A man has died after an oxygen tank got sucked into the magnetic resonance imaging (MRI) machine he was being scanned in. The 60-year-old patient was at a hospital in the city of Gimhae, South Korea, following seizures when the accident took place. Police told the South China Morning Post that he was hit in the head by a 60-kilogram (132-pound) oxygen cylinder that flew into the MRI machine after it had been turned on. MRI machines work by creating powerful magnetic fields (as well as radio waves) targeting hydrogen nuclei (protons) in water. As protons are subjected to the magnetic field (about a thousand times stronger than that produced by a fridge magnet) their axes line up. "This uniform alignment creates a magnetic vector oriented along the axis of the MRI scanner," science editor Abi Berger explains in the BMJ. "When additional energy (in the form of a radio wave) is added to the magnetic field, the magnetic vector is deflected. The radio wave frequency (RF) that causes the hydrogen nuclei to resonate is dependent on the element sought (hydrogen in this case) and the strength of the magnetic field." "When the radiofrequency source is switched off the magnetic vector returns to its resting state, and this causes a signal (also a radio wave) to be emitted. It is this signal which is used to create the MR images." While this is great for seeing inside the body – especially cartilage, tendons, and muscles, which other scanning methods can't produce images of very well – it's not so great if you happen to be carrying anything magnetic. For some idea of the forces involved, check out this video below. This is why hospitals will prevent you from bringing metallic objects into the MRI suite. As such, police are investigating how the oxygen tank was allowed into the room in the first place. This is not the first incident involving an MRI machine and an oxygen tank. In 2018, a man was sucked into an MRI machine while carrying a similar tank, later dying. "Despite being a 'never event,' MRI magnetic projectile accidents still continue to happen pretty regularly, and radiology should hang our heads for that," Tobias Gilk, senior vice president of Radiology-Planning told AuntMinnie.com following the latest accident. "The fact is that almost nowhere in the world are there actual explicit rules or requirements to follow the long-established best practices that would help prevent exactly this sort of accident." Source
