Radiation detector for differential biological temperature readings

• US 5,017,019 A
• Filed: 04/14/1989
• Issued: 05/21/1991
• Est. Priority Date: 04/14/1989
• Status: Expired due to Term

• Current Assignee: PNC Bank National Association (The PNC Financial Services Group, Inc.)
• Original Assignee: Exergen Corporation
• Inventors: Pompei, Francesco
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): GUTIERREZ, DIEGO F
• Application Number:
  US07/339,073
• Time in Patent Office: 767 Days
• Field of Search: 374/121, 374/124, 374/129, 374/130, 374/133, 374/128, 128/664, 128/736, 364/582
• US Class Current: 374/133
• CPC Class Codes: G01J 5/16 Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables

Abstract

A radiation detector provides differential temperature readings of surface tissue. The differential readings are normalized to room temperature ambient. Green and yellow LEDs indicate a normalized temperature of less than 2° C. and red LEDs indicate a normalized temperature differential of greater than 2° C.

Claims

1. A radiation detector comprising:

thermopile means mounted to view target surfaces for sensing the heat flux from said target surfaces and to determine the temperature of said target surfaces;

a temperature sensor for sensing ambient temperature;

an electronic circuit coupled to the thermopile means and temperature sensor and responsive to the voltage across the thermopile means and the temperature sensed by the sensor to provide a difference between temperatures of target surfaces viewed by the thermopile means, the difference being adjusted to provide a normalized temperature differential compensated for difference in surface temperature which results from a deviation of actual ambient temperature to which the surface is exposed from a predetermined ambient temperature; and

a display for providing an indication of the normalized temperature differential.

2. A radiation detector as claimed in claim 1 wherein the electronics compensates for the difference between the actual ambient temperature and predetermined ambient temperature by a factor of about minus seven percent per degree centigrade.

3. A radiation detector as claimed in claim 2 wherein the predetermined ambient temperature is about 20°

C.

4. A radiation detector as claimed in claim 1 which further compensates for the temperature coefficient of the thermopile means with changes in ambient temperature.

5. A radiation detector as claimed in claim 1 wherein the display includes a principal change in indication at about 2°

C. normalized to about 20°

C.

6. A radiation detector as claimed in claim 5 wherein the display further includes a principal change in indication at about 3°

C. normalized to 20°

C.

7. A radiation detector as claimed in claim 5 wherein the display provides changes in indications at 2°

, 3° and

4°

C. normalized to about 20°

C.

8. A radiation detector as claimed in claim 5 wherein the display comprises a green indication for normalized differential temperatures between zero and 2°

C., a yellow indication for normalized temperature differentials between 2°

C. and 3°

C., and a red indication for normalized temperature differentials above 3°

C.

9. A method of providing a differential thermal reading representing the difference in temperatures of surface areas of an animal comprising:

sensing heat flux from first and second surface areas of the animal to determine the temperature of said first and second surfaces areas;

sensing ambient temperature;

providing a normalized temperature differential representing the difference in temperatures of the first and second surface areas compensated for difference in surface temperature which results from a deviation of actual ambient temperature to which the surface is exposed from a predetermined ambient temperature; and

providing a display of the normalized temperature differential.

10. A method as claimed in claim 9 wherein the compensation is by a factor of about -7%/°

C.

11. A method as claimed in claim 10 wherein the predetermined temperature is about 20°

C.

12. A method as claimed in claim 9 wherein the heat flux is sensed by a thermopile, and further comprising the step of compensating for the temperature coefficient of the thermopile with changes in ambient temperature.

13. A method as claimed in claim 9 including providing a principal change in the display at about 2°

C. normalized to 20°

C.

14. A method as claimed in claim 13 further comprising providing a principal change in the display at about 3°

C. normalized to 20°

C.

15. A method as claimed in claim 13 further comprising providing principal changes in the display at 2°

C., 3°

C. and 4°

C. normalized to about 20°

C.

16. A method as claimed in claim 13 comprising displaying a green indication for normalized differential temperatures between zero degree and 2°

C., a yellow indication for normalized temperature differentials between 2°

C. and 3°

C., and a red indication for normalized temperature differentials above 3°

C.

17. A method as claimed in claim 9 wherein the animal is a horse.

18. A method of providing a differential thermal reading representing the difference in temperatures of surface areas comprising:

sensing heat flux from first and second surface areas to determine the temperature of said first and second surfaces areas;

sensing ambient temperature;

providing a normalized temperature differential representing the difference in temperatures of the first and second surface areas compensated for difference in surface temperature which results from a deviation of actual ambient temperature to which the surface is exposed from a predetermined ambient temperature; and

providing a display of the normalized temperature differential.