Institutional experience with implanted cardiac device risk level assessment: Comparing calculation and measurement

Area of Science:

• Medical Physics
• Radiation Oncology
• Dosimetry

Background:

• In-vivo dosimetry is crucial for risk assessment in patients with implanted devices but is labor-intensive.
• A calculation-only approach using treatment planning system (TPS) doses and imaging dose estimates can simplify physics workflows.
• This method aims to maintain patient safety while improving efficiency.

Purpose of the Study:

• To assess the feasibility of a calculation-only method for risk-level evaluation.
• To compare calculation-based dose estimates with in-vivo dosimetry measurements.
• To determine if the calculation-only approach is a viable alternative for patient safety assessments.

Main Methods:

• Retrospective study of 86 patients with implanted electronic medical devices.
• Comparison of in-vivo optically stimulated luminescent dosimeter (OSLD) measurements with calculated doses (TPS + imaging estimates).
• Analysis included absolute/percent dose differences, risk level concordance, and sensitivity/positive predictive value for TG-203 risk assessment.

Main Results:

• The calculation-only approach consistently yielded risk levels equivalent to or more conservative than OSLD measurements.
• 91.9% of patients had identical risk levels between calculated and measured doses.
• The calculation-based method demonstrated high accuracy with a sensitivity of 1.00 and a positive predictive value of 0.92.

Conclusions:

• A calculation-only dosimetry approach is feasible for risk-level assessment in patients with implanted devices.
• This method can significantly reduce workload without compromising patient safety.
• It offers a streamlined and effective alternative to traditional in-vivo dosimetry.