title: Optimization of the intensity gain of multiple-focus phased-array heating patterns.
abstract: A new technique for enhancing the intensity gain at the focal points in multiple-focus patterns is introduced. The new technique is shown to be effective in reducing the interference typically associated with multiple-focus patterns. This reduction in interference patterns allows multiple-focus scanning to generate highly localized heating. Simulation results indicate that multiple-focus scanning not only provides an alternative to single-focus scanning, but also achieves better localization in the heating pattern. The maximization of intensity gain of multiple-focus heating patterns significantly reduces the pre-focal-depth high-temperature regions that can be caused by single-focus scanning. This is shown by computer simulation of a two-dimensional cylindrical-section array (CSA2D) as a heating applicator. Two series of simulations are presented in which different scan trajectories were used to therapeutically heat a small deep-seated target volume. In every case the heating pattern was generated using single-focus scanning and multiple-focus scanning (with and without intensity gain maximization). Multiple-focus scanning with gain maximization offers the best localization of heating to the target volume of the three methods.
authors.affiliation: Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor 48109-2122.
authors.forename: E S
authors.initials: ES
authors.lastname: Ebbini
authors.forename: C A
authors.initials: CA
authors.lastname: Cain
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D003198:Computer Simulation; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008962:Models, Theoretical; D009369:Neoplasms / Q000628:therapy