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[Quality assurance of enhanced dynamic wedge using the aS500-II, EPID]
Z Al kattar El balaa1, J N Foulquier, H El balaa
1Service de radiothérapie, hôpital Tenon, 4 rue de la Chine, Paris, France. zeinakattar1@hotmail.com
Summary
The Varian aS500-II electronic portal imaging device (EPID) demonstrates high suitability for quality assurance of enhanced dynamic wedges (EDW). Its reproducible measurements of wedge factors and profiles make it ideal for regular EDW assessments.
Area of Science:
- Medical Physics
- Radiotherapy Physics
Context:
- The accurate dosimetry of radiation beams is critical in radiotherapy.
- Enhanced dynamic wedges (EDW) are widely used to shape radiation fields, but their precise characterization requires robust measurement tools.
Purpose:
- To assess the dosimetric performance of the Varian EPID aS500-II for quality assurance of enhanced dynamic wedge profiles and factors.
- To evaluate the suitability of the EPID for routine measurements in EDW treatments.
Summary:
- The study evaluated the Varian EPID aS500-II using its integrated asynchronous mode for enhanced dynamic wedge (EDW) treatments.
- EPID measurements of transmission factors and profiles were compared against a diode array and ion chamber, showing good agreement (within 1% for wedge factors).
- Empirical correction functions were developed to improve the accuracy of EPID-derived EDW profiles, accounting for factors like wedge direction and detector-source distance.
Impact:
- The Varian EPID aS500-II is confirmed as a reliable tool for the regular measurement and quality assurance of enhanced dynamic wedges.
- The developed correction functions enhance the utility of EPIDs for precise dosimetric characterization of EDW fields.
- This study contributes to improved quality assurance protocols in radiotherapy, ensuring accurate dose delivery.
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