Imaging Method for Acoustic Impedance Difference for Puncture Needle-Type Ultrasonography using a Thin Rod with Focusing End Face

摘要

In this paper, we propose an imaging method for acoustic impedance difference for puncture needle-type ultrasonography. The difference in acoustic impedance between benign and malignant tissues will provide valuable diagnostic information. In this experiment, a thin rod that has a concave polished end face was constructed using a fused quartz with a diameter of 1 mm and a focus length of 0.3 mm. An ultrasonic wave emitted from the concave end face of the rod is focused on a tissue. The difference in acoustic impedance was determined by the reflection-type interference-based acoustic impedance measurement method. We confirmed that the image shows the difference in impedance between the polyethylene (PE) plate and acrylic rod with a diameter of 3.5 mm embedded therein. The experimental results show that the method is useful for puncture needle-type ultrasonography.