A needle electrode deployment shaft comprising a central member having a proximal end, a distal end, a longitudinal axis therebetween, an outer surface, and a plurality of needle electrode advancement channels. Each channel has an axially aligned proximal portion and an outwardly directed distal ramp portion wherein the proximal portion is straight and parallel to the longitudinal axis and wherein the ramp portion follows an arcuate path and each ramp when viewed axially has (1) a ramp entrance located at a first angular orientation relative to the longitudinal axis of the needle deployment shaft and at a preselected radial distance between the longitudinal axis of the central member and the ramp entrance and (2) a ramp exit located at a second angular orientation angularly offset from the first angular orientation and on an outer surface of the central member, wherein said arcuate path increases a transverse component of the path relative to that of a path not having an offset ramp entrance and exit； and a plurality of needle electrodes having tissue penetrating tips slidably received in said channels.針電極配備シャフトは、中心部材と、複数の針電極とを含む。中心部材は、その中に形成された複数の針前進チャネルを有する。針電極は、前進チャネル内に配置され、各前進チャネルは、針が軸方向に前進させられるにつれて、針を半径方向外向きに偏向させる傾斜部分で終端する。斜面は、針が軸方向に前進させられるにつれて、それを通して針が屈曲されてもよい距離を増加させるために、らせん状または鋭角に構成されてもよい。加えて、中心部材は、組織挿入力を減少させるために、半径方向に縮小した遠位先端を有してもよい。
