A 100-200 MHz ultrasound biomicroscope

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Ultrasound Technology

Background:

• Advancements in ultrasound imaging systems enable visualization of living tissue at the microscopic level.
• Higher frequencies (100-200 MHz) present opportunities for enhanced tissue microstructure imaging.

Purpose of the Study:

• To assess the in vivo potential of ultrasound imaging within the 100-200 MHz frequency range.
• To evaluate ultrasound biomicroscopy (UBM) for microscopic tissue visualization.

Main Methods:

• Fabrication and characterization of spherically focused lithium niobate transducers, including a 200 MHz device.
• Implementation of a linear mechanical scan system and scan converter for B-scan imaging (up to 12 frames/sec).
• Investigation of zone-focus image collection to extend the depth of field.

Main Results:

• Achieved a resolution of 14 µm (lateral) and 12 µm (axial) with f/1.14 focusing at 200 MHz.
• Demonstrated good transducer sensitivity with 18 dB insertion loss at 200 MHz.
• Presented B-mode images of coronary arteries, eye, and skin with preliminary histological correlations.

Conclusions:

• Ultrasound biomicroscopy in the 100-200 MHz range is feasible for in vivo microscopic imaging.
• Frequency-dependent attenuation limits B-mode imaging performance.
• Further development of ultrasound backscatter imaging above 200 MHz can provide valuable tissue microstructure insights.