Most firearm projectiles are made of non-ferromagnetic materials, however, these items are often "contaminated" by ferromagnetic metals.

In this way, the risks versus benefits of conducting an MRI study in a patient with "bullets", shrapnel, or other similar ballistic objects should be carefully considered; although some studies report relative safety in carrying out magnetic resonance imaging studies on 1.5 Tesla equipment, provided that these metal fragments are not close to vital structures.

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