Israel Gelfand, 96, who was considered one of the world's top mathematicians and did important work in the development of medical imaging devices, died Monday at a hospital in New Brunswick, N.J.

Dr. Gelfand, from Ukraine, was a distinguished professor of mathematics at Rutgers University. He conducted pioneering research, mentored mathematicians, and established correspondence schools in Russia and the United States for budding mathematicians in remote areas. He remained active until 2008, running seminars that placed the pursuit of math knowledge ahead of academic titles.

He taught at Moscow State University before moving to this country in 1989. He joined the Rutgers faculty in 1990.

Rutgers University professor Valdimir Retakh, who worked with Dr. Gelfand, said that his work in representation theory was part of the foundation of modern physics and that his research in integral geometry was vital to the advent of medical imaging devices.

Dr. Gelfand won numerous awards, including the Wolf Prize in Mathematics in 1978. He wrote more than 800 articles and 30 books in many areas of math. - AP