Temporal artery temperature detector

• US 7,346,386 B2
• Filed: 10/14/2003
• Issued: 03/18/2008
• Est. Priority Date: 09/11/1998
• Status: Expired due to Term

• Current Assignee: Exergen Corporation
• Original Assignee: Exergen Corporation
• Inventors: Pompei, Francesco
• Primary Examiner(s): Casler; Brian L.
• Assistant Examiner(s): Cheng; Jacqueline
• Application Number:
  US10/684,818
• Publication Number:
  US 20040152991A1
• Time in Patent Office: 1,617 Days
• Field of Search: 600/474, 600/549, 374/100, 374/104, 374/121, 374/126, 374/129
• US Class Current: 600/474
• 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 5/015 By temperature mapping of body part
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: G01J 5/0022 for sensing the radiation of moving bodies
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/05 Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path
• CPC Class Codes: G01J 5/06 Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity for adjusting of solid angle of collected radiation G01J5/07; means for wavelength selection G01J5/0801
• CPC Class Codes: G01J 5/16 Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables

Abstract

Body temperature measurements are obtained by scanning a thermal radiation sensor across the side of the forehead over the temporal artery. A peak temperature measurement is processed to compute an internal temperature of the body as a function of ambient temperature and the sensed surface temperature. The function includes a weighted difference of surface temperature and ambient temperature, the weighting being varied with target temperature through a minimum in the range of 96° F. and 100° F. The radiation sensor views the target surface through an emissivity compensating cup which is spaced from the skin by a circular lip of low thermal conductivity.

Claims

1. A body temperature detector comprising:

a temperature detector;

electronics which measure peak temperature from at least three readings per second during scan of the temperature detector across an artery and which process the detected peak temperature to provide a temperature display based on a model of heat balance relative to a detected arterial temperature.

2. A detector as claimed in claim 1 wherein the temperature detector comprises a radiation sensor which views a target surface area of the forehead.

3. A detector as claimed in claim 2 wherein the radiation sensor views a target through a reflective cup, the cup having a large open diameter close to the target surface and a proximal window at the base of the cup proximal to the radiation sensor through which the radiation sensor views the target and an open distal diameter larger than the window and closer than the window to the target surface, the cup being out of the field of view of the sensor.

4. A detector as claimed in claim 3 wherein the reflective cup is spaced from the target surface by a smooth lip of low thermal conductively material.

5. A detector as claimed in claim 1 wherein the electronics compute an internal temperature of the body as a function of ambient temperature and sensed surface temperature, the function including a weighted difference of surface temperature and ambient temperature, the weighting being varied with target temperature through a minimum in the range of 96°

F. to 100°

F., the weighting increasing above and below the minimum.

6. A detector as claimed in claim 5 wherein the weighting includes an approximation of h/pc at a forehead artery where h is a heat transfer coefficient between the target surface and ambient, p is profusion rate and c is blood specific heat.

7. A detector as claimed in claim 6 wherein the approximation of h/pc at the minimum is about 0.19.

8. A detector as claimed in claim 5 wherein the temperature detector comprises a radiation sensor which views a target surface area of the forehead.

9. A detector as claimed in claim 8 wherein the radiation sensor views a target through a reflective cup, the cup having a large open diameter close to the target surface and a window at the base of the cup through which the radiation sensor views the target, the cup being out of the field of view of the sensor.

10. A detector as claimed in claim 9 wherein the reflective cup is spaced from the target surface by a smooth lip of low thermal conductivity material.

11. A detector as claimed in claim 5 wherein the weighting is a linear approximation having a minimum between 96°

F. and 97°

F.

12. A detector as claimed in claim 5 wherein the weighting includes a polynomial approximation of 1+h/pc =k₁T_s²−

k₂T_s+k₃ where his a heat transfer coefficient between the target surface and ambient, p is perfusion rate, c is blood specific heat, k₁ is approximately 0.00359, k₂ is approximately 0.708 and k₃ is approximately 36.1.

13. A body temperature detector comprising:

a temperature sensor which senses temperature of a skin surface; and

electronics which compute an internal temperature of the body as a function of ambient temperature and sensed surface temperature, the function including a weighted difference of surface temperature and ambient temperature, the weighting being varied with target temperature through a minimum in the range of 96°

F.-100°

F., the weighting increasing above and below the minimum.

14. A detector as claimed in claim 13 wherein the weighting includes an approximation of h/pc at a forehead artery where h is a heat transfer coefficient between the target surface and ambient, p is perfusion rate and c is blood specific heat, the approximation of h/pc at the minimum being about 1.19.

15. A detector as claimed in claim 13 wherein the temperature sensor comprises a radiation sensor which views a target surface area of the forehead.

16. A detector as claimed in claim 15 wherein the radiation sensor views a target through a reflective cup, the cup having a large open diameter close to the target surface and a window at the base of the cup through which the radiation sensor views the target, the cup being out of the field of view of the sensor.

17. A detector as claimed in claim 16 wherein the reflective cup is spaced from the target surface by a smooth lip of low thermal conductivity material.

18. A method of detecting human body temperature comprising:

detecting temperature at a skin surface; and

computing an internal body temperature of the body as a function of ambient temperature and sensed surface temperature, the function including a weighted difference of surface temperature and ambient temperature, the weighting being varied with target temperature through a minimum in the range of 96°

F.-100°

F., the weighting increasing above and below the minimum.

19. A method as claimed in claim 18 wherein the temperature detector comprises a radiation sensor which views a target surface area.

20. A method as claimed in claim 19 wherein the radiation sensor views a target through a reflective cup, the cup having a large open diameter close to the target surface and a window at the base of the cup through which the radiation sensor views the target, the cup being out of the field of view of the sensor.

21. A method as claimed in claim 18 wherein the skin surface is in the vicinity of an artery.

22. A body temperature detector comprising:

a radiation sensor which views a target surface area;

a reflective cup through which the radiation sensor views the target surface area, the cup having a proximal window at the base of the cup through which the radiation sensor views the target and an open distal diameter larger than the window and closer than the window to the target surface, the cup proximal to the radiation sensor being out of the field of view of the sensor; and

electronics which measure peak temperature from at least three readings per second during scan of the temperature detector across the target surface area, the electronics processing the detected peak temperature to provide a temperature display based on a model of heat balance relative to the detected temperature.

23. A detector as claimed in claim 22 wherein the peak detector detects a peak from about ten readings per second.

24. A detector as claimed in claim 22 wherein the reflective cup is spaced from the target surface by a smooth lip of low thermal conductively material.