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A procedure to determine the radiation isocenter size in a linear accelerator
A González1, I Castro, J A Martínez
1Servicio de Radiofísica y Protección Radiológica, Hospital Universitario Virgen de la Arrixaca, Ctra. Madrid-Cartagena S/N, El Palmar (Murcia) E-30120, Spain. afgonzalez@inicia.es
Medical Physics
|July 21, 2004
Summary
This study introduces an automated method for analyzing star-shots to precisely determine the radiation isocenter of linear accelerators (linacs). This improves quality assurance for radiation therapy equipment.
Area of Science:
- Medical Physics
- Radiation Oncology
- Quality Assurance
Background:
- Accurate measurement of the radiation isocenter is critical for linear accelerator (linac) commissioning and quality assurance (QA).
- Traditional methods for isocenter determination can be time-consuming and prone to manual error.
Purpose of the Study:
- To develop and validate an automated procedure for analyzing star-shots to determine the radiation isocenter of a linac.
- To enhance the accuracy and precision of isocenter measurements.
Main Methods:
- Digitization of developed star-shot films.
- Automated image analysis using concentric circle scanning around laser intersection points.
- Determination of the minimum circle intersecting central rays for precise isocenter positioning and sizing.
Main Results:
- The automated procedure achieves accuracy and precision better than 1% of the pixel size for isocenter determination.
- The method is applicable to star-shots in various planes relative to gantry, couch, and collimator rotations.
Conclusions:
- The automated star-shot analysis offers a robust and efficient method for radiation isocenter determination.
- This technique can significantly improve the quality assurance process for linear accelerators in radiation therapy.