Why is piezoelectric crystal using in ultrasound?

Piezoelectric crystals are used in ultrasound because they can convert electrical energy into mechanical vibrations and vice versa. When an electrical voltage is applied to the crystal, it deforms and generates sound waves, which are essential for creating ultrasound images. Conversely, when sound waves hit the crystal, they produce an electrical signal that can be processed to form images. This efficiency and ability to operate at high frequencies make piezoelectric crystals ideal for ultrasound applications in medical imaging and other fields.