As compared to conventional electrodes, the electrode configurations disclosed herein minimize irritation and damage to the skin when they are placed in contact with a patients body over extended of time. The electrodes are formed from a conductive substrate coated with a thin dielectric material, and a plurality of open spaces pass through the electrodes. Those open spaces are distributed and sized to permit moisture on the surface of the patients body to escape when the electrode is placed in contact with the patients body. One intended use for the electrodes is for treating tumors by applying an AC electric field with specific frequency and field strength characteristics over an extended period of time.
