[Decomposing a Beam Profile Constancy into Energy and Symmetry Components and Its Evaluation Using an Ionization
Daisaku Tatsumi1, Hiroshi Okuda2, Yuji Yamamoto2
1Miyakojima IGRT Clinic.
Nihon Hoshasen Gijutsu Gakkai Zasshi
|January 11, 2023
Summary
A new method decomposes linac beam profile constancy into energy and symmetry components. This validated formulation simplifies quality assurance (QA) and quality control (QC) for profile constancy testing.
Area of Science:
- Medical Physics
- Radiotherapy Physics
Context:
- AAPM TG 142 defines profile constancy in radiotherapy.
- Quality assurance (QA) and quality control (QC) are critical in radiation therapy.
Purpose:
- To propose a new formulation to decompose profile constancy into energy and symmetry constancies.
- To validate this formulation using an IC profiler (ICP) and various experimental conditions.
Summary:
- The study proposes a method to decompose linac beam profile constancy into energy and symmetry terms by measuring beam profiles with an IC profiler.
- Lateral inversion of profiles cancels asymmetry, allowing for separate energy and symmetry constancy calculations.
- Validation showed agreement within 0.1-0.2% between calculated and measured constancies under varied conditions.
Impact:
- This formulation enables efficient QA/QC for linac beam profile constancy.
- It provides a more detailed understanding of beam profile variations.
- The method offers a validated approach for ensuring radiotherapy accuracy and safety.
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