A Framework for ExacTrac Dynamic Commissioning for Stereotactic Radiosurgery and Stereotactic Ablative Radiotherapy

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Image Guidance

Background:

• Image-guided radiotherapy (IGRT) and surface-guided radiotherapy (SGRT) are crucial for precise radiation delivery.
• The ExacTrac Dynamic system integrates advanced imaging and surface tracking for enhanced accuracy.
• Commissioning is essential to validate system performance and ensure patient safety.

Purpose of the Study:

• To establish a comprehensive framework for commissioning tests and tolerances for the ExacTrac Dynamic IGRT and SGRT system.
• To detail the commissioning process and results for a newly installed ExacTrac Dynamic system on an Elekta Versa HD linear accelerator.
• To provide guidance for validating system performance in various clinical workflows.

Main Methods:

• Developed and implemented a suite of commissioning tests covering safety, calibration, image quality, SGRT performance, and data integrity.
• Utilized custom phantom designs for evaluating deep inspiration breath-hold (DIBH), implanted markers, and gating workflows.
• Assessed X-ray image fusion reproducibility and SGRT localization accuracy.

Main Results:

• All commissioning tests were successfully completed within established tolerances.
• Maximum translational and rotational deviations for SGRT were 0.3 mm and 0.4°, respectively.
• Standard deviation for X-ray image fusion reproducibility was 0.08 mm.

Conclusions:

• The ExacTrac Dynamic system meets performance specifications for image-guided and surface-guided radiotherapy.
• The established commissioning framework and demonstrated results support the clinical implementation of this system.
• Ongoing validation and workflow-specific testing are recommended for continuous quality assurance.