SU-E-T-184: LINAC Commissioning Measurements Utilizing the Cylindrical Arc Check Phantom.

Area of Science:

• Medical Physics
• Radiation Oncology
• Quality Assurance

Background:

• New devices for Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) quality assurance (QA) are available but underutilized for routine mechanical QA.
• The Arc Check phantom offers a unique cylindrical geometry for comprehensive QA measurements.

Purpose of the Study:

• To demonstrate the utility of the Arc Check phantom for routine mechanical QA of linear accelerators (LINACs).
• To develop a method for performing multiple LINAC QA tests using a single setup with the Arc Check phantom.

Main Methods:

• The Arc Check phantom was set up at the LINAC isocenter, leveled, and aligned.
• 100 MUs with a 10x10 field were delivered at various gantry, couch, and collimator angles.
• The radiation center path was reconstructed in 3D to evaluate the coincidence of mechanical and radiation isocenters.

Main Results:

• A procedure and MATLAB routine were developed to reconstruct the 3D radiation central axis and isocenter.
• The coincidence of the mechanical and radiation isocenter was successfully verified.
• The method allows for the evaluation of multiple mechanical LINAC tests in one setup.

Conclusions:

• The Arc Check phantom's geometry can be utilized to perform multiple essential LINAC mechanical QA tests efficiently.
• This approach integrates commissioning and routine QA procedures, enhancing the utilization of available QA devices.