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  4. Electronic Medical Devices, X-ray Imaging and Radiation Therapy: What to Know and How to Prevent Damage
  5. Preventing Damage to Implantable Electronic Heart Devices During CT Scans
  1. Electronic Medical Devices, X-ray Imaging and Radiation Therapy: What to Know and How to Prevent Damage

Preventing Damage to Implantable Electronic Heart Devices During CT Scans

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A gloved hand holding an implantable device with the title Preventing Damage to Implantable Electronic Heart Devices During CT Scans

Pacemakers, implantable cardioverter defibrillators (ICDs) and other implantable electronic heart devices and radiation procedures

X-ray imaging and CT scans can damage implantable electronic heart devices such as pacemakers, implantable cardioverter defibrillators (ICDs), and others. The chances of damage are extremely low. The recommendations on this page will help prevent damage to these devices from radiation procedures.

The FDA continues to receive a very limited number of reports of problems associated with people with implantable pacemakers and ICDs undergoing CT imaging. Potential problems may include:

  • loss of consciousness
  • an irregular, rapid heart rate (atrial fibrillation)
  • a slower than normal heart rate (bradycardia)
  • a rapid, fluttering or pounding heart (palpitations)
  • device failure
  • device power-on reset (“device reboot”) 
  • memory/data corruption
  • device reset to default pacing
  • early battery depletion
  • in extremely rare cases, death 

Even though the reports we received occurred during CT scanning, there is little evidence that CT exposure was the cause of these events.

Based on the available evidence, the chances of implantable electronic heart device problems due to CT are very low. The risk of problems can be reduced by following the recommendations below.

Recommendations for people with implantable electronic heart devices

If your doctor recommends CT scans for medical reasons, be aware the chances of a problem occurring is extremely low. You can help reduce the risk by doing the following:

  • Tell the doctor who ordered the CT scan, as well as the tech performing the scan, that you have an implanted pacemaker or other device. This will help them plan imaging that minimizes the risk of problems.
  • Tell the radiology tech and your physician immediately if you experience symptoms such as lightheadedness or palpitations during or immediately after the CT scan.
  • Tell the doctor who is monitoring your device at your next regularly scheduled appointment that you have had a CT scan, so they can check the device to make sure it is working correctly.

Recommendations for physicians ordering a CT scan

If a patient has a pacemaker or ICD, it should NOT stop you from performing an appropriate, medically indicated CT scan. The probability of an adverse event being caused by exposing these devices to CT irradiation is extremely low and it is greatly outweighed by the clinical benefit of a medically indicated CT examination. CT continues to be the preferred tomographic imaging technology for patients with these devices. Magnetic Resonance Imaging (MRI) may also be an option for MR Conditional pacemakers or ICDs if the conditions of safe MR use can be met. An MR Unsafe device should not enter the MR environment and any device without explicit MR labeling should be considered MR Unsafe.

  • Communicate with the radiologist and CT tech to help them plan imaging that will minimize the risks of adverse effects.
  • Communicate with the physician who is monitoring the implanted pacemaker or defibrillator to ensure that they check the device at the next regularly scheduled appointment after the CT exam.

Recommendations for radiologists and radiologic technologists

If a patient has a pacemaker or ICD, it should NOT stop you from performing an appropriate, medically indicated CT scan. The probability of an adverse event being caused by exposing these devices to CT irradiation is extremely low and it is greatly outweighed by the clinical benefit of a medically indicated CT examination. CT continues to be the preferred tomographic imaging technology for patients with these devices. Magnetic Resonance Imaging (MRI) may also be an option for MR Conditional pacemakers or ICDs if the conditions of safe MR use can be met. An MR Unsafe device should not enter the MR environment and any device without explicit MR labeling should be considered MR Unsafe.

CT imaging facilities can use the following recommendations to develop protocols for planned and for urgently needed CT scans.

  • Use CT radiographs (for example: scouts or localizer views) while setting up the CT scan to verify if any implanted pacemaker or ICD is present and if so, identify its location relative to the programmed scan range. Note: CT radiography, scout or localizing scans have not been associated with X-ray interference with electronic medical devices.
    • If possible, avoid including the implanted device inside the scanning range. It is important to ensure that CT images of the prescribed anatomy are taken so that the necessary diagnostic information is obtained. Confirm the required anatomic range with the supervising radiologist.
    • For CT procedures in which the medical device is located within the programmed scan range, you should minimize direct X-ray exposure to the electronics of the implanted medical device by using:
      • the lowest dose consistent with the needed level of diagnostic image quality and
      • a lower dose delivery rate, which can be accomplished by using a longer rotation time or lower pitch value, if appropriate for the ordered CT exam.
    • Imaging exams that would involve scanning directly over the electronics of the implanted device for more than several seconds, require additional care because of the potential for pacing to be inhibited for 30 or more seconds or a defibrillating shock to be applied. Examples of these scans are CT perfusion exams or interventional procedures such as CT fluoroscopy. If the procedure is urgently needed, careful monitoring of the device during and after the procedure is required.
  • Be mindful that interference is possible and be ready to stop the scan if the patient experiences adverse symptoms. Although adverse symptoms are rare, they could include lightheadedness from slow heartbeat (bradycardia) or palpitations.

Recommendations for doctors who are monitoring the implantable device

The probability of risks to pacemakers and ICDs from CT exposure is extremely low. However, as a precaution, you should check the device after it was exposed to CT X-ray radiation, at the next scheduled patient checkup. Although rare, the following problems with implantable electronic heart devices have been reported:

  • Power on reset (“device reboot”)
  • Battery depletion
  • Detected noise
  • Changes in device programming (reset to default, shock counter resetting)
  • Inappropriate ICD shocks
  • Capacitor charging
  • Corrupted memory
  • Communications/interrogation issues
  • Over-sensing
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