Multiplexed ultrasound beam summation for side lobe reduction

Area of Science:

• Medical Imaging
• Acoustics
• Biomedical Engineering

Background:

• Conventional two-way focusing in ultrasound imaging suffers from reduced image contrast due to side lobes from diffraction.
• Side lobes degrade the overall quality of ultrasound images, limiting diagnostic accuracy.

Purpose of the Study:

• To present a new beam-shaping method for transmitted ultrasound waveforms to reduce side lobes.
• To improve image quality in ultrasound imaging by minimizing diffraction-induced artifacts.

Main Methods:

• The method involves interlacing two distinct waveforms between transducer elements.
• One waveform creates a single focus, while the second creates two foci designed for destructive interference with side lobes.
• This technique utilizes standard receive beamforming and requires no post-processing.

Main Results:

• Experimental measurements showed a 7.5 dB side lobe reduction at a depth of 60 mm using a 3 MHz phased array transducer.
• The method was validated through experiments with wire targets, tissue-mimicking phantoms, and in vivo rat bladder imaging.
• The real-time method is compatible with conventional ultrasound systems.

Conclusions:

• The proposed beam-shaping technique effectively reduces side lobes and enhances ultrasound image quality.
• This innovative method offers a practical solution for improving diagnostic imaging without requiring additional hardware.
• The technique is analytically described, numerically optimized, and experimentally validated.