Interrelationship between control parameters and tumor/bone conditions for external ultrasound hyperthermia
Journal
Biomedical Engineering - Applications, Basis and Communications
Journal Volume
13
Journal Issue
4
Pages
199-212
Date Issued
2001
Author(s)
Abstract
The purpose of this paper is to examine the relationship between the control parameters and the tumor/bone conditions, and also to determine the domain determined by the treatable tumor size and tumor depth for an external ultrasound hyperthermia. This work employs computer simulation programs based on a simplified model of a scanned ultrasound transducer power deposition, the steady-state bio-heat transfer equation, and a search algorithm. The low bounds of SR (specific absorption rate ratio) and f · SR (f: ultrasound frequency) are determined based on the temperature distributions for large ranges of blood perfusion and ultrasound frequencies. These low bounds of SR and f · SR are then used to investigate the relationship between the control parameters and the tumor/bone conditions and to determine the treatable domain. The control parameters considered are the acoustic window size, ultrasound frequency; and the tumor/bone conditions are tumor size, tumor depth, and the depth of post-target bone. Simulation results demonstrate that a) the low bounds of SR and f · SR are functions of blood perfusion; b) the ultrasound frequency to obtain the largest treatable tumor size depends on the tumor depth and the depth of post-target bone, however it is independent of the acoustic window size; and c) the treatable domain is proportional to the acoustic window size and the depth of post-target bone, and a proper frequency can result in a larger treatable domain. The results of this study can be a guideline for designing an optimal ultrasound heating system, arranging the transducers, and implementing further treatment planning for the external ultrasound hyperthermia.
Other Subjects
Acoustics; Algorithms; Bone; Computer simulation; Hyperthermia therapy; Tumors; Ultrasonics; Bio heat transfer eqaution; Biomedical engineering; acoustics; article; computer simulation; control system; echography; heat transfer; hyperthermia; perfusion; ultrasound transducer
Type
journal article