MICRODEVICE AND REGISTRATION APPARATUS

Disclosed in some embodiments are microdevices, medical devices and a registration apparatuses that allow for tracking of medical device(s) in an ultrasound image while maintaining the quality of the ultrasound image. The microdevice comprises a casing and a magneto mechanical resonator. The magneto mechanical resonator comprises at least two magnetic objects providing a permanent magnetic moment. The magneto mechanical resonator is adapted to transduce an external excitation field into a mechanical movement of the at least two magnetic objects relative to each other such that a changing magnetic response field is generated. A pressure sensor is arranged such that an external ultrasound signal induces an additional movement of the magnetic objects such that the changing magnetic response field is changed in dependency of the external ultrasound signal.