Author: Anthony Hong Cheol Lim, Rayyan L Mahmood, Alexander Stanforth, Chris C. Wang, Mingyao Zhu 👨🔬
Affiliation: Georgia Institute of Technology, Emory University 🌍
Purpose: The purpose of this project is to test the feasibility of proton minibeam lattice radiotherapy within an existing clinical setting.
Methods:
The TOPAS code is used to model a scenario in which there are multiple single energy proton pencil beams that go through a 3-mm diameter and a 6-mm c-t-c brass collimator. This creates a 2D minibeam grid pattern within the water phantom. Proton mini beams of energies 120, 113, 105, 95, 80 MeV and their corresponding weighting factors are selected to deliver their bragg peaks that are separated by a constant value (~ 1 cm) in depth to create the lattice pattern over the entire tumor volume. The dose delivered to the center of each vertex (hot spot) is aimed to be 15 Gy. At a proton center, this plan is then applied to a solid water phantom with many Gafchromic films placed at various depths in the phantom. This allows us to obtain the dose distribution of the lattice pattern.
Results:
We simulated multiple single energy proton beams using TOPAS to model proton pencil beams with a collimator that creates an array of mini beams which delivers the lattice pattern.This will then be verified at a proton center. Agreement of the results will allow us to determine if the treatment time and efficiency is feasible for a real clinical environment. The TOPAS results show that the treatment time for proton minibeam lattice radiotherapy is comparable to that of the standard proton beam therapy as the simulation resulted in a 15 minute treatment time.
Conclusion:
We have shown through the simulations that the treatment time of the proton minibeam lattice radiotherapy is comparable to standard proton therapy treatment time. This conclusion, however, still needs to be verified by the proposed in-phantom experiments.