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Revolutions in Ultrasound Technology: Capacitive Micromachined Ultrasonic Transducers

Ultrasound technology is always evolving, with innovative probe tech continuously improving diagnostic image clarity. The capacitive micromachined ultrasonic transducer (CMUT) is one such innovation, and it has the potential to revolutionize intravascular medicine. CMUT is a departure from traditional piezoelectric probes, and it presents new possibilities for high-quality ultrasound imaging.

CMUT explained

CMUT systems are micro-electromechanical systems (MEMs) featuring a silicon substrate layer complemented by a metallized layer, which serves as the electrodes. Unlike piezoelectric probes, which measure voltage generated by applied pressure, CMUTs transmit and receive acoustic signals via changes in capacitance.

When transmitting, the parallel-plate capacitor remains fixed, and the flexible membrane vibrates to produce ultrasonic waves based on the frequency of modulation. In receiving mode, ultrasonic waves cause membrane vibration, and the probe detects changes in capacitance to deliver precise imaging.

CMUT technology is ideal for intravascular medicine, specifically, the diagnosis and monitoring of coronary arterial diseases. CMUT probes provide clear and accurate depictions of cholesterol and plaque accumulation on inner arterial walls, while also showing real-time vascular function.

Core benefits of CMUT technology

CMUT technology has several extraordinary benefits for intravascular imaging. Namely, these probes are prized for their compact form factor, higher resolution, and higher sensitivity — culminating in comprehensive imaging that exceeds current piezoelectric capabilities.

CMUT technology features include:

  • Frequency ranging from 500 kilohertz to 50 megahertz.
  • Large bandwidth (over 100% in immersion).
  • Low mechanical coupling between elements without crosstalk.
  • RoHS compliance, made with non-toxic materials.
  • High-level customization enabling a small form factor.

A comparative study of CMUT vs. traditional piezoelectric probes concluded, “CMUTs exhibited unique advantages over other ultrasound transducers, such as wide bandwidth and capability of manipulating high-density arrays. Such features make them promising for intravascular ultrasound imaging applications.”

The frequency and bandwidth in immersion applications makes CMUTs capable of delivering significant improvements in medical diagnostic imaging.

CMUT changes the game for intravascular imaging

Current CMUT technology is the result of more than three decades of innovation. The benefits of CMUTs were postulated years ago, but the microfabrication technology required to produce and perfect these probes has been slower to emerge. Even over the last decade, medtech has made tremendous strides in the fabrication of MEMs to produce CMUTs capable of surpassing the existing gold standard for intravascular imaging.

Advancements in microfabrication have also significantly reduced production costs. CMUTs have quickly fallen in price in recent years as MEMs become quicker and more cost-effective to machine. The result is a more powerful probe, a higher standard of imaging, and a lower total cost of ownership for healthcare providers.

CMUTs pave the way for better diagnostic imaging in current medical applications and unlock development for more refined procedures in the future.

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April 2, 2022 Uncategorized