Science, Tech, Math › Science What Happens If You X-Ray Metal? Why Doctors Ask About Metal Before Taking X-Rays Share Flipboard Email Print B2M Productions / Getty Images Science Chemistry Medical Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated January 13, 2020 Metal appears as a bright area on an X-ray, blocking visibility of underlying structures. The reason you're asked to remove metal is to give the radiologist an unobstructed view of the area of interest. Basically, you remove metal because it blocks anatomy. If you have a metal implant, obviously you can't remove it for an X-ray. If the technician is aware of it, he may position you differently to get the best imaging results or take X-rays from multiple angles. The reason metal appears bright on the X-ray image is that it is extremely dense, so X-radiation does not penetrate it as well as it does soft tissues. This is also why bones appear bright on an X-ray. Bones are denser than blood, cartilage, or soft organs. The Issue of Metal in the X-Ray Room Unless the metal item is directly in the path between the X-ray collimator and the image receptor, there's no issue with having metal objects in the same room as an X-ray machine. On the other hand, metal objects are not permitted in a room housing MRI equipment because the objects will be drawn toward the powerful magnets when the machine is turned on. Then, the problem isn't with the image; it's with the items, which could become hazardous projectiles, possibly injuring people or damaging equipment.