Non-invasive device and method for measuring bilirubin levels

• US 9,173,603 B2
• Filed: 07/18/2012
• Issued: 11/03/2015
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: Gerium Medical Ltd. (Mennen Medical Ltd.)
• Original Assignee: Ehud Zmora
• Inventors: Molcho, Jonathan, Zmora, Ehud
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US13/551,862
• Publication Number:
  US 20130023742A1
• Time in Patent Office: 1,203 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14557 specially adapted to extracorporeal circuits
• CPC Class Codes: A61B 5/443 Evaluating skin constituents, e.g. elastin, melanin, water

Abstract

A transcutaneous non-invasive device and method for measuring bilirubin levels is provided. The device and method utilize optical, electrical, and mechanical means in communication with processing means to calculate the serum bilirubin concentration. Blanching pressure is applied to the tissue, whose thickness is measured. The level of bilirubin is calculated from the thickness of the tissue and the detected and measured values of radiation transmitted through the living tissue.

Claims

1. A non-invasive device for measuring the bilirubin level of a subject comprising:

at least one radiation source for radiating a subject'"'"'s living tissue, said at least one radiation source configured to emit radiation in at least first and second wavelengths;

at least one detector for detecting rays transmitted through said tissue;

means for applying blanching pressure to the portion of the subject'"'"'s living tissue;

means for measuring the thickness of the portion of the subject'"'"'s living tissue through which radiation is being transmitted; and

processing means in communication with said at least one radiation source, said at least one detector and said means for measuring thickness,

wherein said processing means are configured to calculate the bilirubin level of said subject using data obtained from said at least one detector and from said thickness measurement means.

2. The device according to claim 1, wherein the means for applying blanching pressure comprise one of group of devices including a pair of rotatable arms, a single moving or rotating arm and a clip or pincer device, configured to be attached to the tissue being measured.

3. The device according to claim 1, wherein said at least first and second wavelengths comprise a first wavelength (λ

1) within a range 520 nm±

5 nm and a second wavelength (λ

2) within a range 470 nm±

10 nm.

4. The device according to claim 1, wherein said at least one radiation source comprises one of a group including at least two laser diodes, at least two light emitting diodes (or LEDs) and at least one laser diode together with at least one LED.

5. The device according to claim 4, wherein the device further comprises optical means configured to direct beams of light emitted from the at least one radiation source towards the subject'"'"'s living tissue.

6. The device according to claim 5, wherein the light beams are transmitted through the tissue at different times.

7. The device according to claim 4, wherein the device further comprises light guiding means and optical coupling means, said optical coupling means configured to direct beams of light received from the light guiding means to said at least one detector.

8. The device according to claim 1, wherein said at least one radiation source comprises a white light emitter and at least two filters for filtering the emitted white light.

9. The device according to claim 1, wherein said at least one radiation source comprises means for emitting a synchronous signal, said synchronous signal comprising:

first and second oscillators, configured to generate first and second electrical signals having first and second frequencies, respectively;

first and second driver units electrically coupled to said first and second oscillators;

first and second light emitting elements adapted to generate first and second light signals, said first and second light emitting elements electrically coupled to said first and second driver units.

10. The device according to claim 9, wherein the device further comprises:

a dichroic beam-combiner, configured to combine said first and second light signals into a single beam, said beam comprising components of the first and second light wavelengths (λ

1 and λ

2) of the first and second modulation frequencies (F1 and F2), respectively.

11. The device according to claim 10, wherein the device further comprises:

a reference detector configured to receive and measure a portion of the light incident on the dichroic beam-combiner.

12. The device according to claim 9, wherein the device further comprises:

a detector-amplifier unit comprising light sensing means adapted to produce electric signals corresponding to said first and second light signals received by the detector-amplifier unit and to amplify the resulting electric signals;

first and second synchronous detectors configured to receive said first and second signals and to extract the magnitude of the transmitted signal in wavelength λ

1 and frequency F1 and wavelength λ

2 and frequency F2 respectively, from the resulting electric signals.

13. The device according to claim 1, wherein the means for measuring the tissue thickness comprises one of a group of devices including a potentiometer, an optical measuring device, Rotary Variable Differential Transformer (RVDT) and a Linear Variable Differential Transformer (LVDT).

14. The device according to claim 1, further comprising gauging means for testing the device.

15. The device according to claim 14, wherein the gauging means comprises a testing jig composed of a transmissive material having known optical properties and thickness.

16. The device according to claim 1, further comprising means to eliminate external interference in the measured transmitted signals.

17. A method for measuring the bilirubin level of a subject comprising the steps of:

applying blanching pressure to the subject'"'"'s living tissue;

determining the thickness of the subject'"'"'s blanched tissue;

transmitting at least two different wavelengths through a subject'"'"'s blanched tissue;

detecting and recording the signals transmitted through the tissue having blanching pressure applied thereto; and

calculating the bilirubin level in the subject using data obtained from said recorded signals and said thickness.

18. The method according to claim 17, further comprising the steps of:

gauging a device configured to measure the bilirubin level; and

calculating first (A0) and second (A1) calibration constants.

19. The method according to claim 18, further comprising a gauging step, said gauging step comprising the steps of:

transmitting at least two different wavelengths through a transmissive material having known optical properties and thickness;

detecting and recording the signals transmitted through the transmissive material and the signal of the thickness measuring means;

calculating the tissue transmittance at each wavelength, T(λ

), according to the equation;

20. The method according to claim 18, wherein the step of calculating the bilirubin level is calculated according to the equation:

21. The method according to claim 17, wherein the step of transmitting comprises the step of:

configuring at least one radiation source for radiating the subject'"'"'s living tissue.

22. The method according to claim 17, wherein said step of detecting comprises the step of

removing ambient noise and interference from the received signal noise and interference from the ambient light.