Thermal Therapy - RF/Microwave Interaction with Biological Tissues - page 193

TABLE 4.5 Classification of Infrared Ray Detectors

Quantum type Photoconductive type Intrinsic semiconductor: HgCdTe, InSb

(cooling) Extrinsic semiconductor: Si-Ga, Si-In

QWIP: GaAs/AlGaAs

Photoelectromotive p - n junction: HgCdTe, InSb

force type Photoelectric emission: PtSi, GeSi

Thermo type Pyroelectricity type BST (barium strontium titanate)

(uncooled) Thermopile type Poly-Si p - n junction

Bolometer type VO x

main parameters needed for NMR imaging are considered to be the thermal
equilibrium magnetization ( M 0 ) and the relaxation times ( T 1 , T 2 ). In 1980,
Lewa and Majewska found experimentally the temperature dependence of T 1
for animal and human tissue using an NMR spectrometer in vitro [42]. In 1981,
Kato et al. also measured the temperature dependence of NMR parameters
( T 1, T 2, M 0 ) for mouse tissue using an NMR spectrometer in vitro [43]. Further,
Kato et al. measured the temperature dependence of T 1 for copper sulfate
solution with NMR-CT and determined the temperature with accuracy better
than 0.5°C for a voxel of 1 cm [44]. In 1983, the temperature dependence of
T 1 for blood was measured by Parker et al. with NMR-CT. They found that it
was 1.4% per degree Celsius [45]. Based on this result, they could estimate the
temperature of a blood sample with accuracy of 2°C in a 5-min scan. In 1983,
Amemiya and Kamimura proved the possibility of real-time thermometry by
measuring thermal equilibrium magnetization M 0 with field focusing (FF)
NMR [46]. Recently, as a temperature-monitoring method using MRI, chem-
ical shift phenomena have been introduced to measure temperature, but the
accuracy has not yet reached a value good enough to warrant applying this
method to hyperthermia treatment.

REFERENCES

[1] “Biological effects of electromagnetic fields and measurement,” in Japanese IEE
Committee , organized by Y. Kotsuka, Corona Publishing, 1995, pp. 215-216.
[2] T. Matsuda, Hyperthermia , Iryou kagaku Sha 1999, pp. 4-9.
[3] “Advanced technology for radiation therapy and measurement,” in Japanese IEE
Committee , organized by Y. Kotsuka, Corona Publishing, 2001, pp. 133-146.
[4] M. Hiraoka, Y. Tanaka, K. Sugimachi, Y. Kotsuka, et al., “Development of RF and
microwave heating equipment and clinical application to cancer treatment in
Japan,” in A. Rosen, A. Vander Vorst, and Y. Kotsuka (Eds.), Special Issue on
Medical Applications and Biological Effect of RF/Microwaves, IEEE Trans.
Microwave Theory Tech ., Vol. 48, No. 48, pp. 1789-1799, Nov. 2000.