Radiologists from two District hospitals are planning to run costly medical imaging centers in Rockville and Clinton, taking advantage of a loophole in Maryland law that allows doctors to buy equipment for medical offices without receiving approval from health planners.

Nine local hospitals in the District and suburban Maryland also are vying for the sophisticated nuclear magnetic resonance scanners, which cost about $2 million each to install and to operate for the first year, and are the basis of the proposed imaging centers.

The hospitals must have their purchases approved by government health planners, in order to avoid duplication and hold down consumer health care costs. But in Maryland, doctors can equip their offices without government approval.

Doctors from Georgetown University Medical Center are working with a New Jersey money-raising firm to open an imaging center on Seven Locks Road in Rockville in January, according to Ken Haas, vice president of Medical Resources Inc. of Teaneck, N.J. The center will contain a nuclear magnetic resonance scanner, a CAT scanner, mammography machines and other devices to make images of various parts of the body.

The center will cost $3.5 million, according to a letter sent to Maryland health authorities, who have no power to decide whether the center is needed or if its services duplicate others in the area.

There are two other nuclear magnetic resonance scanners in Montgomery County -- one in Chevy Chase opened last month by a group of private physicians, and one at the National Institutes of Health, which is not open to the general health care public.

In Prince George's County, radiologists from Greater Southeast Community Hospital are planning to open a free-standing imaging center on Branch Avenue in Clinton next month, according to Audrey Murawski, director of project review for the Southern Maryland Department of Health Systems Planning. The agency opposed its creation, but has no authority to stop the center.

"It's a loophole we're trying to close," said John Osborne, director of the Montgomery County Department of Health Systems Planning. "Unfortunately, it's several years after the barn door has been open." Osborne said the Maryland Governor's Task Force on Health is recommending that the loophole be closed and added that a bill is being introduced in the upcoming legislative session to accomplish that.

Several other groups of doctors, including ones from Shady Grove Hospital, Holy Cross and Doctors' Hospital, all are trying to raise money from investors to start similar imaging centers in Montgomery and Prince George's counties.

Health planners are concerned that an abundance of the new scanners will drive up the costs of health care. A single scan can cost up to $700. The machines are used to take photographs of the brain, spine and soft tissue of the body by using radiomagnetic waves.

But Dr. Larry Elliott, director of radiology at Georgetown Hospital Medical Center, said the technology is needed to practice good medicine and that health planners "have retarded medical advances."

The Georgetown radiologists will not own or invest in the center, but will be hired by Medical Resources to operate the machinery and evaluate the scans.

Haas, of Medical Resources, said his firm intends to charge patients $600 to $650 per picture from the nuclear magnetic resonance scanner and plans to serve some 2,700 patients each year. But Dr. Charles Citrin, director of the Chevy Chase imaging center, said business there has been slower than expected because local physicians are cautious about referring patients for procedures they consider experimental.