Patent ID: 8281663

Claim:
A driver for producing an oscillatory stress in a subject undergoing an imaging examination comprising: a passive driver having an enclosure defining an enclosed space when positioned on the subject; a tube having a first end coupled to the passive driver and extending from the first end to a second end and enclosing an elongated space in communication with the enclosed space defined by the passive driver; an active driver coupled to the second end of the tube and having a housing defining a chamber in communication with the elongated space in the tube, the active driver including: a linear actuator having an armature that reciprocates in response to an alternating current applied to an actuator coil, a diaphragm mounted for reciprocating motion within the chamber, and a drive rod connecting the armature to the diaphragm to cause the diaphragm to produce pressure waves directed through the tube to the passive driver when the diaphragm is stroked.