Comparison of Attenuation Coefficient Estimation in High Intensity Focused Ultrasound Therapy for Cancer Treatment by Levenberg Marquardt and Gauss-Newton Methods

Abstract

Hyperthermia using High-Intensity Focused Ultrasound (HIFU) is an acoustic therapy used in clinical applications to destroy malignant tumors of bone, breast, brain, kidney, pancreas, prostate, rectum and testicle. This technique consists in increase the temperature in the tumor or the specific area, to achieve coagulative necrosis and immediate cell death. Although hyperthermia can cure cancer, it can also cause side effects and even damage healthy cells or tissues. Therefore, for having a successful treatment, it is important to monitor and observe what is the tissue behavior, as well as its changes, before, during and after the procedure. Mathematical models are tools that can be useful to simulate an adequate therapy by differentiating characteristics that will depend on each individual. An attenuation coefficient estimation for a forward model with a rectangular two-dimensional domain is presented, the estimation was made with simulated numerical data and simulated experimental data by Levenberg Marquardt and Gauss-Newton Methods. The results demonstrate that by identifying the attenuation coefficient of each patient. By estimating the attenuation coefficient parameter it is possible to predict the thermal responses of the tissue to be treated and, based on them, to plan an adequate cancer treatment by inducing heat by HIFU.