In an unusual public protest, a New York scientist placed full-page ads in at least three major newspapers, claiming he was unfairly denied the Nobel Prize in Physiology or Medicine, which was awarded to two other scientists for the invention of magnetic resonance imaging, or MRI.

The costly ads — totaling an estimated $290,000 in The New York Times, the Los Angeles Times and The Washington Post — claimed that the actual inventor of MRI was Dr. Raymond Damadian, president and founder of Fonar Corp. on Long Island, N.Y.

The Nobel Prize was awarded Monday to Paul Lauterbur of the University of Illinois and Sir Peter Mansfield of the University of Nottingham in England, two scientists whose contributions to the development of MRI are widely acknowledged.

The ads, paid for by Fonar, claimed that the Nobel committee was “revising history” by failing to acknowledge Damadian’s role in developing the technology, which is now extensively used for imaging internal organs for diagnosing disease.

Damadian has frequently said, “Had I never been born, there would be no MRI today,” and he said it again to reporters Friday. “I can’t escape the fact that I started it all.”

The ads, which appeared Thursday in The Washington Post and Friday in the other newspapers, claimed that Damadian made the “breakthrough” that led to MRI and that the Nobel committee “did one thing it had no right to do: It ignored the truth.”

But other scientists believe Damadian’s claim is groundless.

“Most of us in the field would clearly think (the Nobel committee) got it right this time,” said Dr. E. James Potchen, a radiologist at Michigan State University. “It was a wise, conscientious decision.”

“You shouldn’t be able to buy a Nobel Prize,” added radiologist Paul Bottomley of Johns Hopkins University.

Lauterbur could not be reached for comment, but his wife said that he preferred not to discuss Damadian’s claims. Mansfield also could not be reached for comment.

Controversies about who was or was not named as a Nobel laureate occur virtually every year, according to Svante Lindqvist, director of the Nobel Museum in Stockholm, Sweden. Award choices are often challenged, he said, because of the “three-person rule,” which prohibits dividing a single award among more than three individuals. Modern scientific discoveries are often a group endeavor.

But never in anyone’s memory has a neglected researcher organized such a public brouhaha, placing advertisements and asking people to write, phone and e-mail the Nobel committee urging that the award be overturned.

The ad featured an upside down photo of the Nobel medal and was headlined: “A Shameful Wrong that Must Be Righted.”