Removing jewelry before a CT scan is standard practice at virtually every imaging facility, and for good reason: metal objects create bright and dark streaks on the resulting images that can obscure the anatomy your doctor needs to see. That said, the real-world impact depends on what you’re wearing, what it’s made of, and where on your body the scan is focused. A thin gold necklace during a pelvic CT is unlikely to cause trouble, while the same necklace during a neck CT could ruin the images entirely. Understanding why metal causes problems helps you know when the rule is flexible and when it absolutely isn’t.
Why Metal and CT Scanners Don’t Get Along
A CT scanner works by spinning an X-ray beam around your body and measuring how much radiation passes through your tissues from hundreds of angles. Software then reconstructs those measurements into detailed cross-sectional images. The problem with metal is that it absorbs and scatters X-rays far more intensely than bone, muscle, or fat. When the scanner encounters a piece of metal, the data from the angles that pass through it become wildly inconsistent with the data from angles that don’t. The reconstruction algorithm can’t reconcile that mismatch, so it produces streak artifacts: alternating bands of bright white and deep black that radiate outward from the metal object like spokes on a wheel.1PubMed. Current and Novel Techniques for Metal Artifact Reduction at CT: Practical Guide for Radiologists
These streaks aren’t just cosmetic blemishes on the image. They can completely hide the tissue a radiologist needs to evaluate. If a doctor ordered a CT of your chest to look at a suspicious lymph node, and a heavy pendant is sitting right over your sternum, those streaks might make the node invisible, effectively wasting the scan. The artifacts don’t stay neatly confined to the metal itself either. They spread across a wide swath of the image, sometimes extending several centimeters in every direction. Careful patient positioning and the right scanning settings can reduce artifacts in some situations, but preventing them by removing the metal in the first place is always the easier and more reliable option.2RadioGraphics. Artifacts in CT: recognition and avoidance
What Counts as “Jewelry” in This Context
When the technologist asks you to remove jewelry, they generally mean anything metallic on your body: necklaces, earrings, rings, bracelets, watches, hair clips, belt buckles, bra underwires, and body piercings. Even items you might not think of as jewelry can cause problems. Bobby pins, zipper pulls on clothing, and metallic buttons have all been known to show up on scans and create localized artifacts. Most facilities will give you a gown specifically to avoid these issues.
The density and composition of the metal matter. Denser metals like stainless steel, titanium, and cobalt-chromium alloys produce more severe artifacts than lighter metals. Gold, being extremely dense, can also cause significant streaking. A thin gold chain produces less artifact than a chunky gold pendant, simply because there’s less metal for the X-ray beam to interact with. Platinum, sometimes found in fine jewelry, is among the densest common metals and can generate pronounced artifacts even in small pieces.
Plastic, silicone, and rubber items generally don’t cause problems. If you have a plastic retainer for a piercing or a silicone wedding band, those are typically fine to leave in place. The concern is specifically with materials that are much denser than human tissue.
Location Relative to the Scan Matters More Than You’d Think
Here’s where things get practical. A CT scan doesn’t image your entire body unless your doctor specifically ordered a full-body scan, which is uncommon. Most CT exams target a specific region: head, chest, abdomen, pelvis, or extremities. Metal only creates artifacts in the images where it physically appears within the scanner’s field of view during that particular slice.
If you’re having a CT of your abdomen and pelvis, your earrings are nowhere near the area being imaged. They won’t affect the scan at all. Conversely, if you’re getting a head CT and you’re wearing multiple ear piercings, those are right in the thick of it. A belly button ring matters for an abdominal CT but is irrelevant for a scan of your knee.
Most technologists will still ask you to remove everything metallic regardless of the scan location, partly out of caution and partly because it’s simpler to have a blanket policy than to assess each item on a case-by-case basis. But if you genuinely can’t remove a particular piece, knowing whether it falls inside or outside the scan area helps you have a productive conversation with the tech about whether it’s likely to be a problem.
Body Piercings and the Removal Dilemma
Body piercings present a unique challenge. Many piercings, especially newer ones, can’t be easily removed and reinserted without risk of the hole closing up. The jewelry is often specifically designed to stay put, with threaded balls, clicker mechanisms, or curved barbells that require tools or practiced hands to take out.3Journal of Radiology Nursing. Tattoos, Body Piercing, and Healthcare Concerns For someone with a fresh piercing that’s still healing, removing and reinserting the jewelry could introduce bacteria or cause the piercing to close within minutes.
If you have piercings you can’t easily remove, tell the technologist before the scan. In many cases, if the piercing is outside the scan field, it won’t be an issue. If it is within the field, the radiologist and tech can sometimes adjust the scanning protocol to minimize the impact, although this doesn’t eliminate artifacts entirely. Some people keep non-metallic retainers (made of glass, PTFE plastic, or bioplast) specifically for medical situations. If you know you’ll be having imaging done, swapping to a non-metallic retainer ahead of time is a practical option, though you should check with your piercer about whether your piercing is healed enough to handle a jewelry change.
Tongue piercings, nose piercings, and ear piercings are the most likely to interfere with head and neck CTs. Nipple piercings can affect chest scans. Navel and genital piercings can show up on abdominal and pelvic imaging. The further the piercing is from the area of clinical interest, the less it matters.
Dental Fillings, Crowns, and Implants
Dental work is arguably the most common source of metal artifacts in CT imaging, simply because you can’t remove it. Amalgam fillings, metal crowns, bridges, and dental implants all produce streak artifacts, and anyone who has had a CT of the head, neck, or jaw has probably seen these streaks on their images. The artifacts from dental metal can be especially frustrating when the scan is trying to evaluate the oral cavity, sinuses, or structures at the base of the skull.
Fortunately, this problem is so widespread that researchers have developed specialized software to deal with it. Metal artifact reduction algorithms work by identifying the corrupted data in the scan caused by the metal and replacing it with estimated values. Several approaches exist, and studies have shown they can substantially clean up images. One algorithm called NMAR was shown to significantly reduce streak artifacts from dental fillings compared with standard reconstruction methods, improving the visibility of soft tissues in and around the mouth.4Dentomaxillofacial Radiology. Clinical evaluation of the normalized metal artefact reduction algorithm caused by dental fillings in CT Another algorithm, called O-MAR, was found to make structures visible that were previously impossible to see due to dental metal artifacts.5PubMed. Reduction of dental metallic artefacts in CT: value of a newly developed algorithm for metal artefact reduction (O-MAR)
The takeaway for patients with dental work is reassuring: you don’t need to do anything special. Your radiologist knows the metal is there, and modern scanners often have artifact reduction tools built in. The artifacts may still be present to some degree, but they’re usually manageable, and the radiologist will note in their report if dental hardware limited evaluation of a particular area.
Orthopedic Hardware and Implanted Devices
Joint replacements, screws, plates, rods, and other orthopedic implants are a different beast. These are large pieces of dense metal that can produce massive streak artifacts, sometimes rendering entire regions of a CT image unreadable. Hip replacements are among the worst offenders because of their size and the density of the cobalt-chromium or titanium alloys typically used.
When orthopedic hardware is present and a CT is clinically necessary, radiologists have to work around it. Modern scanners increasingly offer dual-energy CT, a technique that acquires images at two different X-ray energy levels simultaneously. By reconstructing the scan at higher energy levels, streak artifacts can be dramatically reduced. One study of hip prostheses found that reconstructing images at 150 keV reduced the volume of streak artifact by about 74% compared with standard imaging.6PubMed. Reducing the effects of metal artefact using high keV monoenergetic reconstruction of dual energy CT (DECT) in hip replacements Dedicated metal artifact reduction software, evaluated in phantom and clinical studies, has also shown clear improvements in image quality when metal hardware is present.7PubMed Central. Evaluation of the Quality of CT Images Acquired with Smart Metal Artifact Reduction Software
These technologies aren’t perfect. Some artifact reduction algorithms introduce their own subtle distortions, and very large or complex metallic implants can still overwhelm the software.8PubMed Central. Dual-Energy Computed Tomography Applications to Reduce Metal Artifacts in Hip Prostheses: A Phantom Study But they’ve come a long way, and for patients with permanent implants who need CT imaging, the situation is far better than it was a decade ago. The point here is that metal you can’t remove is a known, managed problem. Metal you can remove is just an unnecessary complication.
Does Metal Affect Your Radiation Dose?
This is a concern most patients don’t think about, but it’s worth knowing. Many modern CT scanners use automatic exposure control, a system that adjusts the X-ray output in real time as the tube rotates around your body. When the beam encounters something dense, the scanner ramps up the power to try to get enough signal through it. Metal objects, being extremely dense, can trick this system into dramatically increasing the radiation dose in that region.
One study looked at what happens when metal hip prostheses are in the scan field and found that a single metal hip implant increased the local radiation dose by about 14%, while two bilateral implants increased it by roughly 30%.9PubMed Central. Metal implants influence CT scan parameters leading to increased local radiation exposure: A proposal for correction techniques Now, hip implants are large pieces of metal that can’t be removed, so the dose increase is unavoidable in that case. But a chunky metal necklace or a belt buckle you forgot to take off could trigger the same automatic dose increase in the area around it, delivering extra radiation to your body for no clinical benefit. Removing external metal isn’t just about image quality. It’s also about keeping your radiation exposure as low as reasonably achievable.
What About Rings You Can’t Get Off?
Swollen fingers, arthritis, weight gain: there are plenty of reasons a ring might not come off easily. If you’re having a scan of your hand or wrist, a stuck ring in the field of view will create some local artifact, and the tech may try soap, lubricant, or cold water to help slide it off. For scans of any other body region, a ring on your finger is unlikely to be in the field of view and generally won’t affect the images.
If a ring is truly stuck and the scan involves your hand, the radiologist can usually still work with the images. The artifacts from a single thin band are much less severe than those from, say, a hip replacement. It may obscure a small area immediately adjacent to the ring, but the rest of the scan will be fine. The tech will note the presence of the ring for the radiologist, who will account for it when reading the images.
Emergency Situations Change the Rules
Everything above assumes an outpatient or non-emergency scenario where you have time to undress, remove jewelry, and put on a gown. In the emergency department, the calculus shifts. If you arrive after a car accident and need a trauma CT of your entire body, the team is not going to spend ten minutes carefully removing your earrings and necklace. Speed matters more than image perfection in a life-threatening situation.
In emergency settings, technologists and radiologists expect to see artifacts from clothing hardware, jewelry, and medical devices like cervical collars. They read through the noise, looking for the critical findings: bleeding, fractures, organ damage. Artifacts are documented but don’t stop the scan from happening. Once the patient is stabilized, a follow-up scan without the metal can be done if the initial images left important questions unanswered.
Tattoos and CT Scans
Some patients worry that tattoo ink, which can contain metallic pigments, might interfere with a CT scan. In practice, tattoo ink does not cause any meaningful artifact on CT images. The metallic particles in tattoo pigments are far too small and dispersed within the skin to register as a dense metal object the way a ring or implant would. Tattoo concerns are much more relevant for MRI, where certain metallic inks can heat up or cause localized image distortion due to the powerful magnetic field. For a CT scan, your tattoos are a non-issue.
This is a common point of confusion because patients often hear “remove all metal” in a radiology waiting room and mentally extend that warning to everything metallic they can think of, including the iron oxide in their tattoo ink. The instruction is really about discrete metal objects that are dense enough and large enough to block or scatter the X-ray beam in a measurable way. A piercing stud qualifies. A tattoo does not.
What to Do Before Your Appointment
If you have a CT scan scheduled, the simplest approach is to leave jewelry at home. Don’t bring valuables you’ll need to store in an unsecured changing area. Wear comfortable clothing without metal fasteners: a t-shirt, sweatpants, slip-on shoes. If you have body piercings you can’t remove, consider swapping to non-metallic retainers a few days beforehand so the piercing has time to settle.
If you arrive and realize you’re wearing something you can’t remove, tell the technologist. They deal with this constantly and can make a judgment call about whether the item is likely to affect the scan. In most cases, if the metal isn’t in the area being scanned, you’ll be fine. If it is, the tech may try to work around it with positioning adjustments, or the radiologist may apply software corrections during image processing. What the team doesn’t want is to discover a surprise piece of metal on the images after the scan is already done, because by then the options are limited to either accepting the compromised images or repeating the scan with additional radiation exposure.
For people with permanent metal in their body, from dental fillings to joint replacements to cardiac stents, there’s nothing to worry about from a safety standpoint. Metal implants are completely safe inside a CT scanner (unlike MRI, where certain metals can be dangerous). The only issue is image quality, and that’s the radiologist’s problem to solve, not yours. Just make sure the ordering physician and the imaging facility know about your implants ahead of time, so the technologist can choose the right scanning protocol from the start.