A Virginia man pleaded guilty yesterday to defrauding some of the Washington area's most prestigious hospitals by faking his credentials to inspect their mammography machines and other radiological equipment and sometimes not inspecting them at all.

Perry M. Beale admitted that he gave many hospitals passing marks without leaving his home in Fredericksburg and in some cases never set foot in the buildings, according to federal officials and documents filed with Beale's plea in U.S. District Court in Charlottesville.

For those services, Beale was paid $400,000 to $1 million by medical facilities, which included the George Washington University Ambulatory Care Center, Georgetown University Radiology Associates and the CIA's Office of Medical Services in Langley.

Federal officials reiterated yesterday that they do not think any patients were harmed by Beale's fakery, because other people, including radiological technicians, were also examining the equipment.

But the investigation is continuing, and authorities have tried to reassure more than 100 concerned patients who have called a toll-free number set up for the Beale case, said John L. Brownlee, the U.S. attorney in Roanoke, who prosecuted the case.

"I believe Mr. Beale's conduct created an environment in which patients could have been harmed, and we will continue to talk to former patients," Brownlee said. "This is an important case, and Mr. Beale's conduct is simply intolerable."

Beale, 50, pleaded guilty to all 38 counts of mail fraud with which he was charged in July and remains free on $25,000 bond. He has agreed to pay restitution to the more than 50 medical facilities he defrauded in Virginia, Maryland, the District, Pennsylvania, North Carolina and West Virginia.

Federal law enforcement officials said Beale is likely to receive four to six years in prison when he is sentenced Nov. 22. Officials said they do not expect to charge anyone else in the case.

Beale's home phone is disconnected, and his attorney did not return calls yesterday.

Although the motive for Beale's actions remained unclear yesterday, Brownlee attributed it to "just greed. He found this to be a very lucrative profession, so he made a lot of money doing it."

The investigation, conducted by the Food and Drug Administration's Office of Criminal Investigations and the Nuclear Regulatory Commission, traced Beale's history to 1988. That year, Beale began working as an apprentice to a medical physicist and radiation safety officer in Maryland. Hospitals are required to have state-licensed medical physicists inspect mammography equipment annually.

The NRC mandates that radiation safety officers inspect equipment that uses radiological materials, such as X-ray machines.

Beale's mentor died about 1990. Rather than returning to school and obtaining the proper credentials, Beale falsified his resume and transcripts, according to court documents and law enforcement officials.

Beale then submitted a document to the American Board of Radiology indicating that he was certified in radiation physics. But he had actually altered a board certificate, removing the name and inserting his own.

Court records indicate that the hospital that paid Beale the most was Fauquier Hospital and Warrenton Professional Center, which paid him $50,910.

Other hospitals that employed Beale included Prince William Hospital in Manassas and North Arundel Hospital in Glen Burnie.

U.S. Attorney John L. Brownlee said the investigation continues into whether Perry Beale's actions harmed any patients.