ABSTRACT
This chapter explains electromagnetic (EM) heating mechanisms. It discusses the relationship between EM power deposition and tissue temperature rise. The action of EM fields on tissues produces two types of effects: the oscillation of free charged particles, and the rotation of polar molecules at the frequency of the applied field. When an EM field impinges on the human body, some energy is reflected at the body surface and some penetrates into the body. During hyperthermia treatments, tumor temperature and the accumulated thermal dose distribution are dependent on EM energy deposition pattern and heat redistribution from conduction and convection. The goal of thermal ablation is to directly kill (ablate) tumor volumes in carefully targeted regions that do not include critical normal tissues like skin, nerves, or major blood vessels. Outside the world of cancer therapy, there are numerous clinical applications for EM heating with radiofrequency and microwave sources, using either moderate temperature hyperthermia or high-temperature thermal ablation techniques.
