The National Institutes of Health yesterday dedicated its new research hospital, which the agency's top physician called "the place where medical breakthroughs will occur in the next 50 years" and a patient termed simply "the house of hope."

The 238-bed Mark O. Hatfield Clinical Research Center will replace NIH's current hospital, which opened in 1953. It is named for the Republican senator from Oregon who helped shepherd legislation authorizing its construction through Congress before retiring in 1997.

Like its predecessor, the new building features research labs and patient rooms under the same roof, usually right down the hall from each other. But it incorporates dozens of features no one contemplated half a century ago -- rooms next to the non-denominational chapel where Muslims can wash their feet, for example, and the "surge capacity" to put two patients in single rooms in the event local hospitals filled up in a catastrophe such as a bioterrorism attack.

Many university hospitals have research wards, and there are a handful of small, research-only hospitals in the world. The center on NIH's Bethesda campus is unusual in combining both large size and a research mission. There are 80,000 patients on its active rolls, and every one is part of a scientific study.

Last year, about 8,600 new patients were admitted. There were 100,000 clinic appointments. About 1,100 research protocols are underway at any time, with most lasting about three years but some as long as 15.

The average length of stay is 8.5 days, down from 25 in the 1970s. But some patients, including children, still stay for months. The clinical center has teachers capable of teaching every grade from kindergarten through high school.

The care is entirely free to the patient, and except for a few unusual circumstances, no insurance companies are billed, either. The taxpayer pays for everything.

"This is a unique hospital. There is nothing out there like it," Elias A. Zerhouni, the physician who is NIH's director, told about 600 people in the building's soaring central atrium. Among them were patients, the heads of most of NIH's 27 centers and institutes, many NIH staff and three former directors, several members of Congress, the 82-year-old Hatfield and his wife and family, and Health and Human Services Secretary Tommy G. Thompson.

One of the patients, Susan Lowell Butler of Alexandria, spoke of her time at the old center, where she underwent eight cycles of high-dose chemotherapy, three operations and six weeks of radiation for breast and ovarian cancer in the mid-1990s. She was cured.

"It really is the family of man in all its glory and misery . . . here in the house of hope," she said.

The new building and related road work cost $605 million. An additional $30 million is being spent on furniture and equipment. Scientists are moving their labs over several months, but the patients will all move in on a single day -- Dec. 4.

Parts of the old building will continue to be used, but the patient rooms will be mothballed.

The seven-story new building is lower than its high-rise predecessor. It is notable for an abundance of natural light. There are windows in every patient room, including those of the intensive care units.

The building is designed with its own evolution in mind, said Robert J. Frasca, the chief architect.

Patient rooms can convert to lab space, and vice versa. Above each of those areas is an "interstitial level" where air ducts, wire and cable are hidden in an uncrowded, walk-in story to allow an orderly expansion of utilities as the building's use and demands change.

"In fact, we've changed plans already," John I. Gallin, an infectious diseases specialist who directs the clinical center, said on a tour of the building.

Just 18 months ago, he said, NIH decided to create a unit for research on extremely obese patients, with special chamber for calculating energy expenditure.

"This building has to last at least 50 years, maybe more," said Frasca, whose Portland, Ore., firm had about 60 people working on the design since 1995.

Patients and workers were consulted extensively on the design. Mock-ups of a patient room and a nursing station were built in the old center and critiqued. In one early version, there was a sink with mirror above it on the wall next to the foot of the bed.

Gallin said he remembers a patient telling him, "You go lie in the bed and see what you see."

"You see yourself," Frasca recalled, "and sometimes you don't look so good."

The architects moved the sink to a different wall and the mirror to the bathroom.

John I. Gallin, right, director of the clinical center at the National Institutes of Health, and James H. Shelhamer, deputy chief of critical care, show off one of their intensive care rooms at the new clinical research center.A view highlights the atrium inside the Mark O. Hatfield Clinical Research Center.