191, 356 285, 600476, 600323, 600301, 600309, 600473
• CPC Class Codes: A61B 2576/026 for the brain
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: G01N 21/00 Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light G01N3/00 - G01N19/00 take precedence
• CPC Class Codes: G01R 29/26 Measuring noise figure; Measuring signal-to-noise ratio
• CPC Class Codes: G16H 30/40 for processing medical images, e.g. editing

Abstract

A method and system for spectroscopic measurement of a characteristic of a biological tissue is provided. The method includes the steps of: (1) using at least one light source to emit light that penetrates the biological tissue; (2) using at least one light detector to detect light emitted by the at least one light source and passed through the biological tissue, and to convert the detected light into a detection signal, the detection signal including an unwanted noise component; and (3) using a processor to process the detection signal and to determine an adjusted peak-to-peak amplitude value that is representative of an amplitude of the detection signal adjusted for the unwanted noise component.

Claims

1. A system for spectroscopic measurement of a characteristic of a biological tissue, the system comprising:

at least one light source operable to emit light that penetrates the biological tissue;

at least one light detector operable to detect light emitted by the at least one light source and passed through the biological tissue, and operable to convert the detected light into a detection signal; and

a processor operable to receive the detection signal, and operable to determine an adjusted peak-to-peak amplitude value that is representative of an amplitude of the detection signal adjusted to account for an unwanted noise component present in the detection signal,

wherein the processor includes a detector circuit, the detector circuit comprising;

a differentiating amplifier operable to receive the detection signal, and operable to convert the detection signal into a differentiated detection signal;

an adjustable gain amplifier operable to receive the differentiated detection signal, and operable to convert the differentiated detection signal into a differentiated and gain-adjusted detection signal;

a positive peak detector operable to receive the differentiated and gain-adjusted detection signal, and operable to determine a maximum value of the differentiated and gain-adjusted detection signal; and

a negative peak detector operable to receive the differentiated and gain-adjusted detection signal, and operable to determine a minimum value of the differentiated and gain-adjusted detection signal.

2. The system of claim 1, the detector circuit comprising:

a difference amplifier operable to determine the adjusted peak-to-peak amplitude value using the maximum value received from the positive peak detector and the minimum value received from the negative peak detector; and

a sample and hold device operable to receive and hold the adjusted peak-to-peak amplitude value.

3. The system of claim 1, wherein the characteristic of the biological tissue is selected from the group consisting of:

oxygen saturation, hemoglobin concentration, and melanin concentration.

4. The system of claim 1, wherein the processor is operable to determine the adjusted peak-to-peak amplitude value using the maximum value and the minimum value.

5. A method for spectroscopic measurement of a characteristic of a biological tissue, the method comprising the steps of:

using at least one light source to emit light that penetrates the biological tissue;

using at least one light detector to detect light emitted by the at least one light source and passed through the biological tissue, and to convert the detected light into a detection signal, the detection signal including an unwanted noise component; and

using a processor to process the detection signal and to determine an adjusted peak-to-peak amplitude value that is representative of an amplitude of the detection signal adjusted for the unwanted noise component present within the detection signal,

wherein the processor includes a detector circuit, the detector circuit comprising;

a differentiating amplifier that receives the detection signal and converts the detection signal into a differentiated detection signal;

an adjustable gain amplifier that receives the differentiated detection signal and converts the differentiated detection signal into a differentiated and gain-adjusted detection signal;

a positive peak detector that receives the differentiated and gain-adjusted detection signal and determines a maximum value of the differentiated and gain-adjusted detection signal; and

a negative peak detector that receives the differentiated and gain-adjusted detection signal and determines a minimum value of the differentiated and gain-adjusted detection signal.

6. The method of claim 5, wherein the characteristic of the biological tissue is selected from the group consisting of:

oxygen saturation, hemoglobin concentration, and melanin concentration.

7. The method of claim 5, wherein the step of using the processor to process the detection signal and to determine the adjusted peak-to-peak amplitude value includes determining the adjusted peak-to-peak amplitude value using the maximum value and the minimum value.