A patient with a pacemaker can generally and safely undergo a Positron Emission Tomography (PET) scan. A pacemaker is a small device placed under the skin near the collarbone that uses electrical pulses to control the heart’s rhythm. A PET scan is a type of nuclear medicine imaging that uses a small amount of a radioactive tracer to visualize the metabolic activity of cells within the body. While the presence of a pacemaker requires specific precautions, the PET scanner technology does not pose the safety risks associated with certain other imaging methods.
How PET Scans Differ from Other Imaging Methods
PET scanning is safe for implanted devices because its operational physics are fundamentally different from those of Magnetic Resonance Imaging (MRI). A PET scanner works by detecting gamma rays, which are high-energy photons emitted indirectly by the tracer injected into the patient. This process allows physicians to see how organs and tissues are functioning at a cellular level, rather than just viewing anatomical structure.
The PET imaging process does not involve the powerful, static, or rapidly oscillating magnetic fields that are the source of risk for pacemakers during an MRI. These strong magnetic fields can potentially cause the pacemaker to malfunction, heat the leads, or physically move the device. Because PET scanners do not generate these fields, there is no risk of magnetic interference or mechanical displacement of the cardiac device.
Most clinical PET scans today are performed in combination with a Computed Tomography (CT) scan, known as a PET/CT. The CT component uses X-rays to provide a detailed anatomical map of the body. The small amount of radiofrequency energy and radiation dose from the CT component also do not interfere with the function or programming of the pacemaker.
Necessary Safety Measures and Preparation
Although a PET scan is generally safe for pacemaker patients, proper coordination and preparation are mandatory before the procedure takes place. The patient must inform the PET center and their cardiologist about the implanted device well in advance of the scheduled scan. This allows the medical team to verify the specific model and type of pacemaker, including checking if it is an older device.
The cardiologist must provide clearance for the scan, which often involves a review of the device’s performance and battery status. This is not typically a full reprogramming like that required for an MRI, but a necessary pre-scan status check, or interrogation, to confirm the device is functioning optimally. The medical team uses the pacemaker’s specific details to ensure minimal electromagnetic interference from the scanner components poses no risk.
Following the procedure, a brief follow-up check of the device is often recommended to ensure that the settings and battery life remain unaffected. This protocol ensures that the pacemaker continues to function correctly, maintaining the patient’s heart rhythm without disruption.
When Additional Monitoring is Required
While a standard PET/CT scan presents minimal risk, specific scenarios may require heightened vigilance or specialized planning from the cardiac team. Patients with complex underlying cardiac conditions, or those who have had a very recent pacemaker implantation (generally within the last six weeks), may require additional precautions. The body needs time to fully heal and stabilize around a newly implanted device.
The primary exception requiring specific monitoring is if the physician orders a PET/MR scan, which combines PET technology with MRI. In this case, the pacemaker must be an MRI-conditional model, and the patient must follow the stringent pre-scan interrogation and programming protocols required for any MRI. If the device is not MRI-conditional, the PET/MR scan cannot be performed due to the magnetic risks. In complex or high-risk cases, a cardiac specialist may be physically present during the scan to continuously monitor the patient’s heart rhythm and the device’s telemetry.