Thermal measuring and testing – Temperature measurement – In spaced noncontact relationship to specimen
Reexamination Certificate
2003-03-18
2004-08-10
Verbitsky, Gail (Department: 2859)
Thermal measuring and testing
Temperature measurement
In spaced noncontact relationship to specimen
C374S101000, C374S043000, C374S044000, C374S045000, C600S549000, C600S407000
Reexamination Certificate
active
06773159
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for measuring a temperature of a living body. More particularly, the present invention relates to a non-invasive apparatus for measuring an internal temperature of a living body by measuring the electromagnetic wave characteristics of a medium, and a method therefor.
2. Description of the Related Art
In order to detect and treat an abnormal state of a human body, a non-invasive apparatus and a method for measuring a temperature of a living body by measuring microwaves emitted from the living body have been developed. When the temperature of a medium is greater than absolute zero, electromagnetic waves are emitted according to a principle of black body radiation. If the medium is a living body, electromagnetic wave signals are emitted from the inside of the living body to the outside of the skin of the living body. The temperature of abnormal tissues, which is higher than the temperature of normal tissues, can be detected by measuring the electromagnetic waves emitted from a predetermined portion of the living body and converting the measured electromagnetic waves into a temperature, so that an abnormal state of the living body may be detected at an early stage.
FIG. 1
is a functional diagram of a conventional apparatus employing a microwave radiometer to measure the temperature of a specimen according to the prior art.
Referring to
FIG. 1
, a specimen
100
emits electromagnetic radiation
102
having a certain intensity and frequency-spectrum distribution, each of which is a function of the temperature of the specimen
100
and the characteristics of the material the specimen
100
is composed of. The frequency-spectrum distribution includes a portion of a microwave interval to which a microwave antenna unit
104
is responsive. The temperature of the specimen
100
is sensed by the microwave antenna unit
104
, which is positioned in a cooperative spatial relationship with the specimen
100
to receive part of electromagnetic radiation
102
, which is within this microwave interval.
A microwave radiometer
105
, including a microwave receiver
106
, a reference microwave noise source
108
, and a temperature meter
110
, compares the relative intensity of the microwave noise output from the microwave antenna unit
104
with respect to the intensity of the output from the reference microwave noise source
108
. The temperature of the specimen
100
is indicated by the temperature meter
110
in response to the output from the microwave receiver
106
applied as an input thereto.
The conventional apparatus for measuring a temperature of a living body stores a temperature conversion table, established from a temperature conversion graph, with respect to a specific medium as shown in FIG.
2
. The conventional apparatus determines temperatures according to the measured emitted intensities.
Referring to
FIG. 2
, the emitted intensity and the temperature are in a linearly proportional relationship. In other words, as the emitted intensity increases, the detected temperature increases linearly. Thus, a specific temperature corresponding to a specific emitted intensity can be selected. However, the graph of
FIG. 2
may be applied only to a predetermined portion of a living body having a specific permittivity or conductivity. If the permittivity or the conductivity is changed within the living body, it is preferable to use an alternate graph.
As shown in
FIG. 3
, radiation power, i.e., received electric power, emitted at the same temperature may vary when the permittivity or the conductivity is different so that errors occur in the conversion process of a measured emitted intensity into a temperature by using a single temperature conversion table.
For example, if a received electric power measured at a predetermined portion of a living body having a permittivity of 49.8 is 4×10
−16
W, a converted temperature according to the graph f
1
is 46.5° C. However, a converted temperature for the same electric power according to the graph f
2
, which represents a predetermined portion of a living body having a permittivity of 9.8, is 38° C., so that a difference of 8.5° C. occurs.
For example, in a case where the temperature of breasts that have large deviations of the permittivity and the conductivity from 9.8 to 51.3 S/m and 0.37 to 3.4 S/m, respectively, is measured, the deviation of emitted intensity due to the differences of the permittivity and the conductivity cannot be corrected using a single temperature conversion table. Accordingly, a large deviation occurs in the converted temperature. As a result, abnormal tissues may be determined as normal tissues thereby preventing the detection of an abnormal state in a living body.
SUMMARY OF THE INVENTION
In an effort to solve the above and related problems, it is a feature of an embodiment of the present invention to provide an apparatus and a method for measuring an internal temperature of a living body with improved reliability.
To provide this feature of an embodiment of the present invention, an apparatus for measuring a temperature of a portion of a living body includes a signal receiving unit for receiving electromagnetic wave signals emitted from the portion of a living body to be measured, a signal processing unit for processing the electromagnetic signals input from the signal receiving unit and outputting a radiation power signal, a medium characteristic measurement unit for measuring a value of a conductivity or a permittivity of the portion of the living body to be measured and for outputting the measured value, and a temperature conversion unit, including a computer database for storing a plurality of temperature conversion tables with respect to radiation power according to the conductivity or the permittivity of the portion of the living body, for determining a corresponding temperature using the measured value of the conductivity or the permittivity of the portion of the living body and the radiation power signal of the signal processing unit.
The signal receiving unit preferably includes a receiver for receiving the electromagnetic signals and a transmission line for sending the electromagnetic wave signals from the receiver to the signal processing unit. It is also preferable that the receiver is an antenna or a probe.
The signal processing unit preferably includes an amplifier for amplifying the electromagnetic wave signals input from the signal receiving unit, a filter for extracting a signal value of a predetermined frequency band from the electromagnetic wave signals, a noise source for maintaining a reference signal of a specific temperature, a switch for switching the extracted signal and the reference signal within a specific interval and for connecting to a next stage, an isolator for processing the extracted signal in one direction and matching circuits, and a detector for detecting an enveloped curve of the extracted signal.
The temperature conversion unit preferably includes an information storage unit having a computer database for storing the plurality of temperature conversion tables with respect to radiation power, and an information processing unit for selecting a proper temperature conversion table corresponding to the conductivity or the permittivity measured by the information storage unit and for determining the temperature corresponding to the radiation power signal of the electromagnetic wave input from the signal processing unit, from the temperature conversion tables.
The medium characteristic measurement unit preferably includes a signal generator for generating an electromagnetic wave signal of a specific frequency band, a transmitter for sending the electromagnetic wave signal to the portion of the living body, a receiver for receiving the electromagnetic wave signal passed through the portion of the living body to be measured, a signal processor for receiving the electromagnetic wave signal from the receiver and processing the received signal, and a controller for
Eom Sang-jin
Han Wan-taek
Kim Tae-woo
Lee Jeong-whan
Lee Sang-min
Lee & Sterba, P.C.
Verbitsky Gail
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