Pacemaker response to scattered radiation of different dose rates

Area of Science:

• Medical Physics
• Radiation Oncology
• Biomedical Engineering

Background:

• AAPM Task Group Report 203 (TG203) advises precautions for implantable cardiac pacemaker (ICP) dependent patients, recommending maximum dose rates below 0.2 Gy/min.
• Limited quantitative data exists on modern ICP performance at dose rates approaching this 0.2 Gy/min threshold.

Purpose of the Study:

• To evaluate the behavior and functionality of contemporary implantable cardiac pacemakers (ICPs) under radiation dose rates near the TG203 suggested limit.
• To provide quantitative data on ICP response to clinically relevant radiation therapy conditions.

Main Methods:

• Five single-chamber (Azure XT SR) and five dual-chamber (Azure XT DR) ICPs were tested.
• Devices were irradiated with 6 MV, 6 FFF, 10 MV, and 10 FFF photon beams at dose rates from 0.15 to 0.92 Gy/min.
• Real-time electrogram data and battery life were monitored during and after irradiation.

Main Results:

• No malfunctions or electromagnetic interference artifacts were observed in any ICPs, irrespective of increasing dose rates.
• Post-irradiation battery life assessments showed normal depletion trends consistent with expected device longevity.

Conclusions:

• Modern implantable cardiac pacemakers (ICPs) demonstrate robust performance and stability when exposed to radiation dose rates relevant to patient treatment.
• The findings support the safety of current ICPs for patients undergoing radiation therapy, even at dose rates approaching the 0.2 Gy/min guideline.