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17: MCTP: a new Monte Carlo-based treatment planning tool for hadrontherapy
ICTR-PHE – 2014
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17 MCTP: a new Monte Carlo-based treatment planning tool for hadrontherapy G. Battistoni1, T.T. Böhlen2, A. Mairani3, A. Schiavi1,4, V. Patera1,4 1 INFN Milano, Italy 2 MedAustron, Vienna, Austria 3 CNAO, Italy 4 Universita “La Sapienza”, Roma, Italy Purpose: In the field of radiotherapy Monte Carlo particle transport calculations are recognized for their superior accuracy in predicting dose and fluence distributions in patient geometries compared to analytical algorithms which are generally used for treatment planning due to their shorter execution times. In the present work, a newlydeveloped MC-based treatment planning (MCTP) tool for hadron therapy is proposed to support treatment planning studies and research applications. It allows for single-field and simultaneous multiple-fields optimization in realistic treatment scenarios both for proton and light ion (Z<8) treatments and is based on the MC code FLUKA[1]. Relative biological effectiveness (RBE)-weighted dose can be optimized using a variable RBE according to radiobiological input tables. Examples of treatment plans in water phantoms and in patient-CT geometries together are presented and compared to commercial analytical TP calculations. The MCTP tool is aimed to be used in future for research and to support treatment planning at state-of the-art ion beam therapy facilities. Materials/Methods: The MCTP tool is composed of various program components that require a range of treatment- and facility-specific input information. The basic input information can be provided by an existing Treatment Planning System or by a fast simulation code, so to provide the starting guess to generate a full set of pencil beam simulation of a patient specific case by means of a complete Monte Carlo model. In this work the FLUKA Monte Carlo [1] code has been adopted. Final optimization is performed using Monte Carlo dose and fluence kernels. A new fast simulation and skimming code, called FRED, has been developed as alternative for the input generation to the Monte Carlo optimization. The FLUKA code can be coupled to a radiobiological model so to provide results in terms of dose weighted by Radiobiological Effectiveness (RBE). Results: The MCTP tool has been tested for a number of patient cases both with proton beams at CNAO and with carbon beams at HIT. The results of the Monte Carlo based optimization have been compared with the output of the Treatment Planning Systems in the quoted facilities. Fig. 1 shows the results of the calculation for a proton treatment (chordoma) with three ports in terms of RBEweighted Dose. The distributions are depicted in panels (a), (b) and (c) for the axial, sagittal and coronal view respectively. The first row shows the results of the commercial TPS. The second row is the results of the MC forward calculation starting from (a) results. The third row shows instead the results from MCTP.
Figure 1 Conclusions: MCTP results have been successfully compared against analytical TPS plans and also experimental dosimetric data. The differences between TPS and MC-based recalculations can be mostly attributed to the different handling of scattering effects. The MCTP approach accounts in particular for a much more accurate description of scattering effects with respect to an analytical approach. The developed MCTP tool can calculate RBE-weighted dose either using a constant RBE or using a variable RBE according to radiobiological input tables. In addition, beyond dose prescriptions, this tool can generate at the same time also predictions to be used for monitoring, like for instance a positron annihilation map for in-beam PET application. The MCTP tool is at present mainly aimed to be used for research and to support treatment planning at state-of-the-art ion beam therapy facilities. In particular, studies comparing treatment plans created using different ion species and optimization techniques are envisaged. Keywords: Treatment Planning, hadrontherapy, Monte Carlo References: [1] A. Ferrari, P. R. Sala, A. Fasso , and J. Ranft, “FLUKA: a Multi-Particle Transport Code,” CERN, INFN, SLAC, CERN2005-10, INFN/TC_05/11, SLAC-R-773, 2005. 18 PET/CT-based verification of scanned proton and carbon ion treatment at HIT – an overview J. Bauer1, C. Kurz1,2, D. Unholtz1,2,4, K. Frey3, S.E. Combs1,2, J. Debus1,2, K. Parodi2,3 1 Heidelberg Ion-Beam Therapy Center, Heidelberg, Germany 2 Radiation Oncology, Department of Radiology, Heidelberg University Hospital, Germany 3 Ludwig-Maximilians University, Munich, Germany 4 Leica Microsystems CMS GmbH, Mannheim, Germany Purpose: At the Heidelberg Ion-beam Therapy Center (HIT) a commercial full-ring PET/CT scanner is used for posttherapeutic verification of scanned proton and carbon carbon-ion + activation of the irradiated tissue, conclusions can be drawn about the quality of the applied treatment, especially in terms of beam range, possible anatomic changes in the target region and positioning uncertainties. Material/methods: A Siemens Biograph mCT is installed in a room next to the treatment places and selected patients are either walked to the scanner or transferred by a dedicated
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17 MCTP: a new Monte Carlo-based treatment planning tool for hadrontherapy G. Battistoni1, T.T. Böhlen2, A. Mairani3, A. Schiavi1,4, V. Patera1,4 1 INFN Milano, Italy 2 MedAustron, Vienna, Austria 3 CNAO, Italy 4 Universita “La Sapienza”, Roma, Italy Purpose: In the field of radiotherapy Monte Carlo particle transport calculations are recognized for their superior accuracy in predicting dose and fluence distributions in patient geometries compared to analytical algorithms which are generally used for treatment planning due to their shorter execution times. In the present work, a newlydeveloped MC-based treatment planning (MCTP) tool for hadron therapy is proposed to support treatment planning studies and research applications. It allows for single-field and simultaneous multiple-fields optimization in realistic treatment scenarios both for proton and light ion (Z<8) treatments and is based on the MC code FLUKA[1]. Relative biological effectiveness (RBE)-weighted dose can be optimized using a variable RBE according to radiobiological input tables. Examples of treatment plans in water phantoms and in patient-CT geometries together are presented and compared to commercial analytical TP calculations. The MCTP tool is aimed to be used in future for research and to support treatment planning at state-of the-art ion beam therapy facilities. Materials/Methods: The MCTP tool is composed of various program components that require a range of treatment- and facility-specific input information. The basic input information can be provided by an existing Treatment Planning System or by a fast simulation code, so to provide the starting guess to generate a full set of pencil beam simulation of a patient specific case by means of a complete Monte Carlo model. In this work the FLUKA Monte Carlo [1] code has been adopted. Final optimization is performed using Monte Carlo dose and fluence kernels. A new fast simulation and skimming code, called FRED, has been developed as alternative for the input generation to the Monte Carlo optimization. The FLUKA code can be coupled to a radiobiological model so to provide results in terms of dose weighted by Radiobiological Effectiveness (RBE). Results: The MCTP tool has been tested for a number of patient cases both with proton beams at CNAO and with carbon beams at HIT. The results of the Monte Carlo based optimization have been compared with the output of the Treatment Planning Systems in the quoted facilities. Fig. 1 shows the results of the calculation for a proton treatment (chordoma) with three ports in terms of RBEweighted Dose. The distributions are depicted in panels (a), (b) and (c) for the axial, sagittal and coronal view respectively. The first row shows the results of the commercial TPS. The second row is the results of the MC forward calculation starting from (a) results. The third row shows instead the results from MCTP.
Figure 1 Conclusions: MCTP results have been successfully compared against analytical TPS plans and also experimental dosimetric data. The differences between TPS and MC-based recalculations can be mostly attributed to the different handling of scattering effects. The MCTP approach accounts in particular for a much more accurate description of scattering effects with respect to an analytical approach. The developed MCTP tool can calculate RBE-weighted dose either using a constant RBE or using a variable RBE according to radiobiological input tables. In addition, beyond dose prescriptions, this tool can generate at the same time also predictions to be used for monitoring, like for instance a positron annihilation map for in-beam PET application. The MCTP tool is at present mainly aimed to be used for research and to support treatment planning at state-of-the-art ion beam therapy facilities. In particular, studies comparing treatment plans created using different ion species and optimization techniques are envisaged. Keywords: Treatment Planning, hadrontherapy, Monte Carlo References: [1] A. Ferrari, P. R. Sala, A. Fasso , and J. Ranft, “FLUKA: a Multi-Particle Transport Code,” CERN, INFN, SLAC, CERN2005-10, INFN/TC_05/11, SLAC-R-773, 2005. 18 PET/CT-based verification of scanned proton and carbon ion treatment at HIT – an overview J. Bauer1, C. Kurz1,2, D. Unholtz1,2,4, K. Frey3, S.E. Combs1,2, J. Debus1,2, K. Parodi2,3 1 Heidelberg Ion-Beam Therapy Center, Heidelberg, Germany 2 Radiation Oncology, Department of Radiology, Heidelberg University Hospital, Germany 3 Ludwig-Maximilians University, Munich, Germany 4 Leica Microsystems CMS GmbH, Mannheim, Germany Purpose: At the Heidelberg Ion-beam Therapy Center (HIT) a commercial full-ring PET/CT scanner is used for posttherapeutic verification of scanned proton and carbon carbon-ion + activation of the irradiated tissue, conclusions can be drawn about the quality of the applied treatment, especially in terms of beam range, possible anatomic changes in the target region and positioning uncertainties. Material/methods: A Siemens Biograph mCT is installed in a room next to the treatment places and selected patients are either walked to the scanner or transferred by a dedicated