Temperature Transducers

 

Measurement of skin temperature and body core temperatures are routinely used in patient care and management. Body (core) temperature is one the most tightly controlled variables in the human body: typically 37 degrees C, +/- 0.5 degrees C. Variation of body temperature from this setpoint is an indication of an abnormal condition caused by bacteria, virus, neurological disorders or other causes. Although there is no direct correlation of skin temperature to core temperature, it is useful in its own right for the diagnosis of different medical conditions including poor blood circulation, fractures, bruises and inflammations.

 

Temperature measurement instrumentation can be divided into contact and non-contact measurement systems:

 

1. Contact Measurement Systems

Most instrumentation systems involve contact measurement. Contact temperature measurement involves heat conduction from body tissue to the sensor. A portion of the body‚s thermal radiation is absorbed by the sensor and converted to a useful signal. This introduces a degree of unavoidable error as heat is being removed from the tissue to warm up the sensor. However, this error can be minimized through proper sensor design.

 

 2. Non-Contact Measurement Systems

Non-contact temperature measurement systems based on the principles of radiation thermometry have been developed quite recently for medical use. The technology for radiation thermometry has been widely used in the metallurgical industry previous to its application for medical purposes. Non-contact temperature measurement offers the advantages of no heat absorption from the body or tissue being monitored, and temperature measurement can be made from a distance.

 

For interest in the following areas, please click on the heading below:

Mechanical Thermometers

Electrical Resistance Thermometers

Thermocouple

Semiconductor Devices and Integrated Circuit Thermal Sensors

Radiation Thermometry

Liquid Crystal Thermometry

 

Return to the Introduction

Move back to Transducers and their Applications

Move forward to Mechanical Thermometers

 

Support for the development of this module was provided by the National Science Foundation and The Cooper Union for the Advancement of Science and Art.
 

Please send questions or comments to Professor Ron Adrezin or Professor Daniel Raichel.