SU-E-T-265: Reducing Pacemaker Doses with a Lead Sheet: A Multi-Detector Study

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Dosimetry

Background:

• Pacemakers are sensitive to radiation, necessitating dose reduction strategies during radiotherapy.
• Lead shielding is a potential method for mitigating radiation exposure to implanted medical devices.

Purpose of the Study:

• To evaluate the efficacy and safety of lead shielding for reducing radiation dose to pacemakers.
• To assess the impact of lead shielding placement and beam energy on dose reduction.

Main Methods:

• Measurements were conducted using a solid water phantom at 0.5 cm depth with 6 MV and 23 MV photon beams.
• Dosimetry was performed using a parallel plate ion chamber and a plastic scintillation detector (PSD) prototype.
• Lead shielding (1.6 mm) was tested with various field sizes and positions relative to the phantom.

Main Results:

• Both detectors showed excellent agreement (0.6%) across all measurements.
• Antero-posterior fields at 23 MV showed the greatest dose reduction (65%) with shielding outside the field.
• Shielding inside the field increased the dose for both antero-posterior and postero-anterior beams; benefits diminished beyond 35 cm from the field edge.

Conclusions:

• Lead shielding is recommended for antero-posterior radiotherapy to decrease pacemaker dose.
• For postero-anterior fields, lead shielding should be avoided or placed outside the treatment field.
• Plastic scintillation detectors (PSD) are suitable for in vivo monitoring of radiation dose to pacemakers and other sensitive sites like fetuses.