Initial clinical experience with ArcCHECK for IMRT/VMAT QA.

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy QA

Background:

• Patient-specific quality assurance (QA) is crucial for Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT).
• Commercially available devices aim to streamline and improve the accuracy of this QA process.

Purpose of the Study:

• To report on the clinical experience and initial results using the ArcCHECK device for patient-specific IMRT/VMAT QA.
• To assess the stability, performance, and clinical outcomes of the ArcCHECK device over one year of routine use.

Main Methods:

• Commissioning tests included uniformity, linearity, and repetition rate dependence.
• Clinical data from 3,116 patient-specific IMRT/VMAT QA cases were analyzed.
• Gamma pass rates (3%/3 mm) were evaluated across various factors including treatment site, technique, MLCs, and linear accelerator (LINAC) models.

Main Results:

• Commissioning tests showed expected performance with 1% standard deviation in uniformity and linear dose response.
• Overall, 4.5% of cases failed the 90% pass rate criterion.
• Statistically significant differences in pass rates were observed based on treatment site, MLC type, and LINAC model, largely attributed to field size dependence.

Conclusions:

• The ArcCHECK device demonstrates acceptable performance for routine IMRT/VMAT QA, consistent with AAPM TG-119 recommendations.
• Observed variations in QA pass rates, particularly related to field size, require further investigation and potential correction to enhance device specificity and sensitivity.