Seventy people, including patients and staff, were evacuated after a fire broke out at Singapore General Hospital (SGH) on Monday afternoon.
The Singapore Civil Defence Force (SCDF) responded to a fire at 1 Hospital Drive, in the Basement 1 level of Block 2, at 1.50pm.
The small fire, which involved an electrical component, had burned itself out before firefighters arrived, said SCDF.
SCDF evacuated 70 people from the premises as a safety precaution. No injuries were reported and SCDF is investigating the cause of the fire.
Preliminary investigations by SGH showed that an electrical component inside a scanner had overheated and emitted smoke, said the hospital's chief operating officer Tan Jack Thian.
The scanner was shut down immediately. The hospital arranged for patients to have their tests done using other scanners in the department after the premises were cleared of smoke and SCDF had given clearance to re-enter, he added. The hospital also made arrangements for a few patients to have their scans rescheduled.
"We apologise for the inconvenience caused by this incident," said Mr Tan.
A patient told Chinese-language newspaper Shin Min Daily News that the corridors were filled with smoke and after about an hour, people were allowed to go back into the building.