Feasibility study of performing IGRT system daily QA using a commercial QA device

Area of Science:

• Medical Physics
• Radiation Oncology
• Quality Assurance

Background:

• Daily quality assurance (QA) is critical for linear accelerators (Linacs) and image-guided stereotactic positioning systems (IGSPSs).
• Current QA procedures often require multiple devices, leading to inefficiencies and potential errors.
• Streamlining QA processes is essential for maintaining treatment accuracy and patient safety.

Purpose of the Study:

• To evaluate the feasibility of using a single QA device for comprehensive daily QA of a Linac and three IGSPSs.
• To assess the efficiency and accuracy of the Sun Nuclear Daily QA 3 (DQA3) device for various QA tasks.
• To compare the time and workflow of the DQA3 with previous multi-device QA procedures.

Main Methods:

• The Sun Nuclear Daily QA 3 (DQA3) device was employed for daily dosimetry and mechanical accuracy tests on an Elekta Linac.
• Daily image geometric and isocenter coincidence accuracy tests were performed on three IGSPSs: AlignRT, SonArray optical tracking System (FSA), and Elekta kV CBCT.
• The DQA3 was also utilized for monthly QA tasks, including couch positioning, repositioning, and rotational tests.

Main Results:

• Linac coordinate system accuracy using AlignRT was within 0.7 mm/0.6° of the CBCT system.
• Laser alignment and ODI constancy were within 0.5 mm; isocenter displacement and rotational offsets were within 0.7 mm and 0.5°, respectively.
• Beam output, energy, symmetry, and flatness remained within acceptable clinical tolerances (2% or 1%) over eight months; dosimetry reproducibility showed a standard deviation within 0.2%.

Conclusions:

• The Sun Nuclear Daily QA 3 (DQA3) device is feasible for accurate and efficient daily QA of Linacs and IGSPSs.
• The DQA3 significantly reduces QA session time (from 40 to <15 minutes) and minimizes errors associated with device and phantom changes.
• Implementing the DQA3 streamlines QA workflows, enhancing overall efficiency and reliability in radiation therapy.