Eugene Saenger, an Ohio radiologist who contributed greatly to medical knowledge about the effects of radiation on the human body, and was sued for his role in controversial 1960s studies on cancer patients, died Sunday. He was 90.

Saenger was among the first to report on the growth of cancer cells in children following irradiation for benign conditions, and he published a landmark paper in 1968 demonstrating that, contrary to popular belief, radioiodine therapy was not associated with an increased incidence of leukemia.

That legacy was tarnished, however, by the experiments in which Saenger administered high levels of whole-body radiation to more than 90 poor, black, uneducated patients with inoperable tumors. Saenger maintained that the tests were designed to relieve pain and perhaps shrink the tumors, but critics contended that their purpose was to determine the deleterious effects of radiation on the human body for the benefit of the U.S. military, which provided most of the funding for the studies.

As many as 20 of the patients might have died as a result of the radiation. In 1999, a federal judge approved a $4 million settlement to the families of the patients.

Saenger co-founded the Society for Medical Decision Making in 1978 and served as its first president. He also won the highest honors of the Radiological Society of North America.

Following the Chernobyl nuclear plant disaster in the Soviet Union in 1986, Saenger was one of the international experts called in to assess the hazards. Among other conclusions, he told the military that it was not necessary to evacuate their forces from the downwind regions of Europe.