Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism

Dario B. Rodrigues, Paolo F. Maccarini, Sara Salahi, Erin Colebeck, Erdem Topsakal, Pedro J. S. Pereira, Paulo Limão-Vieira, Paul R. Stauffer

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Citations (Scopus)

Abstract

Background: Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. Methods: A multilayer 3D computational model was created in HFSS™ with 1.5 mm skin, 3-10 mm subcutaneous fat, 200 mm muscle and a BAT region (2-6 cm3) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSS™ were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. Results: The optimized frequency band was 1.5-2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2-9 mdBm (noradrenergic stimulus) and 4-15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Conclusions: Results demonstrated the ability to detect thermal radiation from small volumes (2-6 cm3) of BAT located up to 12 mm deep and to monitor small changes (0.5°C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism.

Original languageEnglish
Title of host publicationEnergy-Based Treatment of Tissue and Assessment VII
EditorsT. P. Ryan
PublisherSPIE-International Society for Optical Engineering
ISBN (Print)9780819493538
DOIs
Publication statusPublished - 10 Jun 2013
Event2013 SPIE Conference: Energy-Based Treatment of Tissue and Assessment VII - San Francisco, CA, United States
Duration: 3 Feb 20134 Feb 2013

Publication series

NameProceedings of SPIE
PublisherSPIE-International Society for Optical Engineering
Volume8584
ISSN (Print)0277-786X

Conference

Conference2013 SPIE Conference: Energy-Based Treatment of Tissue and Assessment VII
CountryUnited States
CitySan Francisco, CA
Period3/02/134/02/13

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Keywords

  • 3D multiphysics modeling
  • Brown fat metabolism
  • log spiral antenna
  • microwave radiometry
  • noninvasive monitoring

Cite this

Rodrigues, D. B., Maccarini, P. F., Salahi, S., Colebeck, E., Topsakal, E., Pereira, P. J. S., ... Stauffer, P. R. (2013). Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism. In T. P. Ryan (Ed.), Energy-Based Treatment of Tissue and Assessment VII [85840S] (Proceedings of SPIE; Vol. 8584). SPIE-International Society for Optical Engineering. https://doi.org/10.1117/12.2004931