Retrieval of temperature-depth profiles in biological objects from multi-frequency microwave radiometric data

A method of retrieving a temperature-depth profile in biological object from a set of multi-frequency microwave radiometric data has been developed. The method is a combination of model-fitting and Monte Carlo techniques and is capable of estimating a profile and its confidence interval as a function of the depth. We use 2σ -intervals as a measure of the precision of tissue temperature measurements. The method was tested and supported by an experiment in which temperature distributions in a muscle equivalent agar phantom were measured using a 5-band, 1-3.8 GHz radiometer with the brightness temperature resolution of 0.05-0.07 K. A typical result of the experiment showed that 2σ -intervals were 1 K or less for 0 < z < 3 cm, 1.4 K at z = 4 cm, and 3 K at z = 5 cm. A numerical simulation study was made using this technique to assess effects of the selection of measurement frequencies, number of frequency bands, brightness temperature resolution of radiometer and thickness of fat layer on the precision. Resul...

[1]  T. V. Samulski,et al.  Thermometry in Therapeutic Hyperthermia , 1990 .

[2]  Alan H. Barrett,et al.  Detection of breast cancer by microwave radiometry , 1977 .

[3]  R. Dicke.  The measurement of thermal radiation at microwave frequencies. , 1946, The Review of scientific instruments.

[4]  Ahmed Mamouni,et al.  Microwave radiometric imaging at 3 GHz for the exploration of breast tumors , 1990 .

[5]  T. Sugiura,et al.  A Three-Band Microwave Radiometer System for Noninvasive Measurement of the Temperature at Various Depths , 1986, 1986 IEEE MTT-S International Microwave Symposium Digest.

[6]  A. Mamouni,et al.  Present Results and Trends in Microwave Thermography , 1983, 1983 IEEE MTT-S International Microwave Symposium Digest.

[7]  S D Prionas,et al.  Noninvasive thermometry using multiple-frequency-band radiometry: a feasibility study. , 1985, Bioelectromagnetics.

[8]  G Bruggmoser,et al.  The applicability of microwave thermography for deep-seated volumes. , 1986, Recent results in cancer research. Fortschritte der Krebsforschung. Progres dans les recherches sur le cancer.

[9]  A. W. Guy,et al.  Electromagnetic Fields and Relative Heating Patterns Due to a Rectangular Aperture Source in Direct Contact with Bilayered Biological Tissue , 1971 .

[10]  J. Shaeffer,et al.  Dual Mode Microwave System to Enhance Early Detection of Cancer , 1980 .

[11]  A. Guy,et al.  Nonionizing electromagnetic wave effects in biological materials and systems , 1972 .

[12]  Ph. Gelin,et al.  Computation of near-field microwave radiometric signals: definition and experimental verification , 1991 .

[13]  A. H. Barrett,et al.  Subcutaneous temperatures: a method of noninvasive sensing , 1975, Science.

[14]  Domenico Solimini,et al.  Singular system analysis of the inversion of microwave radiometric data: applications to biological temperature retrieval , 1987 .

[15]  P. C. Hardee,et al.  Thermography at millimeter wavelengths , 1974 .

[16]  Konstantina S. Nikita,et al.  Analysis of the power coupling from a waveguide hyperthermia applicator into a three-layered tissue model , 1989 .

[17]  Burkhard Schiek,et al.  Radiation balance microwave thermograph for industrial and medical applications , 1978 .

[18]  Domenico Solimini,et al.  Inversion of Microwave Thermographic Data by the Singular Function Method , 1985, 1985 IEEE MTT-S International Microwave Symposium Digest.

[19]  Shizuo Mizushina,et al.  A method of solution for a class of inverse problems involving measurement errors and its application to medical microwave radiometry , 1989, IEEE MTT-S International Microwave Symposium Digest.

[20]  J W Hand,et al.  Quality assurance guidelines for ESHO protocols. , 1989, International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group.

[21]  F. Sterzer,et al.  A Self-Balancing Microwave Radiometer for Non-Invasively Measuring the Temperature of Subcutaneous Tissues During Localized Hyperthermia Treatments of Cancer , 1982, 1982 IEEE MTT-S International Microwave Symposium Digest.

[22]  M. Hawley,et al.  Noninvasive Control of Hyperthermia , 1990 .

[23]  Y. Leroy,et al.  Combination of Local Heating and Radiometry by Microwaves , 1980, IEEE Transactions on Instrumentation and Measurement.