Biological photometric device

• US 7,725,145 B2
• Filed: 02/02/2006
• Issued: 05/25/2010
• Est. Priority Date: 02/16/2005
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Kawasaki, Shingo, Tanaka, Naoki
• Primary Examiner(s): Winakur; Eric F
• Assistant Examiner(s): Berhanu; Etsub D
• Application Number:
  US11/816,452
• Publication Number:
  US 20090054885A1
• Time in Patent Office: 1,573 Days
• Field of Search: 600/322, 600/323, 600/328, 600/336, 702/189, 702/191, 702/195
• US Class Current: 600/328
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B

Abstract

A biological photometric device includes a light irradiating unit for irradiating an object to be examined with light having a predetermined wavelength and sympathizing with oxygenated hemoglobin and deoxygenated hemoglobin through an optical fiber, a light detecting unit for detecting and amplifying light passing through a detecting optical fiber and the object as detected signals, a signal processing unit adapted for computing hemoglobin time change information based on oxygenated hemoglobin, deoxygenated hemoglobin and total hemoglobin in the object from the detected signals light detecting unit, and including a noise detector for arithmetically processing the detected signals and determining/detecting whether the time change information is noise attributed to the presence of obstacles to passing of light between the object and the end face of the optical fiber or noise attributed to the damage to the light irradiating unit, and a display unit for displaying the noise signals.

Claims

1. A biological photometric device comprising:

a light irradiating unit for irradiating light having a predetermined wavelength and responding to oxygenated hemoglobin and deoxygenated hemoglobin, to an object to be examined via irradiating optical fibers;

a light detecting unit for detecting and amplifying the light passed through the object via detecting optical fibers;

a signal processing unit for calculating hemoglobin time variation information of oxygenated hemoglobin, deoxygenated hemoglobin and total hemoglobin in the body of the object from the signals detected by the light detecting unit, which has noise detecting means for determining and detecting from the time variation information at least one type of a noise attributed to the existence of obstructions to the passing of light between the object and end surface of the optical fibers, and the noise attributed to damage of the light irradiating unit; and

a display unit for displaying the noise signals determined and detected by the signal processing unit, in a way capable of discriminating the type of noise.

2. The biological photometric device according to claim 1, wherein the signal processing unit comprises a first noise detecting means for determining and detecting noise attributed to the existence of obstructions to passing of light between the object and end surface of the optical fibers, and a second noise detecting means for determining and detecting noise attributed to damage of the light irradiating unit.

3. The biological photometric device according to claim 2, wherein the first noise detecting means calculates a standard deviation value with respect to time change of the detection signals, and determines the signals as noise signals when the obtained standard deviation value is more than a predetermined threshold value and when a gain in the light detecting unit is more than the predetermined threshold value.

4. The biological photometric device according to claim 2, wherein the second noise detecting means comprises:

means for obtaining time correlation value r with respect to time variation information of the oxygenated hemoglobin and deoxygenated hemoglobin; and

means for obtaining standard deviation values SD_oxy, SD_deoxy and SD_total with respect to time change information of the oxygenated hemoglobin, deoxygenated hemoglobin and total hemoglobin,

characterized in that the second noise detecting means determines the signals as being noise signals when;

r≦

r₀;

SD_oxy≧

S₂×

SD_total; and

SD_deoxy≧

S₃×

SD_total

(r₀, S₂ and S₃ are values set in advance).

5. The biological photometric device according to claim 2, wherein the signal processing unit has a third noise detecting means for determining and detecting noise attributed to gaps between optical fiber apertures and the object over a minute period of time caused by the relative positional displacement of the object and the optical fibers.

6. The biological photometric device according to claim 5, wherein the signal processing unit includes:

means to convert time variation information of the oxygenated hemoglobin, deoxygenated hemoglobin and total hemoglobin into a time variation chart, and outputting it to a display unit; and

means to impart the information to the time variation chart for enabling an operator to recognize the kind of noise.

7. The biological photometric device according to claim 6, wherein the information for making the kind of noise identifiable is the background color of the time variation chart.

8. The biological photometric device according to claim 6, wherein the information for making the kind of noise identifiable is texture information.

9. The biological photometric device according to claim 2, wherein the signal processing unit includes:

means to convert time change information of the oxygenated hemoglobin, deoxygenated hemoglobin and total hemoglobin into a time change chart and output it to a display unit; and

means to impart information to the time variation chart for enabling the operator to discriminate the kind of noise.

10. The biological photometric device according to claim 9, wherein the information for making the kind of noise identifiable is the background color of time variation chart.

11. The biological photometric device according to claim 9, wherein the information for making the kind of noise identifiable is textual information.

12. The biological photometric device according to claim 1, wherein:

the light irradiating unit has a plurality of irradiating optical fibers for irradiating light to a plurality of points of the object;

the light detecting unit has a plurality of detecting optical fibers for detecting light at a plurality of points on the body surface of the object that are respectively different from the plurality of points being irradiated by the irradiating optical fibers; and

the signal processing unit calculates the time change information of the plurality of measurement points determined by the arrangement of the irradiating optical fibers and the detecting optical fibers, performs noise determination, displays the hemoglobin time change information with respect to the plurality of measurement points to a display screen of a display unit by disposing them to correspond to the position of the measurement points, and simultaneously displays discrimination data for indicating to the display region measurement points determined as being noise signals.

13. The biological photometric device according to claim 12, wherein the signal processing unit comprises means to construct a topography image using the hemoglobin time change information with respect to the plurality of measurement points, and to output the constructed topography image to a display unit.

14. The biological photometric device according to claim 13, wherein the signal processing unit is further configured to construct topography images using only normal signals by eliminating the hemoglobin time change information of the measure points, out of the plurality of measurement points, that are determined by the noise detecting unit as noise signals.

15. The biological photometric device according to claim 12, wherein the signal processing unit comprises means for calculating signals that are assumed to be normally measured with respect to the measurement points where noise signals are measured, by interpolation calculation using normal signals of the adjacent plurality of measurement points.

16. The biological photometric device according to claim 15, wherein the signal processing unit is further configured to construct topography images by replacing the hemoglobin time change information of the measure points out of the plurality of measure points that are determined by the noise detecting unit as noise signals, with signals obtained by the interpolation calculation means, and to output the constructed topography images to a display unit.

17. The biological photometric device according to claim 15, wherein the signal processing unit has a disease determining unit for performing disease determination using the hemoglobin time change information of the object, and the disease determining unit determines disease by replacing noise signals detected by the noise detecting unit with the signals obtained by the interpolation calculation means.

18. The biological photometric device according to claim 12, wherein the signal processing unit has a disease determining unit for performing disease detection using the hemoglobin time change information of the object, and the disease detecting unit eliminates the noise signals detected by the noise detecting unit and performs disease detection using only normal signals.

19. The biological photometric device according to claim 1 wherein the noise detecting unit is configured to cause the display unit to display a denotation for inducing re-measurement to the operator when noise signals are detected.

20. The biological photometric device according to claim 19, comprising an input unit for an operator to input operation commands, characterized in performing re-measurement when the command is inputted from the input unit to perform re-measurement with respect to the denotation for inducing the re-measurement.