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Oh G, Lee J, Kim H, Kim W, Kang S, Chung J, Jeong S, Lee H, Yoon M, Lee B. Monte Carlo simulation study of an in vivo four-dimensional tracking system with a diverging collimator for monitoring radiation source (Ir-192) location during brachytherapy: proof of concept and feasibility. Front Physiol 2024; 15:1302301. [PMID: 38590693 PMCID: PMC10999580 DOI: 10.3389/fphys.2024.1302301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/09/2024] [Indexed: 04/10/2024] Open
Abstract
Introduction: The aim of this study was to demonstrate the potential of an in vivo four-dimensional (4D) tracking system to accurately localize the radiation source, Iridium-192 (Ir-192) in high-dose rate brachytherapy. Methods: To achieve time-dependent 3D positioning of the Ir-192 source, we devised a 4D tracking system employing multiple compact detectors. During the system's design phase, we conducted comprehensive optimization and analytical evaluations of the diverging collimator employed for detection purposes. Subsequently, we executed 3D reconstruction and positioning procedures based on the 2D images obtained by six detectors, each equipped with an optimized diverging collimator. All simulations for designing and evaluating the 4D tracking system were performed using the open-source GATE (v9.1) Monte Carlo platform based on the GEANT4 (v10.7) toolkit. In addition, to evaluate the accuracy of the proposed 4D tracking system, we conducted simulations and 3D positioning using a solid phantom and patient data. Finally, the error between the reconstructed position coordinates determined by the tracking system and the original coordinates of the Ir-192 radiation source was analyzed. Results: The parameters for the optimized diverging collimator were a septal thickness of 0.3 mm and a collimator height of 30 mm. A tracking system comprising 6 compact detectors was designed and implemented utilizing this collimator. Analysis of the accuracy of the proposed Ir-192 source tracking system found that the average of the absolute values of the error between the 3D reconstructed and original positions for the simulation with the solid phantom were 0.440 mm for the x coordinate, 0.423 mm for the y coordinate, and 0.764 mm for the z coordinate, and the average Euclidean distance was 1.146 mm. Finally, in a simulation based on data from a patient who underwent brachytherapy, the average Euclidean distance between the original and reconstructed source position was 0.586 mm. Discussion: These results indicated that the newly designed in vivo 4D tracking system for monitoring the Ir-192 source during brachytherapy could determine the 3D position of the radiation source in real time during treatment. We conclude that the proposed positioning system has the potential to make brachytherapy more accurate and reliable.
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Affiliation(s)
- Geon Oh
- Department of Bioengineering, College of Health Sciences, Korea University, Seoul, Republic of Korea
- Department of Radiation Oncology, Inha University Hospital, Incheon, Republic of Korea
| | - Jeongshim Lee
- Department of Radiation Oncology, Inha University Hospital, Incheon, Republic of Korea
| | - Hunjung Kim
- Department of Radiation Oncology, Inha University Hospital, Incheon, Republic of Korea
| | - Woochul Kim
- Department of Radiation Oncology, Inha University Hospital, Incheon, Republic of Korea
| | - Sangwon Kang
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi, Republic of Korea
| | - Jinbeom Chung
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi, Republic of Korea
| | - Seonghoon Jeong
- Department of Neurology, Inje University Ilsan Paik Hospital, Goyang, Gyeonggi, Republic of Korea
| | - Hakjae Lee
- ARALE Laboratory Co., Ltd., Seoul, Republic of Korea
| | - Myonggeun Yoon
- Department of Bioengineering, College of Health Sciences, Korea University, Seoul, Republic of Korea
| | - Boram Lee
- Department of Radiation Oncology, Inha University Hospital, Incheon, Republic of Korea
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ALMisned G, Elshami W, Kilic G, Rabaa E, Zakaly HMH, Ene A, Tekin HO. Utilization of three-layers heterogeneous mammographic phantom through MCNPX code for breast and chest radiation dose levels at different diagnostic X-ray energies: A Monte Carlo simulation study. Front Public Health 2023; 11:1136864. [PMID: 36935709 PMCID: PMC10022908 DOI: 10.3389/fpubh.2023.1136864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/14/2023] [Indexed: 03/06/2023] Open
Abstract
Introduction We report the breast and chest radiation dose assessment for mammographic examinations using a three-layer heterogeneous breast phantom through the MCNPX Monte Carlo code. Methods A three-layer heterogeneous phantom along with compression plates and X-ray source are modeled. The validation of the simulation code is obtained using the data of AAPM TG-195 report. Deposited energy amount as a function of increasing source energy is calculated over a wide energy range. The behavioral changes in X-ray absorption as well as transmission are examined using the F6 Tally Mesh extension of MCNPX code. Moreover, deposited energy amount is calculated for modeled body phantom in the same energy range. Results and discussions The diverse distribution of glands has a significant impact on the quantity of energy received by the various breast layers. In layers with a low glandular ratio, low-energy primary X-ray penetrability is highest. In response to an increase in energy, the absorption in layers with a low glandular ratio decreased. This results in the X-rays releasing their energy in the bottom layers. Additionally, the increase in energy increases the quantity of energy absorbed by the tissues around the breast.
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Affiliation(s)
- Ghada ALMisned
- Department of Physics, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Wiam Elshami
- Medical Diagnostic Imaging Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - G. Kilic
- Faculty of Science, Department of Physics, Eskisehir Osmangazi University, Eskisehir, Türkiye
| | - Elaf Rabaa
- Medical Diagnostic Imaging Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Hesham M. H. Zakaly
- Institute of Physics and Technology, Ural Federal University, Yekaterinburg, Russia
- Physics Department, Faculty of Science, Al-Azhar University, Asyut, Egypt
| | - Antoaneta Ene
- INPOLDE Research Center, Department of Chemistry, Physics and Environment, Faculty of Sciences and Environment, Dunarea de Jos University of Galati, Galaţi, Romania
- Antoaneta Ene
| | - H. O. Tekin
- Medical Diagnostic Imaging Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
- Faculty of Engineering and Natural Sciences, Computer Engineering Department, Istinye University, Istanbul, Türkiye
- *Correspondence: H. O. Tekin tekin765@gmailcom
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Shahmohammadi Beni M, Yu KN, Islam MR, Watabe H. Development of PHITS graphical user interface for simulation of positron emitting radioisotopes production in common biological materials during proton therapy. J Radiat Res 2022; 63:385-392. [PMID: 35349714 PMCID: PMC9124619 DOI: 10.1093/jrr/rrac010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/24/2022] [Indexed: 06/14/2023]
Abstract
The Monte Carlo (MC) method is a powerful tool for modeling nuclear radiation interaction with matter. A variety of MC software packages has been developed, especially for applications in radiation therapy. Most widely used MC packages require users to write their own input scripts for their systems, which can be a time consuming and error prone process and requires extensive user experience. In the present work, we have developed a graphical user interface (GUI) bundled with a custom-made 3D OpenGL visualizer for PHITS MC package. The current version focuses on modeling proton induced positron emitting radioisotopes, which in turn can be used for verification of proton ranges in proton therapy. The developed GUI program does not require extensive user experience. The present open-source program is distributed under GPLv3 license that allows users to freely download, modify, recompile and redistribute the program.
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Affiliation(s)
| | | | - M Rafiqul Islam
- Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hiroshi Watabe
- Corresponding author. Division of Radiation Protection and Safety Control, Cyclotron and Radioisotope Center, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan. Phone: (81)22-795-7803; Fax: (81)22-795-7809;
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Hunzeker A, Mundy DW, Ma J, Mullikin TC, Foote RL. Intensity-Modulated Proton Therapy (IMPT) Treatment of Angiosarcoma of the Face and Scalp. Int J Part Ther 2021; 8:304-310. [PMID: 34285956 PMCID: PMC8270084 DOI: 10.14338/ijpt-d-20-00048.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 01/20/2021] [Indexed: 12/02/2022] Open
Abstract
Purpose To successfully plan and treat a patient with diffuse angiosarcoma involving the face and scalp with intensity-modulated proton therapy (IMPT) before surgical resection. Materials and Methods A patient presented to the radiation oncology department for preoperative treatment of an angiosarcoma diffusely involving the face and scalp. A 4-field IMPT technique was used to create a homogeneous dose distribution to the entire target volume while sparing underlying critical structures from toxicity and low-dose spread. A custom Monte Carlo optimizer was necessary to achieve treatment goals. Biological dose was evaluated with a linear energy transfer–based biological enhancement model. Robustness criteria were evaluated per department standard. The patient was successfully planned and treated according to clinical goals. Results The patient successfully completed the course of IMPT and was able to undergo surgical resection. Pathology indicated no presence of angiosarcoma. Conclusion IMPT using a custom Monte Carlo optimizer is a suitable radiation therapy treatment option for patients with diffuse angiosarcoma of the scalp and face.
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Affiliation(s)
- Ashley Hunzeker
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Daniel W Mundy
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Jiasen Ma
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Trey C Mullikin
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Robert L Foote
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
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Alhamada H, Simon S, Gulyban A, Gastelblum P, Pauly N, VanGestel D, Reynaert N. Monte Carlo as quality control tool of stereotactic body radiation therapy treatment plans. Phys Med 2021; 84:205-213. [PMID: 33771442 DOI: 10.1016/j.ejmp.2021.02.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/20/2021] [Accepted: 02/24/2021] [Indexed: 11/25/2022] Open
Abstract
PURPOSE/OBJECTIVE The objective of this study was to verify the accuracy of treatment plans of stereotactic body radiation therapy (SBRT) and to verify the feasibility of the use of Monte Carlo (MC) as quality control (QC) on a daily basis. MATERIAL/METHODS Using EGSnrc, a MC model of Agility™ linear accelerator was created. Various measurements (Percentage depth dose (PDD), Profiles and Output factors) were done for different fields sizes from 1x1 up to 40x40 (cm2). An iterative model optimization was performed to achieve adequate parameters of MC simulation. 40 SBRT patient's dosimetry plans were calculated by Monaco™ 3.1.1. CT images, RT-STRUCT and RT-PLAN files from Monaco™ being used as input for Moderato MC code. Finally, dose volume histogram (DVH) and paired t-tests for each contour were used for dosimetry comparison of the Monaco™ and MC. RESULTS Validation of MC model was successful, as <2% difference comparing to measurements for all field's sizes. The main energy of electron source incident on the target was 5.8 MeV, and the full width at half maximum (FWHM) of Gaussian electron source were 0.09 and 0.2 (cm) in X and Y directions, respectively. For 40 treatment plan comparisons, the minimum absolute difference of mean dose of planning treatment planning (PTV) was 0.1% while the maximum was 6.3%. The minimum absolute difference of Max dose of PTV was 0.2% while the maximum was 8.1%. CONCLUSION SBRT treatment plans of Monaco agreed with MC results. It possible to use MC for treatment plans verifications as independent QC tool.
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Affiliation(s)
- Husein Alhamada
- Nuclear Metrology Department, Ecole Polytechnique, ULB, Brussels, Belgium.
| | - Stephane Simon
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
| | - Akos Gulyban
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
| | | | - Nicolas Pauly
- Nuclear Metrology Department, Ecole Polytechnique, ULB, Brussels, Belgium.
| | - Dirk VanGestel
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
| | - Nick Reynaert
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
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Xu T, Liu T, Li G, Dugal C, Aydemir NA, Liu Y, Roeske JC. Technical Note: The development of a multi-physics simulation tool to estimate the background dose by systemic targeted alpha therapy. Med Phys 2020; 47:2550-2557. [PMID: 32129888 PMCID: PMC7384137 DOI: 10.1002/mp.14111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/20/2020] [Accepted: 02/18/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To predict biological effects of targeted alpha therapy (TAT) in preclinical studies, dosimetry calculations based on the micro-level distributions of emitters are essential. Due to the saturation of the tumor antigenic sites and bonding breaks by decay, some of Alpha-immuno-conjugate and decay daughters may inevitably be transported by convection and diffusion along with blood or lymphatic circulation. This results in highly nonuniform and unsteady distributions of irradiation sources. Since the micro-level distribution of emitters cannot be measured and obtained in patients with current technology, a modeling toolset to give more insight of the internal dose could be an alternative. METHODS A multi-physics model based on a Monte Carlo microdosimetry technique and computational fluid dynamics (CFD) modeling was developed and applied to multiple internal irradiation sources. The CFD model tracks the path of the radionuclides and the dose model is capable of evaluating the time-dependent absorbed dose to the target. RESULTS The conceptual model is capable of handling complex nonuniform irradiation sources in vasculature. The results from the simulations indicate that the assumption of homogeneous and motionless distribution of the administered activity used in the conventional dose calculation tends to significantly underestimate or overestimate the absorbed dose to the vascular system in various scenarios. CONCLUSION Modeling the in vivo transport of radionuclides has the potential to improve the accuracy of TAT dose estimates. It could be the first step to develop a simulation tool set for assessing absorbed dose to tumor or normal tissues and predict the corresponding biological responses in the future.
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Affiliation(s)
- T. Xu
- Canadian Nuclear LaboratoriesChalk RiverONK0J 1J0Canada
| | - T. Liu
- Canadian Nuclear LaboratoriesChalk RiverONK0J 1J0Canada
| | - G. Li
- Canadian Nuclear LaboratoriesChalk RiverONK0J 1J0Canada
| | - C. Dugal
- Canadian Nuclear LaboratoriesChalk RiverONK0J 1J0Canada
| | - N. A. Aydemir
- Canadian Nuclear LaboratoriesChalk RiverONK0J 1J0Canada
| | - Y. Liu
- Department of Electrical and Computer EngineeringClarkson UniversityPotsdamNY13699USA
| | - J. C. Roeske
- Department of Radiation OncologyLoyola University Medical CenterMaywoodIL60153USA
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Ma C, Parsons D, Chen M, Jiang S, Hou Q, Gu X, Lu W. Electron modulated arc therapy (EMAT) using photon MLC for postmastectomy chest wall treatment I: Monte Carlo-based dosimetric characterizations. Phys Med 2019; 67:1-8. [PMID: 31606657 PMCID: PMC6925626 DOI: 10.1016/j.ejmp.2019.10.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To study the dosimetric properties of electron arc beams delivered by photon-beam multi-leaf collimators (pMLC) in electron modulated arc therapy (EMAT) for postmastectomy chest wall treatments. METHODS Using the Monte Carlo method, we simulated a 2100EX Varian linear accelerator and verified the beam models in a water tank. Dosimetric characterizations were performed on cylindrical water phantoms of elliptical bases with various field sizes, arc ranges and source-to-surface distances (SSDs) for 6, 9 and 12 MeV beam energy. RESULTS The arc beam has a higher bremsstrahlung dose than the static beam at the isocenter due to crossfire, but choosing a field size greater than 5 cm effectively reduces the bremsstrahlung dose. The depths of the 90% maximum dose located at 1.7, 2.8 and 4.1 cm for 6, 9 and 12 MeV, respectively, are similar to those of the static beams and independent of the field size and arc range. CONCLUSION Based on the study, we recommend using the 5 cm field width for electron arc beams considering both bremsstrahlung dose at the isocenter and the arc profile penumbra. To ensure sufficient PTV edge coverage, we recommend a field length extension of at least 4 cm from PTV's edge for all beam energies and an arc extension of around 7°, 5°, and 5° for beam energies 6, 9, and 12 MeV, respectively. These dosimetric characterizations are the basis of pMLC-delivered EMAT treatment planning for postmastectomy chest wall patients.
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Affiliation(s)
- Chaoqiong Ma
- Key Lab for Radiation Physics and Technology of Education Ministry of China, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, Sichuan 610064, China; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - David Parsons
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Mingli Chen
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Steve Jiang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Qing Hou
- Key Lab for Radiation Physics and Technology of Education Ministry of China, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, Sichuan 610064, China
| | - Xuejun Gu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Weiguo Lu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
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Odriozola M, Abraham E, Lousada-Ferreira M, Spanjers H, van Lier JB. Identification of the Methanogenesis Inhibition Mechanism Using Comparative Analysis of Mathematical Models. Front Bioeng Biotechnol 2019; 7:93. [PMID: 31157214 PMCID: PMC6530379 DOI: 10.3389/fbioe.2019.00093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/16/2019] [Indexed: 02/01/2023] Open
Abstract
The application of cationic polymers to enhance membrane fluxes in anaerobic membrane bioreactors has been proposed by several authors. However, literature shows contradictory results on the influence of those chemicals on the biological activity. In this research, we studied the effect of a cationic polymer on the production of methane from acetate by acetoclastic methanogens. We assessed the effect of polymer concentration on the accumulated methane production (AMP) and the specific methanogenic activity (SMA) in batch tests. Batch tests results showed lower SMA values at higher concentrations of polymer and no effect on the final AMP. Different inhibition models were calibrated and compared to find the best fit and to hypothesize the prevailing inhibition mechanisms. The assessed inhibition models were: competitive (M1a), non-competitive (M2a), un-competitive (M3a), biocide-linear (M4a), and biocide-exponential (M5a). The parameters in the model related to the polymer characteristics were adjusted to fit the experimental data. M2a and M3a were the only models that fitted both experimental SMA and AMP. Although M1a and M4a adequately fitted the experimental SMA, M1a simulations slightly deviated from the experimental AMP, and M4a considerably underpredicted the AMP at concentrations of polymer above 0.23 gCOD L−1. M5a did not adequately fit either experimental SMA and AMP results. We compared models a (M1a to M5a), which consider the inhibition by the concentration of polymer in the bulk liquid, with models b (M1b to M5b) considering the inhibition being caused by the total concentration of polymer in the reactor. Results showed that the difference between a and b models' simulations were negligible for all kinetic models considered (M1, M2, M3, M4, and M5). Therefore, the models that better predicted the experimental data were the non-competitive (M2a and M2b) and un-competitive (M3a and M3b) inhibition models, which are biostatic inhibition models. Consequently, the decreased methanogenic activity caused by polymer additions is presumably a reversible process
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Affiliation(s)
- Magela Odriozola
- Department of Water Management, Delft University of Technology, Delft, Netherlands
| | - Edo Abraham
- Department of Water Management, Delft University of Technology, Delft, Netherlands
| | | | - Henri Spanjers
- Department of Water Management, Delft University of Technology, Delft, Netherlands
| | - Jules B van Lier
- Department of Water Management, Delft University of Technology, Delft, Netherlands
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Matsuoka T, Araki F, Ohno T, Sakata J, Tominaga H. Dependence of volume dose indices on dose calculation algorithms for VMAT-SBRT plans for peripheral lung tumor. Med Dosim 2018; 44:284-290. [PMID: 30455092 DOI: 10.1016/j.meddos.2018.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 10/20/2018] [Accepted: 10/23/2018] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to investigate the dependence of volume dose indices on dose calculation algorithms for volumetric modulated arc therapy (VMAT) for stereotactic body radiotherapy (SBRT) plans to treat peripheral lung tumors by comparing them with those of Monte Carlo (MC) calculations. VMAT-SBRT plans for peripheral lung tumors were created using the Eclipse treatment planning system (TPS) for 24 patients with nonsmall cell lung cancer. VMAT dose distributions for gross tumor volume (GTV), internal target volume (ITV), and planning target volume (PTV) were calculated using the analytical anisotropic algorithm (AAA), the Acuros XB (AXB) algorithm, and a MC algorithm. VMAT dose distributions of the 3 algorithms were compared using their volume dose indices from dose volume histograms (DVHs), a dose difference map, and 3-dimensional gamma analysis. The DVHs for GTV and ITV from AAA, AXB, and MC were in good agreement. The difference between the ITV and PTV volume dose indices from AAA and MC increased as D98, D95, D80, D50, and D2. In particular, the difference between D98 for PTV from AAA and MC was up to 48%. A >5% difference between D95 for PTV from AAA and MC was 11 patients, but only 2 patients for ITV. The volume dose indices for AXB were near those of MC. AAA tended to overestimate the PTV volume dose indices compared to AXB and MC. Thus, we propose that the volume dose indices for the ITV be used because they are independent of dose calculation algorithms.
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Affiliation(s)
- Takanori Matsuoka
- Graduate School of Health Sciences, Kumamoto University, Kumamoto, Japan
| | - Fujio Araki
- Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
| | - Takeshi Ohno
- Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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Alhamada H, Simon S, Philippson C, Vandekerkhove C, Jourani Y, Pauly N, Dubus A, Reynaert N. Shielding disk position in intra-operative electron radiotherapy (IOERT): A Monte Carlo study. Phys Med 2018; 51:1-6. [PMID: 30278980 DOI: 10.1016/j.ejmp.2018.05.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/30/2018] [Accepted: 05/25/2018] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In IOERT breast treatments, a shielding disk is frequently used to protect the underlying healthy structures. The disk is usually composed of two materials, a low-Z material intended to be oriented towards the beam and a high-Z material. As tissues are repositioned around the shield before treatment, the disk is no longer visible and its correct alignment with respect to the beam is guaranteed. This paper studies the dosimetric characteristics of four possible clinical positioning scenarios of the shielding disk. A new alignment method for the shielding disk in the beam is introduced. Finally, it suggests a new design for the shielding disk. METHODS As the first step, the IOERT machine "Mobetron 1000" was modeled by using Monte Carlo simulation, tuning the MC model until an excellent match with the measured PDDs and profiles was achieved. Four possible shielding disk positioning scenarios were considered, determining the dosimetric impact. Furthermore, in our center, to prevent beam misalignment, we have developed a shielding disk equipped with guiding rods. Having ascertained a correct alignment between the disk and the beam, we can propose a new internal design of the shielding disk that can improve the dose distribution with a better coverage of the treated area. RESULTS All MC simulations were performed with a 12 MeV beam, the maximum energy of Mobetron 1000 and a 5.5 cm diameter flat tip applicator, this applicator being the most clinically used. The simulations were compared with measurements performed in a water phantom and showed good results within 2.2% of root mean square difference (RMSD). The misplacement positions of the shielding disk have dosimetric impacts in the treatment volume and a small translation could have a significant influence on healthy tissues. The D-scenario is the worst which could happens when the shielding disk is flipped upside down, giving up to 144% dose instead of 90% at the surface of the Pb/Al shielding disk. A new shielding design used, together with our alignment tool, is able to give a more homogeneous dose in the target area. CONCLUSIONS The accuracy of shielding disk position can still be problematic in IOERT dosimetry. Any method that can ascertain the good alignment between the shielding disk and the beam is beneficial for the dose distribution and is a prerequisite for an optimized shield internal design that could improve the coverage of the treated area and the protection of healthy tissues.
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Affiliation(s)
- Husein Alhamada
- Nuclear Metrology, Ecole Polytechnique, Universite Libre de Bryxellers, Belgium.
| | - Stephane Simon
- Radiotherapy Department, Institute Jules Bordet, Belgium.
| | | | | | - Younes Jourani
- Radiotherapy Department, Institute Jules Bordet, Belgium.
| | - Nicolas Pauly
- Nuclear Metrology, Ecole Polytechnique, Universite Libre de Bryxellers, Belgium.
| | - Alain Dubus
- Nuclear Metrology, Ecole Polytechnique, Universite Libre de Bryxellers, Belgium.
| | - Nick Reynaert
- Radiotherapy Department, Institute Jules Bordet, Belgium.
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Xu T, Liu Y, Liu T, Li G, Aydemir N. Multiphysics Modelling of Background Dose by Systemic Targeted Alpha Therapy. J Med Imaging Radiat Sci 2018; 49:270-276. [PMID: 32074053 DOI: 10.1016/j.jmir.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/01/2018] [Accepted: 06/13/2018] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Nontargeted molecules of alpha-immunoconjugate (AIC) intravenously injected in clinical trials of targeted alpha therapy (TAT) could be transported by convection and diffusion along with blood or lymphatic circulation. MATERIALS AND METHODS A coupled model based on the Geant4 Monte Carlo microdosimetry technique and computational fluid dynamics was established. The transient drug delivery process and background dose to the cells along the pathway were investigated using the model. A mesoscale numerical simulation in a simple 2D capillary was performed to determine the transient toxicity of the alpha-immunoconjugate to the DNA of a targeted cell. RESULTS The simulation results indicate that the multiphysics simulation is essential to improve the accuracy of TAT simulation. CONCLUSION In this work, a solution strategy for modelling AIC delivery in a blood vessel at a mesoscale level has been established. This work is the first to model different phenomena through the multiphysics simulation to investigate the whole picture of TAT.
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Affiliation(s)
- Tao Xu
- Research Scientist, Canadian Nuclear Laboratories, Chalk River, Ontario, Canada.
| | - Yu Liu
- Assistant Professor, Department of Electrical and Computer Engineering, Clarkson University, Potsdam, NY, USA
| | - Tong Liu
- Research Scientist, Canadian Nuclear Laboratories, Chalk River, Ontario, Canada
| | - Gang Li
- Applied Physicist, Canadian Nuclear Laboratories, Chalk River, Ontario, Canada
| | - Nusret Aydemir
- Thermalhydraulics Specialist, Canadian Nuclear Laboratories, Chalk River, Ontario, Canada
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