John B. Garrison, 60, a principal staff physicist at the Johns Hopkins Applied Physics Laboratory who retired in September after more than 30 years of service, died of cardiac arrest Wednesday at Holy Cross Hospital. He was stricken at his home in Silver Spring.

Dr. Garrison specialized in missile guidance systems and radar technology for part of his career and then in the applications of electronics to biomedical research.

He was a member of the space department of the Applied Physics Laboratory at the time of his retirement, but for several years he was assigned to work with physicians of the Johns Hopkins Medical Institutions. His work there concerned the development of electronics for monitoring heart-wall contours and other phenomena.

Dr. Garrison was born on Prince Edward Island, Canada, and grew up in St. Clairsville, Ohio. He graduated from Oberlin College, worked at the Massachusetts Institute of Technology radiation laboratory during World War II, and earned a doctorate in physics at MIT in 1947. He taught at the University of Chicago until 1950, when he moved to this area and joined the Applied Physics Laboratory.

Since retiring there, he had been a researcher with the System Planning Corporation in Arlington.

Survivors include his wife, Shirley, of Silver Spring, and three daughters, Nancy, of Washington, Wendy, of Urbana, Ill., and Barbara Cornyn of Alexandria.