In the hottest days of the cold war, when both East and West were planning for the worst, the American military had a frighteningly practical question: in the event of a nuclear explosion, how much radiation could a soldier withstand before becoming disoriented or disabled?

The Pentagon turned to the University of Cincinnati for answers. There, from 1960 to 1971, an eminent radiologist, Dr. Eugene L. Saenger, and his colleagues conducted experiments on 88 cancer patients, ages 9 to 84, exposing them to intense doses of radiation and recording their physical and mental responses. All but one of the patients were terminally ill and, with the exception of that young woman, have been dead for years. Most were poor; 60 percent were black.

The Cincinnati study exposed patients to the highest levels of whole-body radiation and, some experts say, probably caused the most deaths of all the known Government-sponsored radiation experiments since World War II. There is disagreement about how many died of radiation poisoning rather than cancer. But whole-body radiation has been discounted by doctors as an accepted cancer treatment in all but a handful of cancers, among them leukemia. Questions Still Not Answered

Among other questions about the research that have never been settled and continue to haunt this and other radiation studies conducted at the Government's behest are these:

*Did the radiation levels help treat the patients' cancers?

*Did top University of Cincinnati administrators conceal reviews by top medical faculty members who criticized how the experiment by one of their leading researchers was done?