2021 James Joule Medal and Prize
Professor Bajram Zeqiri for distinguished contributions to the development of acoustic measurement techniques and sensors; in particular, underpinning the provision of international standards enabling the safe clinical application of medical ultrasound.
For three decades, Professor Bajram Zeqiri’s technical leadership and seminal research contributions to ultrasonic measurement have supported traceable calibration and specification standards that have been a major enabling factor in the widespread application of clinical ultrasound imaging.
His research has generated a detailed understanding of sensors applied to the key, safety-relevant observables of acoustic pressure and acoustic power, ensuring their traceability to the relevant international system of units (SI units). His measurement methodologies are embodied within international specification standards and ultimately underpin patient safety.
Through his influential leadership, the National Physical Laboratory (NPL) Ultrasound Group has established a global pre-eminence among national measurement institutes through the development of critical measurement devices and the understanding of their performance.
This includes significant contributions to the global measurement and calibration infrastructure for sound in matter, which ensure that medical ultrasound techniques are applied safely and effectively. The majority of the world’s medical ultrasound equipment manufacturers carry out acoustic measurements directly traceable to Zeqiri’s group for regulatory compliance and to support emerging clinical techniques.
Zeqiri is a serial innovator and a number of these innovations have been successfully commercialised. His record for innovation and as a technology enabler has been strongly requirement-focused and collaborations with industrial partners have been critical in driving adoption of novel developments over several sectors.
A key example was his patented solid-state thermal measurement method for ultrasonic power measurement, exploiting the pyroelectric effect in a thin piezoelectric membrane. The high sensitivity of the detector concept is being exploited as part of a new phase-insensitive ultrasound tomographic imaging technique, offering enhanced imaging capability over conventional detectors.
The subject of two patents, genuinely quantitative imaging capability has been demonstrated with application to breast-tissue composition and disease characterisation.
Due to the complex, sensor-hostile environment and the stochastic process of cavitation (occurring when sound pressure amplitude is high enough to rupture the medium), measurement standards have been extremely challenging to develop for the industrial ultrasound area.
In response, Zeqiri conceived the concept of the broadband NPL cavitation sensor, designed to capture the full cavitation bubble collapse energy. This research has generated valuable insights on cavitation inception and development through a range of unique reference facilities and pioneering experimentation. Acoustic cavitation provides the driving force behind many industrial processes and ultrasound therapeutics.
Zeqiri’s research has been instrumental in reawakening global interest in this area.