I was deeply saddened when I heard that Professor Floyd Dunn, a groundbreaking pioneer in the science of ultrasound and bioacoustics, passed away on January 24, 2015. His death came just 30 days after that of his wife Elsa.

He was born in Kansas City, MO, USA in 1924. He attended the University of Illinois (UI) at Urbana-Champaign in the Department of Electrical and Computer Engineering, earning three degrees, including his Ph.D. in 1956. He remained at UI for 50 years, and during that period he directed the Bioacoustics Research Laboratory at UI for more than 20 years. His research interests included bioeffects, safety of ultrasound, ultrasonic imaging used for prenatal sonograms, the ultrasonic microscope, and numerous measurement tools. He carried an appointment at the University of Arizona, Tucson after his retirement from UI in 1995. He was a member of both the National Academy of Sciences and the National Academy of Engineering. He was also the past President of the Acoustical Society of America (ASA). He was a recipient of the IEEE Edison Medal, the ASA Gold and Silver Medals, as well as the AIUM William J. Fry Memorial Lecture Award in 1984 and the AIUM Joseph P. Holmes Basic Science Pioneer Award in 1990.

Not only in the US, USSR, or United Kingdom, he also taught and led ultrasound research in Japan. Of note, he annually visited Sendai for more than 15 years after he spent 1 year on his sabbatical at Tohoku University in 1989. During his stay in Sendai, he taught young researchers topics ranging from the principle of ultrasound to advanced technology in medical ultrasound. I was grateful that he edited my papers for both content and English grammar before submission to Ultrasound in Medicine and Biology again and again. Together with Professors Motonao Tanaka, Shigeo Ohtsuki, and me, he edited a monogram titled “Ultrasonic Tissue Characterization” published by Springer in 1996. He influenced many of Japan’s leading researchers in medical ultrasound including Professors Daitaro Okuyama, Noriyoshi Chubachi, Motonao Tanaka, Hiroshi Inoue, Jun-ichi Kushibiki, Nobuyuki Endoh, Shin-ichiro Umemura, Hiroaki Okawai, Hiroshi Kanai, and Hideyuki Hasegawa. For his achievements in research and education in medical ultrasound in Japan, he was awarded as an honorary member of the Japan Society of Ultrasonics in Medicine in 1990.

Personally, I visited him in 2012 when the AIUM annual meeting was held in Phoenix, AZ. At that time, I drove a Ford rent-a-car to Tuscan from Phoenix and he drove his Lexus sports car to the meeting venue. He was very sharp and remembered the names of most people he met in Sendai, not only researchers but also their families and secretaries.

I will forever be grateful for Dr. Dunn’s generosity and support. My deepest sympathies and prayers for his family, friends, and colleagues.