George Richard Grove, 55, who retired last year as head of the radiopharmaceutical drug group of the Bureau of Drugs of the Food and Drug Administration, died of cancer Tuesday at his home in Rockville.

He had joined the FDA in 1974 after serving two years as assistant director of materials licensing and agreement states programs with the former Atomic Energy Commission.

From 1951 to 1972, Dr. Grove worked for the Mound Laboratories of the Monsanto Research Corporation in Miamisburg, Ohio, which was conducting programs for the AEC.

Dr. Grove was born in Columbus, Ohio. He was a graduate of Ohio State University, where he earned a master's degree in physics and a doctorate in nuclear physics. He was a physicist at the National Bureau of Standards here in 1950-51.

He was the author or co-author of a number of pulications in his field. He was a fellow of the American Physical Society and American College of Radiology, the Society of Nuclear Medicine and the American Association of Physicists in Medicine.

A registered professional engineer, he was a diplomate of the American Board of Radiology in Radiological Physics.

Dr. Grove was chairman of the board of deacons, director of the Men's Brotherhood and a Sunday School teacher at Norbeck Baptist Church in Rockville.

He is survived by his wife, the former Dorothy Marie Borror, of Rockville; three children, Daniel Richard, of Middletown, Ohio, Timothy Richard, of Jefferson City, Mo., and Diana Marie Campbell of Silver Spring; a sister, Helen Ginsler of Glen Ellyn, Ill., and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the G. Richard Baptist Church.