A mammogram is an X-ray screening method used to examine breast tissue for changes too small to feel, making it a common tool for early breast cancer detection. To ensure clear and accurate images, standard preparation involves avoiding certain products. Patients are instructed not to use deodorant, antiperspirant, body powders, or lotions on the breast or underarm area before the examination.
The Chemical Reason for Interference
The primary reason for this instruction lies in the common ingredients found in most underarm products, particularly antiperspirants. These products frequently contain metallic compounds, such as aluminum chlorohydrate or zinc salts, which block sweat ducts and control moisture. These metallic components, even in minute quantities, are considered radiopaque, meaning they absorb X-rays.
When X-rays pass through the body during the mammogram, these dense mineral particles on the skin effectively block the radiation. The deodorant residue appears on the resulting X-ray image as bright, white specks or dense clusters. Powders and some lotions containing talc or other minerals can also leave similar residue that interferes with image clarity.
How Artifacts Affect the Diagnosis
The white spots caused by product residue are known as artifacts and pose a problem for the radiologist interpreting the image. These artifacts are difficult to distinguish from microcalcifications, which are tiny calcium deposits within the breast tissue. While most microcalcifications are benign, certain patterns can be an early sign of malignancy.
Because the metallic particles mimic the appearance of these deposits, the radiologist may not be able to confidently determine the source of the white spots. This uncertainty can lead to a “callback,” where the patient is asked to return for additional imaging (such as a diagnostic mammogram or an ultrasound). This interference causes patient anxiety, delays a clear result, and subjects the patient to further testing to rule out a harmless substance.
Preparing for a Clear Image
The best preparation is to avoid applying any product to the entire area from the waist up on the day of the exam, including the underarms, breasts, chest, and surrounding skin. If you forget and apply deodorant or antiperspirant, you do not need to cancel the appointment.
Thoroughly cleanse the area with soap and water to remove all traces of residue before the procedure begins. Many mammography centers keep cleansing wipes available for patients who may have forgotten the instruction or need to clean the area. Ensuring the skin is clear of products helps the technologist capture the clearest possible images, allowing the radiologist to provide the most accurate interpretation without delay.