Thermal Therapy - RF/Microwave Interaction with Biological Tissues - page 191

TABLE 4.3 Specifications of Core/Clad Diameter: Sensor

Fiber Fiber length 2, 4, 6, 10, and 30 m

Core/clad diameter 305 and 362 mm

Fiber covering Diameter 0.80 ± 0.05 mm, material PFA

Protection tube Diameter 2.8 ± 0.2 mm, material PVC

Tip Length 1 m (sensor 8 mm)

Sensor covering Diameter 0.80 ± 0.05 mm, material PFA

Sensor material YF 3 (Doped material, Yb, Er)

TABLE 4.4 Specifications of Thermometer: Main Body

Thermometry range 30-80°C

Accuracy ± 0.2°C

Measurring time Switching of 1 or 2 s

Display Four-degit LED display

Output form Digital/analog output, intermittent control output

Temperature calibration Automatic calibration function

Power souce 100 V AC (50/60 Hz)

External form One channel, 325 ( W ) ¥ 280 ( D ) ¥ 125 ( H )

Four channels, 430 ( W ) ¥ 450 ( D ) ¥ 150 ( H )

It is possible to have a length of optical fiber from 2 to 30 m. Usually, the
multicomponent system optical fiber is used. Part of the probe is coated by
Teflon. The range of measuring temperature is extended from 30 to 80°C. This
thermometer may have multiple channels in order to enable the simultaneous
multiple-point measurement. The specification for this thermometer is given
in Table 4.4.

4.4.2 Noninvasive Thermometry

Thermometer Using IR Photodetector Noninvasive thermometry using IR
photodetectors has been put into practice, as illustrated in Figure 4.40. Such a
thermometer can measure only the surface temperature of an object by detect-
ing IR energy that is radiated by the object. The IR ray is an EM wave. Usually,
EM waves with wavelengths larger than 0.7 mm and smaller than 1 mm are
defined as IR rays. The IR range is specific regarding the corresponding fields:
Infrared irradiation is principally based on the vibration of the atom that con-
stitutes the molecule, that is, molecular vibration. Another specificity is lattice
vibration, which depends on the molecular structure. Generally, since the IR
ray image pickup is often used outdoors, one has to use a wavelength at which
the transparency of the atmosphere is excellent. Frequency bands where the