MARIETTA — WellStar Health System has filed a letter of intent with the state to create a $12.7 million pediatric diagnostic center at 1180 Barrett Parkway NW in Kennesaw, the former site of Progressive Lighting.

WellStar spokesman Keith Bowermaster said the health system filed the required certificate of need application on Aug. 31 and expects to open the center in May 2014. WellStar plans to renovate the 11,650-square-foot former retail building but has not selected the architect and general contractor.

The center will offer pediatric ambient MRI, CT, digital radiography, ultrasound, fluoroscopy and mammography. Bowermaster said WellStar expects to hire at least 12 employees, in addition to radiologists and anesthesiologists that will be on site.

Bowermaster said WellStar physicians stressed the need for additional outpatient pediatric diagnostic services in the area, especially amid expected population increases of nearly 11 percent over the next four years.

“WellStar already sees a lot of pediatric patients, and we see that market only growing,” he said.

WellStar has 80 pediatricians on staff at its Cobb, Douglas and Kennestone Hospitals and 44 pediatricians in the WellStar Medical Group.

County Commissioner Helen Goreham, who represents northwest Cobb, said the addition of medical services in the Town Center area will only add to the quality of life for residents.

“The more comprehensive services present here would also be a plus to those businesses considering relocating to northwest Cobb County,” she said.

In July, Kaiser Permanente expanded its comprehensive care center at 750 TownPark Lane off Chastain Road in Kennesaw by 78,000 square feet. Kaiser’s center offers 24-hour urgent care, as well as high-end imaging and diagnostic services for people of all ages.

Children’s Healthcare of Atlanta has an urgent care location at 2985 George Busbee Parkway in Kennesaw, which offers some diagnostic services.

WellStar has 15 outpatient diagnostic centers in its five-county service area.