Understanding Electric Fields for Clinical Use

Abstract

For physicians or researchers from the biological sciences, it is usually not necessary to deal with the in-depth scientific theory of the electric field in order to handle procedures involving electrotransfer. On the other hand, it is very often of utmost importance to know the basic concept, from a pragmatic point of view, to understand simple electric field distributions. In this chapter, we initially address the basic physics and definitions of electrostatics in order to prepare the reader for the practical topics that follow. The electric field strength and the electric vector field are explained in connection with tissue characteristics, especially heterogeneity and anisotropy. The role of the pulse generator and the electrode geometry is addressed in relation to electric field distributions and electric field strength. The reader is provided with electric field visualization methods, which are important for both comprehension and interpretation of otherwise complicated data. Finally, critical steps for ensuring the intended delivery of the appropriate electric field for treatment procedures are proposed. It is stressed that numerical derivation of the electric field is the only reasonable way of handling individual nonstandardized electrotransfer procedures.