A cancer patient was left in a CT scanner for more than four hours after a technologist apparently forgot she was there.

Elvira Tellez, 67, of Tucson, Ariz., had to free herself from the device, and then called her son in a panic because the office was locked and abandoned. He advised her to call 911, and the police arrived to help the woman.

The Pima County sheriff's deputies arrived at the oncology office and had her unlock the office door. The deputies contacted the office manager, who was not aware of the situation.

Tellez was taken to a hospital for precautionary measures, but released early the next day.

"I don't know what to think," Tellez said of the disturbing incident last week. "I think and think and think, but I can't understand it," according to Arizona Daily Star, which reported on the story last week.

Tellez said that she has had trouble sleeping since Saturday’s incident. She and her family said they want an explanation from the medical office, Arizona Oncology Associates (AOA), but have yet to receive one because AOA has not commented publicly.

Tellez said the technologist did call to apologize the next day.