Metallic items including shrapnel cannot go into an MRI because they can become dislodged. If a client has past military duty, further questioning should be done to determine if he served in combat and was exposed to any shrapnel. Caution should also be used with anyone who may have had a gunshot wound in the past. Vertigo, atrial fibrillation, and allergy to contrast dye do not affect an MRI. Clients with allergy to contrast dye may require prophylactic treatment before undergoing a CT with contrast.