Click here to


Are you sure ?

Yes, do it No, cancel

Validation and Implementation of Proton Pencil Beam Scanning Nozzle Using TOPAS Monte Carlo Simulation

C Lin1*, Y Feng2, (1) ,Greenville, NC, (2) East Carolina Univ, Greenville, NC


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: The goal of this work is to construct and validate a pencil beam scanning (PBS) proton beam system by the tool for particle simulation (TOPAS) Monte Carlo (MC) simulation. Dose comparisons of MC simulations with the measurements and calculations in Eclipse treatment planning system (TPS) were analyzed.

Methods: The Sumitomo scanning nozzle was simulated based on the manufacturer blueprints using TOPAS MC code, which is a user-friendly MC simulation tool extended from Geant4. This model was implemented to reproduce the integrated depth-dose curves (IDD) and lateral profiles and was compared and validated with the measurement data collected during acceptance and commissioning of the proton therapy machine in order to verify the proton scanning beam modeling. Three homogeneous phantoms were set up, and the dose distribution was compared to the TPS calculated data.

Results: The comparison of IDD with R90 range and lateral profiles between TOPAS calculation and measurements showed good agreement and within clinical required accuracy. The doses on lateral profile in homogeneous media demonstrated only slight discrepancies compared to calculated data on the tails because of the low dose halo. TPS may underestimate the long-range scattering on lateral profile dose distribution.

Conclusion: The development and commissioning of a TOPAS MC based PBS nozzle model was successful.


Not Applicable / None Entered.


Not Applicable / None Entered.

Contact Email