51
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Ferretti A, Martignano A, Simonato F, Paiusco M. Validation of a commercial TPS based on the VMC++ Monte Carlo code for electron beams: Commissioning and dosimetric comparison with EGSnrc in homogeneous and heterogeneous phantoms. Phys Med 2014; 30:25-35. [DOI: 10.1016/j.ejmp.2012.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 11/24/2022] Open
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52
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Lu L. Dose calculation algorithms in external beam photon radiation therapy. INTERNATIONAL JOURNAL OF CANCER THERAPY AND ONCOLOGY 2013. [DOI: 10.14319/ijcto.0102.5] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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53
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Rodriguez M, Sempau J, Brualla L. PRIMO: a graphical environment for the Monte Carlo simulation of Varian and Elekta linacs. Strahlenther Onkol 2013; 189:881-6. [PMID: 24005581 DOI: 10.1007/s00066-013-0415-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/19/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND The accurate Monte Carlo simulation of a linac requires a detailed description of its geometry and the application of elaborate variance-reduction techniques for radiation transport. Both tasks entail a substantial coding effort and demand advanced knowledge of the intricacies of the Monte Carlo system being used. METHODS PRIMO, a new Monte Carlo system that allows the effortless simulation of most Varian and Elekta linacs, including their multileaf collimators and electron applicators, is introduced. PRIMO combines (1) accurate physics from the PENELOPE code, (2) dedicated variance-reduction techniques that significantly reduce the computation time, and (3) a user-friendly graphical interface with tools for the analysis of the generated data. PRIMO can tally dose distributions in phantoms and computerized tomographies, handle phase-space files in IAEA format, and import structures (planning target volumes, organs at risk) in the DICOM RT-STRUCT standard. RESULTS A prostate treatment, conformed with a high definition Millenium multileaf collimator (MLC 120HD) from a Varian Clinac 2100 C/D, is presented as an example. The computation of the dose distribution in 1.86×3.00×1.86 mm3 voxels with an average 2% standard statistical uncertainty, performed on an eight-core Intel Xeon at 2.67 GHz, took 1.8 h-excluding the patient-independent part of the linac, which required 3.8 h but it is simulated only once. CONCLUSION PRIMO is a self-contained user-friendly system that facilitates the Monte Carlo simulation of dose distributions produced by most currently available linacs. This opens the door for routine use of Monte Carlo in clinical research and quality assurance purposes. It is free software that can be downloaded from http://www.primoproject.net.
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Affiliation(s)
- M Rodriguez
- Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, Diagonal 647, 08028, Barcelona, Spain,
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Borges C, Cunha G, Monteiro-Grillo I, Vaz P, Teixeira N. Comparison of different breast planning techniques and algorithms for radiation therapy treatment. Phys Med 2013; 30:160-70. [PMID: 23735838 DOI: 10.1016/j.ejmp.2013.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 04/23/2013] [Accepted: 04/30/2013] [Indexed: 12/25/2022] Open
Abstract
This work aims at investigating the impact of treating breast cancer using different radiation therapy (RT) techniques--forwardly-planned intensity-modulated, f-IMRT, inversely-planned IMRT and dynamic conformal arc (DCART) RT--and their effects on the whole-breast irradiation and in the undesirable irradiation of the surrounding healthy tissues. Two algorithms of iPlan BrainLAB treatment planning system were compared: Pencil Beam Convolution (PBC) and commercial Monte Carlo (iMC). Seven left-sided breast patients submitted to breast-conserving surgery were enrolled in the study. For each patient, four RT techniques--f-IMRT, IMRT using 2-fields and 5-fields (IMRT2 and IMRT5, respectively) and DCART - were applied. The dose distributions in the planned target volume (PTV) and the dose to the organs at risk (OAR) were compared analyzing dose-volume histograms; further statistical analysis was performed using IBM SPSS v20 software. For PBC, all techniques provided adequate coverage of the PTV. However, statistically significant dose differences were observed between the techniques, in the PTV, OAR and also in the pattern of dose distribution spreading into normal tissues. IMRT5 and DCART spread low doses into greater volumes of normal tissue, right breast, right lung and heart than tangential techniques. However, IMRT5 plans improved distributions for the PTV, exhibiting better conformity and homogeneity in target and reduced high dose percentages in ipsilateral OAR. DCART did not present advantages over any of the techniques investigated. Differences were also found comparing the calculation algorithms: PBC estimated higher doses for the PTV, ipsilateral lung and heart than the iMC algorithm predicted.
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Affiliation(s)
- C Borges
- Medicalconsult SA, Campo Grande, n° 56 - 8° A, 1700-093 Lisboa, Portugal.
| | - G Cunha
- Escola Superior de Tecnologias da Saúde, Avenida Dom João II, 1900-096 Lisboa, Portugal
| | - I Monteiro-Grillo
- Departamento de Radioterapia, Hospital de Santa Maria, Centro Hospitalar Lisboa, Norte, EPE, Avenida Professor Egas Moniz, 1649-035 Lisboa, Portugal
| | - P Vaz
- Instituto Superior Técnico, Campus Tecnológico e Nuclear, Unidade de Protecção e Segurança Radiológica, Estrada Nacional 10 (ao km 139,7), 2695-066 Bobadela LRS, Portugal
| | - N Teixeira
- Escola Superior de Tecnologias da Saúde, Avenida Dom João II, 1900-096 Lisboa, Portugal
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55
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Martínez-Rovira I, Sempau J, Prezado Y. Monte Carlo-based dose calculation engine for minibeam radiation therapy. Phys Med 2013; 30:57-62. [PMID: 23597423 DOI: 10.1016/j.ejmp.2013.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 02/25/2013] [Accepted: 02/28/2013] [Indexed: 10/27/2022] Open
Abstract
Minibeam radiation therapy (MBRT) is an innovative radiotherapy approach based on the well-established tissue sparing effect of arrays of quasi-parallel micrometre-sized beams. In order to guide the preclinical trials in progress at the European Synchrotron Radiation Facility (ESRF), a Monte Carlo-based dose calculation engine has been developed and successfully benchmarked with experimental data in anthropomorphic phantoms. Additionally, a realistic example of treatment plan is presented. Despite the micron scale of the voxels used to tally dose distributions in MBRT, the combination of several efficiency optimisation methods allowed to achieve acceptable computation times for clinical settings (approximately 2 h). The calculation engine can be easily adapted with little or no programming effort to other synchrotron sources or for dose calculations in presence of contrast agents.
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Affiliation(s)
- I Martínez-Rovira
- Service Hospitalier Frédéric Joliot (DSV/I2BM/SHFJ), Commissariat à l'Énergie Atomique et aux énergies alternatives (CEA), 4, Place du Général Leclerc, F-91401 Orsay, France; Institut de Tècniques Energètiques (INTE), Universitat Politècnica de Catalunya (UPC), Diagonal 647, E-08028 Barcelona, Spain; ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), B.P. 220, 6 rue Jules Horowitz, F-38043 Grenoble Cedex, France.
| | - J Sempau
- Institut de Tècniques Energètiques (INTE), Universitat Politècnica de Catalunya (UPC), Diagonal 647, E-08028 Barcelona, Spain; Networking Research Centre, CIBER-BBN, Barcelona, Spain
| | - Y Prezado
- Laboratoire Imagerie et Modélisation en Neurobiologie et Cancérologie, Centre National de la Recherche Scientifique (CNRS), 15 rue Georges Clemenceau, Bât. 440F-91406 Orsay Cedex, France
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56
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Accurate estimation of dose distributions inside an eye irradiated with 106Ru plaques. Strahlenther Onkol 2012; 189:68-73. [DOI: 10.1007/s00066-012-0245-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 09/17/2012] [Indexed: 10/27/2022]
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57
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Sterpin E, Verboomen C, Vynckier S. Impact of the number of discrete angles used during dose computation for TomoTherapy treatments. Med Phys 2012; 39:6947-56. [PMID: 23127088 DOI: 10.1118/1.4762684] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To quantify systematically the effect on accuracy of discretizing gantry rotation during the dose calculation process of TomoTherapy treatments. METHODS Up to version 4.0.x included, TomoTherapy treatment planning system (TPS) approximates gantry rotation by computing dose from 51 discrete angles corresponding to the center of the projections used to control the binary multileaf collimator. Potential effects on dose computation accuracy for off-axis targets and low modulation factors have been shown previously for a few treatment configurations. In versions 4.1.x and later, TomoTherapy oversamples the projections to better account for gantry rotation, but only during full scatter optimization and final calculation (i.e., not during optimization in "beamlet" mode). The effect on accuracy of changing the number of angles was quantified with the following framework: (1) predict the impact of the discretization of gantry rotation for various modulation factors, target sizes, and off-axis positions using a simplified analytical algorithm; (2) perform regular quality assurance using measurements with EDR2 radiographic films; (3) isolating the effect of changing the number of discretized angles only (51, 153, and 459) using a previously validated Monte Carlo model (TomoPen). The diameters of the targets were 2, 3, and 5 cm; off-axis central positions of target volumes were 5, 10 and 15, and 17 cm (when accepted by the treatment unit); planned modulation factors were 1.3 and 2.0. RESULTS For extreme configurations (3 cm tumor, 1.3 modulation factor, 15 cm off-axis position), effects on dose distributions were significant with 89.3% and 95.4% of the points passing gamma tests with 2%∕2 mm and 3%∕3 mm criteria, respectively, for TPS software version 4.0.x (51 gantry angles). The passing rate was 100% for both gamma criteria for the 4.1.x version (153 gantry angles). Those differences could be attributed almost completely to gantry motion discretization using TomoPen. Using 51 gantry angles for dose computation, TomoPen reproduced within statistical uncertainties (<1% standard deviation) dose distributions computed with version 4.0.x. Using 153 and 459 gantry angles, TomoPen reproduced within statistical uncertainties measurements and dose distributions computed with version 4.1.x. CONCLUSIONS When low modulation factors and significant off-axis positions are used, accounting for gantry rotation during dose computation using at least 153 gantry angles is required to ensure optimal accuracy.
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Affiliation(s)
- E Sterpin
- Université catholique de Louvain, Brussels, Belgium
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58
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Sterpin E, Janssens G, Orban de Xivry J, Goossens S, Wanet M, Lee JA, Delor A, Bol V, Vynckier S, Gregoire V, Geets X. Helical tomotherapy for SIB and hypo-fractionated treatments in lung carcinomas: a 4D Monte Carlo treatment planning study. Radiother Oncol 2012; 104:173-80. [PMID: 22841518 DOI: 10.1016/j.radonc.2012.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 05/29/2012] [Accepted: 06/17/2012] [Indexed: 12/25/2022]
Abstract
PURPOSE To evaluate the impact of intra-fraction motion induced by regular breathing on treatment quality for helical tomotherapy treatments. MATERIAL AND METHODS Four patients treated by simultaneous-integrated boost (SIB) and three by hypo-fractionated stereotactic treatments (hypo-fractionated, 18 Gy/fraction) were included. All patients were coached to ensure regular breathing. For the SIB group, the tumor volume was delineated using CT information only (CTV(CT)) and the boost region was based on PET information (GTV(PET), no CTV extension). In the hypo-fractionated group, a GTV based on CT information was contoured. In both groups, ITVs were defined according to 4D data. The PTV included the ITV plus a setup error margin. The treatment was planned using the tomotherapy TPS on 3D CT images. In order to verify the impact of intra-fraction motion and interplay effects, dose calculations were performed using a previously validated Monte Carlo model of tomotherapy (TomoPen): first on the planning 3D CT ("planned dose") and second, on the 10 phases of the 4D scan. For the latter, two dose distributions, termed "interplay simulated" or "no interplay" were computed with and without beamlet-phase correlation over the 10 phases and combined using deformable dose registration. RESULTS In all cases, DVHs of "interplay simulated" dose distributions complied within 1% of the original clinical objectives used for planning, defined according to ICRU (report 83) and RTOG (trials 0236 and 0618) recommendations, for SIB and hypo-fractionated groups, respectively. For one patient in the hypo-fractionated group, D(mean) to the CTV(CT) was 2.6% and 2.5% higher than "planned" for "interplay simulated" and "no interplay", respectively. CONCLUSION For the patients included in this study, assuming regular breathing, the results showed that interplay of breathing and tomotherapy delivery motions did not affect significantly plan delivery accuracy. Hence, accounting for intra-fraction motion through the definition of an ITV volume was sufficient to ensure tumor coverage.
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59
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Ma CM, Lin MH, Dai XF, Koren S, Klayton T, Wang L, Li JS, Chen L, Price RA. Investigation of pulsed low dose rate radiotherapy using dynamic arc delivery techniques. Phys Med Biol 2012; 57:4613-26. [PMID: 22750648 DOI: 10.1088/0031-9155/57/14/4613] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
There has been no consensus standard of care to treat recurrent cancer patients who have previously been irradiated. Pulsed low dose rate (PLDR) external beam radiotherapy has the potential to reduce normal tissue toxicities while still providing significant tumor control for recurrent cancers. This work investigates the dosimetry feasibility of PLDR treatment using dynamic arc delivery techniques. Five treatment sites were investigated in this study including breast, pancreas, prostate, head and neck, and lung. Dynamic arc plans were generated using the Varian Eclipse system and the RapidArc delivery technique with 6 and 10 MV photon beams. Each RapidArc plan consisted of two full arcs and the plan was delivered five times to achieve a daily dose of 200 cGy. The dosimetry requirement was to deliver approximately 20 cGy/arc with a 3 min interval to achieve an effective dose rate of 6.7 cGy min⁻¹. Monte Carlo simulations were performed to calculate the actual dose delivered to the planning target volume (PTV) per arc taking into account beam attenuation/scattering and intensity modulation. The maximum, minimum and mean doses to the PTV were analyzed together with the dose volume histograms and isodose distributions. The dose delivery for the five plans was validated using solid water phantoms inserted with an ionization chamber and film, and a cylindrical detector array. Two intensity-modulated arcs were used to efficiently deliver the PLDR plans that provided conformal dose distributions for treating complex recurrent cancers. For the five treatment sites, the mean PTV dose ranged from 18.9 to 22.6 cGy/arc. For breast, the minimum and maximum PTV dose was 8.3 and 35.2 cGy/arc, respectively. The PTV dose varied between 12.9 and 27.5 cGy/arc for pancreas, 12.6 and 28.3 cGy/arc for prostate, 12.1 and 30.4 cGy/arc for H&N, and 16.2 and 27.6 cGy/arc for lung. Advanced radiation therapy can provide superior target coverage and normal tissue sparing for PLDR reirradiation of recurrent cancers, which can be delivered using dynamic arc delivery techniques with ten full arcs and an effective dose rate of 6.7 ± 4.0 cGy min⁻¹.
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Affiliation(s)
- C-M Ma
- Radiation Oncology Department, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
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60
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Kim JH, Hill R, Kuncic Z. An evaluation of calculation parameters in the EGSnrc/BEAMnrc Monte Carlo codes and their effect on surface dose calculation. Phys Med Biol 2012; 57:N267-78. [DOI: 10.1088/0031-9155/57/14/n267] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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61
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Electron Irradiation of Conjunctival Lymphoma—Monte Carlo Simulation of the Minute Dose Distribution and Technique Optimization. Int J Radiat Oncol Biol Phys 2012; 83:1330-7. [DOI: 10.1016/j.ijrobp.2011.09.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 08/09/2011] [Accepted: 09/11/2011] [Indexed: 11/17/2022]
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62
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Martínez-Rovira I, Sempau J, Prezado Y. Monte Carlo-based treatment planning system calculation engine for microbeam radiation therapy. Med Phys 2012; 39:2829-38. [DOI: 10.1118/1.4705351] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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63
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Moosekian SR, Jeong S, Marks BP, Ryser ET. X-Ray Irradiation as a Microbial Intervention Strategy for Food. Annu Rev Food Sci Technol 2012; 3:493-510. [DOI: 10.1146/annurev-food-022811-101306] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
First recognized in 1895, X-ray irradiation soon became a breakthrough diagnostic tool for the dental and medical professions. However, the food industry remained slow to adopt X-ray irradiation as a means for controlling insects and microbial contaminants in food, instead using gamma and electron beam (E-beam) irradiation. However, the reinvention of X-ray machines with increased efficiency, combined with recent developments in legislation and engineering, is now allowing X-ray to actively compete with gamma irradiation and E-beam as a microbial reduction strategy for foods. This review summarizes the historical developments of X-rays and discusses the key technological advances over the past two decades that now have led to the development of several different X-ray irradiators capable of enhancing the safety and shelf life of many heat-sensitive products, including lettuce, spinach, tomatoes, and raw almonds, all of which have been linked to high profile outbreaks of foodborne illness.
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Affiliation(s)
- Scott R. Moosekian
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824;,
| | - Sanghyup Jeong
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824;,
| | - Bradley P. Marks
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824;,
- Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824;,
| | - Elliot T. Ryser
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824;,
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Sempau J, Badal A, Brualla L. A PENELOPE-based system for the automated Monte Carlo simulation of clinacs and voxelized geometries-application to far-from-axis fields. Med Phys 2012; 38:5887-95. [PMID: 22047353 DOI: 10.1118/1.3643029] [Citation(s) in RCA: 177] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Two new codes, PENEASY and PENEASYLINAC, which automate the Monte Carlo simulation of Varian Clinacs of the 600, 1800, 2100, and 2300 series, together with their electron applicators and multileaf collimators, are introduced. The challenging case of a relatively small and far-from-axis field has been studied with these tools. METHODS PENEASY is a modular, general-purpose main program for the PENELOPE Monte Carlo system that includes various source models, tallies and variance-reduction techniques (VRT). The code includes a new geometry model that allows the superposition of voxels and objects limited by quadric surfaces. A variant of the VRT known as particle splitting, called fan splitting, is also introduced. PENEASYLINAC, in turn, automatically generates detailed geometry and configuration files to simulate linacs with PENEASY. These tools are applied to the generation of phase-space files, and of the corresponding absorbed dose distributions in water, for two 6 MV photon beams from a Varian Clinac 2100 C∕D: a 40 × 40 cm(2) centered field; and a 3 × 5 cm(2) field centered at (4.5, -11.5) cm from the beam central axis. This latter configuration implies the largest possible over-traveling values of two of the jaws. Simulation results for the depth dose and lateral profiles at various depths are compared, by using the gamma index, with experimental values obtained with a PTW 31002 ionization chamber. The contribution of several VRTs to the computing speed of the more demanding off-axis case is analyzed. RESULTS For the 40 × 40 cm(2) field, the percentages γ(1) and γ(1.2) of voxels with gamma indices (using 0.2 cm and 2% criteria) larger than unity and larger than 1.2 are 0.2% and 0%, respectively. For the 3 × 5 cm(2) field, γ(1) = 0%. These figures indicate an excellent agreement between simulation and experiment. The dose distribution for the off-axis case with voxels of 2.5 × 2.5 × 2.5 mm(3) and an average standard statistical uncertainty of 2% (1σ) is computed in 3.1 h on a single core of a 2.8 GHz Intel Core 2 Duo processor. This result is obtained with the optimal combination of the tested VRTs. In particular, fan splitting for the off-axis case accelerates execution by a factor of 240 with respect to standard particle splitting. CONCLUSIONS PENEASY and PENEASYLINAC can simulate the considered Varian Clinacs both in an accurate and efficient manner. Fan splitting is crucial to achieve simulation results for the off-axis field in an affordable amount of CPU time. Work to include Elekta linacs and to develop a graphical interface that will facilitate user input is underway.
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Affiliation(s)
- Josep Sempau
- Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, Barcelona, Spain.
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65
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Garny S, Rühm W, Zankl M, Wagner FM, Paretzke HG. First steps towards a fast-neutron therapy planning program. Radiat Oncol 2011; 6:163. [PMID: 22118299 PMCID: PMC3261826 DOI: 10.1186/1748-717x-6-163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 11/25/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Monte Carlo code GEANT4 was used to implement first steps towards a treatment planning program for fast-neutron therapy at the FRM II research reactor in Garching, Germany. Depth dose curves were calculated inside a water phantom using measured primary neutron and simulated primary photon spectra and compared with depth dose curves measured earlier. The calculations were performed with GEANT4 in two different ways, simulating a simple box geometry and splitting this box into millions of small voxels (this was done to validate the voxelisation procedure that was also used to voxelise the human body). RESULTS In both cases, the dose distributions were very similar to those measured in the water phantom, up to a depth of 30 cm. In order to model the situation of patients treated at the FRM II MEDAPP therapy beamline for salivary gland tumors, a human voxel phantom was implemented in GEANT4 and irradiated with the implemented MEDAPP neutron and photon spectra. The 3D dose distribution calculated inside the head of the phantom was similar to the depth dose curves in the water phantom, with some differences that are explained by differences in elementary composition. The lateral dose distribution was studied at various depths. The calculated cumulative dose volume histograms for the voxel phantom show the exposure of organs at risk surrounding the tumor. CONCLUSIONS In order to minimize the dose to healthy tissue, a conformal treatment is necessary. This can only be accomplished with the help of an advanced treatment planning system like the one developed here. Although all calculations were done for absorbed dose only, any biological dose weighting can be implemented easily, to take into account the increased radiobiological effectiveness of neutrons compared to photons.
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Affiliation(s)
- Sylvia Garny
- Helmholtz Zentrum München, Institut für Strahlenschutz, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
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Energy deposition by a 106Ru/106Rh eye applicator simulated using LEPTS, a low-energy particle track simulation. Appl Radiat Isot 2011; 69:1198-204. [DOI: 10.1016/j.apradiso.2011.04.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 04/18/2011] [Accepted: 04/19/2011] [Indexed: 11/24/2022]
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67
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Sterpin E, Chen Y, Chen Q, Lu W, Mackie TR, Vynckier S. Monte Carlo-based simulation of dynamic jaws tomotherapy. Med Phys 2011; 38:5230-8. [DOI: 10.1118/1.3626486] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Petoukhova AL, van Egmond J, Eenink MGC, Wiggenraad RGJ, van Santvoort JPC. The ArcCHECK diode array for dosimetric verification of HybridArc. Phys Med Biol 2011; 56:5411-28. [DOI: 10.1088/0031-9155/56/16/021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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69
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Ma CM, Li J. Dose specification for radiation therapy: dose to water or dose to medium? Phys Med Biol 2011; 56:3073-89. [DOI: 10.1088/0031-9155/56/10/012] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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70
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Sterpin E, Chen Y, Lu W, Mackie TR, Olivera GH, Vynckier S. On the relationships between electron spot size, focal spot size, and virtual source position in Monte Carlo simulations. Med Phys 2011; 38:1579-86. [DOI: 10.1118/1.3556560] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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71
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Plante I, Ponomarev A, Cucinotta FA. 3D visualisation of the stochastic patterns of the radial dose in nano-volumes by a Monte Carlo simulation of HZE ion track structure. RADIATION PROTECTION DOSIMETRY 2011; 143:156-161. [PMID: 21199826 DOI: 10.1093/rpd/ncq526] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The description of energy deposition by high charge and energy (HZE) nuclei is of importance for space radiation risk assessment and due to their use in hadrontherapy. Such ions deposit a large fraction of their energy within the so-called core of the track and a smaller proportion in the penumbra (or track periphery). We study the stochastic patterns of the radial dependence of energy deposition using Monte Carlo track structure codes RITRACKS and RETRACKS, that were used to simulate HZE tracks and calculate energy deposition in voxels of 40 nm. The simulation of a (56)Fe(26+) ion of 1 GeV u(-1) revealed zones of high-energy deposition which maybe found as far as a few millimetres away from the track core in some simulations. The calculation also showed that ∼43 % of the energy was deposited in the penumbra. These 3D stochastic simulations combined with a visualisation interface are a powerful tool for biophysicists which may be used to study radiation-induced biological effects such as double strand breaks and oxidative damage and the subsequent cellular and tissue damage processing and signalling.
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Affiliation(s)
- Ianik Plante
- NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058, USA
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Maigne L, Perrot Y, Schaart DR, Donnarieix D, Breton V. Comparison of GATE/GEANT4 with EGSnrc and MCNP for electron dose calculations at energies between 15 keV and 20 MeV. Phys Med Biol 2011; 56:811-27. [DOI: 10.1088/0031-9155/56/3/017] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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73
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Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans. Int J Radiat Oncol Biol Phys 2010; 78:955-63. [DOI: 10.1016/j.ijrobp.2009.08.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 05/31/2009] [Accepted: 08/15/2009] [Indexed: 12/14/2022]
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74
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Brualla L, Sauerwein W. On the efficiency of azimuthal and rotational splitting for Monte Carlo simulation of clinical linear accelerators. Radiat Phys Chem Oxf Engl 1993 2010. [DOI: 10.1016/j.radphyschem.2010.03.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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75
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Fragoso M, Wen N, Kumar S, Liu D, Ryu S, Movsas B, Munther A, Chetty IJ. Dosimetric verification and clinical evaluation of a new commercially available Monte Carlo-based dose algorithm for application in stereotactic body radiation therapy (SBRT) treatment planning. Phys Med Biol 2010; 55:4445-64. [PMID: 20668343 DOI: 10.1088/0031-9155/55/16/s02] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Fragoso M, Kawrakow I, Faddegon BA, Solberg TD, Chetty IJ. Fast, accurate photon beam accelerator modeling using BEAMnrc: a systematic investigation of efficiency enhancing methods and cross-section data. Med Phys 2010; 36:5451-66. [PMID: 20095258 DOI: 10.1118/1.3253300] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In this work, an investigation of efficiency enhancing methods and cross-section data in the BEAMnrc Monte Carlo (MC) code system is presented. Additionally, BEAMnrc was compared with VMC++, another special-purpose MC code system that has recently been enhanced for the simulation of the entire treatment head. BEAMnrc and VMC++ were used to simulate a 6 MV photon beam from a Siemens Primus linear accelerator (linac) and phase space (PHSP) files were generated at 100 cm source-to-surface distance for the 10 x 10 and 40 x 40 cm2 field sizes. The BEAMnrc parameters/techniques under investigation were grouped by (i) photon and bremsstrahlung cross sections, (ii) approximate efficiency improving techniques (AEITs), (iii) variance reduction techniques (VRTs), and (iv) a VRT (bremsstrahlung photon splitting) in combination with an AEIT (charged particle range rejection). The BEAMnrc PHSP file obtained without the efficiency enhancing techniques under study or, when not possible, with their default values (e.g., EXACT algorithm for the boundary crossing algorithm) and with the default cross-section data (PEGS4 and Bethe-Heitler) was used as the "base line" for accuracy verification of the PHSP files generated from the different groups described previously. Subsequently, a selection of the PHSP files was used as input for DOSXYZnrc-based water phantom dose calculations, which were verified against measurements. The performance of the different VRTs and AEITs available in BEAMnrc and of VMC++ was specified by the relative efficiency, i.e., by the efficiency of the MC simulation relative to that of the BEAMnrc base-line calculation. The highest relative efficiencies were approximately 935 (approximately 111 min on a single 2.6 GHz processor) and approximately 200 (approximately 45 min on a single processor) for the 10 x 10 field size with 50 million histories and 40 x 40 cm2 field size with 100 million histories, respectively, using the VRT directional bremsstrahlung splitting (DBS) with no electron splitting. When DBS was used with electron splitting and combined with augmented charged particle range rejection, a technique recently introduced in BEAMnrc, relative efficiencies were approximately 420 (approximately 253 min on a single processor) and approximately 175 (approximately 58 min on a single processor) for the 10 x 10 and 40 x 40 cm2 field sizes, respectively. Calculations of the Siemens Primus treatment head with VMC++ produced relative efficiencies of approximately 1400 (approximately 6 min on a single processor) and approximately 60 (approximately 4 min on a single processor) for the 10 x 10 and 40 x 40 cm2 field sizes, respectively. BEAMnrc PHSP calculations with DBS alone or DBS in combination with charged particle range rejection were more efficient than the other efficiency enhancing techniques used. Using VMC++, accurate simulations of the entire linac treatment head were performed within minutes on a single processor. Noteworthy differences (+/- 1%-3%) in the mean energy, planar fluence, and angular and spectral distributions were observed with the NIST bremsstrahlung cross sections compared with those of Bethe-Heitler (BEAMnrc default bremsstrahlung cross section). However, MC calculated dose distributions in water phantoms (using combinations of VRTs/AEITs and cross-section data) agreed within 2% of measurements. Furthermore, MC calculated dose distributions in a simulated water/air/water phantom, using NIST cross sections, were within 2% agreement with the BEAMnrc Bethe-Heitler default case.
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77
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Monte Carlo-based analytical model for small and variable fields delivered by TomoTherapy. Radiother Oncol 2010; 94:229-34. [DOI: 10.1016/j.radonc.2009.12.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 12/15/2009] [Accepted: 12/20/2009] [Indexed: 11/19/2022]
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Bueno G, Déniz O, Carrascosa CB, Delgado JM, Brualla L. Fast Monte Carlo simulation on a voxelized human phantom deformed to a patient. Med Phys 2010; 36:5162-74. [PMID: 19994526 DOI: 10.1118/1.3245877] [Citation(s) in RCA: 9] [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 A method for performing fast simulations of absorbed dose using a patient's computerized tomography (CT) scan without explicitly relying on a calibration curve is presented. METHODS The method is based on geometrical deformations performed on a standard voxelized human phantom. This involves spatially transforming the human phantom to align it with the patient CT image. Since the chemical composition and density of each voxel are given in the phantom data, a calibration curve is not used in the proposed method. For this study, the Monte Carlo (MC) code PENELOPE has been used as the simulation of reference. The results obtained with PENELOPE simulations are compared to those obtained with PENFAST and with the collapsed cone convolution algorithm implemented in a commercial treatment planning system. RESULTS The comparisons of the absorbed doses calculated with the different algorithms on two patient CTs and the corresponding deformed phantoms show a maximum distance to agreement of 2 mm, and in general, the obtained absorbed dose distributions are compatible within the reached statistical uncertainty. The validity of the deformation method for a broad range of patients is shown using MC simulations in random density phantoms. A PENFAST simulation of a 6 MV photon beam impinging on a patient CT reaches 2% statistical uncertainty in the absorbed dose, in a 0.1 cm3 voxel along the central axis, in 10 min running on a single core of a 2.8 GHz CPU. CONCLUSIONS The proposed method of the absorbed dose calculation in a deformed voxelized phantom allows for dosimetric studies in the geometry of a patient CT scan. This is due to the fact that the chemical composition and material density of the phantom are known. Furthermore, simulation using the phantom geometry can provide dosimetric information for each organ. The method can be used for quality assurance procedures. In relation to PENFAST, it is shown that a purely condensed-history algorithm (class I) can be used for absorbed dose estimation in patient CTs.
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Affiliation(s)
- G Bueno
- E.T.S.I. Industriales, Universidad de Castilla-La Mancha, Avenida Camilo José Cela s/n, E-13071 Ciudad Real, Spain.
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Vassiliev ON, Wareing TA, McGhee J, Failla G, Salehpour MR, Mourtada F. Validation of a new grid-based Boltzmann equation solver for dose calculation in radiotherapy with photon beams. Phys Med Biol 2010; 55:581-98. [PMID: 20057008 DOI: 10.1088/0031-9155/55/3/002] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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80
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Massa JM, Doorn JH, Wainschenker RS. Low-coupled parallel strategy for Monte Carlo radiation dose calculation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2010:1771-1774. [PMID: 21096418 DOI: 10.1109/iembs.2010.5626742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this work a parallelization technique for Monte Carlo calculation of the radiation absorbed dose is presented. The proposed method reduces the overall time of calculation exploiting the probabilistic nature of the problem. Reducing dose calculation times to meet practical application of use of results is a topic of great interest in the Monte Carlo simulation, dosimetry evaluation and treatment planning. The general problem of dose calculation parallelization was analyzed. The optimal number of calculation units for a given context was also determined.
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Affiliation(s)
- Jose Maria Massa
- INTIA, Fac. de Ciencias Exactas, UNICEN, Paraje Arroyo Seco, 7000, Tandil, Argentina.
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81
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Optimization and Numerical Modeling in Irreversible Electroporation Treatment Planning. IRREVERSIBLE ELECTROPORATION 2010. [DOI: 10.1007/978-3-642-05420-4_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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82
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Künzler T, Fotina I, Stock M, Georg D. Experimental verification of a commercial Monte Carlo-based dose calculation module for high-energy photon beams. Phys Med Biol 2009; 54:7363-77. [DOI: 10.1088/0031-9155/54/24/008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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83
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Mukumoto N, Tsujii K, Saito S, Yasunaga M, Takegawa H, Yamamoto T, Numasaki H, Teshima T. A preliminary study of in-house Monte Carlo simulations: an integrated Monte Carlo verification system. Int J Radiat Oncol Biol Phys 2009; 75:571-9. [PMID: 19735883 DOI: 10.1016/j.ijrobp.2009.02.088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 02/18/2009] [Accepted: 02/27/2009] [Indexed: 11/17/2022]
Abstract
PURPOSE To develop an infrastructure for the integrated Monte Carlo verification system (MCVS) to verify the accuracy of conventional dose calculations, which often fail to accurately predict dose distributions, mainly due to inhomogeneities in the patient's anatomy, for example, in lung and bone. METHODS AND MATERIALS The MCVS consists of the graphical user interface (GUI) based on a computational environment for radiotherapy research (CERR) with MATLAB language. The MCVS GUI acts as an interface between the MCVS and a commercial treatment planning system to import the treatment plan, create MC input files, and analyze MC output dose files. The MCVS consists of the EGSnrc MC codes, which include EGSnrc/BEAMnrc to simulate the treatment head and EGSnrc/DOSXYZnrc to calculate the dose distributions in the patient/phantom. In order to improve computation time without approximations, an in-house cluster system was constructed. RESULTS The phase-space data of a 6-MV photon beam from a Varian Clinac unit was developed and used to establish several benchmarks under homogeneous conditions. The MC results agreed with the ionization chamber measurements to within 1%. The MCVS GUI could import and display the radiotherapy treatment plan created by the MC method and various treatment planning systems, such as RTOG and DICOM-RT formats. Dose distributions could be analyzed by using dose profiles and dose volume histograms and compared on the same platform. With the cluster system, calculation time was improved in line with the increase in the number of central processing units (CPUs) at a computation efficiency of more than 98%. CONCLUSIONS Development of the MCVS was successful for performing MC simulations and analyzing dose distributions.
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Affiliation(s)
- Nobutaka Mukumoto
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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84
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Pisaturo O, Moeckli R, Mirimanoff RO, Bochud FO. A Monte Carlo-based procedure for independent monitor unit calculation in IMRT treatment plans. Phys Med Biol 2009; 54:4299-310. [DOI: 10.1088/0031-9155/54/13/022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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85
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Sterpin E, Salvat F, Olivera G, Vynckier S. Monte Carlo evaluation of the convolution/superposition algorithm of Hi-Art™ tomotherapy in heterogeneous phantoms and clinical cases. Med Phys 2009; 36:1566-75. [DOI: 10.1118/1.3112364] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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86
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Evaluation of PENFAST--a fast Monte Carlo code for dose calculations in photon and electron radiotherapy treatment planning. Phys Med 2009; 26:17-25. [PMID: 19342258 DOI: 10.1016/j.ejmp.2009.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 02/10/2009] [Accepted: 03/04/2009] [Indexed: 11/23/2022] Open
Abstract
The aim of the present study is to demonstrate the potential of accelerated dose calculations, using the fast Monte Carlo (MC) code referred to as PENFAST, rather than the conventional MC code PENELOPE, without losing accuracy in the computed dose. For this purpose, experimental measurements of dose distributions in homogeneous and inhomogeneous phantoms were compared with simulated results using both PENELOPE and PENFAST. The simulations and experiments were performed using a Saturne 43 linac operated at 12 MV (photons), and at 18 MeV (electrons). Pre-calculated phase space files (PSFs) were used as input data to both the PENELOPE and PENFAST dose simulations. Since depth-dose and dose profile comparisons between simulations and measurements in water were found to be in good agreement (within +/-1% to 1 mm), the PSF calculation is considered to have been validated. In addition, measured dose distributions were compared to simulated results in a set of clinically relevant, inhomogeneous phantoms, consisting of lung and bone heterogeneities in a water tank. In general, the PENFAST results agree to within a 1% to 1 mm difference with those produced by PENELOPE, and to within a 2% to 2 mm difference with measured values. Our study thus provides a pre-clinical validation of the PENFAST code. It also demonstrates that PENFAST provides accurate results for both photon and electron beams, equivalent to those obtained with PENELOPE. CPU time comparisons between both MC codes show that PENFAST is generally about 9-21 times faster than PENELOPE.
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87
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Chetty I. Monte Carlo Treatment Planning-An Introduction: Report 16 of the Netherlands Commission on Radiation Dosimetry. Med Phys 2008. [DOI: 10.1118/1.2998203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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88
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Spezi E, Lewis G. An overview of Monte Carlo treatment planning for radiotherapy. RADIATION PROTECTION DOSIMETRY 2008; 131:123-129. [PMID: 18930928 DOI: 10.1093/rpd/ncn277] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The implementation of Monte Carlo dose calculation algorithms in clinical radiotherapy treatment planning systems has been anticipated for many years. Despite a continuous increase of interest in Monte Carlo Treatment Planning (MCTP), its introduction into clinical practice has been delayed by the extent of calculation time required. The development of newer and faster MC codes is behind the commercialisation of the first MC-based treatment planning systems. The intended scope of this article is to provide the reader with a compact 'primer' on different approaches to MCTP with particular attention to the latest developments in the field.
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Affiliation(s)
- Emiliano Spezi
- Department of Medical Physics, Velindre Cancer Centre, Velindre Road, Whitchurch, Cardiff CF14 2TL, Wales, UK.
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Abstract
The goal of radiation therapy is to achieve maximal therapeutic benefit expressed in terms of a high probability of local control of disease with minimal side effects. Physically this often equates to the delivery of a high dose of radiation to the tumour or target region whilst maintaining an acceptably low dose to other tissues, particularly those adjacent to the target. Techniques such as intensity modulated radiotherapy (IMRT), stereotactic radiosurgery and computer planned brachytherapy provide the means to calculate the radiation dose delivery to achieve the desired dose distribution. Imaging is an essential tool in all state of the art planning and delivery techniques: (i) to enable planning of the desired treatment, (ii) to verify the treatment is delivered as planned and (iii) to follow-up treatment outcome to monitor that the treatment has had the desired effect. Clinical imaging techniques can be loosely classified into anatomic methods which measure the basic physical characteristics of tissue such as their density and biological imaging techniques which measure functional characteristics such as metabolism. In this review we consider anatomical imaging techniques. Biological imaging is considered in another article. Anatomical imaging is generally used for goals (i) and (ii) above. Computed tomography (CT) has been the mainstay of anatomical treatment planning for many years, enabling some delineation of soft tissue as well as radiation attenuation estimation for dose prediction. Magnetic resonance imaging is fast becoming widespread alongside CT, enabling superior soft-tissue visualization. Traditionally scanning for treatment planning has relied on the use of a single snapshot scan. Recent years have seen the development of techniques such as 4D CT and adaptive radiotherapy (ART). In 4D CT raw data are encoded with phase information and reconstructed to yield a set of scans detailing motion through the breathing, or cardiac, cycle. In ART a set of scans is taken on different days. Both allow planning to account for variability intrinsic to the patient. Treatment verification has been carried out using a variety of technologies including: MV portal imaging, kV portal/fluoroscopy, MVCT, conebeam kVCT, ultrasound and optical surface imaging. The various methods have their pros and cons. The four x-ray methods involve an extra radiation dose to normal tissue. The portal methods may not generally be used to visualize soft tissue, consequently they are often used in conjunction with implanted fiducial markers. The two CT-based methods allow measurement of inter-fraction variation only. Ultrasound allows soft-tissue measurement with zero dose but requires skilled interpretation, and there is evidence of systematic differences between ultrasound and other data sources, perhaps due to the effects of the probe pressure. Optical imaging also involves zero dose but requires good correlation between the target and the external measurement and thus is often used in conjunction with an x-ray method. The use of anatomical imaging in radiotherapy allows treatment uncertainties to be determined. These include errors between the mean position at treatment and that at planning (the systematic error) and the day-to-day variation in treatment set-up (the random error). Positional variations may also be categorized in terms of inter- and intra-fraction errors. Various empirical treatment margin formulae and intervention approaches exist to determine the optimum strategies for treatment in the presence of these known errors. Other methods exist to try to minimize error margins drastically including the currently available breath-hold techniques and the tracking methods which are largely in development. This paper will review anatomical imaging techniques in radiotherapy and how they are used to boost the therapeutic benefit of the treatment.
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Affiliation(s)
- Philip M Evans
- Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT, UK.
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Ma CM, Li JS, Deng J, Fan J. Implementation of Monte Carlo Dose calculation for CyberKnife treatment planning. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/102/1/012016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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91
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Sterpin E, Salvat F, Olivera GH, Vynckier S. Analytical model of the binary multileaf collimator of tomotherapy for Monte Carlo simulations. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/102/1/012022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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92
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Sterpin E, Salvat F, Cravens R, Ruchala K, Olivera GH, Vynckier S. Monte Carlo simulation of helical tomotherapy with PENELOPE. Phys Med Biol 2008; 53:2161-80. [DOI: 10.1088/0031-9155/53/8/011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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93
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Badal A, Kyprianou I, Badano A, Sempau J. Monte Carlo simulation of a realistic anatomical phantom described by triangle meshes: application to prostate brachytherapy imaging. Radiother Oncol 2008; 86:99-103. [PMID: 18061695 PMCID: PMC2292116 DOI: 10.1016/j.radonc.2007.11.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 11/06/2007] [Accepted: 11/06/2007] [Indexed: 11/21/2022]
Abstract
PURPOSE Monte Carlo codes can simulate the transport of radiation within matter with high accuracy and can be used to study medical applications of ionising radiations. The aim of our work was to develop a Monte Carlo code capable of generating projection images of the human body. In order to obtain clinically realistic images a detailed anthropomorphic phantom was prepared. These two simulation tools are intended to study the multiple applications of imaging in radiotherapy, from image guided treatments to portal imaging. METHODS We adapted the general-purpose code PENELOPE 2006 to simulate a radiation source, an ideal digital detector, and a realistic model of the patient anatomy. The anthropomorphic phantom was developed using computer-aided design tools, and is based on the NCAT phantom. The surface of each organ is modelled using a closed triangle mesh, and the full phantom contains 330 organs and more than 5 million triangles. A novel object-oriented geometry package, which includes an octree structure to sort the triangles, has been developed to use this complex geometry with PENELOPE. RESULTS As an example of the capabilities of the new code, projection images of the human pelvis region were simulated. Radioactive seeds were included inside the phantom's prostate. Therefore, the resulting simulated images resemble what would be obtained in a clinical procedure to assess the positioning of the seeds in a prostate brachytherapy treatment. CONCLUSIONS The new code can produce projection images of the human body that are comparable to those obtained by a real imaging system (within the limitations of the anatomical phantom and the detector model). The simulated images can be used to study and optimise an imaging task (i.e., maximise the object detectability, minimise the delivered dose, find the optimum beam energy, etc.). Since PENELOPE can simulate radiation from 50 eV to 1 GeV, the code can also be used to simulate radiotherapy treatments and portal imaging. Using the octree data structure, the new geometry model does not significantly increase the computing time when compared to the simulation of a much simpler quadric geometry. In conclusion, we have shown that it is feasible to use PENELOPE and a complex triangle mesh geometry to simulate real medical physics applications.
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Affiliation(s)
- Andreu Badal
- Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, Spain.
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95
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Tissue segmentation in Monte Carlo treatment planning: A simulation study using dual-energy CT images. Radiother Oncol 2008; 86:93-8. [DOI: 10.1016/j.radonc.2007.11.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 11/06/2007] [Accepted: 11/07/2007] [Indexed: 11/21/2022]
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96
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Chetty IJ, Curran B, Cygler JE, DeMarco JJ, Ezzell G, Faddegon BA, Kawrakow I, Keall PJ, Liu H, Ma CMC, Rogers DWO, Seuntjens J, Sheikh-Bagheri D, Siebers JV. Report of the AAPM Task Group No. 105: Issues associated with clinical implementation of Monte Carlo-based photon and electron external beam treatment planning. Med Phys 2007; 34:4818-53. [PMID: 18196810 DOI: 10.1118/1.2795842] [Citation(s) in RCA: 438] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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