- Email: [email protected]
Abstract ID: 16 Automated Monte Carlo QA system for volumetric modulated arc therapy: Possibilities and challenges
2
Abstracts / Physica Medica 42 (2017) 1–50
Abstract ID: 10 Monte Carlo based validation of Compton scattering for 5 MV and 10 MV photon beams using aluminium and tungsten targets Amol Jagtap Savitribai Phule Pune University, Department of Physics, Pune, India The scattered photon energy spectrum from Tungsten and Aluminium target for photon of energies 5MV and 10MV have been studied at angle 0, 45, 90 degree and in target region by using EGSnrc based FLURZnrc Monte Carlo code. Photon cross section calculations are briefly reviewed by HJ Hubbell [1]. The physical interaction models and approximations for electron and photon transport which are used in Monte Carlo Simulation codes are reviewed by Salvet et al. [2]. Parallel monoenergetic photon beam of radius 0.1 cm was made incident on target of thickness 1 cm and radius 1 cm. All the spectrums are scored in 1 1 cm2 area at 10 cm distance in vacuum. Verification and validation of EGSnrc Monte Carlo code with the Compton scattering formula is done for Cs-137 and Co-60 and results are found in good agreement. It is observed that presence of energy spread of scattered photon of energy 0.4 MV and 1.4 MV for 5 MV and 10 MV photon beams respectively at an angle of 0 degree for both the target materials. The calculated energy of scattered photon at angles 0 and 45 degree are consistent with Compton scattering formula. It is observed that Compton scattering formula does not give correct value for energy of scattered photon for both photon energies of 5 MV and 10 MV at an angle of 90 degree when compared with the Monte Carlo results. Calculation of total fluence in all region of interest involves photons of energy 0.511 MV which are created in annihilation process.
References 1. Hubbell JH. Review and history of photon cross section calculations. Phys Med Biol 2006;51:R245–62. 2. Salvat F, Jose MFV. Overview of physical interaction models for photon and electron transport used in Monte Carlo codes. Metrologia 2009;46:S112–38. http://dx.doi.org/10.1016/j.ejmp.2017.09.004
Abstract ID: 14 Montecarlo calculation of reaction cross sections for the production of innovative radionuclides Andrea Fontana a,*, Luciano Canton b, Juan Esposito c, Liliana Mou c, Gaia Pupillo c, Carlos Rossi Alvarez c a
INFN – Sezione di Pavia, Pavia, Italy INFN – Sezione di Padova, Padova, Italy c INFN – Laboratori Nazionali di Legnaro, Legnaro, Italy ⇑ Presenting author. b
The production of innovative radionuclides in the context of theranostics is currently a topic of great interest. Various INFN projects are underway in search of new data and new techniques for radionuclides production. Among the possible channels under study, recent developments indicate 67Cu and 47Sc as good candidates competitive with more traditional nuclides, thanks to their application both for diagnostic and for therapy. INFN recently started two projects for the measurement of proton-induced reactions, considering the forthcoming use of the high-performance cyclotron installed at INFN-LNL (70 MeV maximum energy): COME in CSN3 (2016) and PASTA in CSN5 (Young Researchers grants 2016). The knowledge of reaction cross sections at low-intermediate energies is crucial in this context and, in parallel to the need of new measurements, it is important also to review the current situation in the reaction-model simulation of the production yields, by
using the existing and available nuclear reaction codes. In particular the FLUKA code, based on the PEANUT (Pre-Equilibrium Approach to Nuclear Thermalisation) model, was used to calculate the production of residual nuclei in different experiments and is already validated with data. In this study we use FLUKA to calculate the reaction cross sections for the production of copper and scandium isotopes at the energy of interest for the LARAMED project (10–100 MeV). A comparison of the results obtained with dedicated codes (Talys and Empire) and with available experimental data is also given. http://dx.doi.org/10.1016/j.ejmp.2017.09.005
Abstract ID: 15 Experimental verification of 4D Monte Carlo calculations of dose delivered to a deforming anatomy Joanna E. Cygler a,b,*, Sara Gholampourkashi b, Emily Heath b a The Ottawa Hospital Cancer Centre, Medical Physics Department, Ottawa, Canada b Carleton University, Department of Physics, Ottawa, Canada ⇑ Presenting author.
The aim of this work is to validate 4D Monte Carlo (MC) simulation method [1] for reconstructing dose delivered to a breathing patient. Static and VMAT plans were delivered to a deformable lung phantom by an Elekta Agility linear accelerator and measured doses were compared with simulations. Measurements were performed in a deformable lung phantom containing a 2.6 cm diameter tumour with the phantom in stationary and moving (sinusoidal) states. Dose within the tumor was measured using EBT3 film and a RADPOS detector connected to the RADPOS 4D dosimetry system [2]. Dose inside the lung was measured by another RADPOS detector mounted outside the tumor at 1.5 cm from the tumor center. A single 6 MV 3 3 cm2 square field and a VMAT plan, both covering the tumour, were created on the end-of-inhale CT scans using Monaco V.5.10.02. A validated BEAMnrc model of our Elekta linac was used for all MC simulations. For 4D simulations, deformation vectors were generated by deformable registration of end-of-exhale to end-ofinhale 4DCT images using Velocity AI 3.2.0 as input to the 4DdefDOSXYZnrc code along with the phantom motion trace recorded with RADPOS. Dose values from MC simulations and measurements were found to be within 3.5% of each other. The passing rate for a gamma comparison of 3%/2 mm between Monte Carlo simulations and film measurements were found to be better than 98%. In conclusion, our 4D Monte Carlo simulations using the defDOSXYZnrc code accurately calculates dose delivered to a deforming anatomy. Future work will focus on irregular respiratory motion patterns.
References 1. Gholampourkashi S, Vujicic M, Belec J, Cygler JE, Heath E. Experimental verification of 4D Monte Carlo simulations of dose delivery to a moving anatomy. Med Phys 2017;44(1):299–310. 2. Cherpak A, Ding W, Hallil A, Cygler JE. Evaluation of a novel 4D in vivo dosimetry system. Med Phys 2009;36(5):1672–8. http://dx.doi.org/10.1016/j.ejmp.2017.09.006
Abstract ID: 16 Automated Monte Carlo QA system for volumetric modulated arc therapy: Possibilities and challenges Roumiana Chakarova a,b,*, Marcus Krantz a, Rickard Cronholm c, Peter Andersson a, Andreas Hallqvist d
Abstracts / Physica Medica 42 (2017) 1–50 a Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden b Department of Radiation Physics, Sahlgrenska Academy at the University of Gothenburg, Sweden c Department of Radiation Physics, Skåne University Hospital, Lund, Sweden d Department of Oncology, Sahlgrenska Academy at the University of Gothenburg, Sweden ⇑ Presenting author.
The objective of the work is to develop and implement an automated MC system for patient specific VMAT QA generating treatment planning system (TPS) compliant DICOM objects and including a stand-alone module for 3D analysis of dose deviations based on the normalized dose difference (NDD) method. The MC system developed is based on the EGSnrc code package with modifications [1]. The workflow consists of a number of modules connected to the TPS by means of DICOM exports and imports which are executed sequentially without user interaction. DVH comparison is performed in the TPS. In addition, MC- and TPS dose distributions are imported to the stand-alone analysis module based on the NDD formalism [2]. NDD failure maps and a pass rate for a certain threshold are obtained. 70 clinical plans are selected for analysis; 21 thorax plans, 26 prostate plans, 13 H&N plans and 10 gynecological plans. Agreement within 1.5% has been found between clinical- and MC data for the mean dose to the target volumes. The agreement is within 3% for parameters more sensitive to the shape of the DVH, e.g. D95% PTV or minimum dose to CTV. Tolerance criteria of 2%/3 mm are recommended for NDD analysis of prostate plans and 3%/3 mm for rest of the cases. Evaluation procedure is suggested where NDD analysis is the first step. For pass rate lower than 95% the evaluation continues with comparison of DVH parameters. For deviations larger than 2%, a visual inspection of the clinical- and MC dose distributions is performed. A fully automated evaluation is hindered by artefacts in the CT images, presence of contrast in the bladder, dose to air included in the target volume, interpretation of HU in rectum etc.
References 1. Lobo J, Popescu IA. Two new DOSXYZnrc sources for 4D Monte Carlo simulations of continuously variable beam configurations, with applications to RapidArc, VMAT, TomoTherapy and CyberKnife. Phys Med Biol 2010;55:4431–43. 2. Jiang SB, Sharp GC, Neicu T, Berbeco RI, Flampouri S, Bortfeld T. On dose distribution comparison. Phys Med Biol 2006;51:759–76. http://dx.doi.org/10.1016/j.ejmp.2017.09.007
Abstract ID: 18 FLUKA validation of MONET code for dose calculation in Hadrontherapy Alessia Embriaco a,b,*, Valentina Elettra Bellinzona a, Andrea Fontana b, Alberto Rotondi a,b a
Dipartimento di Fisica, Università di Pavia, Pavia, Italy Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy ⇑ Presenting author. b
The accurate evaluation of the dose distribution is an open issue in Hadrontherapy. MONET (MOdel of ioN dosE for Therapy) is a code for the computation of the 3D dose distribution for protons in water. The model accounts for all the interactions and is benchmarked with the FLUKA code, that is already validated for protons and Helium
3
beams in water, as testified by its use in different facilities. In the FLUKA simulation, the physical process can be easily switched on or off: therefore the MC code is an important tools for the verification of our formulas, implemented in MONET. In particular, FLUKA has been used for the study of nuclear interactions in the lateral and longitudinal profiles. For the lateral profile, MONET is based on the Molière theory of multiple Coulomb scattering with an additional Cauchy-Lorentz function for the nuclear interactions, with two parameters obtained by a fit to FLUKA [1]. For the longitudinal profile, we have implemented a new calculation of the average energy loss, the straggling based on the convolution with a Gaussian function and a linear parametrization for the nuclear contributions, with two free parameters obtained by a fit to simulation [1]. After the implementation, MONET has been validated with FLUKA in two cases: a single Gaussian beam and a lateral scan as a sum of many beams. In both cases, we have obtained a good agreement for different energy of protons in water. Recently, we are investigating the possibility to extend MONET code to the case of He beam. For the implementation of Helium beam in the MONET code, we study the effect of nuclear interactions again with FLUKA. For the lateral profile, the nuclear interaction is parametrized with a Cauchy-Lorentz distribution, as in case of protons. With the lateral profile of FLUKA, we have estimated the decrease of primary particles as a function of depth, in good agreement with experimental data. For the last step, the implementation of MONET for Helium beams in water, we are studying the depth-dose distribution and the contributions of straggling and the nuclear interactions. References 1. Bellinzona et al., PMB 2016;61:N102. http://dx.doi.org/10.1016/j.ejmp.2017.09.008
Abstract ID: 21 Simulation of synchrotron-based microbeam radiation therapy using Geant4 Susanna Guatelli a,*, Matthew Cameron a, Andrew Dipuglia a, Jeremy Davis a, Iwan Cornelius a,b, Anatoly Rozenfeld a, Michael Lerch a a
University of Wollongong, Centre for Medical Radiation Physics, Wollongong, NSW, Australia b Amentum Defence and Security, Sydney, NSW, Australia ⇑ Presenting author. Microbeam Radiation Therapy (MRT) is a preclinical radiotherapy modality characterised by the use of many micron-sized, spatially fractionated, high intensity radiation fields produced by a MultiSlit Collimator and synchrotron light [1]. A typical MRT radiation field consists of multiple high dose ‘peaks’ separated by low dose ‘valleys’ (width 25–50 lm; pitch 100–400 lm) delivered with dose rates of up to 10 kGy/s. The minute field size and high dose rate of MRT requires good Quality Assurance in order to transition into the clinical field. Dose Verification and Treatment Planning Systems (TPS) are crucial aspects of quality assurance, allowing for independent prediction and verification of dose distributions delivered to patients. The most accurate form of TPS is Monte Carlo computer simulations. The Centre for Medical Radiation Physics (CMRP), University of Wollongong, has developed a Geant4-based synchrotron beamline model for dose verification at the Australian Synchrotron Imaging and Medical Beamline (IMBL). This model, denoted G4IMBL, uses a multi-stage procedure to generate synchrotron light, transport through the beamline model, and calculate dose deposition in a phantom. G4IMBL models the production of X-ray photons entirely using Geant4 by transporting electrons through the sinu-
Abstracts / Physica Medica 42 (2017) 1–50
Abstract ID: 10 Monte Carlo based validation of Compton scattering for 5 MV and 10 MV photon beams using aluminium and tungsten targets Amol Jagtap Savitribai Phule Pune University, Department of Physics, Pune, India The scattered photon energy spectrum from Tungsten and Aluminium target for photon of energies 5MV and 10MV have been studied at angle 0, 45, 90 degree and in target region by using EGSnrc based FLURZnrc Monte Carlo code. Photon cross section calculations are briefly reviewed by HJ Hubbell [1]. The physical interaction models and approximations for electron and photon transport which are used in Monte Carlo Simulation codes are reviewed by Salvet et al. [2]. Parallel monoenergetic photon beam of radius 0.1 cm was made incident on target of thickness 1 cm and radius 1 cm. All the spectrums are scored in 1 1 cm2 area at 10 cm distance in vacuum. Verification and validation of EGSnrc Monte Carlo code with the Compton scattering formula is done for Cs-137 and Co-60 and results are found in good agreement. It is observed that presence of energy spread of scattered photon of energy 0.4 MV and 1.4 MV for 5 MV and 10 MV photon beams respectively at an angle of 0 degree for both the target materials. The calculated energy of scattered photon at angles 0 and 45 degree are consistent with Compton scattering formula. It is observed that Compton scattering formula does not give correct value for energy of scattered photon for both photon energies of 5 MV and 10 MV at an angle of 90 degree when compared with the Monte Carlo results. Calculation of total fluence in all region of interest involves photons of energy 0.511 MV which are created in annihilation process.
References 1. Hubbell JH. Review and history of photon cross section calculations. Phys Med Biol 2006;51:R245–62. 2. Salvat F, Jose MFV. Overview of physical interaction models for photon and electron transport used in Monte Carlo codes. Metrologia 2009;46:S112–38. http://dx.doi.org/10.1016/j.ejmp.2017.09.004
Abstract ID: 14 Montecarlo calculation of reaction cross sections for the production of innovative radionuclides Andrea Fontana a,*, Luciano Canton b, Juan Esposito c, Liliana Mou c, Gaia Pupillo c, Carlos Rossi Alvarez c a
INFN – Sezione di Pavia, Pavia, Italy INFN – Sezione di Padova, Padova, Italy c INFN – Laboratori Nazionali di Legnaro, Legnaro, Italy ⇑ Presenting author. b
The production of innovative radionuclides in the context of theranostics is currently a topic of great interest. Various INFN projects are underway in search of new data and new techniques for radionuclides production. Among the possible channels under study, recent developments indicate 67Cu and 47Sc as good candidates competitive with more traditional nuclides, thanks to their application both for diagnostic and for therapy. INFN recently started two projects for the measurement of proton-induced reactions, considering the forthcoming use of the high-performance cyclotron installed at INFN-LNL (70 MeV maximum energy): COME in CSN3 (2016) and PASTA in CSN5 (Young Researchers grants 2016). The knowledge of reaction cross sections at low-intermediate energies is crucial in this context and, in parallel to the need of new measurements, it is important also to review the current situation in the reaction-model simulation of the production yields, by
using the existing and available nuclear reaction codes. In particular the FLUKA code, based on the PEANUT (Pre-Equilibrium Approach to Nuclear Thermalisation) model, was used to calculate the production of residual nuclei in different experiments and is already validated with data. In this study we use FLUKA to calculate the reaction cross sections for the production of copper and scandium isotopes at the energy of interest for the LARAMED project (10–100 MeV). A comparison of the results obtained with dedicated codes (Talys and Empire) and with available experimental data is also given. http://dx.doi.org/10.1016/j.ejmp.2017.09.005
Abstract ID: 15 Experimental verification of 4D Monte Carlo calculations of dose delivered to a deforming anatomy Joanna E. Cygler a,b,*, Sara Gholampourkashi b, Emily Heath b a The Ottawa Hospital Cancer Centre, Medical Physics Department, Ottawa, Canada b Carleton University, Department of Physics, Ottawa, Canada ⇑ Presenting author.
The aim of this work is to validate 4D Monte Carlo (MC) simulation method [1] for reconstructing dose delivered to a breathing patient. Static and VMAT plans were delivered to a deformable lung phantom by an Elekta Agility linear accelerator and measured doses were compared with simulations. Measurements were performed in a deformable lung phantom containing a 2.6 cm diameter tumour with the phantom in stationary and moving (sinusoidal) states. Dose within the tumor was measured using EBT3 film and a RADPOS detector connected to the RADPOS 4D dosimetry system [2]. Dose inside the lung was measured by another RADPOS detector mounted outside the tumor at 1.5 cm from the tumor center. A single 6 MV 3 3 cm2 square field and a VMAT plan, both covering the tumour, were created on the end-of-inhale CT scans using Monaco V.5.10.02. A validated BEAMnrc model of our Elekta linac was used for all MC simulations. For 4D simulations, deformation vectors were generated by deformable registration of end-of-exhale to end-ofinhale 4DCT images using Velocity AI 3.2.0 as input to the 4DdefDOSXYZnrc code along with the phantom motion trace recorded with RADPOS. Dose values from MC simulations and measurements were found to be within 3.5% of each other. The passing rate for a gamma comparison of 3%/2 mm between Monte Carlo simulations and film measurements were found to be better than 98%. In conclusion, our 4D Monte Carlo simulations using the defDOSXYZnrc code accurately calculates dose delivered to a deforming anatomy. Future work will focus on irregular respiratory motion patterns.
References 1. Gholampourkashi S, Vujicic M, Belec J, Cygler JE, Heath E. Experimental verification of 4D Monte Carlo simulations of dose delivery to a moving anatomy. Med Phys 2017;44(1):299–310. 2. Cherpak A, Ding W, Hallil A, Cygler JE. Evaluation of a novel 4D in vivo dosimetry system. Med Phys 2009;36(5):1672–8. http://dx.doi.org/10.1016/j.ejmp.2017.09.006
Abstract ID: 16 Automated Monte Carlo QA system for volumetric modulated arc therapy: Possibilities and challenges Roumiana Chakarova a,b,*, Marcus Krantz a, Rickard Cronholm c, Peter Andersson a, Andreas Hallqvist d
Abstracts / Physica Medica 42 (2017) 1–50 a Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden b Department of Radiation Physics, Sahlgrenska Academy at the University of Gothenburg, Sweden c Department of Radiation Physics, Skåne University Hospital, Lund, Sweden d Department of Oncology, Sahlgrenska Academy at the University of Gothenburg, Sweden ⇑ Presenting author.
The objective of the work is to develop and implement an automated MC system for patient specific VMAT QA generating treatment planning system (TPS) compliant DICOM objects and including a stand-alone module for 3D analysis of dose deviations based on the normalized dose difference (NDD) method. The MC system developed is based on the EGSnrc code package with modifications [1]. The workflow consists of a number of modules connected to the TPS by means of DICOM exports and imports which are executed sequentially without user interaction. DVH comparison is performed in the TPS. In addition, MC- and TPS dose distributions are imported to the stand-alone analysis module based on the NDD formalism [2]. NDD failure maps and a pass rate for a certain threshold are obtained. 70 clinical plans are selected for analysis; 21 thorax plans, 26 prostate plans, 13 H&N plans and 10 gynecological plans. Agreement within 1.5% has been found between clinical- and MC data for the mean dose to the target volumes. The agreement is within 3% for parameters more sensitive to the shape of the DVH, e.g. D95% PTV or minimum dose to CTV. Tolerance criteria of 2%/3 mm are recommended for NDD analysis of prostate plans and 3%/3 mm for rest of the cases. Evaluation procedure is suggested where NDD analysis is the first step. For pass rate lower than 95% the evaluation continues with comparison of DVH parameters. For deviations larger than 2%, a visual inspection of the clinical- and MC dose distributions is performed. A fully automated evaluation is hindered by artefacts in the CT images, presence of contrast in the bladder, dose to air included in the target volume, interpretation of HU in rectum etc.
References 1. Lobo J, Popescu IA. Two new DOSXYZnrc sources for 4D Monte Carlo simulations of continuously variable beam configurations, with applications to RapidArc, VMAT, TomoTherapy and CyberKnife. Phys Med Biol 2010;55:4431–43. 2. Jiang SB, Sharp GC, Neicu T, Berbeco RI, Flampouri S, Bortfeld T. On dose distribution comparison. Phys Med Biol 2006;51:759–76. http://dx.doi.org/10.1016/j.ejmp.2017.09.007
Abstract ID: 18 FLUKA validation of MONET code for dose calculation in Hadrontherapy Alessia Embriaco a,b,*, Valentina Elettra Bellinzona a, Andrea Fontana b, Alberto Rotondi a,b a
Dipartimento di Fisica, Università di Pavia, Pavia, Italy Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy ⇑ Presenting author. b
The accurate evaluation of the dose distribution is an open issue in Hadrontherapy. MONET (MOdel of ioN dosE for Therapy) is a code for the computation of the 3D dose distribution for protons in water. The model accounts for all the interactions and is benchmarked with the FLUKA code, that is already validated for protons and Helium
3
beams in water, as testified by its use in different facilities. In the FLUKA simulation, the physical process can be easily switched on or off: therefore the MC code is an important tools for the verification of our formulas, implemented in MONET. In particular, FLUKA has been used for the study of nuclear interactions in the lateral and longitudinal profiles. For the lateral profile, MONET is based on the Molière theory of multiple Coulomb scattering with an additional Cauchy-Lorentz function for the nuclear interactions, with two parameters obtained by a fit to FLUKA [1]. For the longitudinal profile, we have implemented a new calculation of the average energy loss, the straggling based on the convolution with a Gaussian function and a linear parametrization for the nuclear contributions, with two free parameters obtained by a fit to simulation [1]. After the implementation, MONET has been validated with FLUKA in two cases: a single Gaussian beam and a lateral scan as a sum of many beams. In both cases, we have obtained a good agreement for different energy of protons in water. Recently, we are investigating the possibility to extend MONET code to the case of He beam. For the implementation of Helium beam in the MONET code, we study the effect of nuclear interactions again with FLUKA. For the lateral profile, the nuclear interaction is parametrized with a Cauchy-Lorentz distribution, as in case of protons. With the lateral profile of FLUKA, we have estimated the decrease of primary particles as a function of depth, in good agreement with experimental data. For the last step, the implementation of MONET for Helium beams in water, we are studying the depth-dose distribution and the contributions of straggling and the nuclear interactions. References 1. Bellinzona et al., PMB 2016;61:N102. http://dx.doi.org/10.1016/j.ejmp.2017.09.008
Abstract ID: 21 Simulation of synchrotron-based microbeam radiation therapy using Geant4 Susanna Guatelli a,*, Matthew Cameron a, Andrew Dipuglia a, Jeremy Davis a, Iwan Cornelius a,b, Anatoly Rozenfeld a, Michael Lerch a a
University of Wollongong, Centre for Medical Radiation Physics, Wollongong, NSW, Australia b Amentum Defence and Security, Sydney, NSW, Australia ⇑ Presenting author. Microbeam Radiation Therapy (MRT) is a preclinical radiotherapy modality characterised by the use of many micron-sized, spatially fractionated, high intensity radiation fields produced by a MultiSlit Collimator and synchrotron light [1]. A typical MRT radiation field consists of multiple high dose ‘peaks’ separated by low dose ‘valleys’ (width 25–50 lm; pitch 100–400 lm) delivered with dose rates of up to 10 kGy/s. The minute field size and high dose rate of MRT requires good Quality Assurance in order to transition into the clinical field. Dose Verification and Treatment Planning Systems (TPS) are crucial aspects of quality assurance, allowing for independent prediction and verification of dose distributions delivered to patients. The most accurate form of TPS is Monte Carlo computer simulations. The Centre for Medical Radiation Physics (CMRP), University of Wollongong, has developed a Geant4-based synchrotron beamline model for dose verification at the Australian Synchrotron Imaging and Medical Beamline (IMBL). This model, denoted G4IMBL, uses a multi-stage procedure to generate synchrotron light, transport through the beamline model, and calculate dose deposition in a phantom. G4IMBL models the production of X-ray photons entirely using Geant4 by transporting electrons through the sinu-