Theoretical study of temperature elevation at muscle/bone interface during ultrasound hyperthermia
Journal
Medical Physics
Journal Volume
27
Journal Issue
5
Pages
1131-1140
Date Issued
2000
Author(s)
Abstract
This paper examines the distributions of the SAR (specific absorption rate) ratio and temperature elevation when an ultrasound beam propagates through the interface of muscle and bone. This interface is regarded as a flat boundary to partition the energy of the ultrasound beam, and the analytical solution of temperature distribution is based on the steady-state bio-heat transfer equation. The parameters considered are the incident angle of ultrasound beam, the ultrasound frequency, the acoustic attenuation coefficients of refracted longitudinal and shear waves in bone, and the blood perfusion in muscle. The results show that the peak of the SAR ratio is always at the interface of muscle and bone, while the peak of temperature is located in the bone region beyond the interface. A muscle with lower perfusion or a bone with higher acoustic attenuation results in the shifting of the temperature peak closer to the interface. It is more difficult to heat a higher perfused muscle in front of a bone using a lower frequency ultrasound since the temperature elevation for bone relative to muscle is greater. (C) 2000 American Association of Physicists in Medicine.
Subjects
Absorbed power deposition; Muscle/bone interface; Temperature elevation; Ultrasound hyperthermia
Other Subjects
Heat transfer; Muscle; Shear flow; Shear waves; Thermoacoustics; Ultrasonics; Absorbed power; Acoustic attenuation; Bioheat transfer equations; Specific absorption rate; Temperature elevation; Temperature peaks; Theoretical study; Ultrasound frequency; Interface states; acoustics; animal experiment; article; beam therapy; heat transfer; hyperthermic therapy; mathematical analysis; muscle; nonhuman; priority journal; steady state; swine; temperature; ultrasound therapy
Type
journal article