A device handle is disclosed for grinding substances inside a body lumen, the device handle comprising: a high-speed drive source configured to rotate a treatment member connected to a distal end of a drive shaft and a low-speed drive source connected to a revolution shaft, and wherein the revolution shaft is configured to cause the treatment member to move about a central axis of the revolution shaft, and wherein the central axis of a proximal portion of the revolution shaft is different from a central axis of the treatment member.
