PARENT SESSION
1:30 PM to 3:30 PM
Monday, April 22, 2002
Poster Session 3 Heating Devices and High Temperature Therapy
Room: Nevada 1-2

(MP03-32) Model predictive control of ultrasound hyperthermia treatments.

Arora, Dhiraj^*,1, Skliar, Mikhail², Roemer, Robert¹, ¹ Department of Mechanical Engineering, Salt Lake City, UT² Department of Chemical and Fuels Engineering, Salt Lake City, UT

ABSTRACT-
A MPC-based approach to control the thermal dose in short-time, pulsed ultrasound hyperthermia cancer treatments has been developed and evaluated. The work presented here is the first effort in a) the direct control of the treatment thermal dose (rather than the treatment temperatures) and b) the application of MPC to hyperthermia treatments. Simulations were performed using a one-point and a one-dimensional model of a tumor, to ascertain the robustness and sensitivity of this technique with different blood flow rates in the tumor and constraints on temperatures in normal tissues. The results demonstrate a) that thermal dose can be controlled in the presence of plant- model mismatch; b) constraints in terms of maximum allowable temperatures in normal tissue and pulsed power can be met while delivering the desired thermal dose to the tumor. The results show that for relatively high blood flow rates (10-15 kg/m3sec) in tissue and low transducer surface intensities (~ 8000 Watts/m2), the linearization of dose-temperature relationship works adequately and the results of linear MPC theory can be used. The control strategy presented in this study shows a promising potential for incorporation of model predictive control in accurately delivering thermal dose in both standard and HIFU hyperthermia treatments.

KEYWORDS: Hyperthermia, Thermal Dose, Model Predictive Control, Ultrasound