A device (16) positions an ultrasound transducer (14) for ultrasound therapy to focus a treatment beam (12) emitted by the ultrasound transducer (14) at tissue of interest. The device (16) includes at least three anchors (20) which support the ultrasound transducer (14). The device (16) further includes at least three extendable structures (24), each with a coupling (22) that supports a corresponding one of the at least three anchors (20). A drive mechanism (100) of the device (16) independently drives each of the at least three extendable structures (24) towards or away from a subject to move the ultrasound transducer (14) within at least three degrees of freedom.