A method of generating an electric field in a target region of a patient includes inserting a set of electrodes having respective distal ends enclosed within a single elongate introducer shaft having a distal tip, into the vicinity of the target region； extending at least a pair of the electrodes to an extended position such that the electrode distal ends are deflected away from a longitudinal axis of the shaft in such a way that at least one planar projection taken in a plane perpendicular to the longitudinal axis of a distance between a pair of distal ends of the electrodes is larger than a maximal extent of a cross-section of the introducer shaft, the cross-section taken in a plane perpendicular to the a longitudinal axis at a distal end of the introducer shaft； and applying one or more electric pulses to the target tissue through the electrodes.
