A continuous glucose monitor (CGM) is a small, wearable device that tracks glucose levels throughout the day and night, providing real-time data for managing diabetes. A mammogram is a specialized X-ray used to screen for breast cancer by compressing the breast tissue between two plates and capturing an image. The question of whether to wear the CGM during this screening arises because the imaging technology and the electronic device can conflict. This article provides practical guidance on how to navigate the necessary precautions to ensure both your health screening and glucose monitoring remain effective.
Sensor Location and Physical Risk
The primary concern with wearing a CGM during a mammogram relates to the mechanical compression of the breast tissue. CGM sensors are typically placed on the back of the upper arm or the abdomen, which are usually well outside the imaging field. However, if a sensor or transmitter is placed anywhere near the breast tissue, it presents a risk of physical damage during the compression process.
The mammography machine exerts significant, controlled pressure to flatten the breast. If the compression plates contact the hard plastic casing of a CGM transmitter or sensor, it could cause the device to break. This intense pressure could also cause the sensor to puncture or tear the skin, leading to pain, injury, and potential infection. Therefore, any device positioned in the path of the compression paddle must be removed before the procedure begins.
Understanding Image Artifacts
Even if a CGM sensor is not directly in the path of the compression plates, its presence can still compromise the diagnostic quality of the mammogram. The sensor components, including thin wires and plastic casing, are denser than the surrounding soft breast tissue. This difference in density causes artifacts on the X-ray image.
An artifact appears as a bright spot, shadow, or distortion that can obscure the underlying tissue, creating a blind spot. Since the purpose of a mammogram is to detect subtle changes, an obscured area may lead to a missed diagnosis or an inconclusive result. This may require the patient to return for a repeat imaging session. For the most accurate screening, it is recommended that all devices be removed from the chest area, though some newer CGM models have been cleared by the FDA to remain on during X-ray procedures.
Planning for Temporary Removal
When removal is necessary, coordinating the process in advance can minimize the disruption to your glucose management routine. An effective strategy is to schedule the mammogram near the end of your current sensor’s wear period, such as the day before a scheduled replacement. This timing reduces the time you must go without a sensor and minimizes the financial loss of discarding a nearly new device.
You should remove the sensor and transmitter at home before your appointment to prevent delays at the imaging center. While the sensor is off, you must rely on traditional fingerstick blood glucose monitoring to track your sugar levels. This temporary testing ensures you can make appropriate insulin dosing or dietary adjustments without the continuous data stream from the CGM.
To manage the logistics of replacement, patients should contact the CGM manufacturer prior to the appointment. Many companies have programs to replace sensors removed for medical imaging procedures at no cost. You will likely need to provide information about the imaging test and the date of removal to initiate this process, ensuring a new sensor is available shortly after the mammogram.