Imaging Thermograms at Centimeter and Millimeter Wavelengths*

Edrich, J.; Jobe, W. E.; Cacak, Robert K.; Hendee, William R.; Smyth, Charley J.; Gautherie, M; Gros, C; Zimmer, R.; Robert, Jean Louis; Thouvénot, Pierre; Escanyé, Jean Marie; Itty, C.

doi:10.1111/j.1749-6632.1980.tb50769.x

Cited by 27 publications

(16 citation statements)

References 9 publications

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“…During the past years, several research efforts have been reported, aiming primarily at the development of nontraumatic temperature measurement methods [4]- [6] in conjunction with hyperthermia [7] in order to raise the temperature inside tumors up to 42.5 C-43 C while keeping healthy tissues at less than 41 C. Efforts also have been made towards the implementation of noncontacting microwave radiometry in some of the proposed imaging systems [8], [9]. Theoretical analysis of the microwave radiometric measurement of the human body has been carried out in the past [10] based on the fundamental dissipation-fluctuation theorem [11] and Green's function theory.…”

Section: Introductionmentioning

confidence: 99%

Towards Functional Noninvasive Imaging of Excitable Tissues Inside the Human Body Using Focused Microwave Radiometry

Karanasiou

Uzunoglu

Papageorgiou

2004

IEEE Trans. Microwave Theory Techn.

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Focused microwave radiometry, aiming mainly in clinical applications at measuring temperature distributions inside the human body, may provide the capability of detecting electrical conductivity variations at microwave frequencies of excitable cell clusters, such as in the case of brain tissues. A novel microwave radiometric system, including an ellipsoidal conductive wall cavity, which provides the required beamforming and focusing, is developed for the imaging of biological tissues via contactless measurements. The measurement is realized by placing the human head in the region of the first focus and collecting the radiation converged at the second by an almost isotropic dipole antenna connected to a sensitive radiometer operating at 3.5 GHz. In order to compute the focusing properties of the ellipsoidal reflector, an accurate electromagnetic numerical analysis is developed using a semianalytical method. The experimental part of this study focuses on measurements of activation of the primary somatosensory (SI) brain area, elicited during the application of the cold pressor test, a standard experimental condition inducing pain. Analysis of the measured data from 16 healthy subjects suggests that this methodology may be able to pick up activation of the SI during the pain conditions as compared with the nonpainful control conditions. Future research is needed in order to elucidate all the interacting factors involved in the interpretation of the presented results. Finally, potential limitations to the generalization of our results and strategies to improve the system's response are discussed.Index Terms-Activation of primary somatosensory (SI) cortex, ellipsoidal conductive wall cavity, focused microwave radiometry, imaging of conductivity variations in biological tissues.

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Section: Introductionmentioning

confidence: 99%

Towards Functional Noninvasive Imaging of Excitable Tissues Inside the Human Body Using Focused Microwave Radiometry

Karanasiou

Uzunoglu

Papageorgiou

2004

IEEE Trans. Microwave Theory Techn.

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“…RadT maybe capable of measuring electromagnetic emission in human tissue at a depth of several centimeters but spatial resolution is compromised by the use of longer wavelengths needed to interrogate greater depth [24]. At a frequency of 4 GHz the spatial depth resolution is reported to be approximately 2 centimeters in phantom models [25]. Measurement of tissue temperature using RadT is a promising non-invasive technology that has been studied for almost three decades; however, the technology lacks clinical validation.…”

Section: Introductionmentioning

confidence: 99%

Non-invasive measurement of brain temperature using radiometric thermometry: Experimental validation and clinical observations in asphyxiated newborns

Bass

Lattanzio

Brayman

et al. 2014

Journal of Neonatal-Perinatal Medicine

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BACKGROUND: Therapeutic hypothermia (HT) has been shown to decrease death and severe disability in infants with hypoxicischemic encephalopathy (HIE). Rectal temperature (RT) is used to determine the temperature set-points for treatment with HT, however experimental studies have shown significant differences between RT and brain temperature during HT. Knowledge of actual brain temperature during HT might allow better determination of optimal degree of cooling and improve outcomes. OBJECTIVES: To compare measurements of brain temperature obtained by non-invasive radiometric thermometry (RadT) to direct tissue measurements in an experimental model of HT, and to use RadT in newborn infants with HIE undergoing HT. STUDY DESIGN: RadT measurements of brain temperature were compared to fiber optic (Luxtron) thermometry measurements placed at a depth of 1.5 centimeters into the brain of cooled miniswine. Following validation studies, brain RadT and RT measurements were continuously recorded in thirty infants with HIE during HT and rewarming. RESULTS: RadT and Luxtron probe temperatures were comparable in miniswine throughout a temperature range similar to therapeutic HT. RadT measurements of brain temperature were higher than RT in 60% of infants with HIE undergoing HT. Higher RadT measurements compared to RT were associated with cerebral white matter abnormalities (p = 0.01). CONCLUSIONS:RadT provides a safe, passive and non-invasive way to measure brain temperature that can be used in the clinical setting. RadT may be helpful in determining the optimal degree of cooling and identifying infants at highest risk of brain injury.

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“…Total power radiometric systems developed over the years for medical and other applications [7][8][9][10], are discussed in numerous papers. Non-contacting microwave radiometry has also been implemented for the imaging of hot/cold spots in biological tissues [3,11,12].…”

Section: Introductionmentioning

confidence: 99%