Non-invasive temperature monitoring during microwave heating applying a miniaturized radiometer

Jacobsen, Sven

doi:10.5772/21574

Cited by 3 publications

(2 citation statements)

References 35 publications

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“…They used an elliptical radiometric antenna and a rectangular dualconcentric‐conductor heating antenna . However, all these studies mainly used bistatic methods and separate antennas for radiometry and temperature measurement …”

Section: Introductionmentioning

confidence: 99%

Monostatic radiometry system for temperature measurement during RF hyperthermia treatment

Byambaakhuu

Nyamsuren

Park

et al. 2017

Microw. Opt. Technol. Lett.

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In this article, we propose a monostatic radiometry system for measuring the internal temperature of human tissue, while simultaneously performing radio frequency (RF) hyperthermia treatment. To demonstrate the adequacy of the proposed scheme, we present the results of experiments conducted on pork samples, which have a biological structure and electrical characteristics that are quite similar to those of the human body. We propose to use S‐band total power radiometry. The radiometry frequency was set at 3.85 GHz, with an operating bandwidth of 220 MHz, system gain of 66.95 dB, total system noise figure of 1.75 dB, and a sensitivity of 0.27 K. In order to prevent damage to the radiometry system, an RF switch and a low‐pass filter were added at the front‐end of the monostatic radiometry system to obtain sufficient isolation from the heating system. Using the skin, fat, and muscle tissue models, we performed both experiments and numerical simulations for a biological tissue model using a single dual‐band rectangular waveguide antenna operated at 5.725 GHz for microwave heating. In addition, we tested the proposed monostatic radiometry system in real‐time using pork samples, with an experimental setup capable of simultaneous microwave heating and radiometric temperature measurement. The system performance was verified by comparing the experimental radiometric results with the actual measured temperatures and simulation results.

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Section: Introductionmentioning

confidence: 99%

Monostatic radiometry system for temperature measurement during RF hyperthermia treatment

Byambaakhuu

Nyamsuren

Park

et al. 2017

Microw. Opt. Technol. Lett.

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show abstract

“…Microwave radiometry, a well-known technology used for the observation of universe, was introduced over 30 years ago [ 1 - 3 ] as a diagnostic non-invasive and completely passive imaging method of temperature distributions inside the human body. The technique has been used over the years in a variety of applications including breast imaging [ 4 - 6 ], brain imaging and brain temperature monitoring [ 7 - 11 ], detection of vulnerable plaque [ 12 ], long term monitoring of brown fat metabolism [ 11 ], detection of vesicoureteral reflux [ 13 ], radiometric signatures of anomalies [ 14 ], core body temperature measurement [ 15 , 16 ], in conjunction with microwave hyperthermia [ 17 - 19 ] as well as in multi-modal clinical setups [ 20 ]. Theoretical and experimental results obtained during the past decade imply that focused microwave radiometry is able to detect local concentrated gradual temperature and/ or conductivity changes reflected as an increase of the output radiometric voltage [ 7 ], [ 9 , 10 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Imaging of Conductivity Changes of Excitable Tissues Based on Focused Passive Microwave

Karanasiou

2015

TOBEJ

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Aims: Modeling of ionic distribution fluctuations of excitable tissues based on data elicited using focused microwave radiometry. Methodology: Focused Microwave Radiometry implemented to carry out measurements of in depth body temperature distributions, may provide the capability of sensing local electrical conductivity fluctuations during the cycle of actions potentials in the case of brain excitable cell clusters. An analog beamformer consisting of a conductive inner-surface ellipsoidal cavity is used to focus the chaotic-black body radiation emerging from human tissues by providing convergence of the electromagnetic energy from one focus area where the phantom or subject is placed, to the other where the antennas of sensitive radiometric receivers are positioned. During the past 10 years numerous phantom, animal and human volunteer experiments have been performed with the focused radiometry imaging system. The results show that the detected changes of the output radiometric voltage are attributed to temperature and/or conductivity changes that occur locally concentrated at the areas of interest under measurement. Theoretical and experimental studies are continuously carried out at various frequency bands in conjunction with the use of matching materials placed around the human head or phantom to improve focusing and detection depth. It seems that the manipulation of the focusing area in the tissue in terms of detection depth and spatial resolution is feasible depending on the suitable combination of operation frequencies and matching material. In this paper, theoretical analysis of ion charge diffusion during the cycle of action potentials, propagating along the axons in case of measurements of specific cortical regions is presented. The ion charge diffusion modeling is based on electromagnetic diffusion analogies in the effort to explain the observed experimental results obtained under various psychophysiological conditions in the case of human volunteer measurements. Results: By implementing an analysis based on the continuity equations of ionic charges it is concluded that the microwave radiometry output voltage is not affected by the temporal and spatial average fluctuations of Na+, K+, and Cl- ions of neural cell axons.Conclusion: The analysis of conductivity fluctuations in the central neural system in conjunction with the electromagnetic analysis of the system, leads to the interpretation of the previously acquired experimental data. The application of this technique with other brain functional mapping methods, may provide complementary knowledge to the understanding of the functional organization of psychophysiological processes.

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A broadband spiral applicator antenna for microwave radiothermometry

Leushin,

Agasieva,

Porokhov

et al. 2024

Biomed Eng

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Non-invasive temperature monitoring during microwave heating applying a miniaturized radiometer

Cited by 3 publications

References 35 publications

Monostatic radiometry system for temperature measurement during RF hyperthermia treatment

Monostatic radiometry system for temperature measurement during RF hyperthermia treatment

Imaging of Conductivity Changes of Excitable Tissues Based on Focused Passive Microwave

A broadband spiral applicator antenna for microwave radiothermometry

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