A removable device for axial force and orientation measurement on medical ultrasound probe

Ultrasound imaging is becoming a part of emergency medical or surgical decision making. There is a greater need for this technique to be accessible in the areas lacking ultrasound specialists. Tele-echography and robot-based echography could be a solution to provide ultrasound imaging to these locations. In this case, the force applied by the probe and its position have to be known at each instant. Maintaining the contact with an appropriate force between probe and patient's body is required all the time for proper scanning. The probe is most often held close to the normal direction of the skin and tilted during examination. In this paper, a new low cost removable device that can be mounted on medical ultrasound probe is presented. This device includes a strain gauge force sensor to measure the axial force, a three-axis MEMS accelerometer used as tilt sensor and a magnetic two-axis magnetic compass to assess the probe orientation relative to the north. Their calibrations have been carried out and their behaviors discussed.