Self-calibrating optical imaging system

• US 6,735,458 B2
• Filed: 10/01/2002
• Issued: 05/11/2004
• Est. Priority Date: 08/04/2000
• Status: Expired due to Term

• Current Assignee: Photonify Technologies Incorporated
• Original Assignee: Photonify Technologies Incorporated
• Inventors: Wang, Ming, Li, Feng, Wang, Lai, Zhou, Shuoming, Cheng, Xuefeng, Hu, Guobao, Xu, Xiaorong
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US10/262,523
• Publication Number:
  US 20030144583A1
• Time in Patent Office: 588 Days
• Field of Search: 600/310, 600/322, 600/323, 600/328, 600/473, 600/475, 600/476, 250/252.1, 250/341.1
• US Class Current: 600/323
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: G01N 2021/3144 for oxymetry
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/49 within a body or fluid

Abstract

The present invention generally relates to optical imaging systems and methods for providing images of two-dimensional and/or three-dimensional distribution of properties of chromophores in various physiological media. More particularly, the present invention relates to optical imaging systems, optical probes thereof, and methods therefor utilizing self-calibration of their output signals. A typical self-calibrating optical imaging system includes at least one wave source, at least one wave detector, a signal analyzer, a signal processor, and an image processor. The signal analyzer receives, from the wave detector, an output signal representative of the distribution of the chromophores or their properties in target areas of the medium. The signal analyzer analyzes amplitudes of the output signal and selects multiple points of the output signal having substantially similar amplitudes. The signal processor calculates a baseline corresponding to a representative amplitude of the similar amplitudes and provides a self-calibrated output signal. The image processor constructs the images of the distribution of the chromophores or their properties from the self-calibrated first output signals.

Claims

1. An optical imaging system configured to generate images of target areas of a physiological medium, said images representing distribution of chromophores or properties thereof in said target areas, said system comprising:

a movable member including at least one of said wave source and at least one wave detector, said at least one wave source configured to irradiate electromagnetic waves into said medium and said at least one wave detector configured to generate a first output signal from a first target area of said medium, wherein said first output signal is representative of said distribution in a first target area of said medium;

an actuator member configured to generate at least one movement of said movable member;

a signal analyzer configured to receive said first output signal, to analyze amplitudes of said first output signal, and to select a plurality of point of said first output signal having substantially similar amplitudes;

a signal processor configured to calculate a first baseline predominantly from said first output signal and to provide a self-calibrated first output signal by manipulating both of said first output signal and its first baseline, wherein said first baseline corresponds to a representative amplitude of said similar amplitudes; and

an image processor configured to construct said images of said distribution of at least one of said chromophores and said properties thereof from said self-calibrated first output signal.

2. The system of claim 1 wherein said signal processor is configured to provide said self-calibrated first output signal on a substantially real time basis.

3. The system of claim 1 wherein said image processor is configured to construct said images on a substantially real-time basis.

4. The system of claim 1 wherein said chromophores in said first target area are at least one of oxygenated hemoglobin and deoxygenated hemoglobin.

5. The system of claim 1 wherein said images relate to said distribution of at least one of oxygen saturation, concentration of oxygenated hemoglobin, concentration of deoxygenated hemoglobin, blood volume, and changes in blood volume in said first target area, wherein said oxygen saturation is defined as a ratio of said concentration of oxygenated hemoglobin to a sum of said concentrations of oxygenated and deoxygenated hemoglobins.

6. The system of claim 1 wherein said distribution includes at least one of spatial distribution of chromphores in said first target area and temporal changes in said distribution of chromophores in said first target area over time.

7. The system of claim 1 further comprising a memory unity configured to store at least one of said first output signal, first baseline, and self-calibrated first output signal.

8. An optical imaging system configured to analyze target areas of a physiological medium for distribution of chromophores or their properties in said target areas, said system comprising:

an optical probe having at least one wave source and at least one wave detector, wherein said at least one wave source is configured to irradiate electromagnetic waves into a first target area of said physiological medium and wherein said at least one wave detector is configured to detect said electromagnetic waves from said first target area of said medium and to generate a first output signal in response thereto;

a signal analyzer which is configured to receive said first output signal, to analyze amplitudes of said first output signal, and to select a plurality of points of said first output signal having substantially similar amplitudes; and

a signal processor which is configured to calculate a first baseline from said first output signal and to provide a self-calibrated first output signal by manipulating both of said first output signal and its first baseline, wherein said first baseline is a representative amplitude of said similar amplitudes.

9. The system of claim 8 wherein said signal processor is configured to provide said self-calibrated first output signal on a substantially real time basis.

10. The system of claim 8 further comprising an image processor configured to construct said images of said distribution of chromophores in said first target area from said self-calibrated first output signals.

11. The system of claim 10 wherein said image processor is configured to construct said images on a substantially real-time basis.

12. The system of claim 10 wherein said chromophores in said first target area are at least one of oxygenated hemoglobin and deoxygenated hemoglobin.

13. The system of claim 10 wherein said images relate to said distribution of at least one of oxygen saturation, concentration of oxygenated hemoglobin, concentration of deoxygenated hemoglobin, blood volume, and changes in blood volume in said first target area, wherein said oxygen saturation is defined as a ratio of said concentration of oxygenated hemoglobin to a sum of said concentrations of oxygenated and deoxygenated hemoglobins.

14. The system of claim 10 wherein said distribution includes at least one of spatial distribution of chromophores in said first target area and temporal changes in said distribution of chromophores in said first target area over time.

15. The system of claim 8 further comprising a memory unity configured to store at least one of said first output signal, first baseline, and self-calibrated first output signal.