For more than a decade, Perry M. Beale had some of the Washington area's most prestigious hospitals as clients. He inspected their mammography machines and other radiological equipment, gave them passing marks and collected paychecks for his services in the hundreds of thousands of dollars.

But it turned out that Beale had faked his credentials and did many of his inspections from his home in Fredericksburg, federal authorities charged yesterday. He never even set foot in some of the facilities, which included the George Washington University Ambulatory Care Center, Georgetown University Radiology Associates and the CIA's Office of Medical Services in Langley, prosecutors said.

John L. Brownlee, the U.S. attorney based in Roanoke who filed fraud charges against Beale yesterday, said he "jeopardized the health and safety of thousands of patients" who received mammograms and other tests. But Brownlee and federal health officials said there appeared to be no harm to patients because other people, such as radiological technicians, were also inspecting the equipment.

"Although Mr. Beale's actions were a flagrant disregard of federal mammography regulations . . . women who had mammograms at the involved facilities should not be concerned about the quality of their mammograms," said Charles Finder, a senior official at the Food and Drug Administration, which regulates mammography equipment.

But the investigation is continuing, and a breast cancer advocacy group expressed concern about the charges. "Women need to be assured that when they get their mammograms, the equipment is the highest quality," said Carolina Hinestrosa, a vice president with the National Breast Cancer Coalition in Washington.

Beale, 50, was arraigned yesterday in U.S. District Court in Charlottesville on 38 counts of mail fraud because he was allegedly paid by checks sent through the mail. Prosecutors filed court papers yesterday in which Beale agreed to plead guilty, but no plea hearing has been set.

A judge released Beale on $25,000 bond. He and his attorney did not return telephone calls.

Federal officials did not explain the motive for Beale's alleged actions, but they traced his history to 1988, when he began working as an apprentice to a medical physicist and radiation safety officer in Maryland. Hospitals are required to have medical physicists, who are licensed by state authorities, to annually inspect mammography equipment to ensure that it meets federal standards.

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

About 1990, Beale's mentor died, Brownlee said. Rather than returning to school and obtaining the proper credentials, he said, Beale falsified his resume and transcripts and essentially replaced his mentor.

Investigators said Beale altered his college transcript to show that he took science and physics courses and inflated his grades. He also submitted documentation indicating he had a master of science degree from the University of Virginia, although he never took graduate-level courses anywhere, they said.

Beale then submitted to the American Board of Radiology, an FDA-designated body that certifies medical physicists, a certificate "indicating that he was certified in radiation physics," Brownlee said.

In truth, Beale had allegedly altered a real board certificate, whited out the name and inserted his own.

By the early 1990s, court documents said, Beale was working in medical facilities that ranged from small doctors' offices to large university medical schools and government institutions. He also was an adjunct faculty member at Prince George's Community College until the fall of 2002, the school said yesterday.

Beale was employed by more than 50 facilities in Virginia, Maryland, the District, Pennsylvania, North Carolina and West Virginia. Nearly half of those were in the Washington area, according to court documents.

The George Washington University Ambulatory Care Center, for example, paid Beale $1,050 in 2001 and 2002. Georgetown University Radiology Associates paid him at least $2,000 between 1993 and 1995; court documents said those figures are incomplete.

Marianne Worley, a spokeswoman for Georgetown University Hospital, said it turned out from later inspections that the equipment Beale inspected was working properly. "We don't believe that any patients were impacted," she said. Calls to George Washington for comment were not returned yesterday.

The hospital that court records indicate paid Beale the most was Fauquier Hospital and Warrenton Professional Center, which paid him $50,910 from 1993 to 1997.

Prince William Hospital in Manassas paid him $42,593 from 1997 to 2002. In a statement yesterday, hospital officials said that they conducted an evaluation when Beale's contract was terminated and that "there is no evidence of any harm to Prince William Hospital's patients resulting from Mr. Beale's fraudulent reporting."

The statement said the hospital has numerous controls in place to ensure that its equipment is safe, such as checks by radiation physicists and a radiation safety officer. In addition, staff members are trained to use low doses of radiation and protective apparel to reduce radiation exposure.

North Arundel Hospital in Glen Burnie paid Beale at least $28,613 between 1981 and 2000; court records said those figures are only partial.

Kathy McCollum, a hospital spokeswoman, said that "to the best of our knowledge,'' there was no harm to patients from Beale's alleged actions. "It certainly is disturbing,'' she added.

U.S. Attorney John L. Brownlee said Perry M. Beale "jeopardized the health and safety of thousands of patients."