It happened at about 6.40pm on Monday triggering an emergency response from police and Oban Mountain Rescue.
It was only when the woman returned to the emergency department at Lorn and Islands Hospital for a third time that she was finally admitted and tests showed she had cancer.
The scanner is housed in a newly designed CT room with more space and brighter colours to help patients relax.
New Attend Anywhere consultant appointments are proving popular so far with pregnant women living in remote areas of Oban and the islands.
When the existing scanner is removed, a mobile scanner will keep up the service from the hospital car park until the new machine is installed as part of a £1.2m investment.
MSP Donald Cameron says figure for Lorn and Islands Hospital calls into questions hygiene and infection control procedures.