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Amato E, Gnesin S, Cicone F, Auditore L. Fundamentals of internal radiation dosimetry. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00142-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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2
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Auditore L, Pistone D, Amato E, Italiano A. Monte Carlo methods in nuclear medicine. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00136-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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3
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Mendes BM, Guimarães Antunes PC, Soares Lopes Branco I, Nascimento ED, Seniwal B, Ferreira Fonseca TC, Yoriyaz H. Calculation of dose point kernel values for monoenergetic electrons and beta emitting radionuclides: Intercomparison of Monte Carlo codes. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109327] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Liu R, Zhang S, Zhao T, O'Sullivan JA, Williamson JF, Webb T, Porras-Chaverri M, Whiting B. Impact of bowtie filter and detector collimation on multislice CT scatter profiles: A simulation study. Med Phys 2020; 48:852-870. [PMID: 33296513 DOI: 10.1002/mp.14652] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 09/30/2020] [Accepted: 11/13/2020] [Indexed: 01/20/2023] Open
Abstract
PURPOSE To investigate via Monte Carlo simulations, the impact of scan subject size, antiscatter grid (ASG), collimator size, and bowtie filter on the distribution of scatter radiation in a typical realistically modeled third generation 16 slice diagnostic computed tomography (CT) scanner. METHODS Full radiation transport was simulated with Geant4 in a realistic CT scanner geometric model, including the imaging phantom, bowtie filter (BTF), collimators and detector assembly, except for the ASGs. An analytical method was employed to quantify the probable transmission through the ASG of each photon intersecting the detector array. Normalized scatter profiles (NSP) and scatter-to-primary-ratio (SPR) profiles were simulated for 90 and 140 kVp beams for different size phantoms and slice thicknesses. The impact of CT scatter on the reconstructed attenuation coefficient factor was also studied as were the modulating effects of phantom- and patient-tissue heterogeneities on scatter profiles. A method to characterize the relative spatial frequency content of sinogram signals was developed to assess the latter. RESULTS For the 21.4-cm diameter phantom, NSP and SPR increase linearly with collimator opening for both tube potentials, with the 90 kVp scan exhibiting slightly larger NSP and SPR. The BTF modestly modulates scatter under the phantom center, reducing the prominent off-axis lobes by factors of 1.1-1.3. The ASG reduces scatter on the central axis NSP threefold, and reduces scatter at the detectors outside the phantom shadow by factors of 25 to 500. For the phantoms with diameters of 27 and 32 cm, the scatter increases roughly three- and fourfold, respectively, demonstrating that scatter monotonically increases with phantom size, despite deployment of the ASG and BTF. In the absence of a scan subject, the ASG reduces the signal profile arising photons scattered by the BTF. Without ASG, the in-air scatter profile is relatively flat compared to the scatter profile when the ASG is present. For both 90 and 140 kVp photon spectra, the calculated attenuation coefficient decreases linearly with increasing collimation size. For both homogeneous and heterogeneous objects, NSPs are dominated by low spatial frequency content compared to the primary signal. However, the SPR, which quantifies the local magnitude of nonlinear detector response and is dominated by the high frequency content of the primary profile, can contribute strongly to high-spatial frequency streaking artifacts near high-density structures in reconstructed image artifacts. CONCLUSION Public-domain Monte Carlo codes, Geant-4 in particular, is a feasible method for characterizing CT detector response to scattered- and off-focal radiation. Our study demonstrates that the ASG substantially reduces the scatter radiation and reshapes scatter-radiation profiles and affects the accuracy with which the detector array can measure narrow-beam attenuation due its inability to distinguish between true uncollided primary and narrow-angle coherently scattered photons. Hence, incorporating the impact of detector array collimation into the forward-projection signal formation models used by iterative reconstruction algorithms is necessary to use CT for accurately characterizing material properties. While tissue heterogeneities exercise a modest influence on local NPS shape and magnitude, they do not add significant high spatial frequency content.
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Affiliation(s)
- Ruirui Liu
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Shuangyue Zhang
- Department of Electrical and Systems Engineering, Washington University, St. Louis, MO, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joseph A O'Sullivan
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jeffrey F Williamson
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Tyler Webb
- Department of Electrical and Systems Engineering, Washington University, St. Louis, MO, USA
| | - Mariela Porras-Chaverri
- Atomic, Nuclear and Molecular Sciences Research Center (CICANUM), University of Costa Rica, San José, Coast Rica
| | - Bruce Whiting
- Radiology Department, University of Pittsburgh, Pittsburgh, PA, USA
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Shi M, Myronakis M, Jacobson M, Ferguson D, Williams C, Lehmann M, Baturin P, Huber P, Fueglistaller R, Lozano IV, Harris T, Morf D, Berbeco RI. GPU-accelerated Monte Carlo simulation of MV-CBCT. Phys Med Biol 2020; 65:235042. [PMID: 33263311 DOI: 10.1088/1361-6560/abaeba] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Monte Carlo simulation (MCS) is one of the most accurate computation methods for dose calculation and image formation in radiation therapy. However, the high computational complexity and long execution time of MCS limits its broad use. In this paper, we present a novel strategy to accelerate MCS using a graphic processing unit (GPU), and we demonstrate the application in mega-voltage (MV) cone-beam computed tomography (CBCT) simulation. A new framework that generates a series of MV projections from a single simulation run is designed specifically for MV-CBCT acquisition. A Geant4-based GPU code for photon simulation is incorporated into the framework for the simulation of photon transport through a phantom volume. The FastEPID method, which accelerates the simulation of MV images, is modified and integrated into the framework. The proposed GPU-based simulation strategy was tested for its accuracy and efficiency in a Catphan 604 phantom and an anthropomorphic pelvis phantom with beam energies at 2.5 MV, 6 MV, and 6 MV FFF. In all cases, the proposed GPU-based simulation demonstrated great simulation accuracy and excellent agreement with measurement and CPU-based simulation in terms of reconstructed image qualities. The MV-CBCT simulation was accelerated by factors of roughly 900-2300 using an NVIDIA Tesla V100 GPU card against a 2.5 GHz AMD Opteron™ Processor 6380.
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Affiliation(s)
- Mengying Shi
- Medical Physics Program, Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, MA, United States of America. Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
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Tang W, Tang B, Li X, Wang Y, Li Z, Gao Y, Gao H, Yan C, Sun L. Cellular S-value evaluation based on real human cell models using the GATE MC package. Appl Radiat Isot 2020; 168:109509. [PMID: 33214023 DOI: 10.1016/j.apradiso.2020.109509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 10/28/2020] [Accepted: 11/06/2020] [Indexed: 11/25/2022]
Abstract
Exploring the spatial distribution of the energy loss of ionising radiation at the subcellular level is indispensable for evaluating the radiobiological effects of targeted radionuclide therapy accurately. Believing that S-values are important for obtaining the target dose, the Committee on Medical Internal Radiation Dose (MIRD) proposed a method to obtain the cellular dosimetric parameter. However, most available data on cellular S-values were calculated based on simple geometric models, such as ellipsoids or spheres, which do not accurately reflect biological reality. To investigate the influence of the cellular model on S-values, calculations were performed for two kinds of polygon-surface phantom models of realistic, individual human cells, the lung epithelial cell model (the B2B Phantom model) and the hepatocyte model (the Liver Phantom model), using the Monte Carlo (MC) software package GATE. To analyse the influence of cell geometry on the final S-value, the differences in the S-values between the realistic cell models and simple geometric sphere and ellipsoid models with similar volumes were calculated and compared for six different combinations of source and target regions. The irradiation conditions were 0.01-1.10 MeV monoenergetic electron sources and the Auger electronic therapy nuclides Ga-67, Tc-99m, In-111, I-125 and Tl-201, which are commonly used in nuclear medicine. The S-values calculated in this study are different from the results of the simple geometry models proposed by previous researchers. Two more precise polygon-surface phantom models of realistic, individual human cells were used, which provided more accurate information about the cell dose and will be very useful for the diagnostic application of radiotherapy in the future.
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Affiliation(s)
- Wei Tang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China
| | - Bo Tang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China; Department of Radiation Protection Safety, Shandong Center for Disease Control and Prevention, Jinan, 250014, China
| | - Xiang Li
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China
| | - Yidi Wang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China
| | - Zhanpeng Li
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China
| | - Yunan Gao
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China
| | - Han Gao
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China
| | - Congchong Yan
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China
| | - Liang Sun
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China; Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, China.
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Shi M, Myronakis M, Jacobson M, Lehmann M, Ferguson D, Baturin P, Huber P, Fueglistaller R, Harris T, Lozano IV, Williams C, Morf D, Berbeco RI. A rapid, accurate image simulation strategy for mega-voltage cone-beam computed tomography. ACTA ACUST UNITED AC 2020; 65:135004. [DOI: 10.1088/1361-6560/ab868a] [Citation(s) in RCA: 3] [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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Tiwari A, Gravesa SA, Sunderland J. The Impact of Tissue Type and Density on Dose Point Kernels for Patient-Specific Voxel-Wise Dosimetry: A Monte Carlo Investigation. Radiat Res 2020; 193:531-542. [PMID: 32315249 DOI: 10.1667/rr15563.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/11/2020] [Indexed: 11/03/2022]
Abstract
We report the generation of dose point kernels for clinically-relevant radionuclide beta decays and monoenergetic electrons in various tissues to understand the impact of tissue type on dose point kernels. Currently available voxel-wise dosimetry approaches using dose point kernels ignore tissue composition and density heterogeneities. Therefore, the study on the impact of tissue type on dose point kernels is warranted. Simulations were performed using the GATE Monte Carlo toolkit, which encapsulates GEANT4 libraries. Dose point kernels were simulated in phantoms of water, compact bone, lung, adipose tissue, blood and red marrow for radionuclides 90Y, 188Re, 32P, 89Sr, 186Re, 153Sm and 177Lu and monoenergetic electrons (0.015-10 MeV). All simulations were performed by assuming an isotropic point source of electrons at the center of a homogeneous spherical phantom. Tissue-specific differences between kernels were investigated by normalizing kernels for effective pathlength. Transport of 20 million particles was found to provide sufficient statistical precision in all simulated kernels. The simulated dose point kernels demonstrate excellent agreement with other Monte Carlo packages. Deviation from kernels reported in the literature did not exceed a 10% global difference, which is consistent with the variability among published results. There are no significant differences between the dose point kernel in water and kernels in other tissues that have been scaled to account for density; however, tissue density predictably demonstrated itself to be a significant variable in dose point kernel distribution.
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Affiliation(s)
- Ashok Tiwari
- Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242.,Department of Physics, University of Iowa, Iowa City, Iowa 52242
| | - Stephen A Gravesa
- Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242
| | - John Sunderland
- Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242.,Department of Physics, University of Iowa, Iowa City, Iowa 52242
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Graves SA, Flynn RT, Hyer DE. Dose point kernels for 2,174 radionuclides. Med Phys 2019; 46:5284-5293. [PMID: 31461537 DOI: 10.1002/mp.13789] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Rapid adoption of targeted radionuclide therapy as an oncologic intervention has motivated the development of patient-specific voxel-wise approaches to radiation dosimetry. These approaches often rely on pretabulated dose point kernels for convolution-based calculations; however, these dose kernels are sparse in literature and often have suboptimal characteristics. The purpose of this work was to generate an extensive library of dose point kernels with sufficient size and resolution for general clinical application of voxel-wise dosimetry. METHODS Nuclear data were acquired for 2174 radionuclides from the National Nuclear Data Center (Brookhaven National Laboratory, accessed March 2018). Based on these data, isotropic point sources of radioactivity in water were simulated using Monte Carlo N-Particle transport v6.2 (MCNP6.2, Los Alamos National Laboratory). Simulations were separated by emission type for each radionuclide - photons (γ-rays, x rays), beta particles (positrons, electrons); and discrete electrons (conversion electrons, Auger electrons, Coster-Kronig electrons). Dose was tallied in concentric spherical shells about the point source using an energy deposition pulse-height tally (MCNP *F8 tally). Bins were spaced every 0.1 mm until a radius of 10 cm, and every 1 mm until a radius of 2 m. Positron emissions where treated as electrons for transport, with annihilation photons generated at the origin within the photon simulation. Alpha particle emissions were not simulated since their energy is deposited within ~0.2 mm of the source. Neutron and spallation effects were not considered. A subset of the resultant dose point kernels (11 C, 18 F, 32 P, 52g Mn, 64 Cu, 67 Ga, 89 Sr, 89 Zr, 90 Y, 99m Tc, 111 In, 117m Sn, 123 I, 124 I, 125 I, 131 I, 153 Sm, 177 Lu, 186 Re, 188 Re, 211 As, 212 Pb, 213 Bi, 223 Ra, and 225 Ac) were evaluated for accuracy based on conservation of energy, comparison to kernels in the literature, and statistical precision. RESULTS Among dose point kernels that were manually reviewed, good agreement with previously published dose point kernels was observed. Energy within the kernels was found to be conserved to within 1% of the value expected from nuclear data, suggesting that a radius of 2 m was sufficient to capture the almost all of the energy released during decay for all isotopes considered. Local dosimetric uncertainty, evaluated at the radius of 99% energy deposition, was found to be less than 9% for all radioisotopes evaluated. Rebinning data more coarsely by a factor of 10, similar to what would be done for a clinical dose calculation, results in all evaluated kernels having a relative error of less than 1.1% at R50% , 1.5% at R90% , and 2.7% at R99% (the radius corresponding to 50%, 90%, and 99% of total energy deposition, respectively). The kernels produced in this work have been made freely available (https://zenodo.org/record/2564036). CONCLUSIONS An extensive library of high-resolution radial dose kernels was generated and validated against published data. In addition to enabling patient-specific voxel-wise internal dosimetry by convolution superposition, the generated dose point kernels data may prove useful to the wider health physics community.
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Affiliation(s)
- Stephen A Graves
- Department of Radiology, University of Iowa, 3883 JPP, 200 Hawkins Dr., Iowa City, IA, 52242-1077, USA
| | - Ryan T Flynn
- Department of Radiation Oncology, University of Iowa, LL-W PFP, 200 Hawkins Dr., Iowa City, IA, 52242-1089, USA
| | - Daniel E Hyer
- Department of Radiation Oncology, University of Iowa, LL-W PFP, 200 Hawkins Dr., Iowa City, IA, 52242-1089, USA
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Shi M, Myronakis M, Hu YH, Jacobson M, Lehmann M, Fueglistaller R, Huber P, Baturin P, Wang A, Ferguson D, Harris T, Morf D, Berbeco R. A novel method for fast image simulation of flat panel detectors. ACTA ACUST UNITED AC 2019; 64:095019. [DOI: 10.1088/1361-6560/ab12aa] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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A comparison between GATE and MCNPX for photon dose calculations in radiation protection using a male voxel phantom. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2018.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Lee J, Lee J, Ryu D, Lee H, Ye SJ. Fano cavity test for electron Monte Carlo transport algorithms in magnetic fields: comparison between EGSnrc, PENELOPE, MCNP6 and Geant4. Phys Med Biol 2018; 63:195013. [PMID: 30183683 DOI: 10.1088/1361-6560/aadf29] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A Fano cavity test was performed for four general-purpose Monte Carlo codes, EGSnrc, PENELOPE, MCNP6 and Geant4 to evaluate the accuracy of their electron transport algorithms in magnetic fields. In the simulations, a plane-parallel ionization chamber was modelled as a circular gas disk sandwiched between two circular solid wall disks. It was assumed that an isotropic and uniform line source per unit mass along the central axis of the gas and solid emits mono-energetic electrons with energies 0.01, 0.1, 1.0 and 3.0 MeV at different magnetic field strengths 0, 0.35, 1.0, 1.5 and 3.0 T in the electron transport mode (no Bremsstrahlung). The relative difference between the calculated dose to the gas region and the initial total energy of emitted electrons per unit mass was defined as the accuracy of Monte Carlo codes. In all results, EGSnrc with the enhanced electric and magnetic field (EEMF) macros was not considerably sensitive to the step size parameters and showed accuracy less than 0.18% ± 0.06% with a coverage factor k = 2. The other codes could not achieve competent accuracy with their default settings of step size parameters, compared to EGSnrc with the EEMF macros. With the step size parameters carefully selected, the accuracy of PENELOPE and MCNP6 was within 1.0% and 0.4%, respectively. However, Geant4 showed accuracy within 1.7% except in 3.0 T. EGSnrc with the EEMF macros achieved the best accuracy for the Fano test at the electron energies and the magnetic field strengths investigated in this study and thus, would be recommended to simulate dose responses of ionization chambers in the presence of magnetic fields.
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Affiliation(s)
- Jaegi Lee
- Department of Transdisciplinary Studies, Program in Biomedical Radiation Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
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Shi M, Myronakis M, Hu YH, Morf D, Rottmann J, Berbeco R. A Monte Carlo study of the impact of phosphor optical properties on EPID imaging performance. Phys Med Biol 2018; 63:165013. [PMID: 30051879 DOI: 10.1088/1361-6560/aad647] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have developed a Monte Carlo computational model of a clinically employed electronic portal imaging device (EPID), and demonstrated the impact of phosphor optical properties on the imaging performance. The EPID model was built with Geant4 application for tomographic emission. Both radiative and optical transport were included in the model. Modulation transfer function (MTF), normalized noise-power spectrum times the incident x-ray fluence (qNNPS), and detective quantum efficiency (DQE) were calculated for simulated and measured data, and their agreement was quantified by the normalized root-mean-square error (NRMSE). MTF was computed using a 100 µm wide slit tilted by 1.5° and qNNPS was estimated using the Fujita-Lubberts-Swank method. DQE was calculated from MTF and qNNPS data. The NRMSE value was 0.0467 for MTF, 0.0217 for qNNPS, and 0.0885 for DQE, showing good agreement between measurement and simulation. Five major optical properties, phosphor grain size, phosphor thickness, phosphor refractive index, binder refractive index, and packing ratio were tested for their influence on the qNNPS, MTF, and DQE(0) of the model. Generally, the effect on the qNNPS is greater than MTF, and no impact on DQE(0), except from phosphor thickness, was observed. Multiple applications, such as imager design optimization and investigations of the dosimetric performance, are expected to benefit from the validated model.
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Affiliation(s)
- Mengying Shi
- Medical Physics Program, Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, MA 01854, United States of America. Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, United States of America
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Slimani FAA, Hamdi M, Bentourkia M. G4DARI: Geant4/GATE based Monte Carlo simulation interface for dosimetry calculation in radiotherapy. Comput Med Imaging Graph 2018; 67:30-39. [PMID: 29738914 DOI: 10.1016/j.compmedimag.2018.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/15/2018] [Accepted: 04/24/2018] [Indexed: 11/17/2022]
Abstract
Monte Carlo (MC) simulation is widely recognized as an important technique to study the physics of particle interactions in nuclear medicine and radiation therapy. There are different codes dedicated to dosimetry applications and widely used today in research or in clinical application, such as MCNP, EGSnrc and Geant4. However, such codes made the physics easier but the programming remains a tedious task even for physicists familiar with computer programming. In this paper we report the development of a new interface GEANT4 Dose And Radiation Interactions (G4DARI) based on GEANT4 for absorbed dose calculation and for particle tracking in humans, small animals and complex phantoms. The calculation of the absorbed dose is performed based on 3D CT human or animal images in DICOM format, from images of phantoms or from solid volumes which can be made from any pure or composite material to be specified by its molecular formula. G4DARI offers menus to the user and tabs to be filled with values or chemical formulas. The interface is described and as application, we show results obtained in a lung tumor in a digital mouse irradiated with seven energy beams, and in a patient with glioblastoma irradiated with five photon beams. In conclusion, G4DARI can be easily used by any researcher without the need to be familiar with computer programming, and it will be freely available as an application package.
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Affiliation(s)
- Faiçal A A Slimani
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Canada
| | - Mahdjoub Hamdi
- Département de Génie Électrique, Université de Mostaganem, Algeria
| | - M'hamed Bentourkia
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Canada.
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Taha E, Djouider F, Banoqitah E. Monte Carlo simulations for dose enhancement in cancer treatment using bismuth oxide nanoparticles implanted in brain soft tissue. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2018; 41:363-370. [DOI: 10.1007/s13246-018-0633-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/21/2018] [Indexed: 01/12/2023]
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Wilson E, Anderson M, Prendergasty D, Cheneler D. Comparison of CdZnTe neutron detector models using MCNP6 and Geant4. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201817008008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The production of accurate detector models is of high importance in the development and use of detectors. Initially, MCNP and Geant were developed to specialise in neutral particle models and accelerator models, respectively; there is now a greater overlap of the capabilities of both, and it is therefore useful to produce comparative models to evaluate detector characteristics. In a collaboration between Lancaster University, UK, and Innovative Physics Ltd., UK, models have been developed in both MCNP6 and Geant4 of Cadmium Zinc Telluride (CdZnTe) detectors developed by Innovative Physics Ltd. Herein, a comparison is made of the relative strengths of MCNP6 and Geant4 for modelling neutron flux and secondary γ-ray emission. Given the increasing overlap of the modelling capabilities of MCNP6 and Geant4, it is worthwhile to comment on differences in results for simulations which have similarities in terms of geometries and source configurations.
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Lee MS, Kim JH, Paeng JC, Kang KW, Jeong JM, Lee DS, Lee JS. Whole-Body Voxel-Based Personalized Dosimetry: The Multiple Voxel S-Value Approach for Heterogeneous Media with Nonuniform Activity Distributions. J Nucl Med 2017; 59:1133-1139. [DOI: 10.2967/jnumed.117.201095] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 11/21/2017] [Indexed: 11/16/2022] Open
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Papadimitroulas P. Dosimetry applications in GATE Monte Carlo toolkit. Phys Med 2017; 41:136-140. [DOI: 10.1016/j.ejmp.2017.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/08/2017] [Accepted: 02/10/2017] [Indexed: 10/20/2022] Open
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Shiiba T, Kuga N, Kuroiwa Y, Sato T. Evaluation of the accuracy of mono-energetic electron and beta-emitting isotope dose-point kernels using particle and heavy ion transport code system: PHITS. Appl Radiat Isot 2017; 128:199-203. [PMID: 28735112 DOI: 10.1016/j.apradiso.2017.07.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 05/25/2017] [Accepted: 07/14/2017] [Indexed: 10/19/2022]
Abstract
We assessed the accuracy of mono-energetic electron and beta-emitting isotope dose-point kernels (DPKs) calculated using the particle and heavy ion transport code system (PHITS) for patient-specific dosimetry in targeted radionuclide treatment (TRT) and compared our data with published data. All mono-energetic and beta-emitting isotope DPKs calculated using PHITS, both in water and compact bone, were in good agreement with those in literature using other MC codes. PHITS provided reliable mono-energetic electron and beta-emitting isotope scaled DPKs for patient-specific dosimetry.
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Affiliation(s)
- Takuro Shiiba
- Department of Radiological Technology, Faculty of Fukuoka Medical Technology, Teikyo University, 6-22 Misakimachi, Omuta, Fukuoka 836-8505, Japan.
| | - Naoya Kuga
- Department of Radiological Technology, Koga General Hospital, 1749-1 Sudaki, Ikeuchi-cho, Miyazaki 880-0041, Japan
| | - Yasuyoshi Kuroiwa
- Department of Radiological Technology, Koga General Hospital, 1749-1 Sudaki, Ikeuchi-cho, Miyazaki 880-0041, Japan; Department of Pathology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| | - Tatsuhiko Sato
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Shirakata 2-4, Tokai, Ibaraki 319-1195, Japan
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Myronakis M, Star-Lack J, Baturin P, Rottmann J, Morf D, Wang A, Hu YH, Shedlock D, Berbeco RI. A novel multilayer MV imager computational model for component optimization. Med Phys 2017; 44:4213-4222. [PMID: 28555935 DOI: 10.1002/mp.12382] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/18/2017] [Accepted: 05/21/2017] [Indexed: 12/28/2022] Open
Abstract
PURPOSE A novel Megavoltage (MV) multilayer imager (MLI) design featuring higher detective quantum efficiency and lower noise than current conventional MV imagers in clinical use has been recently reported. Optimization of the MLI design for multiple applications including tumor tracking, MV-CBCT and portal dosimetry requires a computational model that will provide insight into the physics processes that affect the overall and individual components' performance. The purpose of the current work was to develop and validate a comprehensive computational model that can be used for MLI optimization. METHODS The MLI model was built using the Geant4 Application for Tomographic Emission (GATE) application. The model includes x-ray and charged-particle interactions as well as the optical transfer within the phosphor. A first prototype MLI device featuring a stack of four detection layers was used for model validation. Each layer of the prototype contains a copper buildup plate, a phosphor screen and photodiode array. The model was validated against measured data of Modulation Transfer Function (MTF), Noise-Power Spectrum (NPS), and Detective Quantum Efficiency (DQE). MTF was computed using a slanted slit with 2.3° angle and 0.1 mm width. NPS was obtained using the autocorrelation function technique. DQE was calculated from MTF and NPS data. The comparison metrics between simulated and measured data were the Pearson's correlation coefficient (r) and the normalized root-mean-square error (NRMSE). RESULTS Good agreement between measured and simulated MTF and NPS values was observed. Pearson's correlation coefficient for the combined signal from all layers of the MLI was equal to 0.9991 for MTF and 0.9992 for NPS; NRMSE was 0.0121 for MTF and 0.0194 for NPS. Similarly, the DQE correlation coefficient for the combined signal was 0.9888 and the NRMSE was 0.0686. CONCLUSIONS A comprehensive model of the novel MLI design was developed using the GATE toolkit and validated against measured MTF, NPS, and DQE data acquired with a prototype device featuring four layers. This model will be used for further optimization of the imager components and configuration for clinical radiotherapy applications.
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Affiliation(s)
- Marios Myronakis
- Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center and Harvard Medical School, Boston, MA, 02115, USA
| | - Josh Star-Lack
- Varian Medical Systems Ginzton Technology Center, Palo Alto, CA, 94304-1030, USA
| | - Paul Baturin
- Varian Medical Systems Ginzton Technology Center, Palo Alto, CA, 94304-1030, USA
| | - Joerg Rottmann
- Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center and Harvard Medical School, Boston, MA, 02115, USA
| | - Daniel Morf
- Varian Medical Systems, Baden-Dattwil, CH- 5405, Switzerland
| | - Adam Wang
- Varian Medical Systems Ginzton Technology Center, Palo Alto, CA, 94304-1030, USA
| | - Yue-Houng Hu
- Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center and Harvard Medical School, Boston, MA, 02115, USA
| | | | - Ross I Berbeco
- Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center and Harvard Medical School, Boston, MA, 02115, USA
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Fallahpoor M, Abbasi M, Kalantari F, Parach AA, Sen A. Practical Nuclear Medicine and Utility of Phantoms for Internal Dosimetry: XCAT Compared with Zubal. RADIATION PROTECTION DOSIMETRY 2017; 174:191-197. [PMID: 27247443 DOI: 10.1093/rpd/ncw115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/13/2016] [Indexed: 06/05/2023]
Abstract
PURPOSE The absorbed doses for two radioisotopes, 99mTc and 131I, between previously validated Zubal phantom and the recently developed XCAT phantom were compared. MATERIALS AND METHODS GATE Monte Carlo code was used to simulate the statistical process of radiation. A XCAT phantom with voxel and matrix sizes similar to a standard Zubal phantom was generated. According to Medical International Radiation Dose formalism, specific absorbed fraction (SAF) values for photons and S-factors for beta particles were tabulated. The amounts of absorbed doses were calculated and compared in different organs. RESULTS The differences of gamma radiation doses, SAFs, between Zubal and XCAT are >50% in adrenal from adrenal, pancreas from pancreas and thyroid from thyroid, in lung from kidney, kidneys from lungs and in kidneys from thyroid and thyroid from kidneys. The beta radiation doses differences between Zubal and XCAT are >50% in thyroid from thyroid, bladder from bladder, kidney from kidney, liver from bladder, thyroid from bladder and kidney from thyroid. The size and distances of the organs were different between XCAT and Zubal phantoms. Denoted differences of SAF and S-factors correspond to the different organ geometries in phantoms. CONCLUSION The results of absorbed doses in Zubal and XCAT phantoms are different. The variations prohibit easy comparison or interchangeability of dosimetry between these phantoms.
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Affiliation(s)
- Maryam Fallahpoor
- Department of Nuclear Medicine, Vali-Asr Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran 1419731351, Iran
| | - Mehrshad Abbasi
- Department of Nuclear Medicine, Vali-Asr Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran 1419731351, Iran
| | - Faraz Kalantari
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75235
| | - Ali Asghar Parach
- Department of Medical Physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Anando Sen
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77004
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Ahmad SB, Sarfehnia A, Kim A, Wronski M, Sahgal A, Keller BM. Backscatter dose effects for high atomic number materials being irradiated in the presence of a magnetic field: A Monte Carlo study for the MRI linac. Med Phys 2017; 43:4665. [PMID: 27487883 DOI: 10.1118/1.4955175] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To quantify and explain the backscatter dose effects for clinically relevant high atomic number materials being irradiated in the presence of a 1.5 T transverse magnetic field. METHODS Interface effects were investigated using Monte Carlo simulation techniques. We used gpumcd (v5.1) and geant4 (v10.1) for this purpose. gpumcd is a commercial software written for the Elekta AB, MRI linac. Dose was scored using gpumcd in cubic voxels of side 1 and 0.5 mm, in two different virtual phantoms of dimensions 20 × 20 × 20 cm and 5 × 5 × 13.3 cm, respectively. A photon beam was generated from a point 143.5 cm away from the isocenter with energy distribution sampled from a histogram representing the true Elekta, MRI linac photon spectrum. A slab of variable thickness and position containing either bone, aluminum, titanium, stainless steel, or one of the two different dental filling materials was inserted as an inhomogeneity in the 20 × 20 × 20 cm phantom. The 5 × 5 × 13.3 cm phantom was used as a clinical test case in order to explain the dose perturbation effects for a head and neck cancer patient. The back scatter dose factor (BSDF) was defined as the ratio of the doses at a given depth with and without the presence of the inhomogeneity. Backscattered electron fluence was calculated at the inhomogeneity interface using geant4. A 1.5 T magnetic field was applied perpendicular to the direction of the beam in both phantoms, identical to the geometry in the Elekta MRI linac. RESULTS With the application of a 1.5 T magnetic field, all the BSDF's were reduced by 12%-47%, compared to the no magnetic field case. The corresponding backscattered electron fluence at the interface was also reduced by 45%-64%. The reduction in the BSDF at the interface, due to the application of the magnetic field, is manifested in a different manner for each material. In the case of bone, the dose drops at the interface contrary to the expected increase when no magnetic field is applied. In the case of aluminum, the dose at the interface is the same with and without the presence of the aluminum. For all of the other materials the dose increases at the interface. CONCLUSIONS The reduction in dose at the interface, in the presence of the magnetic field, is directly related to the reduction in backscattered electron fluence. This reduction occurs due to two different reasons. First, the electron spectrum hitting the interface is changed when the magnetic field is turned on, which results in changes in the electron scattering probability. Second, some electrons that have curved trajectories due to the presence of the magnetic field are absorbed by the higher density side of the interface and no longer contribute to the backscattered electron fluence.
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Affiliation(s)
- Syed Bilal Ahmad
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada and Sunnybrook Health Sciences Center, Odette Cancer Center, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada
| | - Arman Sarfehnia
- Sunnybrook Health Sciences Center, Odette Cancer Center, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
| | - Anthony Kim
- Sunnybrook Health Sciences Center, Odette Cancer Center, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
| | - Matt Wronski
- Sunnybrook Health Sciences Center, Odette Cancer Center, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
| | - Arjun Sahgal
- Sunnybrook Health Sciences Center, Odette Cancer Center, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
| | - Brian M Keller
- Sunnybrook Health Sciences Center, Odette Cancer Center, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
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Villoing D, Marcatili S, Garcia MP, Bardiès M. Internal dosimetry with the Monte Carlo code GATE: validation using the ICRP/ICRU female reference computational model. Phys Med Biol 2017; 62:1885-1904. [DOI: 10.1088/1361-6560/62/5/1885] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Khazaee Moghadam M, Kamali Asl A, Geramifar P, Zaidi H. Evaluating the Application of Tissue-Specific Dose Kernels Instead of Water Dose Kernels in Internal Dosimetry: A Monte Carlo Study. Cancer Biother Radiopharm 2017; 31:367-379. [PMID: 27996311 DOI: 10.1089/cbr.2016.2117] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The aim of this work is to evaluate the application of tissue-specific dose kernels instead of water dose kernels to improve the accuracy of patient-specific dosimetry by taking tissue heterogeneities into consideration. MATERIALS AND METHODS Tissue-specific dose point kernels (DPKs) and dose voxel kernels (DVKs) for yttrium-90 (90Y), lutetium-177 (177Lu), and phosphorus-32 (32P) are calculated using the Monte Carlo (MC) simulation code GATE (version 7). The calculated DPKs for bone, lung, adipose, breast, heart, intestine, kidney, liver, and spleen are compared with those of water. The dose distribution in normal and tumorous tissues in lung, liver, and bone of a Zubal phantom is calculated using tissue-specific DVKs instead of those of water in conventional methods. For a tumor defined in a heterogeneous region in the Zubal phantom, the absorbed dose is calculated using a proposed algorithm, taking tissue heterogeneity into account. The algorithm is validated against full MC simulations. RESULTS The simulation results indicate that the highest differences between water and other tissue DPKs occur in bone for 90Y (12.2% ± 0.6%), 32P (18.8% ± 1.3%), and 177Lu (16.9% ± 1.3%). The second highest discrepancy corresponds to the lung for 90Y (6.3% ± 0.2%), 32P (8.9% ± 0.4%), and 177Lu (7.7% ± 0.3%). For 90Y, the mean absorbed dose in tumorous and normal tissues is calculated using tissue-specific DVKs in lung, liver, and bone. The results are compared with doses calculated considering the Zubal phantom water equivalent and the relative differences are 4.50%, 0.73%, and 12.23%, respectively. For the tumor in the heterogeneous region of the Zubal phantom that includes lung, liver, and bone, the relative difference between mean calculated dose in tumorous and normal tissues based on the proposed algorithm and the values obtained from full MC dosimetry is 5.18%. CONCLUSIONS A novel technique is proposed considering tissue-specific dose kernels in the dose calculation algorithm. This algorithm potentially enables patient-specific dosimetry and improves estimation of the average absorbed dose of 90Y in a tumor located in lung, bone, and soft tissue interface by 6.98% compared with the conventional methods.
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Affiliation(s)
| | - Alireza Kamali Asl
- 1 Department of Radiation Medicine Engineering, Shahid Beheshti University , Tehran, Iran
| | - Parham Geramifar
- 2 Research Center for Nuclear Medicine, Shariati Hospital, Tehran University of Medical Sciences , Tehran, Iran
| | - Habib Zaidi
- 3 Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital , Geneva, Switzerland .,4 Geneva Neuroscience Center, Geneva University , Geneva, Switzerland .,5 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen , Groningen, The Netherlands
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Timmermand OV, Nilsson J, Strand SE, Elgqvist J. High resolution digital autoradiographic and dosimetric analysis of heterogeneous radioactivity distribution in xenografted prostate tumors. Med Phys 2016; 43:6632. [PMID: 27908170 DOI: 10.1118/1.4967877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
PURPOSE The first main aim of this study was to illustrate the absorbed dose rate distribution from 177Lu in sections of xenografted prostate cancer (PCa) tumors using high resolution digital autoradiography (DAR) and compare it with hypothetical identical radioactivity distributions of 90Y or 7 MeV alpha-particles. Three dosimetry models based on either dose point kernels or Monte Carlo simulations were used and evaluated. The second and overlapping aim, was to perform DAR imaging and dosimetric analysis of the distribution of radioactivity, and hence the absorbed dose rate, in tumor sections at an early time point after injection during radioimmunotherapy using 177Lu-h11B6, directed against the human kallikrein 2 antigen. METHODS Male immunodeficient BALB/c nude mice, aged 6-8 w, were inoculated by subcutaneous injection of ∼107 LNCaP cells in a 200 μl suspension of a 1:1 mixture of medium and Matrigel. The antibody h11B6 was conjugated with the chelator CHX-A″-DTPA after which conjugated h11B6 was mixed with 177LuCl3. The incubation was performed at room temperature for 2 h, after which the labeling was terminated and the solution was purified on a NAP-5 column. About 20 MBq 177Lu-h11B6 was injected intravenously in the tail vein. At approximately 10 h postinjection (hpi), the mice were sacrificed and one tumor was collected from each of the five animals and cryosectioned into 10 μm thick slices. The tumor slices were measured and imaged using the DAR MicroImager system and the M3Vision software. Then the absorbed dose rate was calculated using a dose point kernel generated with the Monte Carlo code gate v7.0. RESULTS The DAR system produced high resolution images of the radioactivity distribution, close to the resolution of single PCa cells. The DAR images revealed a pronounced heterogeneous radioactivity distribution, i.e., count rate per area, in the tumors, indicated by the normalized intensity variations along cross sections as mean ± SD: 0.15 ± 0.15, 0.20 ± 0.18, 0.12 ± 0.17, 0.15 ± 0.16, and 0.23 ± 0.22, for each tumor section, respectively. The absorbed dose rate distribution for 177Lu at the time of dissection 10 hpi showed a maximum value of 2.9 ± 0.4 Gy/h (mean ± SD), compared to 6.0 ± 0.9 and 159 ± 25 Gy/h for the hypothetical 90Y and 7 MeV alpha-particle cases assuming the same count rate densities. Mean absorbed dose rate values were 0.13, 0.53, and 6.43 Gy/h for 177Lu, 90Y, and alpha-particles, respectively. CONCLUSIONS The initial uptake of 177Lu-h11B6 produces a high absorbed dose rate, which is important for a successful therapeutic outcome. The hypothetical 90Y case indicates a less heterogeneous absorbed dose rate distribution and a higher mean absorbed dose rate compared to 177Lu, although with a potentially increased irradiation of surrounding healthy tissue. The hypothetical alpha-particle case indicates the possibility of a higher maximum absorbed dose rate, although with a more heterogeneous absorbed dose rate distribution.
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Affiliation(s)
- Oskar V Timmermand
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund 22185, Sweden
| | - Jenny Nilsson
- Sahlgrenska Academy, Institute of Clinical Sciences, Department Radiation Physics, University of Gothenburg, Gothenburg 41345, Sweden
| | - Sven-Erik Strand
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund 22185, Sweden and Faculty of Medicine, Department of Clinical Sciences Lund, Medical Radiation Physics, Lund University, Lund 22185, Sweden
| | - Jörgen Elgqvist
- Faculty of Science, Department of Physics, University of Gothenburg, Gothenburg 41296, Sweden
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Marcatili S, Villoing D, Mauxion T, McParland BJ, Bardiès M. Model-based versus specific dosimetry in diagnostic context: comparison of three dosimetric approaches. Med Phys 2016; 42:1288-96. [PMID: 25735284 DOI: 10.1118/1.4907957] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PURPOSE The dosimetric assessment of novel radiotracers represents a legal requirement in most countries. While the techniques for the computation of internal absorbed dose in a therapeutic context have made huge progresses in recent years, in a diagnostic scenario the absorbed dose is usually extracted from model-based lookup tables, most often derived from International Commission on Radiological Protection (ICRP) or Medical Internal Radiation Dose (MIRD) Committee models. The level of approximation introduced by these models may impact the resulting dosimetry. The aim of this work is to establish whether a more refined approach to dosimetry can be implemented in nuclear medicine diagnostics, by analyzing a specific case. METHODS The authors calculated absorbed doses to various organs in six healthy volunteers administered with flutemetamol ((18)F) injection. Each patient underwent from 8 to 10 whole body 3D PET/CT scans. This dataset was analyzed using a Monte Carlo (MC) application developed in-house using the toolkit gate that is capable to take into account patient-specific anatomy and radiotracer distribution at the voxel level. They compared the absorbed doses obtained with GATE to those calculated with two commercially available software: OLINDA/EXM and STRATOS implementing a dose voxel kernel convolution approach. RESULTS Absorbed doses calculated with gate were higher than those calculated with OLINDA. The average ratio between gate absorbed doses and OLINDA's was 1.38 ± 0.34 σ (from 0.93 to 2.23). The discrepancy was particularly high for the thyroid, with an average GATE/OLINDA ratio of 1.97 ± 0.83 σ for the six patients. Differences between STRATOS and GATE were found to be higher. The average ratio between GATE and STRATOS absorbed doses was 2.51 ± 1.21 σ (from 1.09 to 6.06). CONCLUSIONS This study demonstrates how the choice of the absorbed dose calculation algorithm may introduce a bias when gamma radiations are of importance, as is the case in nuclear medicine diagnostics.
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Affiliation(s)
- S Marcatili
- Inserm, UMR1037 CRCT, Toulouse F-31000, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, Toulouse F-31000, France
| | - D Villoing
- Inserm, UMR1037 CRCT, Toulouse F-31000, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, Toulouse F-31000, France
| | - T Mauxion
- Inserm, UMR1037 CRCT, Toulouse F-31000, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, Toulouse F-31000, France
| | - B J McParland
- Imaging Technology Group, GE Healthcare, Life Sciences, B22U The Grove Centre, White Lion Road, Amersham, England HP7 9LL, United Kingdom
| | - M Bardiès
- Inserm, UMR1037 CRCT, Toulouse F-31000, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, Toulouse F-31000, France
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Hilaire E, Sarrut D, Peyrin F, Maxim V. Proton therapy monitoring by Compton imaging: influence of the large energy spectrum of the prompt-γradiation. Phys Med Biol 2016; 61:3127-46. [DOI: 10.1088/0031-9155/61/8/3127] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Marcatili S, Villoing D, Garcia MP, Bardiès M. Multi-scale hybrid models for radiopharmaceutical dosimetry with Geant4. Phys Med Biol 2016; 59:7625-41. [PMID: 25415621 DOI: 10.1088/0031-9155/59/24/7625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The accuracy of radiopharmaceutical absorbed dose distributions computed through Monte Carlo (MC) simulations is mostly limited by the low spatial resolution of 3D imaging techniques used to define the simulation geometry. This issue also persists with the implementation of realistic hybrid models built using polygonal mesh and/or NURBS as they require to be simulated in their voxel form in order to reduce computation times. The existing trade-off between voxel size and simulation speed leads on one side, in an overestimation of the size of small radiosensitive structures such as the skin or hollow organs walls and, on the other, to unnecessarily detailed voxelization of large, homogeneous structures.We developed a set of computational tools based on VTK and Geant4 in order to build multi-resolution organ models. Our aim is to use different voxel sizes to represent anatomical regions of different clinical relevance: the MC implementation of these models is expected to improve spatial resolution in specific anatomical structures without significantly affecting simulation speed. Here we present the tools developed through a proof of principle example. Our approach is validated against the standard Geant4 technique for the simulation of voxel geometries.
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Affiliation(s)
- S Marcatili
- UMR 1037 INSERM-Centre de Recherche en Cancérologie de Toulouse, Toulouse, France
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White SA, Reniers B, de Jong EEC, Rusch T, Verhaegen F. A comparison of the relative biological effectiveness of low energy electronic brachytherapy sources in breast tissue: a Monte Carlo study. Phys Med Biol 2015; 61:383-99. [DOI: 10.1088/0031-9155/61/1/383] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Costa GCA, Sa LVD, Bonifacio DAB. Application of GATE/Geant4 for internal dosimetry using male ICRP reference voxel phantom by specific absorbed fractions calculations for photon irradiation. Biomed Phys Eng Express 2015. [DOI: 10.1088/2057-1976/1/4/045201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Didi S, Moussa A, Yahya T, Mustafa Z. Simulation of the 6 MV Elekta Synergy Platform linac photon beam using Geant4 Application for Tomographic Emission. J Med Phys 2015; 40:136-43. [PMID: 26500399 PMCID: PMC4594382 DOI: 10.4103/0971-6203.165077] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The present work validates the Geant4 Application for Tomographic Emission Monte Carlo software for the simulation of a 6 MV photon beam given by Elekta Synergy Platform medical linear accelerator treatment head. The simulation includes the major components of the linear accelerator (LINAC) with multi-leaf collimator and a homogeneous water phantom. Calculations were performed for the photon beam with several treatment field sizes ranging from 5 cm × 5 cm to 30 cm × 30 cm at 100 cm distance from the source. The simulation was successfully validated by comparison with experimental distributions. Good agreement between simulations and measurements was observed, with dose differences of about 0.02% and 2.5% for depth doses and lateral dose profiles, respectively. This agreement was also emphasized by the Kolmogorov-Smirnov goodness-of-fit test and by the gamma-index comparisons where more than 99% of the points for all simulations fulfill the quality assurance criteria of 2 mm/2%.
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Affiliation(s)
- Samir Didi
- Department of Physics, Laboratory of Physics of Radiation and Matter, Faculty of Sciences, University Mohammed First, Oujda 60000, Morocco ; Department of Physics, Regional Hassan II Oncology Center, Oujda 60000, Morocco
| | - Abdelilah Moussa
- Department of Physics, Laboratory of Physics of Radiation and Matter, Faculty of Sciences, University Mohammed First, Oujda 60000, Morocco ; Department of Physics, National School of Applied sciences of Al-Hoceima, Morocco
| | - Tayalati Yahya
- Department of Physics, Laboratory of Physics of Radiation and Matter, Faculty of Sciences, University Mohammed First, Oujda 60000, Morocco
| | - Zerfaoui Mustafa
- Department of Physics, Laboratory of Physics of Radiation and Matter, Faculty of Sciences, University Mohammed First, Oujda 60000, Morocco ; Department of Physics, Regional Hassan II Oncology Center, Oujda 60000, Morocco
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Sarrut D, Bardiès M, Boussion N, Freud N, Jan S, Létang JM, Loudos G, Maigne L, Marcatili S, Mauxion T, Papadimitroulas P, Perrot Y, Pietrzyk U, Robert C, Schaart DR, Visvikis D, Buvat I. A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications. Med Phys 2015; 41:064301. [PMID: 24877844 DOI: 10.1118/1.4871617] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy, hadrontherapy, molecular radiotherapy, and in vivo dose monitoring. Investigations that have been performed using GEANT4 only are also mentioned to illustrate the potential of GATE. The very practical feature of GATE making it easy to model both a treatment and an imaging acquisition within the same framework is emphasized. The computational times associated with several applications are provided to illustrate the practical feasibility of the simulations using current computing facilities.
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Affiliation(s)
- David Sarrut
- Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1; Centre Léon Bérard, France
| | - Manuel Bardiès
- Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse, France
| | | | - Nicolas Freud
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, 69008 Lyon, France
| | | | - Jean-Michel Létang
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, 69008 Lyon, France
| | - George Loudos
- Department of Medical Instruments Technology, Technological Educational Institute of Athens, Athens 12210, Greece
| | - Lydia Maigne
- UMR 6533 CNRS/IN2P3, Université Blaise Pascal, 63171 Aubière, France
| | - Sara Marcatili
- Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse, France
| | - Thibault Mauxion
- Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse, France
| | - Panagiotis Papadimitroulas
- Department of Biomedical Engineering, Technological Educational Institute of Athens, 12210, Athens, Greece
| | - Yann Perrot
- UMR 6533 CNRS/IN2P3, Université Blaise Pascal, 63171 Aubière, France
| | - Uwe Pietrzyk
- Institut für Neurowissenschaften und Medizin, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany and Fachbereich für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, 42097 Wuppertal, Germany
| | - Charlotte Robert
- IMNC, UMR 8165 CNRS, Universités Paris 7 et Paris 11, Orsay 91406, France
| | - Dennis R Schaart
- Delft University of Technology, Faculty of Applied Sciences, Radiation Science and Technology Department, Delft Mekelweg 15, 2629 JB Delft, The Netherlands
| | | | - Irène Buvat
- IMNC, UMR 8165 CNRS, Universités Paris 7 et Paris 11, 91406 Orsay, France and CEA/DSV/I2BM/SHFJ, 91400 Orsay, France
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Poškus A. Monte Carlo estimation of average energy required to produce an ion pair in noble gases by electrons with energies from 1 keV to 100 MeV. J NUCL SCI TECHNOL 2014. [DOI: 10.1080/00223131.2014.974710] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Lu CC, Lin HH, Chuang KS, Dong SL, Wu J, Ni YC, Jan ML. Development and validation of a fast voxel-based dose evaluation system in nuclear medicine. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2014.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Dosimetric perturbations at high-Z interfaces with high dose rate (192)Ir source. Phys Med 2014; 30:782-90. [PMID: 25008150 DOI: 10.1016/j.ejmp.2014.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 04/02/2014] [Accepted: 06/10/2014] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To investigate dose perturbations created by high-atomic number (Z) materials in high dose rate (HDR) Iridium-192 ((192)Ir) treatment region. METHODS AND MATERIALS A specially designed parallel plate ion chamber with 5 μm thick window was used to measure the dose rates from (192)Ir source downstream of the high-Z materials. A Monte Carlo (MC) code was employed to calculate the dose rates in both upstream and downstream of the high-Z interfaces at distances ranging from 0.01 to 2 mm. The dose perturbation factor (DPF) was defined as the ratio of dose rate with and without high-Z material in a water phantom. For verifying the Z dependence, both 0.1- and 1.0 mm-thick sheets of Pb, Au, Ta, Sn, Cu, Fe, Ti and Al were used. RESULTS/CONCLUSIONS The DPF depends on the Z and thickness of layer. At the downstream of a 0.1 mm layer of Pb, Au, Ta, Sn, Cu, Fe, Ti and Al, the DPF by MC were 3.73, 3.42, 3.04, 1.71, 1.04, 0.98, 0.92, or 0.94 respectively. When Z is greater than or equal to 50, the MC and experimental results disagree significantly (>20%) due to large DPF gradient but are in agreement for Z less than or equal to 29. Thin layers of Z greater than or equal to 50 near a (192)Ir source in water produce significant dose perturbations (i.e. increases) in the vicinity of the medium-high-Z interfaces and may thus cause local over-dose in (192)Ir brachytherapy. Conversely, this effect may potentially be used to deliver locally higher doses to targeted tissue.
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Hecht A, Blakeley R, Martin W, Leonard E. Comparison of Geant4 and MCNP6 for use in delayed fission radiation simulation. ANN NUCL ENERGY 2014. [DOI: 10.1016/j.anucene.2014.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Perrot Y, Degoul F, Auzeloux P, Bonnet M, Cachin F, Chezal JM, Donnarieix D, Labarre P, Moins N, Papon J, Rbah-Vidal L, Vidal A, Miot-Noirault E, Maigne L. Internal dosimetry through GATE simulations of preclinical radiotherapy using a melanin-targeting ligand. Phys Med Biol 2014; 59:2183-98. [PMID: 24710744 DOI: 10.1088/0031-9155/59/9/2183] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Fernández M, Hänscheid H, Mauxion T, Bardiès M, Kletting P, Glatting G, Lassmann M. A fast method for rescaling voxel S values for arbitrary voxel sizes in targeted radionuclide therapy from a single Monte Carlo calculation. Med Phys 2013; 40:082502. [DOI: 10.1118/1.4812684] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Koivunoro H, Siiskonen T, Kotiluoto P, Auterinen I, Hippelainen E, Savolainen S. Accuracy of the electron transport in mcnp5 and its suitability for ionization chamber response simulations: A comparison with the egsnrc and penelope codes. Med Phys 2013; 39:1335-44. [PMID: 22380366 DOI: 10.1118/1.3685446] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In this work, accuracy of the mcnp5 code in the electron transport calculations and its suitability for ionization chamber (IC) response simulations in photon beams are studied in comparison to egsnrc and penelope codes. METHODS The electron transport is studied by comparing the depth dose distributions in a water phantom subdivided into thin layers using incident energies (0.05, 0.1, 1, and 10 MeV) for the broad parallel electron beams. The IC response simulations are studied in water phantom in three dosimetric gas materials (air, argon, and methane based tissue equivalent gas) for photon beams ((60)Co source, 6 MV linear medical accelerator, and mono-energetic 2 MeV photon source). Two optional electron transport models of mcnp5 are evaluated: the ITS-based electron energy indexing (mcnp5(ITS)) and the new detailed electron energy-loss straggling logic (mcnp5(new)). The electron substep length (ESTEP parameter) dependency in mcnp5 is investigated as well. RESULTS For the electron beam studies, large discrepancies (>3%) are observed between the MCNP5 dose distributions and the reference codes at 1 MeV and lower energies. The discrepancy is especially notable for 0.1 and 0.05 MeV electron beams. The boundary crossing artifacts, which are well known for the mcnp5(ITS), are observed for the mcnp5(new) only at 0.1 and 0.05 MeV beam energies. If the excessive boundary crossing is eliminated by using single scoring cells, the mcnp5(ITS) provides dose distributions that agree better with the reference codes than mcnp5(new). The mcnp5 dose estimates for the gas cavity agree within 1% with the reference codes, if the mcnp5(ITS) is applied or electron substep length is set adequately for the gas in the cavity using the mcnp5(new). The mcnp5(new) results are found highly dependent on the chosen electron substep length and might lead up to 15% underestimation of the absorbed dose. CONCLUSIONS Since the mcnp5 electron transport calculations are not accurate at all energies and in every medium by general clinical standards, caution is needed, if mcnp5 is used with the current electron transport models for dosimetric applications.
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Mauxion T, Barbet J, Suhard J, Pouget JP, Poirot M, Bardiès M. Improved realism of hybrid mouse models may not be sufficient to generate reference dosimetric data. Med Phys 2013; 40:052501. [DOI: 10.1118/1.4800801] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wu J, Liu YL, Chang SJ, Chao MM, Tsai SY, Huang DE. Dose point kernel simulation for monoenergetic electrons and radionuclides using Monte Carlo techniques. RADIATION PROTECTION DOSIMETRY 2012; 152:119-124. [PMID: 22923242 DOI: 10.1093/rpd/ncs204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Monte Carlo (MC) simulation has been commonly used in the dose evaluation of radiation accidents and for medical purposes. The accuracy of simulated results is affected by the particle-tracking algorithm, cross-sectional database, random number generator and statistical error. The differences among MC simulation software packages must be validated. This study simulated the dose point kernel (DPK) and the cellular S-values of monoenergetic electrons ranging from 0.01 to 2 MeV and the radionuclides of (90)Y, (177)Lu and (103 m)Rh, using Fluktuierende Kaskade (FLUKA) and MC N-Particle Transport Code Version 5 (MCNP5). A 6-μm-radius cell model consisting of the cell surface, cytoplasm and cell nucleus was constructed for cellular S-value calculation. The mean absolute percentage errors (MAPEs) of the scaled DPKs, simulated using FLUKA and MCNP5, were 7.92, 9.64, 4.62, 3.71 and 3.84 % for 0.01, 0.1, 0.5, 1 and 2 MeV, respectively. For the three radionuclides, the MAPEs of the scaled DPKs were within 5 %. The maximum deviations of S(N←N), S(N←Cy) and S(N←CS) for the electron energy larger than 10 keV were 6.63, 6.77 and 5.24 %, respectively. The deviations for the self-absorbed S-values and cross-dose S-values of the three radionuclides were within 4 %. On the basis of the results of this study, it was concluded that the simulation results are consistent between FLUKA and MCNP5. However, there is a minor inconsistency for low energy range. The DPK and the cellular S-value should be used as the quality assurance tools before the MC simulation results are adopted as the gold standard.
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Affiliation(s)
- J Wu
- Department of Biomedical Imaging and Radiological Science, China Medical University, 40402 Taichung, Taiwan, ROC
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Papadimitroulas P, Loudos G, Nikiforidis GC, Kagadis GC. A dose point kernel database using GATE Monte Carlo simulation toolkit for nuclear medicine applications: comparison with other Monte Carlo codes. Med Phys 2012; 39:5238-47. [PMID: 22894448 DOI: 10.1118/1.4737096] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE GATE is a Monte Carlo simulation toolkit based on the Geant4 package, widely used for many medical physics applications, including SPECT and PET image simulation and more recently CT image simulation and patient dosimetry. The purpose of the current study was to calculate dose point kernels (DPKs) using GATE, compare them against reference data, and finally produce a complete dataset of the total DPKs for the most commonly used radionuclides in nuclear medicine. METHODS Patient-specific absorbed dose calculations can be carried out using Monte Carlo simulations. The latest version of GATE extends its applications to Radiotherapy and Dosimetry. Comparison of the proposed method for the generation of DPKs was performed for (a) monoenergetic electron sources, with energies ranging from 10 keV to 10 MeV, (b) beta emitting isotopes, e.g., (177)Lu, (90)Y, and (32)P, and (c) gamma emitting isotopes, e.g., (111)In, (131)I, (125)I, and (99m)Tc. Point isotropic sources were simulated at the center of a sphere phantom, and the absorbed dose was stored in concentric spherical shells around the source. Evaluation was performed with already published studies for different Monte Carlo codes namely MCNP, EGS, FLUKA, ETRAN, GEPTS, and PENELOPE. A complete dataset of total DPKs was generated for water (equivalent to soft tissue), bone, and lung. This dataset takes into account all the major components of radiation interactions for the selected isotopes, including the absorbed dose from emitted electrons, photons, and all secondary particles generated from the electromagnetic interactions. RESULTS GATE comparison provided reliable results in all cases (monoenergetic electrons, beta emitting isotopes, and photon emitting isotopes). The observed differences between GATE and other codes are less than 10% and comparable to the discrepancies observed among other packages. The produced DPKs are in very good agreement with the already published data, which allowed us to produce a unique DPKs dataset using GATE. The dataset contains the total DPKs for (67)Ga, (68)Ga, (90)Y, (99m)Tc, (111)In, (123)I, (124)I, (125)I, (131)I, (153)Sm, (177)Lu (186)Re, and (188)Re generated in water, bone, and lung. CONCLUSIONS In this study, the authors have checked GATE's reliability for absorbed dose calculation when transporting different kind of particles, which indicates its robustness for dosimetry applications. A novel dataset of DPKs is provided, which can be applied in patient-specific dosimetry using analytical point kernel convolution algorithms.
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Nogueira P, Zankl M, Schlattl H, Vaz P. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations. Phys Med Biol 2011; 56:6919-34. [DOI: 10.1088/0031-9155/56/21/010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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