Geant4 Simulation Study of Dose Distribution and Energy Straggling for Proton and Carbon Ion Beams in Water

Qiang Zhao,Zheng Zhang,Yang Li,R.K Agarwal,H Abd Rahman

doi:10.1051/matecconf/20166502002

Qiang Zhao, Zheng Zhang + Show 3 more

Open Access

https://doi.org/10.1051/matecconf/20166502002

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Abstract

Dose distribution and energy straggling for proton and carbon ion beams in water are investigated by using a hadrontherapy model based on the Geant4 toolkit. By gridding water phantom in N × N × N voxels along X, Y and Z axes, irradiation dose distribution in all the voxels is calculated. Results indicate that carbon ion beams have more advantages than proton beams. Proton beams have bigger width of the Bragg peak and broader lateral dose distribution than carbon ion beams for the same position of Bragg peaks. Carbon ion has a higher local ionization density and produces more secondary electrons than proton, so carbon ion beams can achieve a higher value of relative biological effectiveness.

Highlights

In the forties of last century, Wilson suggested that using the beams of charged particles such as protons and light nuclei for treating malignant tumors [1]
For carbon ion beams, the Bragg peaks’ width and lateral width are smaller than that for proton beams when they have the same position of Bragg peak
The proton beams show more straggling along the incident direction, while the carbon ion beams show distinct tail dose beyond the Bragg peaks

Summary

Introduction

In the forties of last century, Wilson suggested that using the beams of charged particles such as protons and light nuclei for treating malignant tumors [1]. Therapy with protons or heavy ions (such as carbon ions) have advantages in that the beneficial dose profile with a sharp dose fall-off at the end of the particle range [2] This special advantage makes that killing tumors without destroying healthy tissues becomes possible. Doses from secondary nuclear fragments can enhance the biological effect, and have unexpected energy deposition beyond Bragg peak. This feature makes a very selective impact on the tumor possible, and it requires thorough treatment planning based on more reliable calculation. We use the Geant toolkit to calculate dose distribution and energy straggling of proton and carbon ion beams in water (a tissue-like medium)

Model and simulation details

Results and discussion

Conclusion