Application of Adaptive Nulling to Electromagnetic Hyperthermia for Improved Thermal Dose Distribution in Cancer Therapy
Abstract
Adaptive nulling is applied to the problem of generating a therapeutic thermal dose distribution in electromagnetic hyperthermia treatment of cancer. A system design concept for implementing adaptive hyperthermia is introduced. With the proposed design concept, it may be possible to maximize the applied electric field at a tumor position in th target body and simultaneously minimize or reduce the electric field at target positions where undesired high temperature regions (hot spots) occur. In a clinical situation, either a gradient search algorithm or sample matrix inversion algorithm would be used to rapidly form the adaptive null (or nulls) prior to any significant tissue heating. Analysis of an annular phased array antenna embedded in an infinite homogeneous medium shows the potential merit of combining adaptive nulling with conventional near-field focusing used in hyperthermia. The analysis is based on a well-known moment-method theory for conducting thin wire antennas in a homogeneous conducting medium. The theory and software used to compute the moment-method received voltage at a short-dipole probe due to a transmitting dipole array are documented. Computer simulations show that adaptive nulling can prevent undesired high-temperature regions from occurring while simultaneously heating a deep-seated tumor site.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 03, 1991
- Accession Number
- ADA241026
Entities
People
- Alan J. Fenn
Organizations
- Massachusetts Institute of Technology