A 61-year-old man has died after he was sucked into a Magnetic Resonance Imaging (MRI) machine at a medical centre in New York.
He was wearing a "large metallic chain" when he entered a room on Wednesday, local time, without permission, as a MRI machine was running, police said.
The accident highlighted the importance of checking for any metallic objects before going near the powerful magnets used in medical imaging machines.
Here's what we know.
What happened?
On Wednesday afternoon, the man entered a MRI room while a scan was underway at Nassau Open MRI in Westbury, New York, on Long Island.
The machine's strong magnetic force drew him in by the weight-training chain around his neck, according to a statement from the Nassau County Police Department.
This prompted an unspecified "medical episode", police said.
Though police have not named the victim, a patient at the facility told local media her husband, Keith, was the one who died.
Adrienne Jones-McAllister said she was having a scan on her knee when she asked the technician to get her husband to help her get off the table, a task he normally did at her appointments.
She said he was wearing a 9-kilogram chain with a lock that he used for weight training.
"At that instant, the machine switched him around, pulled him in, and he hit the MRI," she said.
Ms Jones-McAllister said the technician helped her try to pull Keith off the machine, but it was impossible.
"I said: 'Could you turn off the machine, call 911, do something, turn this damn thing off!'
"He waved goodbye to me, and then his whole body went limp."
In the interview with local media, Ms Jones-McAllister said this wasn't the first time she and her husband had been to Nassau Open MRI.
"That was not the first time that guy has seen that chain" on her husband, she said.
"They had a conversation about it before."
The man was taken to hospital in critical condition before he died on Thursday after suffering several heart attacks.
The police investigation is ongoing.
How does an MRI work?
MRI machines use a strong magnetic field to produce detailed images of the inside of a body.
A MRI scanner is often shaped like a tunnel, with a table for a person to lie on that slides through the middle.
Here's a bit more on that, according to Health Direct:
The scanner uses strong magnetic fields and radio waves to generate signals from the body.
These are picked up by a radio antenna and processed by a computer to create detailed pictures.
Patients are typically asked to remove metal items and change out of their clothes before undergoing scans or going near the machine.
What are the risks of a MRI scan?
A MRI scan is generally safe and poses almost no risk to the average person.
Although it doesn't emit the ionising radiation that is found in X-ray and CT imaging, it does employ a strong magnetic field.
The magnetic field extends beyond the machine and exerts very powerful forces on objects of iron, some steels, and other magnetisable objects.
For example, something as small as keys to something as large, or larger, than an oxygen tank can become a projectile.
The US National Institute of Biomedical Imaging and Bioengineering (NIBIB) said MRI units are "strong enough to fling a wheelchair across the room".
Because of these types of risks, patients must notify their doctors about any medical implants prior to a MRI in case they contain any metallic materials.
But the US Food and Drug Administration (FDA) said adverse events for MRI scans were rare.
Millions of MRI scans are performed in the US every year.
The FDA receives about 300 adverse event reports for MRI scanners and coils each year from manufacturers, distributors and patients.
In 2001, a six-year-old boy died of a fractured skull at a New York City medical centre while undergoing a MRI exam. Its powerful magnetic force propelled an oxygen tank across the room and into the chamber.
ABC with wires
