- Email: [email protected]
216. Biological treatment planning with multiple ion beams
Abstracts / Physica Medica 56 (2018) 133–278
Conclusions. The implications of waiting list for radiotherapy treatment include perceived lower cancer control rates and patient suffering. The model represents a tool for effectively managing the capacity in a radiotherapy department to optimize the waiting lists for treatment.
References 1. Fomundam, S., & Herrmann, J. (2007). A survey of Queuing Theory Applications in healthcare. ISR Technical Report 24. 2. Seshaiah C, Thiagaraj H. A queuing network congestion model in hospitals. Eur J Sci Res 2011;63:419–27. 3. Yasara O. Queuing Models and Capacity Planning. In: Yasara O, editor. Queuing Methods in Health care management. San Francisco: Jossey-Bass; 2009. p. 348–56.
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Results. For all the three cases investigated, the main difference regard dose to D2cc of the rectum. In particular, we observed a percentage difference between 0.6% and 0.2% for AW case, between 4.2% and 0.9% for UDV case and between 4.6% and 0.6% for HUB case. The variation of D100 for TV is about between 0.2% and 0.3% in AW, between 1.8% and 0.3% in UDV and between 1.4% and 0.2% in HUB. Conclusions. From AW, UDV and HUB cases we note it seems to be not necessary to use ACE algorithms in VUB. Using them we can say it is crucial to select the predefined material closer to the electron density of each structure. Furthermore, it is necessary to establish when, for a given structure, it is preferable to use the HU or mass density assignment. For example, an incorrect selection of material could result to percentage differences up to 15% in D2cc of the rectum. https://doi.org/10.1016/j.ejmp.2018.04.226
https://doi.org/10.1016/j.ejmp.2018.04.225
215. Comparison of dose calculation using TG43 dose formalism and Collapsed-Cone Algorithm in vaginal and uterine brachytherapy D. Becci a, A. Bruno a, M.G. Leo a, A. Terlizzi a, G. De Zisa a, D. Mola a, A. Crastolla b, A.R. Marsella b, G. Silvano b a b
ASL Taranto, Medical Physics Unit, Taranto, Italy ASL Taranto, Radiation Oncology Unit, Taranto, Italy
Purpose. The aim of this study is to investigate differences in dose calculation resulting from the use of TG-43 formalism and Collapsed Cone Algorithm in vaginal and uterine brachytherapy (VUB). Methods. In this study we present an experimental evaluation of Oncentra Brachytherapy Advanced Collapsed-Cone Engine (ACE) using three different applicators: vaginal, Fletcher CT/MR with and without the interstitial applicator. We applied ACE algorithm first considering all of these structures composed of water (AW). Then we choose for them an uniform density value (UDV) and finally an HU-based density assignment (HUB). However, in HUB, a value of uniform density has been set for bladder, CTV and brachytherapy applicator. Evaluation has been performed in terms of D0.1 cc, D1cc and D2cc for rectum, sigmoid and bladder and in terms of the dose received from the entire volume (D100) for target volume (TV), in five patients undergoing intracavitary brachytherapy for cervical and uterine cancer over the course of 5 HDR fractions.
216. Biological treatment planning with multiple ion beams O. Sokol a, E. Scifoni b, S. Hild b, M. Durante b, M. Krämer a a
GSI, Biophysics, Darmstadt, Germany Trento Institute for Fundamental Physics and Applications (TIFPA), Istituto Nazionale di Fisica Nucleare (INFN), Trento, Italy b
Purpose. To exploit the potential and different advantages of different ion beams when used at the same time, in a mixed irradiation, accounting for biological effects (relative biological effectiveness (RBE) and oxygen enhancement ratio (OER)) at an advanced level in inverse planning. Methods. Firstly, a biologically oriented treatment planning system for particles (TRiP98) was upgraded with the possibility to perform ‘‘kill painting” [1] in hypoxic targets, i.e. restoring a uniform cell killing in the all over the target, accounting for the differently oxygenated regions. The code is further enabled to perform simultaneous biological optimization of multiple ion species (MIBO), especially tuned for cases of hypoxic tumors. Calculation on idealized geometries as well as on selected patient cases have been considered. Results. A comparative assessment of treatment plans using different ion beams singly or in combinations has been performed. In particular, the use of oxygen beams appears to be more effective when used in combination with lower LET ions like He, rather than using only oxygen beams [2]; improvements up to a 12% relative effect
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Abstracts / Physica Medica 56 (2018) 133–278
can be found, on the level of peak to entrance ratio for idealized geometries, as well as in critical organs sparing in test patient plans cases. Conclusions. MIBO can provide in selected conditions an indication for an alternative treatment, where combination of different ions lead to better therapeutic ratio as compared to any of the single ion plans. The present approach has been proposed and accepted to be tested on in vitro phantoms at the MIT ion beam facility (Marburg, Germany) which provides different ions in a fast source switching mode.
References 1. Tinganelli W et al.. Kill-painting of hypoxic tumours in charged particle therapy. Sci Rep 2015;5:17016. 2. Sokol O et al.. Oxygen beams for therapy: advanced biological treatment planning and experimental verification. Phys Med Biol 2017;62:7798. https://doi.org/10.1016/j.ejmp.2018.04.227
Methods. The patients were treated with CyberKnife Linear accelerator in a ipofractionated radiotherapy regimen. We first divided the patients in two groups depending on tumor localization ( peripheral and central lesions) and then, in each group, we created three volume classes (GTV610 cc; 10 cc
217. Differences on GTV and PTV dose coverage for lung tumor stereotactic cyberknife treatments using Raytracing and MC algorithm: A retrospective study M. Mormile a, L. Iadanza b, C. Zambella c, P. Muto c a
ASL NA1 Centro, PO del Mare, UOC Radioterapia, Napoli, Italy Azienda Ospedaliera G. Rummo, UOC Radioterapia, Benevento, Italy c Istituto Nazionale dei Tumori di Napoli, Napoli, Italy b
Purpose. The aim of this work is to compare the coverage of GTVs and corresponding PTVs lung lesions in 86 patients treated at the National Tumor Institute of Naples ‘‘G. PASCALE”, between January 2015 and June 2016, with CyberKnife using two different algorithms (Ray-tracing and MonteCarlo) with the same beams and the same number of monitor units per beam.
218. Jarvik2000 and radiotherapy. Irradiation with high-energy photon beams and first results R. Giménez De Lorenzo a,d, R. Navarra a,c, D. Marinelli b, N. Adorante a, S. Giancaterino a, D. Genovesi a, G. Di Giammarco b, M.D. Falco a a
Department of Radiation Oncology, SS. Annunziata Hospital, University ‘‘G. d’Annunzio”, Chieti, Italy b Department of Cardiac Surgery, SS. Annunziata Hospital, University ‘‘G. d’Annunzio”, Chieti, Italy c Department of Neuroimaging and Cognitive Science, University ‘‘G. d’Annunzio”, Chieti, Italy d Department of Radiation Oncology, Azienda Ospedaliera-Universitaria ‘‘Ospedali Riuniti”, Foggia, Italy
Conclusions. The implications of waiting list for radiotherapy treatment include perceived lower cancer control rates and patient suffering. The model represents a tool for effectively managing the capacity in a radiotherapy department to optimize the waiting lists for treatment.
References 1. Fomundam, S., & Herrmann, J. (2007). A survey of Queuing Theory Applications in healthcare. ISR Technical Report 24. 2. Seshaiah C, Thiagaraj H. A queuing network congestion model in hospitals. Eur J Sci Res 2011;63:419–27. 3. Yasara O. Queuing Models and Capacity Planning. In: Yasara O, editor. Queuing Methods in Health care management. San Francisco: Jossey-Bass; 2009. p. 348–56.
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Results. For all the three cases investigated, the main difference regard dose to D2cc of the rectum. In particular, we observed a percentage difference between 0.6% and 0.2% for AW case, between 4.2% and 0.9% for UDV case and between 4.6% and 0.6% for HUB case. The variation of D100 for TV is about between 0.2% and 0.3% in AW, between 1.8% and 0.3% in UDV and between 1.4% and 0.2% in HUB. Conclusions. From AW, UDV and HUB cases we note it seems to be not necessary to use ACE algorithms in VUB. Using them we can say it is crucial to select the predefined material closer to the electron density of each structure. Furthermore, it is necessary to establish when, for a given structure, it is preferable to use the HU or mass density assignment. For example, an incorrect selection of material could result to percentage differences up to 15% in D2cc of the rectum. https://doi.org/10.1016/j.ejmp.2018.04.226
https://doi.org/10.1016/j.ejmp.2018.04.225
215. Comparison of dose calculation using TG43 dose formalism and Collapsed-Cone Algorithm in vaginal and uterine brachytherapy D. Becci a, A. Bruno a, M.G. Leo a, A. Terlizzi a, G. De Zisa a, D. Mola a, A. Crastolla b, A.R. Marsella b, G. Silvano b a b
ASL Taranto, Medical Physics Unit, Taranto, Italy ASL Taranto, Radiation Oncology Unit, Taranto, Italy
Purpose. The aim of this study is to investigate differences in dose calculation resulting from the use of TG-43 formalism and Collapsed Cone Algorithm in vaginal and uterine brachytherapy (VUB). Methods. In this study we present an experimental evaluation of Oncentra Brachytherapy Advanced Collapsed-Cone Engine (ACE) using three different applicators: vaginal, Fletcher CT/MR with and without the interstitial applicator. We applied ACE algorithm first considering all of these structures composed of water (AW). Then we choose for them an uniform density value (UDV) and finally an HU-based density assignment (HUB). However, in HUB, a value of uniform density has been set for bladder, CTV and brachytherapy applicator. Evaluation has been performed in terms of D0.1 cc, D1cc and D2cc for rectum, sigmoid and bladder and in terms of the dose received from the entire volume (D100) for target volume (TV), in five patients undergoing intracavitary brachytherapy for cervical and uterine cancer over the course of 5 HDR fractions.
216. Biological treatment planning with multiple ion beams O. Sokol a, E. Scifoni b, S. Hild b, M. Durante b, M. Krämer a a
GSI, Biophysics, Darmstadt, Germany Trento Institute for Fundamental Physics and Applications (TIFPA), Istituto Nazionale di Fisica Nucleare (INFN), Trento, Italy b
Purpose. To exploit the potential and different advantages of different ion beams when used at the same time, in a mixed irradiation, accounting for biological effects (relative biological effectiveness (RBE) and oxygen enhancement ratio (OER)) at an advanced level in inverse planning. Methods. Firstly, a biologically oriented treatment planning system for particles (TRiP98) was upgraded with the possibility to perform ‘‘kill painting” [1] in hypoxic targets, i.e. restoring a uniform cell killing in the all over the target, accounting for the differently oxygenated regions. The code is further enabled to perform simultaneous biological optimization of multiple ion species (MIBO), especially tuned for cases of hypoxic tumors. Calculation on idealized geometries as well as on selected patient cases have been considered. Results. A comparative assessment of treatment plans using different ion beams singly or in combinations has been performed. In particular, the use of oxygen beams appears to be more effective when used in combination with lower LET ions like He, rather than using only oxygen beams [2]; improvements up to a 12% relative effect
194
Abstracts / Physica Medica 56 (2018) 133–278
can be found, on the level of peak to entrance ratio for idealized geometries, as well as in critical organs sparing in test patient plans cases. Conclusions. MIBO can provide in selected conditions an indication for an alternative treatment, where combination of different ions lead to better therapeutic ratio as compared to any of the single ion plans. The present approach has been proposed and accepted to be tested on in vitro phantoms at the MIT ion beam facility (Marburg, Germany) which provides different ions in a fast source switching mode.
References 1. Tinganelli W et al.. Kill-painting of hypoxic tumours in charged particle therapy. Sci Rep 2015;5:17016. 2. Sokol O et al.. Oxygen beams for therapy: advanced biological treatment planning and experimental verification. Phys Med Biol 2017;62:7798. https://doi.org/10.1016/j.ejmp.2018.04.227
Methods. The patients were treated with CyberKnife Linear accelerator in a ipofractionated radiotherapy regimen. We first divided the patients in two groups depending on tumor localization ( peripheral and central lesions) and then, in each group, we created three volume classes (GTV610 cc; 10 cc
217. Differences on GTV and PTV dose coverage for lung tumor stereotactic cyberknife treatments using Raytracing and MC algorithm: A retrospective study M. Mormile a, L. Iadanza b, C. Zambella c, P. Muto c a
ASL NA1 Centro, PO del Mare, UOC Radioterapia, Napoli, Italy Azienda Ospedaliera G. Rummo, UOC Radioterapia, Benevento, Italy c Istituto Nazionale dei Tumori di Napoli, Napoli, Italy b
Purpose. The aim of this work is to compare the coverage of GTVs and corresponding PTVs lung lesions in 86 patients treated at the National Tumor Institute of Naples ‘‘G. PASCALE”, between January 2015 and June 2016, with CyberKnife using two different algorithms (Ray-tracing and MonteCarlo) with the same beams and the same number of monitor units per beam.
218. Jarvik2000 and radiotherapy. Irradiation with high-energy photon beams and first results R. Giménez De Lorenzo a,d, R. Navarra a,c, D. Marinelli b, N. Adorante a, S. Giancaterino a, D. Genovesi a, G. Di Giammarco b, M.D. Falco a a
Department of Radiation Oncology, SS. Annunziata Hospital, University ‘‘G. d’Annunzio”, Chieti, Italy b Department of Cardiac Surgery, SS. Annunziata Hospital, University ‘‘G. d’Annunzio”, Chieti, Italy c Department of Neuroimaging and Cognitive Science, University ‘‘G. d’Annunzio”, Chieti, Italy d Department of Radiation Oncology, Azienda Ospedaliera-Universitaria ‘‘Ospedali Riuniti”, Foggia, Italy