Verification of stereotactic radiosurgery plans for multiple brain metastases using a virtual phantom-based procedure

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiosurgery Technology

Background:

• Stereotactic radiosurgery (SRS) involves precise radiation delivery.
• Single-isocenter multitarget (SIMT) techniques enable treating multiple brain metastases simultaneously.
• Patient-specific quality assurance (PSQA) is crucial for verifying SRS plan accuracy.

Purpose of the Study:

• To evaluate the efficacy of VIPER software for PSQA of SIMT SRS plans.
• To demonstrate VIPER's capability in reconstructing dose distributions from electronic portal imaging device (EPID) data.
• To compare VIPER's performance against established quality assurance methods.

Main Methods:

• Twenty intensity-modulated (IMRT) SIMT SRS plans for brain metastases were analyzed.
• VIPER software reconstructed 3D dose distributions using EPID images within a virtual cylindrical water phantom (VCP).
• A 3D gamma analysis compared reconstructed doses to Eclipse-planned doses, with varying dose thresholds.

Main Results:

• High 3D Gamma Passing Rates (GPRs) were achieved across different dose thresholds.
• Average GPRs ranged from 99.9 ± 0.2% at 10% to 98.5 ± 3.3% at 90% dose threshold.
• These results indicate robust agreement between planned and reconstructed doses.

Conclusions:

• VIPER software is a feasible tool for PSQA of SIMT SRS plans.
• It presents a reliable alternative to conventional 2D detector arrays for SRS quality assurance.
• This technology enhances the verification process for complex radiosurgery treatments.