Apparatus and method for treating multiple tumors in patients with metastatic disease by electric fields

A method of using an electrode array to deliver tumor treating electric fields to a patient, comprising the steps of:

• placing a plurality of electrode elements in optimized locations on the patient, each of the electrode elements being independently programmable, the optimized locations are selected relative to a target area wherein at least one tumor is located, the plurality of electrode elements including at least one master electrode element and a plurality of slave electrode elements;
• programming a control device with a frequency range, a firing configuration and a firing sequence for the plurality of electrode elements;
• generating electrical signals in the frequency range, the electrical signals being directed to at least two of the plurality of electrode elements in a sequence determined by the firing sequence;
• controlling the firing configuration of the slave electrode elements that are coupled to the at least one master electrode element by the at least one master electrode element directing the electrical signals from a field generator to selected ones of the slave electrode elements;
• and
• the master electrode element directing at least one of the slave electrode elements to fire active or be a return, the master electrode element having a microprocessor and at least one light emitting diode placed thereon, but the slave electrode elements not having a microprocessor nor a light emitting diode thereon.