Abstract
High-intensity focused ultrasound (HIFU) is a non-invasive therapeutic technique that relies on the precise delivery of acoustic energy to ablate diseased tissue. The presence of subcutaneous fat can significantly alter focal accuracy and treatment efficiency due to its distinct thermal and acoustic behavior. This study characterized the temperature-dependent thermal conductivity, thermal diffusivity, specific heat capacity, acoustic attenuation, and acoustic velocity of human subcutaneous fat to improve pretreatment modeling for HIFU therapies. Measurements were performed using a dual needle probe for thermal conductivity and diffusivity, differential scanning calorimetry for specific heat capacity, radiation force balance for attenuation, and through-transmission methods for velocity. Results showed that thermal conductivity and diffusivity exhibited only modest decreases with temperature, while specific heat capacity increased steadily across the tested range. In contrast, acoustic properties demonstrated stronger temperature dependence: attenuation rose nonlinearly with both frequency and temperature, and velocity decreased with heating at lower frequencies. These findings align with trends reported in the literature but extend prior work by providing explicit temperature-dependent functions across multiple frequencies. The results indicate acoustic properties change more than the thermal properties do with temperature increase. Incorporating these temperature-dependent functions into pretreatment simulations could improve the accuracy of predicted heating patterns, reduce the risk of unintended near-field damage, and enhance the safety margin of HIFU procedures. This work provides a foundation for more robust, patient-specific treatment planning in HIFU therapy and other clinical applications where ultrasound must propagate through fat.
Degree
MS
College and Department
Ira A. Fulton College of Engineering; Mechanical Engineering
Rights
https://lib.byu.edu/about/copyright/
BYU ScholarsArchive Citation
Easthope, Brian, "Characterizing Temperature-Dependent Properties of Fat for Improving High Intensity Focused Ultrasound Simulations" (2025). Theses and Dissertations. 11100.
https://scholarsarchive.byu.edu/etd/11100
Date Submitted
2025-12-15
Document Type
Thesis
Keywords
high-intensity focused ultrasound, subcutaneous fat, acoustic attenuation, acoustic velocity, thermal conductivity, thermal diffusivity, specific heat capacity, temperature dependence
Language
english