Warren James Nelson, 61, a radiologist who taught at the George Washington University medical school and practiced in Washington, died Tuesday at the Shady Grove Adventist Hospital in Gaithersburg following a heart attack. He was stricken at his home in Potomac.

Dr. Nelson, a native of Wisconsin, served in the Army Air Forces in Europe during World War II. He earned his bachelor's degree at the University of Wisconsin and his medical degree at George Washington, where he graduated in 1953. He later served an internship and practiced in Arizona.

In 1959, he returned here and did a fellowship at the Armed Forces Institute of Pathology. He was an associate professor of radiology at the GW medical school until 1972, when he resigned and entered a private practice in Washington. He continued to teach part time at the medical school. He retired from his practice in 1978.

Dr. Nelson was a member of the D.C. Medical Society, the American Medical Association, the American College of Radiology, the American College of Surgeons and the American Cancer Society.

His wife, Mary Frank Nelson, died last month.

Survivors include two children, James F. and Mary Jeanette, both of Potomac, and two sisters, Margie Hobbs of Wilmington, Del., and Virginia Clark of Yuma, Ariz.