Highlights
- •Monte-Carlo simulation of a proton pencil beam scanning machine.
- •Dose distributions in water were measured and compared with simulations using a Geant4 Monte Carlo platform (TOPAS).
- •The low-dose envelope of scanned proton beams was characterised.
Abstract
The aim of this work is to perform Monte Carlo simulations of a proton pencil beam
scanning machine, characterise the low-dose envelope of scanned proton beams and assess
the differences between various approximations for nozzle geometry. Measurements and
Monte Carlo simulations were carried out in order to describe the dose distribution
of a proton pencil beam in water for energies between 100 and 220 MeV. Dose distributions
were simulated by using a Geant4 Monte Carlo platform (TOPAS), and were measured in
water using a two-dimensional ion chamber array detector. The beam source in air was
adjusted for each configuration. Double Gaussian parameterisation was proposed for
definition of the beam source model in order to improve simulations starting at the
nozzle exit. Absolute dose distributions and field size factors were measured and
compared with simulations. The influence of the high-density components present in
the treatment nozzle was also investigated by analysis of proton phase spaces at the
nozzle exit. An excellent agreement was observed between experimental dose distributions
and simulations for energies higher than 160 MeV. However, minor differences were
observed between 100 and 160 MeV, suggesting poorer modelling of the beam when the
full treatment head was not taken into account. We found that the first ionisation
chamber was the main cause of the tail component observed for low proton beam energies.
In this work, various parameterisations of proton sources were proposed, thereby allowing
reproduction of the low-dose envelope of proton beams and excellent agreement with
measured data.
Keywords
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References
- Clinical implementation of full Monte Carlo dose calculation in proton beam therapy.Phys Med Biol. 2008; 53: 4825-4853
- GATE V6 : a major enhancement of the GATE simulation platform enabling modelling of CT and radiotherapy.Phys Med Biol. 2011; 56: 881-901
- A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications.Med Phys. 2014; 41064301
- Monte Carlo modelling of the treatment line of the proton therapy center in Orsay.Phys Med Biol. 2009; 54: 2377-2394
- Benchmarking Monte Carlo simulations against experimental data in clinically relevant passive scattering proton therapy beamline configurations.Radioprotection. 2016; 51: 113-122
- Experimental validation of a Monte Carlo proton therapy nozzle model incorporating magnetically steered protons.Phys Med Biol. 2009; 54: 3217-3229
- A Monte Carlo pencil beam scanning model for proton treatment plan simulation using gate/geant4.Phys Med Biol. 2011; 56: 5203-5219
- Monte Carlo simulations to support start-up and treatment planning of scanned proton and carbon ion therapy at a synchrotron-based facility.Phys Med Biol. 2012; 57: 3759-3784
- Characterizing a proton beam scanning system for Monte Carlo dose calculation in patients.Phys Med Biol. 2015; 60: 633-645
- Characterization and validation of a Monte Carlo code for independent dose calculation in proton therapy treatments with pencil beam scanning.Phys Med Biol. 2015; 60: 8601-8619
- A beam model for focused proton pencil beams.Phys Med: Eur J Med Phys. 2018; 52: 27-32
- Monte carlo investigation of the low-dose envelope from scanned proton pencil beams.Phys Med Biol. 2010; 55: 711-721
- Experimental characterization of two-dimensional spot proles for two proton pencil beam scanning nozzles.Phys Med Biol. 2014; 59: 493-504
- Experimental characterization and physical modelling of the dose distribution of scanned proton pencil beams.Phys Med Biol. 2005; 50: 541-561
- A pencil beam algorithm for intensity modulated proton therapy derived from monte carlo simulations.Phys Med Biol. 2005; 50: 5089-5104
- Golden beam data for proton pencil-beam scanning.Phys Med Biol. 2012; 57: 1147
- On the parametrization of lateral dose profiles in proton radiation therapy.Phys Med. 2015; 31: 484-492
- Beyond Gaussians: a study of single-spot modeling for scanning proton dose calculation.Phys Med Biol. 2012; 57: 983-997
- A model for the accurate computation of the lateral scattering of protons in water.Phys Med Biol. 2016; 61: N102-N117
- Dosimetric impact of the low-dose envelope of scanned proton beams at a probeam facility: comparison of measurements with TPS and MC calculations.Phys Med Biol. 2016; 61: 958-973
- Evaluation of the influence of double and triple Gaussian proton kernel models on accuracy of dose calculations for spot scanning technique.Med Phys. 2016; 43: 1437-1450
- On the nuclear halo of a proton pencil beam stopping in water.Phys Med Biol. 2015; 60: 5627-5654
- Validation of nuclear models in geant4 using the dose distribution of a 177 MeV proton pencil beam.Phys Med Biol. 2016; 61: N1-N10
- TOPAS: an innovative proton Monte Carlo platform for research and clinical applications.Med Phys. 2012; 39: 6818-6837
- Optimization of geant4 settings for proton pencil beam scanning simulations using gate.Nucl Instrum Methods Phys Res, Sect B. 2010; 268: 3295-3305
- Experimentally validated pencil beam scanning source model in TOPAS.Phys Med Biol. 2014; 59: 6859-6873
- A novel technique for measuring the low-dose envelope of pencil-beam scanning spot profiles.Phys Med Biol. 2013; 58: N171-N180
- Dosimetric consequences of pencil beam width variations in scanned beam particle therapy.Phys Med Biol. 2013; 58: 3979-3993
- Impacts of gantry angle dependent scanning beam properties on proton PBS treatment.Phys Med Biol. 2017; 62: 344
Sigmund P, Schinner A and Paul H Errata and addenda: ICRU report 73 (stopping of ions heavier than helium).
- Comprehensive analysis of proton range uncertainties related to patient stopping-power-ratio estimation using the stoichiometric calibration.Phys Med Biol. 2012; 57: 4095-4115
- Analytical expressions for water-to-air stopping-power ratios relevant for accurate dosimetry in particle therapy.Phys Med Biol. 2011; 56: 2515-2533
Article info
Publication history
Published online: July 23, 2019
Accepted:
July 17,
2019
Received in revised form:
June 20,
2019
Received:
December 5,
2018
Identification
Copyright
© 2019 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
