SU-E-T-505: BrainLab Plan Comparisons: Brain Scan Pencil Beam versus IPlan Monte Carlo

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• The transition to new treatment planning systems (TPS) necessitates careful evaluation of dose calculation algorithms.
• BrainLab's IPlan TPS introduces Monte Carlo (MC) dose modeling, replacing the older BrainScan system's pencil beam (PB) algorithm.

Purpose of the Study:

• To quantitatively assess differences in dose calculations between MC and PB modeling in BrainLab's IPlan TPS.
• To investigate potential impacts of these dose calculation changes on patient treatments and outcomes.

Main Methods:

• Collected beam data for the BrainLab IPlan TPS according to manufacturer guidelines.
• Compared treatment plans generated using PB modeling in both BrainScan and IPlan TPS.
• Compared treatment plans generated using MC modeling in IPlan TPS against PB models.

Main Results:

• Significant differences were observed in dose distribution, DVH values, and monitor units between MC and PB modeling.
• These differences varied based on patient anatomy and tumor site.
• Comparisons for Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT) will be presented.

Conclusions:

• Clinical implementation of new TPS requires caution and adherence to AAPM guidelines.
• Thorough comparisons between old and new dose calculation models are essential.
• Independent end-to-end system checks using phantoms like the RPC phantom are recommended.