Measurement and Analysis of Tissue Temperature During Microwave Liver Ablation

We measured tissue temperature changes during ex vivo microwave ablation (MWA) procedures for bovine liver tissue. Tissue temperature increased rapidly at the beginning of the MW power application. It came to a plateau at 100 degC to 104 degC before it increased again. We split the changes of tissue temperature versus time into four phases. This suggests that tissue temperature changes may be directly related to tissue water related phenomena during MWA, including evaporation, diffusion, condensation and tissue water composition. An additional analysis indicated the lesion boundary at ~50 degC to 60 degC temperature. We also measured the water content of ablated tissue lesions and examined the relationship of tissue water content and tissue temperature by mapping temperature to remaining tissue water after ablation. The results demonstrate significant tissue water content changes and lead to a better understanding of tissue water movement

[1]  Leonid Bobe,et al.  Vapor Phase Heat and Mass Transfer: Condensing Vapor Mixtures and Evaporating Liquids , 1999 .

[2]  K. Foster,et al.  Dielectric properties of tissues and biological materials: a critical review. , 1989, Critical reviews in biomedical engineering.

[3]  R. W. Lau,et al.  The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissues. , 1996, Physics in medicine and biology.

[4]  John G. Webster,et al.  Expanding the Bioheat Equation to Include Tissue Internal Water Evaporation During Heating , 2007, IEEE Transactions on Biomedical Engineering.

[5]  John G. Webster,et al.  A floating sleeve antenna yields localized hepatic microwave ablation , 2006, IEEE Transactions on Biomedical Engineering.

[6]  C Brú.  [Percutaneous treatment of hepatocellular carcinoma]. , 1996, Revista de gastroenterologia de Mexico.

[7]  R. Parks,et al.  Interstitial ablative techniques for hepatic tumours , 2003, The British journal of surgery.

[8]  W R Lees,et al.  Minimally invasive treatment of malignant hepatic tumors: at the threshold of a major breakthrough. , 2000, Radiographics : a review publication of the Radiological Society of North America, Inc.

[9]  F Piscaglia,et al.  Review article: percutaneous treatment of hepatocellular carcinoma. , 2003, Alimentary pharmacology & therapeutics.

[10]  K. Sreenivasan,et al.  Water vaporization from heated tissue: An in vitro study by differential scanning calorimetry , 1996, Lasers in surgery and medicine.

[11]  Hans Janestad,et al.  A model for simultaneous heat, water and vapour diffusion , 1999 .

[12]  Koulis Pericleous,et al.  Heat and mass transfer in two-phase porous materials under intensive microwave heating , 2004 .

[13]  J. Gore,et al.  Theoretical Model for Water Diffusion in Tissues , 1995, Magnetic resonance in medicine.

[14]  Dieter Haemmerich,et al.  In vitro measurements of temperature-dependent specific heat of liver tissue. , 2006, Medical engineering & physics.

[15]  Ryosuke Nakayama,et al.  Possible pulmonary gas embolism associated with localized thermal therapy of the liver. , 2003, Anesthesiology.

[16]  B. Wilson,et al.  Hepatic interstitial laser photocoagulation: demonstration and possible clinical importance of intravascular gas. , 1994, Radiology.

[17]  F. Duck.  Physical properties of tissue , 1990 .

[18]  S. R. Smith,et al.  Dielectric properties of low-water-content tissues , 1985 .