A Computed Tomography (CT) scan is a diagnostic imaging procedure that uses multiple X-ray measurements taken from different angles to produce cross-sectional images of the body. These images allow doctors to see inside the body. A common concern for patients preparing for this test is whether they will be required to undress. The requirements for patient clothing are based on scientific necessity to ensure the quality of the diagnostic images.
The Decision: Street Clothes Versus Hospital Gown
The determination of whether you must change into a hospital gown depends entirely on the material, fit, and location of your street clothes relative to the area being scanned. If your clothing is loose-fitting, made of thin, natural fibers like cotton, and contains absolutely no metal, you may be permitted to wear it. The technologist assesses your attire to ensure it will not interfere with the X-ray beam or the positioning required for the procedure.
A gown becomes mandatory if your clothing is thick, restrictive, or has non-removable components that could compromise the scan quality. This includes items with large seams, dense embroidery, or any metallic elements. Changing into a gown also ensures easy access to the body, which is particularly relevant if the procedure involves injecting a contrast agent into a vein.
Why Metal and Accessories Must Be Removed
Metal objects and certain accessories must be removed before a CT scan because they cause “artifacts” on the resulting images. An artifact is a distortion or streak that appears on the scan, caused by dense materials completely blocking the passage of the X-ray beam. This interference prevents the detector from accurately measuring the radiation that passes through the body.
Common culprits that must be removed include jewelry, watches, belts, metallic buttons, large zippers, and underwire bras. Even metallic threads sometimes woven into athletic wear or hidden metal components in clothing tags can cause minor but significant artifacts. These streaks can obscure or mimic disease, making it impossible for the radiologist to interpret the area accurately. Removing these items is a direct measure to guarantee the diagnostic reliability of the scan.
Practical Guidance: Clothing Rules Based on Scan Location
The specific area of the body scheduled for the CT scan dictates which items of clothing and accessories must be removed. The general rule is that nothing dense or metallic should be visible in the plane of the X-ray beam. For scans of the head, neck, or chest, you will need to remove all earrings, necklaces, glasses, hairpins, and any upper body clothing that contains metal, such as an underwire bra. A shirt change is highly likely in these scenarios to eliminate potential interference.
When the CT is focused on the abdomen or pelvis, a full gown change is the most common requirement. This is because belts, pants or skirts with zippers and snaps, and even belly-button piercings all fall directly within the imaging field. Similarly, if the scan is of an extremity, you may only need to adjust or remove the clothing covering that specific limb. If the viewing field for the extremity scan includes any part of the torso, the technologist may still require a full change to a gown.