It is the powerful magnetic force that creates a concern, not only to those who are tattooed, but also to anyone with metal objects in their bodies such as implants (dental or otherwise), pacemakers or even metal fragments. The magnetic force of an MRI machine is so strong, even the “weakest” machine used (about 0.5-tesla) is 10,000 times the strength of the Earth’s magnetic field. Even small metal objects such as paperclips or keys can become projectile weapons if left in an MRI room during a scan. So, what does all of this have to do with tattoos? Well, it appears that about 20 years ago and further, tattoo ink was sometimes comprised of small fragments of metal as well as other ingredients. This was long before tattoos were ever regulated and before more serious thought was given as to the safety of tattoo ink ingredients. Some MRI patients who have had tattoos that dated back far enough to have received ink that contained metal bits have reported slight discomfort to severe pain during an MRI scan.