Temperature Measurement Device

• US 20080071189A1
• Filed: 05/18/2005
• Published: 03/20/2008
• Est. Priority Date: 05/20/2004
• Status: Active Grant

• Current Assignee: Medisim Limited
• Original Assignee: Medisim Limited
• Inventors: Barak, Menashe, Yarden, Moshe
• Granted Patent: US 7,479,116 B2
• Time in Patent Office: Days
• US Class Current: 600/549
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: G01K 1/08 Protective devices, e.g. casings
• CPC Class Codes: G01K 1/16 Special arrangements for conducting heat from the object to the sensitive element
• CPC Class Codes: G01K 1/165 for application in zero heat flux sensors
• CPC Class Codes: G01K 1/20 Compensating for effects of temperature changes other than those to be measured, e.g. changes in ambient temperature
• CPC Class Codes: G01K 13/20 Clinical contact thermometers for use with humans or animals

Abstract

A device for non-invasive measurement of the internal temperature of a physical body or thermal resistivity, the body comprising a thermally conductive medium between an internal region with a substantially constant internal temperature and an external surface with a surface temperature. The device comprises: a patch comprising one or more contact components for attachment to the external surface and an insulating cover for substantially thermally insulating the contact component from ambient thermal conditions; a reader for acquiring one or more thermal magnitudes on the patch; a processing unit for processing the thermal magnitudes to derive the internal temperature of the internal region or the thermal resistivity of the conductive medium.

Claims

1. A device for a non-invasive measurement of the internal temperature of a physical body or thermal resistivity, the body comprising a thermally conductive medium between an internal region with a substantially constant internal temperature and an external surface with a surface temperature, the device comprising:

a patch comprising at least one contact component for attachment to the external surface and an insulating cover for substantially thermally insulating the contact component from ambient thermal conditions;

a reader for acquiring one or more thermal magnitudes on the patch;

a processing unit for processing said at least one or more thermal magnitudes to derive the internal temperature of the internal region or the thermal resistivity of the conductive medium.

2. The device of claim 1, wherein gas is provided between the insulating cover and the contact component.

3. The device of claim 2, wherein the gas is transparent to infra-red radiation.

4. The device of claim 3, wherein the gas is air.

5. The device of claim 1, wherein a vacuum is provided between the insulating cover and the contact component.

6. The device of claim 1, wherein the patch comprises at least one of a plurality of measurement locations characterized in that different measurement locations facilitate different thermal boundary conditions on the external surface.

7. The device of claim 6, wherein the patch comprises three measurement locations.

8. The device of claim 6, wherein the measurement locations are characterized as having distinct properties selected from the group of properties comprising:

different thermal conductivity, different thickness, or different emissivity, thus facilitating different boundary conditions on the external surface.

9. The device of claim 6, wherein the patch comprises at least one of a plurality of measurement locations characterized in that each measurement location facilitates two or more measurement spots facilitating different thermal boundary conditions on the external surface.

10. The device of claim 9, wherein the different thermal boundary conditions are characterized as having distinct properties selected from the group of properties comprising:

different thermal conductivity or different thickness.

11. The device of claim 9, wherein the measurement locations are separated by thermal insulation.

12. The device of claim 9, wherein said two or more measurement spots are separated by a distance that is substantially smaller than the distance separating adjacent measurement locations to eliminate or greatly reduce two dimensional effects.

13. The device of claim 7, wherein the patch is provided with at least one pair of thermally separated heat or temperature transducers for each measurement location, each transducer provided with leads to terminals external to the patch, which the reader can contact for reading.

14. The device of claim 1, wherein the reader is an infra-red radiation radiometer.

15. The device of claim 14, wherein the insulating cover is provided with a point of access through which the radiometer can acquire one or more thermal magnitudes on the patch.

16. The device of claim 15, wherein the point of access is selected from the group comprising:

a window, an opening, a diaphragm, or a shutter.

17. The device of claim 1, wherein the contact component comprises one location of substantially low thermal resistivity and substantially low emissivity, the cover has low emissivity, and wherein the cover is large enough to avoid lateral heat flux, thereby allowing at a thermal steady state the temperature on the contact component to be substantially equal to the internal temperature.

18. The device of claim 1, further comprising a user interface for enabling a user to calibrate and operate the reader and to be informed of the calculated internal temperature.

19. The device of claim 1, wherein the patch further comprises identification information about the physical body, the reader further comprises means for reading identification information.

20. The device of claim 19, wherein the means for reading the identification information is a bar code reader.

21. The device of claim 19, wherein the patch includes patient identification information.

22. The device of claim 1, wherein the contact component is provided with adhesive material for adhering the contact component to the external surface.

23. The device of claim 1, wherein the patch is provided with at least one adhesive surface.

24. The device of claim 1, wherein the reader is provided with a data communication interface to another device for storage or further processing the data

25. The device of claim 1, wherein the processing unit is provided with a data communication interface.

26. The device of claim 1, wherein the patch further comprises an aligner for proper alignment of the reader.

27. The device of claim 1, wherein the reader further comprises a reading end that comes into contact with the patch during reading, the reading end provided with a disposable cover.

28. The device of claim 13 wherein the reader further comprises a reading end that comes into contact with the patch during reading, the reading end provided with a disposable cover. wherein the disposable probe cover is provided with electrically conductive coating enabling electrical contact to the terminals external to the patch.

29. A method for non-invasively measuring the internal temperature or thermal resistivity of a physical body, the body comprising a thermally conductive medium between an internal region with a substantially constant internal temperature and an external surface with a surface temperature, the method comprising:

placing a patch comprising at least one contact component and an insulating cover with the contact component in contact with the external surface and allowing the contact component to reach a thermal steady state;

acquiring one or more thermal magnitudes on the patch using a reader;

processing with a processing unit said at least one or more thermal magnitudes to derive the internal temperature of the internal region or the thermal resistivity of the conductive medium;

30. The method of claim 29, comprising measuring the thermal resistivity of the physical body.

31. The method of claim 29, comprising:

acquiring thermal magnitudes at a plurality of measurement locations on the patch;

solving a set of equations relating to a plurality of measurement locations to derive the internal temperature or the thermal resistivity of the conductive medium, using the relation at each location given by

$q_K^{\mathrm{″<br><br>}}=\left(\frac{K_{\mathrm{eff}}}{\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>X}\right)<br><br>\left(\mathrm{Tdeep}-\mathrm{Ts}\right)$

where

q″

_K is the heat flux across the thermally conductive medium

K_eff is the effective conductivity of the thermally conductive medium

Δ

X is the thickness of the thermally conductive medium

T_s is the temperature measured on the skin surface

T_deep is the internal temperature

32. The method of claim 29, comprising:

acquiring thermal magnitudes is done at different measurement spots at each of a plurality of measurement locations on the patch,

solving a set of equations relating to a plurality of measurement locations to derive the internal temperature or the thermal resistivity of the conductive medium, using the relation at each location given by

$q^{\mathrm{″<br><br>}}=\frac{\mathrm{Ksi}}{\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Xsi}}<br><br>\underset{\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>T}{\underset{\mathrm{︸<br><br>}}{\left(\mathrm{Tsi}-\mathrm{Tci}\right)}}=\left(\frac{K_{\mathrm{eff}}}{\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>X}\right)<br><br>\left(\mathrm{Tdeep}-\mathrm{Tsi}\right)$

where

q″

is the heat flux

K_si is the conductivity of the contact component at spot S of the i-th location Δ

Xsi is the thickness of the contact component at spot S of the i-th location

T_si is the temperature of the contact component at spot S of the I-th location

T_ci is the temperature of the contact component at spot C of the I-th location

K_eff is the effective conductivity of the thermally conductive medium

Δ

X is the e thickness of the thermally conductive medium

T_deep is the internal temperature

33. The method of claim 29, wherein the contact component comprises one location of substantially low thermal resistivity, allowing the temperature on it at a steady state to be substantially equal to the internal temperature, and wherein the step of deriving temperature comprises taking the internal temperature to be substantially equal to the external temperature.

34. The method of claim 29, wherein deriving the internal temperature involves adding a known correction value from a predetermined calibration table.

35. The method of claim 29, further comprising repeatedly determining heat flux at the contact component and indicating if the contact component has reached a thermal steady state when the heat flux is substantially constant.

36. The method of claim 29, further comprising repeatedly determining the temperature at the contact component and indicating if the contact component has reached a thermal steady state when the temperature is substantially constant.