Duke Raleigh Hospital is preparing a long-range expansion plan that will continue transforming the once-sleepy community hospital into a specialty medical campus.

Since the Duke University Health System bought the former Raleigh Community Hospital in 1998, it has pumped nearly $120 million into renovations and improvements at the facility on Wake Forest Road.

Initial plans, which the Duke health system board is expected to approve this month, call for expanding the Raleigh hospital's emergency department and operating rooms. Some parts also will require approval from state regulators and could run into opposition from competitors.

Hospital officials have been working with the architecture firm HOK since March on a master campus plan that eventually could include replacing several aging medical office buildings.

The plan follows major changes in recent years, at the facility, which had been largely neglected by its previous owner.