JACKSONVILLE, Fla. -- An off-duty Jacksonville Sheriff's Office deputy was hurt Wednesday when her hand was trapped between her police-issued Glock handgun and the powerful magnet inside an MRI machine.

Police said Joy Smith was in the MRI room with her mother when she apparently forgot about her gun, which was pulled by the magnetic force of the machine, trapping her hand between the gun and the MRI.

Smith was able to free herself, but the gun remained stuck for hours while the machine was powered down, which takes 24 hours. Jacksonville Beach police said Smith's hand was injured and she had difficulty bending her thumb, but it was not known if she sought medical treatment.

"It's a huge magnet. The whole thing just has a plastic case around it," said Beth Ratliff, who operates the MRI machines at Shands.

More than 30 patients a day go through Shands' machines, and there are strict rules for patients and visitors to follow.

Ratliff doesn't work at the Beaches office were the gun got stuck, but she helped explain how it happened.

"The magnet is pulling the gun, so the mass of the gun and the velocity of the magnet gets together and makes it a lot stronger," Ratliff said.

She also explained how the MRI works.

"We use regular waves," she said. "It hits the magnet, the magnet turns and it causes the molecules in your body to turn around, and we get a picture."

Beaches MRI had to close for the rest of the day and a MRI technician had to be flown in to fix the machine. Channel 4's Adam Landau was told that between repairs and lost revenue, the incident cost the center $150,000.

Beaches MRI reopened on Thursday.