scholarly journals Dosimetric characteristics of 6 MV photons from TrueBeam STx medical linear accelerator: simulation and experimental data

2019 ◽  
Vol 9 (2) ◽  
pp. 37-44
Author(s):  
N. D. Ton Ton ◽  
B. D. Linh Linh ◽  
Q.T. Pham Pham
Keyword(s):  
Monte Carlo ◽  
Particle Physics ◽  
Nuclear Physics ◽  
Planning System ◽  
Treatment Planning System ◽  
Linear Accelerators ◽  
Index Method ◽  
Beam Radiation ◽  
Depth Dose ◽  
Check Calculation

A TrueBeam STx is one of the most technologically advanced linear accelerators forradiotherapy and radiosurgery. The Monte Carlo simulation widely used in many applications in various fields such as nuclear physics, astrophysics, particle physics, and medicine. The Geant4/GATE Monte Carlo toolkit is developed for the simulation in imaging diagnostics, nuclear medicine, radiotherapy, and radiation biology to more accurately predict beam radiation dosimetry. In this work, we present the simulation results of the dosimetric characteristics of a 6 MV photon beam of TrueBeam STx medical LINAC using Monte Carlo Geant4/GATE. The percentage depth dose (PDD), central axis depth dose (Profile) have been simulated and compared with those measured in a water phantom for field sizes 10×10 cm2 via the gamma-index method. These results will permit to check calculation data given by the treatment planning system.

scholarly journals Phantom design and dosimetric characterization for multiple simultaneous cell irradiations with active pencil beam scanning

2019 ◽  
Vol 58 (4) ◽  
pp. 563-573 ◽  
Author(s):  
Monika Clausen ◽  
Suphalak Khachonkham ◽  
Sylvia Gruber ◽  
Peter Kuess ◽  
Rolf Seemann ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Target Location ◽  
Reference Conditions ◽  
Absorbed Dose ◽  
Planning System ◽  
Treatment Planning System ◽  
Pencil Beam ◽  
Depth Dose

Abstract A new phantom was designed for in vitro studies on cell lines in horizontal particle beams. The phantom enables simultaneous irradiation at multiple positions along the beam path. The main purpose of this study was the detailed dosimetric characterization of the phantom which consists of various heterogeneous structures. The dosimetric measurements described here were performed under non-reference conditions. The experiment involved a CT scan of the phantom, dose calculations performed with the treatment planning system (TPS) RayStation employing both the Pencil Beam (PB) and Monte Carlo (MC) algorithms, and proton beam delivery. Two treatment plans reflecting the typical target location for head and neck cancer and prostate cancer treatment were created. Absorbed dose to water and dose homogeneity were experimentally assessed within the phantom along the Bragg curve with ionization chambers (ICs) and EBT3 films. LETd distributions were obtained from the TPS. Measured depth dose distributions were in good agreement with the Monte Carlo-based TPS data. Absorbed dose calculated with the PB algorithm was 4% higher than the absorbed dose measured with ICs at the deepest measurement point along the spread-out Bragg peak. Results of experiments using melanoma (SKMel) cell line are also presented. The study suggested a pronounced correlation between the relative biological effectiveness (RBE) and LETd, where higher LETd leads to elevated cell death and cell inactivation. Obtained RBE values ranged from 1.4 to 1.8 at the survival level of 10% (RBE10). It is concluded that dosimetric characterization of a phantom before its use for RBE experiments is essential, since a high dosimetric accuracy contributes to reliable RBE data and allows for a clearer differentiation between physical and biological uncertainties.

scholarly journals Benchmarking Monte-Carlo dose calculation for MLC CyberKnife treatments

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
P.-H. Mackeprang ◽  
D. Vuong ◽  
W. Volken ◽  
D. Henzen ◽  
D. Schmidhalter ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Dose Distributions ◽  
Depth Dose ◽  
Gamma Analysis ◽  
Threshold Time ◽  
Dose Difference

Abstract Background Vendor-independent Monte Carlo (MC) dose calculation (IDC) for patient-specific quality assurance of multi-leaf collimator (MLC) based CyberKnife treatments is used to benchmark and validate the commercial MC dose calculation engine for MLC based treatments built into the CyberKnife treatment planning system (Precision MC). Methods The benchmark included dose profiles in water in 15 mm depth and depth dose curves of rectangular MLC shaped fields ranging from 7.6 mm × 7.7 mm to 115.0 mm  × 100.1 mm, which were compared between IDC, Precision MC and measurements in terms of dose difference and distance to agreement. Dose distributions of three phantom cases and seven clinical lung cases were calculated using both IDC and Precision MC. The lung PTVs ranged from 14 cm3 to 93 cm3. Quantitative comparison of these dose distributions was performed using dose-volume parameters and 3D gamma analysis with 2% global dose difference and 1 mm distance criteria and a global 10% dose threshold. Time to calculate dose distributions was recorded and efficiency was assessed. Results Absolute dose profiles in 15 mm depth in water showed agreement between Precision MC and IDC within 3.1% or 1 mm. Depth dose curves agreed within 2.3% / 1 mm. For the phantom and clinical lung cases, mean PTV doses differed from − 1.0 to + 2.3% between IDC and Precision MC and gamma passing rates were > =98.1% for all multiple beam treatment plans. For the lung cases, lung V20 agreed within ±1.5%. Calculation times ranged from 2.2 min (for 39 cm3 PTV at 1.0 × 1.0 × 2.5 mm3 native CT resolution) to 8.1 min (93 cm3 at 1.1 × 1.1 × 1.0 mm3), at 2% uncertainty for Precision MC for the 7 examined lung cases and 4–6 h for IDC, which, however, is not optimized for efficiency but used as a gold standard for accuracy. Conclusions Both accuracy and efficiency of Precision MC in the context of MLC based planning for the CyberKnife M6 system were benchmarked against MC based IDC framework. Precision MC is used in clinical practice at our institute.

scholarly journals Reconstrução de Espectros de Raios X de Aceleradores Lineares Clínicos usando o Método de Recozimento Simulado Generalizado

2016 ◽  
Vol 10 (2) ◽  
pp. 2
Author(s):  
John Peter Oyardo Manrique ◽  
Alessandro Martins Da Costa
Keyword(s):  
Monte Carlo ◽  
Simulated Annealing ◽  
Treatment Planning ◽  
Planning System ◽  
Treatment Planning System ◽  
Percentage Depth Dose ◽  
Depth Dose

A distribuição espectral de raios X de megavoltagem utilizados em departamentos de radioterapia é uma grandeza fundamental a partir da qual, em princípio, todas as informações requeridas relevantes para tratamentos de radioterapia podem ser determinadas. Para o calculo das doses administradas ao paciente que faz radioterapia se usam sistemas de planejamento de tratamento (TPS, do inglês Treatment Planning System), que fazem uso de algoritmos de convolução e superposição os quais requerem um conhecimento prévio do espectro de fluência de fótons para realizar o cálculo acurado das doses tridimensionais e assim assegurar uma melhor probabilidade de controle tumoral mantendo baixa a probabilidade de complicações do tecido normal. Neste trabalho foi obtido o espectro de fluência de fótons de raios X de um acelerador linear clínico SIEMENS ONCOR de 6 MV, usando um método de caráter inverso para a reconstrução dos espectros, a partir das curvas de transmissão de fótons medidas para diferentes espessuras de alumínio; o método usado para a reconstrução dos espectros é uma técnica estocástica conhecida como recozimento simulado generalizado (GSA, do inglês Generalized Simulated Annealing), baseado no trabalho da estatística de quase equilíbrio de Tsallis.  Para a validação dos espectros reconstruídos foram calculadas as curvas de porcentagem de dose em profundidade (PDD, do inglês Percentage Depth Dose) para a energia de 6 MV do acelerador, usando simulação Monte Carlo com o código PENELOPE, e a partir da PDD se fez o cálculo o índice de qualidade do feixe TPR20/10.

scholarly journals A benchmarking method to evaluate the accuracy of a commercial proton monte carlo pencil beam scanning treatment planning system

2017 ◽  
Vol 18 (2) ◽  
pp. 44-49 ◽  
Author(s):  
Liyong Lin ◽  
Sheng Huang ◽  
Minglei Kang ◽  
Petri Hiltunen ◽  
Reynald Vanderstraeten ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Treatment Planning ◽  
Planning System ◽  
Treatment Planning System ◽  
Pencil Beam ◽  
Beam Scanning ◽  
Pencil Beam Scanning

scholarly journals Evaluation of a treatment planning system developed for clinical boron neutron capture therapy and validation against an independent Monte Carlo dose calculation system

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Naonori Hu ◽  
Hiroki Tanaka ◽  
Ryo Kakino ◽  
Syuushi Yoshikawa ◽  
Mamoru Miyao ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Treatment Planning ◽  
Neutron Capture ◽  
Gamma Ray ◽  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Neutron Capture Therapy ◽  
Boron Neutron Capture ◽  
Monte Carlo Dose Calculation

AbstractBoron neutron capture therapy (BNCT) for the treatment of unresectable, locally advanced, and recurrent carcinoma of the head and neck cancer has been approved by the Japanese government for reimbursement under the national health insurance as of June 2020. A new treatment planning system for clinical BNCT has been developed by Sumitomo Heavy Industries, Ltd. (Sumitomo), NeuCure® Dose Engine. To safely implement this system for clinical use, the simulated neutron flux and gamma ray dose rate inside a water phantom was compared against experimental measurements. Furthermore, to validate and verify the new planning system, the dose distribution inside an anthropomorphic head phantom was compared against a BNCT treatment planning system SERA and an in-house developed Monte Carlo dose calculation program. The simulated results closely matched the experimental results, within 5% for the thermal neutron flux and 10% for the gamma ray dose rate. The dose distribution inside the head phantom closely matched with SERA and the in-house developed dose calculation program, within 3% for the tumour and a difference of 0.3 Gyw for the brain.

scholarly journals An Integrated Framework Based on Full Monte Carlo Simulations for Double-Scattering Proton Therapy

2019 ◽  
Vol 6 (2) ◽  
pp. 31-41
Author(s):  
Jiankui Yuan ◽  
David Mansur ◽  
Min Yao ◽  
Tithi Biswas ◽  
Yiran Zheng ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Proton Therapy ◽  
Treatment Plan ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Double Scattering ◽  
Integrated Framework ◽  
End To End ◽  
Clinical Cases

ABSTRACT Purpose: We developed an integrated framework that employs a full Monte Carlo (MC) model for treatment-plan simulations of a passive double-scattering proton system. Materials and Methods: We have previously validated a virtual machine source model for full MC proton-dose calculations by comparing the percentage of depth-dose curves, spread-out Bragg peaks, and lateral profiles against measured commissioning data. This study further expanded our previous work by developing an integrate framework that facilitates its clinical use. Specifically, we have (1) constructed patient-specific applicator and compensator numerically from the plan data and incorporated them into the beamline, (2) created the patient anatomy from the computed tomography image and established the transformation between patient and machine coordinate systems, and (3) developed a graphical user interface to ease the whole process from importing the treatment plan in the Digital Imaging and Communications in Medicine format to parallelization of the MC calculations. End-to-end tests were performed to validate the functionality, and 3 clinical cases were used to demonstrate clinical utility of the framework. Results: The end-to-end tests demonstrated that the framework functioned correctly for all tested functionality. Comparisons between the treatment planning system calculations and MC results in 3 clinical cases revealed large dose difference up to 17%, especially in the beam penumbra and near the end of beam range. The discrepancy likely originates from a variety of sources, such as the dose algorithms, modeling of the beamline, and the dose metric. The agreement for other regions was acceptable. Conclusion: An integrated framework was developed for full MC simulations of double-scattering proton therapy. It can be a valuable tool for dose verification and plan evaluation.

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