Patent attributes
A medical material needle, applicable for detection and positioning by an ultrasound, includes a needle body having a three-layer structure. The three-layer structure includes an outer structure, an inner structure, and a middle structure disposed between the outer structure and the inner structure. The outer structure and the middle structure have different characteristic acoustic impedance with respect to the ultrasound, the inner structure and the middle structure have different characteristic acoustic impedance with respect to the ultrasound, and at least one of the outer structure, the middle structure and the inner structure is provided with a dimension in at least one direction less than a wavelength at a frequency of the ultrasound in water.
