Temporal artery temperature detector

• US 6,292,685 B1
• Filed: 09/11/1998
• Issued: 09/18/2001
• 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): Lateef, Marvin M.
• Assistant Examiner(s): Lin, Jeoyuh
• Application Number:
  US09/151,482
• Time in Patent Office: 1,103 Days
• Field of Search: 374/124, 374/121, 374/100, 374/104, 374/126, 374/127, 374/128, 374/129, 374/133, 600/310, 600/309, 600/473, 600/474, 600/475, 600/549
• 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 method of detecting human body temperature comprising:

laterally scanning a temperature detector across a forehead; and

providing a peak temperature reading from plural readings during the step of scanning.

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

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

4. A method as claimed in claim 1 further comprising computing an internal body temperature as a function of ambient temperature and the peak temperature reading.

5. A method as claimed in claim 4 wherein the function includes a weighted difference of surface temperature and ambient temperature, the weighting including an approximation of h/pc at a forehead artery where h is a heat transfer coefficient between a target surface of the forehead and ambient, p is perfusion rate and c is blood specific heat.

6. A method as claimed in claim 5 wherein the approximation of h/pc at the minimum is about 0.19.

7. A method as claimed in claim 4 wherein the temperature detector comprises a radiation sensor which views a target surface area of the forehead.

8. A method as claimed in claim 7 wherein the radiation sensor views the target surface area through a reflective cup, the cup having a large open diameter close to the target surface area and a window at the base of the cup through which the radiation sensor views the target surface area, the cup being out of the field of view of the sensor.

9. A method as claimed in claim 8 wherein the reflective cup is spaced from the target surface area by a smooth lip of low thermal conductivity material.

10. A method as claimed in claim 4 wherein the weighting is a linear approximation having a minimum between 96°

F. and 97°

F.

11. A method as claimed in claim 4 wherein the weighting includes a polynomial approximation of 1+h/pc=k₁T_s²−

k₂T_s+k₃ where h is 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.

12. A method as claimed in claim 1 wherein the temperature detector is scanned across an artery.

13. A method as claimed in claim 1 wherein the temperature detector is scanned across a temporal artery.

14. A method of detecting human body temperature comprising:

detecting temperature at a forehead through a lateral scan across the temporal artery; and

computing an internal body temperature of the body as a function of ambient temperature and sensed surface temperature.

15. A method as claimed in claim 14 wherein 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.-100°

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

16. A method as claimed in claim 14 wherein the function includes a weighted difference of surface temperature and ambient temperature, the weighting including 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.

17. A method as claimed in claim 14 wherein the temperature detector comprises a radiation sensor which views a target surface area of the forehead.

18. A method as claimed in claim 17 wherein the radiation sensor views the target surface area through a reflective cup, the cup having a large open diameter close to the target surface area and a window at the base of the cup through which the radiation sensor views the target surface area, the cup being out of the field of view of the sensor.

19. A method as claimed in claim 18 wherein the reflective cup is spaced from the target surface area by a smooth lip of low thermal conductivity material.

20. A method as claimed in claim 14 wherein temperature is detected in the vicinity of an artery.

21. A method as claimed in claim 14 wherein temperature is detected in the vicinity of a temporal artery.

22. A method of detecting human body temperature comprising:

laterally scanning a temperature detector across an artery; and

providing a peak temperature reading from plural readings during the step of scanning.

23. A method as claimed in claim 22 wherein the temperature detector comprises a radiation sensor which views a target surface area over the artery.

24. A method as claimed in claim 23 wherein the radiation sensor views the target surface area through a reflective cup, the cup having a large open diameter close to the target surface area and a window at the base of the cup through which the radiation sensor views the target surface area, the cup being out of the field of view of the sensor.

25. A method as claimed in claim 22 further comprising computing 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.

26. A method as claimed in claim 22 wherein the temperature detector is scanned across a temporal artery.

27. A method of detecting human body temperature comprising measuring temperature of the temporal artery through skin.

28. A method as claimed in claim 27 wherein temporal artery temperature is measured with an infrared detector.

29. A method as claimed in claim 28 wherein the infrared detector is scanned across the temporal artery.

30. A method as claimed in claim 27 further comprising computing an internal temperature of the body as a function of ambient temperature and sensed surface temperature.

31. A method as claimed in claim 30 wherein the function includes a weighted difference of surface temperature and ambient temperature, the weighting including 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.

32. A method of detecting human body temperature comprising:

detecting temperature at a forehead; 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 including 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.

33. A body temperature detector system comprising:

a temperature detector; and

electronic circuitry which measures peak temperature from at least three readings per second during scan of the temperature detector across an artery and which processes the measured peak temperature to provide a temperature display based on a model of heat balance relative to a detected arterial temperature, the electronic circuitry computing 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 including 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.

34. A detector system as claimed in claim 33 wherein the approximation of h/pc at the minimum is about 0.19.

35. A body temperature detector system comprising:

a temperature detector; and

electronic circuitry which measures peak temperature from at least three readings per second during scan of the temperature detector across an artery and which processes the measured peak temperature to provide a temperature display based on a model of heat balance relative to a detected arterial temperature, the electronic circuitry computing 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 a linear approximation having a minimum between 96°

F. and 97°

F.

36. A body temperature detector system comprising:

a temperature detector; and

electronic circuitry which measures peak temperature from at least three readings per second during scan of the temperature detector across an artery and which processes the measured peak temperature to provide a temperature display based on a model of heat balance relative to a detected arterial temperature, the electronic circuitry computing 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 including a polynomial approximation of 1+h/pc=k₁T_s²−

k₂T_s+k₃ where h is 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.

37. A body temperature detection system comprising:

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

electronic circuitry which computes 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, the weighting including 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 0.19.