The experiment involved injecting seven patients with tracer doses of radioactive sodium, according to Sweet and the published work. The doctors then drew blood from the patients about an hour later to measure how well the bodymetabolized tracers.

According to Sweet, who retired in 1977, the1951 experiment was just one of many similar testshe and his colleagues at Massachusetts GeneralHospital performed.

"[We] did a number of such studies withradioisotopes of one sort or another," Sweet said.

He said the study and others like it "were aremarkably valuable means of finding out things wehad no idea about."

The professor repeatedly mentioned experimentshe did with radioactive uranium.

Sweet said the experiment would be done thesame way today, except that "we'd have it allwritten down."

The doctor stressed that the amount ofradiation used in his experiments "was minimal,"and said that many of the test subjects were eagerto participate in his studies.

"We discussed these points with the patients,especially in the studies where the experiment didthe patient no good but was done for medicalknowledge generally," Sweet said. "Only thepatients that were very enthusiasticparticipated."

"Patients would ask `Is there any way we couldhelp you?" said Sweet, adding that he is eager toreview his work with anyone interested.

Michelle Marcella, a spokesperson forMassachusetts General Hospital, said yesterdaythat the study is being reviewed by the hospital'sin-house committee involving radiation performedduring the Cold War era.

As part of its investigation, she said, thecommittee will determine what kind of consent, ifany, was obtained for all experiments conductedduring that period, Marcella said.

The scientists worked out of the NeurosurgicalService of the Massachusetts General Hospital andthe Harvard Medical School Department of Surgery,according to the journal.

Contacted at his home last night, Harvardspokesperson Joe Wrinn referred questions to theMassachusetts General Hospital. He said that anyUniversity documents on the matter would be turnedover to the appropriate state or federalauthorities.

The experiment was designed to study the rateat which radioactive substances mixed in the bloodstream.

Scientists believed at the time that thisknowledge would help in determining thesubstances' rate of transfer out of the blood andinto other body fluids.

"Radioactive isotopes are being injected forinvestigative and therapeutic purposes into theblood stream of man with increasing frequency,"the published study says.

Funding for the experiment was provided in partby the National Institutes of Health, PublicHealth Service, and from an anonymous donor to theNeurosurgical Service of the Massachusetts GeneralHospital.

Sweet repeatedly said that MGH now requires anextensive consent process for all of its patients.

Selverstone died last year, Sweet said.

Bakay could not be reached for comment