Re: Is an MRI Machine really a good example?
A normally conducted MRI scan itself is harmless. And unlike X-Ray there is no cumulative / repeated exposure risk or long-term health implications.
There are some dangers, but not from a normal scan:
Field. It's a really big magnet. Ferromagnetic tools and items flying into the bore are dangerous, every MRI site has strict screening to make sure you don't bring something magnetic near the scanner. Medical implants (most are now non-magnetic) and injuries involving shrapnel or metal splinters need careful checking.
Heating. There are strict specific absorption rate limits, and people often get weighed before a scan. Sequences are designed not to exceed safe power limits, and if you try to run one that might exceed it for a given weight the scanner wont let you. These are set conservatively. Tattoos and certain metal implants absorb more RF power, there are lower SAR limits for people with these, which may restrict the sequences you can use.
Contrast agents. MRI doesn't fundamentally require contrast agents, but they're used for certain things (often tumour investigation), injecting contrast agents for any imaging method carries a risk of adverse reactions.
Biting the hand that feeds IT
