MRI compatible motor and positioning system

A thermal therapy system is provided. The system includes an applicator and a device for supporting and moving the applicator within a patient's body during therapy. Some embodiments include an elongated ultrasound energy applicator that is positioned using a plurality of positioners along a corresponding plurality of axes. Also, a rotational driver or motor is provided to rotate the thermal therapy applicator in the patient's body during treatment. The apparatus is constructed of magnetically-compatible materials and has a design to avoid or minimize interference between the drive components of the apparatus and a MRI imaging system in use during the treatment.