1. If the results of bone mineral density displayed by the ultrasonic instrument are obviously inconsistent with the actual situation of the patient, it may be caused by the probe being installed backwards.
2. Ultrasonic probes are usually marked with some marks and signs on the outside to help operators use them correctly. Check the marks on the surface of the probe and connecting wire to ensure that they are consistent with the equipment instructions. If the logo or sign shows the opposite direction, the probe is inverted.