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A planning study to optimise a simultaneously integrated boost treatment of larynx cancer with seven intensity-modulated radiation therapy (IMRT) beams. JOURNAL OF RADIOTHERAPY IN PRACTICE 2018. [DOI: 10.1017/s1460396918000201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
AbstractBackgroundIntensity-modulated radiation therapy (IMRT) is one of the most reported techniques for head and neck cancer treatment, as it allows a good coverage of the planning target volume (PTV) while sparing the surrounding organs at risk (OAR) better than conventional conformal radiotherapy. The objective of this work is to optimise an IMRT technique for the simultaneously integrated boost (SIB) treatment of larynx cancer delivering a total dose of 69·96 Gy to the boost volume and 54·45 Gy to the elective volume in 33 fractions.MethodsThree IMRT techniques, each using seven equally spaced beams, were planned for a sample of 10 patients. The first two techniques (IMRT-0 and IMRT-26) differ only for the starting angle of the seven beams, whereas the third (IMRT-CT) combines both these techniques by delivering IMRT-0 in the first half of treatment, and IMRT-26 in the second half, thus taking advantage of using 14 beams in total while using seven at a time only. The planning results were compared according to the dose coverage, homogeneity and conformity of the two PTVs, as well as to the dose to OARs, that is, spinal cord, parotids, mandible, brainstem and healthy tissue (defined as the body volume minus the sum of PTVs).ResultsBasically the PTV coverage resulted acceptable and comparable with all the three techniques. Concerning OARs, statistically better results are obtained in IMRT-CT when compared with IMRT-26 and IMRT-0.ConclusionThe IMRT-CT technique, combining two different seven-beam setups, delivered in two treatment phases, improves dose distribution without increasing delivery time.
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Mendes BM, Trindade BM, Fonseca TCF, de Campos TPR. Assessment of radiation-induced secondary cancer risk in the Brazilian population from left-sided breast-3D-CRT using MCNPX. Br J Radiol 2017; 90:20170187. [PMID: 28937271 PMCID: PMC6047661 DOI: 10.1259/bjr.20170187] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 09/06/2017] [Accepted: 09/08/2017] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE The aim of this work was to simulate a 6MV conventional breast 3D conformational radiation therapy (3D-CRT) with physical wedges (50 Gy/25#) in the left breast, calculate the mean absorbed dose in the body organs using robust models and computational tools and estimate the secondary cancer-incidence risk to the Brazilian population. METHODS The VW female phantom was used in the simulations. Planning target volume (PTV) was defined in the left breast. The 6MV parallel-opposed fields breast-radiotherapy (RT) protocol was simulated with MCNPx code. The absorbed doses were evaluated in all the organs. The secondary cancer-incidence risk induced by radiotherapy was calculated for different age groups according to the BEIR VII methodology. RESULTS RT quality indexes indicated that the protocol was properly simulated. Significant absorbed dose values in red bone marrow, RBM (0.8 Gy) and stomach (0.6 Gy) were observed. The contralateral breast presented the highest risk of incidence of a secondary cancer followed by leukaemia, lung and stomach. The risk of a secondary cancer-incidence by breast-RT, for the Brazilian population, ranged between 2.2-1.7% and 0.6-0.4%. CONCLUSION RBM and stomach, usually not considered as OAR, presented high second cancer incidence risks of 0.5-0.3% and 0.4-0.1%, respectively. This study may be helpful for breast-RT risk/benefit assessment. Advances in knowledge: MCNPX-dosimetry was able to provide the scatter radiation and dose for all body organs in conventional breast-RT. It was found a relevant risk up to 2.2% of induced-cancer from breast-RT, considering the whole thorax organs and Brazilian cancer-incidence.
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Affiliation(s)
| | - Bruno Machado Trindade
- Programa de Ciências e Técnicas Nucleares - Departamento de Engenharia Nuclear, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Telma Cristina Ferreira Fonseca
- Programa de Ciências e Técnicas Nucleares - Departamento de Engenharia Nuclear, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Tarcisio Passos Ribeiro de Campos
- Programa de Ciências e Técnicas Nucleares - Departamento de Engenharia Nuclear, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Stützer K, Jakobi A, Bandurska-Luque A, Barczyk S, Arnsmeyer C, Löck S, Richter C. Potential proton and photon dose degradation in advanced head and neck cancer patients by intratherapy changes. J Appl Clin Med Phys 2017; 18:104-113. [PMID: 28921843 PMCID: PMC5689930 DOI: 10.1002/acm2.12189] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/28/2017] [Accepted: 08/21/2017] [Indexed: 12/25/2022] Open
Abstract
Purpose Evaluation of dose degradation by anatomic changes for head‐and‐neck cancer (HNC) intensity‐modulated proton therapy (IMPT) relative to intensity‐modulated photon therapy (IMRT) and identification of potential indicators for IMPT treatment plan adaptation. Methods For 31 advanced HNC datasets, IMPT and IMRT plans were recalculated on a computed tomography scan (CT) taken after about 4 weeks of therapy. Dose parameter changes were determined for the organs at risk (OARs) spinal cord, brain stem, parotid glands, brachial plexus, and mandible, for the clinical target volume (CTV) and the healthy tissue outside planning target volume (PTV). Correlation of dose degradation with target volume changes and quality of rigid CT matching was investigated. Results Recalculated IMPT dose distributions showed stronger degradation than the IMRT doses. OAR analysis revealed significant changes in parotid median dose (IMPT) and near maximum dose (D1ml) of spinal cord (IMPT, IMRT) and mandible (IMPT). OAR dose parameters remained lower in IMPT cases. CTV coverage (V95%) and overdose (V107%) deteriorated for IMPT plans to (93.4 ± 5.4)% and (10.6 ± 12.5)%, while those for IMRT plans remained acceptable. Recalculated plans showed similarly decreased PTV conformity, but considerable hotspots, also outside the PTV, emerged in IMPT cases. Lower CT matching quality was significantly correlated with loss of PTV conformity (IMPT, IMRT), CTV homogeneity and coverage (IMPT). Target shrinkage correlated with increased dose in brachial plexus (IMRT, IMPT), hotspot generation outside the PTV (IMPT) and lower PTV conformity (IMRT). Conclusions The study underlines the necessity of precise positioning and monitoring of anatomy changes, especially in IMPT which might require adaptation more often. Since OAR doses remained typically below constraints, IMPT plan adaptation will be indicated by target dose degradations.
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Affiliation(s)
- Kristin Stützer
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF 41, 01307, Dresden, Germany.,Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Annika Jakobi
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF 41, 01307, Dresden, Germany.,Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Bautzner Landstr. 400, 01328, Dresden, Germany.,Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307, Dresden, Germany
| | - Anna Bandurska-Luque
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF 41, 01307, Dresden, Germany.,Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307, Dresden, Germany
| | - Steffen Barczyk
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF 41, 01307, Dresden, Germany.,Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307, Dresden, Germany
| | - Carolin Arnsmeyer
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF 41, 01307, Dresden, Germany
| | - Steffen Löck
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF 41, 01307, Dresden, Germany.,Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Christian Richter
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF 41, 01307, Dresden, Germany.,Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Bautzner Landstr. 400, 01328, Dresden, Germany.,Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307, Dresden, Germany.,German Cancer Consortium (DKTK), partner site Dresden, Germany and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69192, Heidelberg, Germany
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Ranganathan V, Maria Das KJ. Determination of optimal number of beams in direct machine parameter optimization-based intensity modulated radiotherapy for head and neck cases. J Med Phys 2016; 41:129-34. [PMID: 27217625 PMCID: PMC4871002 DOI: 10.4103/0971-6203.181633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This paper aims to introduce an algorithm called “sensitivity-based beam number selection (SBBNS)” for fully automated and case-specific determination of an optimal number of equispaced beams in intensity-modulated radiotherapy (IMRT). We tested the algorithm in five head and neck cases of varying complexity. We used direct machine parameter optimization method coupled with Auto Plan feature available in Pinnacle TPS (Version 9.10.0) for optimization. The Pearson correlation test shows a correlation of 0.88 between predicted and actual optimal number of beams, which indicates that SBBNS method is capable of predicting optimal number of beams for head and neck cases with reasonable accuracy. The major advantage of the algorithm is that it intrinsically takes into account various case- and machine-specific factors for the determination of optimal number. The study demonstrates that the algorithm can be effectively applied to IMRT scenarios to determine case specific and optimal number of beams for head and neck cases.
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Affiliation(s)
- Vaitheeswaran Ranganathan
- Philips Radiation Oncology Systems, Philips Ltd., Bengaluru, Karnataka, India; Research and Development Center, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - K J Maria Das
- Department of Radiotherapy, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
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Popple RA, Brezovich IA, Fiveash JB. Beam geometry selection using sequential beam addition. Med Phys 2014; 41:051713. [PMID: 24784379 DOI: 10.1118/1.4870977] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The selection of optimal beam geometry has been of interest since the inception of conformal radiotherapy. The authors report on sequential beam addition, a simple beam geometry selection method, for intensity modulated radiation therapy. METHODS The sequential beam addition algorithm (SBA) requires definition of an objective function (score) and a set of candidate beam geometries (pool). In the first iteration, the optimal score is determined for each beam in the pool and the beam with the best score selected. In the next iteration, the optimal score is calculated for each beam remaining in the pool combined with the beam selected in the first iteration, and the best scoring beam is selected. The process is repeated until the desired number of beams is reached. The authors selected three treatment sites, breast, lung, and brain, and determined beam arrangements for up to 11 beams from a pool comprised of 25 equiangular transverse beams. For the brain, arrangements were additionally selected from a pool of 22 noncoplanar beams. Scores were determined for geometries comprised equiangular transverse beams (EQA), as well as two tangential beams for the breast case. RESULTS In all cases, SBA resulted in scores superior to EQA. The breast case had the strongest dependence on beam geometry, for which only the 7-beam EQA geometry had a score better than the two tangential beams, whereas all SBA geometries with more than two beams were superior. In the lung case, EQA and SBA scores monotonically improved with increasing number of beams; however, SBA required fewer beams to achieve scores equivalent to EQA. For the brain case, SBA with a coplanar pool was equivalent to EQA, while the noncoplanar pool resulted in slightly better scores; however, the dose-volume histograms demonstrated that the differences were not clinically significant. CONCLUSIONS For situations in which beam geometry has a significant effect on the objective function, SBA can identify arrangements equivalent to equiangular geometries but using fewer beams. Furthermore, SBA provides the value of the objective function as the number of beams is increased, allowing the planner to select the minimal beam number that achieves the clinical goals. The method is simple to implement and could readily be incorporated into an existing optimization system.
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Affiliation(s)
- Richard A Popple
- Department of Radiation Oncology, The University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, Alabama 35294
| | - Ivan A Brezovich
- Department of Radiation Oncology, The University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, Alabama 35294
| | - John B Fiveash
- Department of Radiation Oncology, The University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, Alabama 35294
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Lissner S, Schubert K, Wiezorek T, Sterzing F, Herfarth K, Sroka-Perez G, Debus J. Investigations of peripheral dose for helical tomotherapy. Z Med Phys 2013; 23:324-31. [PMID: 23876598 DOI: 10.1016/j.zemedi.2013.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 02/14/2013] [Accepted: 06/14/2013] [Indexed: 11/19/2022]
Abstract
PURPOSE Whenever treating a patient with percutaneous radiotherapy, a certain amount of dose is inevitably delivered to healthy tissue. This is mainly due to beam's entry and exit in the region of the target volume. In regions distant from the target volume, dose is delivered by leakage from the MLC and head scatter from the accelerator head and phantom scatter from the target volume (peripheral dose). Helical tomotherapy is a form of radiation therapy with a uniquely designed machine and delivery pattern which influence the peripheral dose. The goal of this work was to investigate peripheral dose in helical tomotherapy. The experiments were used to establish a complex characterization of the peripheral dose. MATERIALS AND METHODS A 30*30*60cm(3) slab phantom and TLD-100 (Lithium fluoride) were used for the experiments. Treatment procedures were generated with the tomotherapy planning system (TPS). Additionally, procedures were created on the Operator Station of the tomotherapy system without a calculation of the dose distribution. The peripheral dose which was produced by a typical tomotherapy treatment plan was measured. Furthermore, these procedures were used to differentiate the parts of the peripheral dose in phantom scatter dose and head scatter and leakage dose. Additionally, the relation between peripheral dose and treatment time and between peripheral dose and delivered dose was investigated. Additionally, the peripheral dose was measured in an Alderson phantom. RESULTS Distances of 30cm or more resulted in a decrease of the peripheral dose to less than 0.1% of the target dose. The measured doses have an offset of approximately 1cGy in comparison to the calculated doses from the TPS. The separated head scatter and leakage dose was measured in the range of 1cGy for typical treatments. Furthermore, the investigations show a linear correlation between head scatter leakage dose and treatment time and between scatter dose parts and delivered dose. A peripheral dose of 0.28% of the target dose was measured in the Alderson phantom at a distance of 17.5cm from the edge of the target volume. CONCLUSIONS The peripheral dose delivered by a tomotherapy treatment is clinically unobjectionable. The measurements confirmed a linear correlation between head scatter and leakage and treatment time and between scatter dose and delivered dose.
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Affiliation(s)
- Steffen Lissner
- Department of Radiation Oncology, University Hospital Heidelberg, Germany.
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Narayanan VKS, Vaitheeswaran R, Bhangle JR, Basu S, Maiya V, Zade B. An experimental investigation on the effect of beam angle optimization on the reduction of beam numbers in IMRT of head and neck tumors. J Appl Clin Med Phys 2012; 13:3912. [PMID: 22766955 PMCID: PMC5716515 DOI: 10.1120/jacmp.v13i4.3912] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 02/16/2012] [Accepted: 03/21/2012] [Indexed: 01/11/2023] Open
Abstract
In static intensity-modulated radiation therapy (IMRT), the fundamental factors that determine the quality of a plan are the number of beams and their angles. The objective of this study is to investigate the effect of beam angle optimization (BAO) on the beam number in IMRT. We used six head and neck cases to carry out the study. Basically the methodology uses a parameter called "Beam Intensity Profile Perturbation Score" (BIPPS) to determine the suitable beam angles in IMRT. We used two set of plans in which one set contains plans with equispaced beam configuration starting from beam numbers 3 to 18, and another set contains plans with optimal beam angles chosen using the in-house BAO algorithm. We used quadratic dose-based single criteria objective function as a measure of the quality of a plan. The objective function scores obtained for equispaced beam plans and optimal beam angle plans for six head and neck cases were plotted against the beam numbers in a single graphical plot for effective comparison. It is observed that the optimization of beam angles reduces the beam numbers required to produce clini-cally acceptable dose distribution in IMRT of head and neck tumors. Especially N0.1 (represents the beam number at which the objective function reaches a value of 0.1) is considerably reduced by beam angle optimization in almost all the cases included in the study. We believe that the experimental findings of this study will be helpful in understanding the interplay between beam angle optimization and beam number selection process in IMRT which, in turn, can be used to improve the performance of BAO algorithms and beam number selection process in IMRT.
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Zwicker F, Hauswald H, Nill S, Rhein B, Thieke C, Roeder F, Timke C, Zabel-du Bois A, Debus J, Huber PE. New multileaf collimator with a leaf width of 5 mm improves plan quality compared to 10 mm in step-and-shoot IMRT of HNC using integrated boost procedure. Strahlenther Onkol 2010; 186:334-43. [PMID: 20495969 DOI: 10.1007/s00066-010-2103-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 03/18/2010] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate whether a new multileaf collimator with a leaf width of 5 mm (MLC-5) over the entire field size of 40 x 40 cm(2) improves plan quality compared to a leaf width of 10 mm (MLC-10) in intensity-modulated radiotherapy (IMRT) with integrated boost for head and neck cancer. PATIENTS AND METHODS A plan comparison was performed for ten patients with head and neck cancer. For each patient, seven plans were calculated: one plan with MLC-10 and nine beams, four plans with MLC-5 and nine beams (with different intensity levels and two-dimensional median filter sizes [2D-MFS]), and one seven-beam plan with MLC-5 and MLC-10, respectively. Isocenter, beam angles and planning constraints were not changed. Mean values of common plan parameters over all ten patients were estimated, and plan groups of MLC-5 and MLC-10 with nine and seven beams were compared. RESULTS The use of MLC-5 led to a significantly higher conformity index and an improvement of the 90% coverage of PTV1 (planning target volume) and PTV2 compared with MLC-10. This was noted in the nine- and seven-beam plans. Within the nine-beam group with MLC-5, a reduction of the segment number by up to 25% at reduced intensity levels and for increased 2D-MFS did not markedly worsen plan quality. Interestingly, a seven-beam IMRT with MLC-5 was inferior to a nine-beam IMRT with MLC-5, but superior to a nine-beam IMRT with MLC-10. CONCLUSION The use of an MLC-5 has significant advantages over an MLC-10 with respect to target coverage and protection of normal tissues in step-and-shoot IMRT of head and neck cancer.
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Affiliation(s)
- Felix Zwicker
- Department of Radiation Oncology, University of Heidelberg, Germany.
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