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Research paper thumbnail of Assessment of computed tomography dose index (CTDI) using the platform GEANT4/GATE

Perspectives in Science, 2019

Absorbed dose during a CT exam can be estimated by the computed tomography dose index (CTDI). The... more Absorbed dose during a CT exam can be estimated by the computed tomography dose index (CTDI). The aim of this study is to validate a simulated CTDI with measured data for a 16-slice CT system. To measure the CTDI we have used an ion chamber, electrometer and two Polymethylmethacrylate (PMMA) phantoms (head and body). GATE (GEANT4 Application for Tomographic Emission) platform is a Monte Carlo code for medical physics applications, especially dosimetry studies. CTDI and CTDIw were recorded to compare simulated results for different x-ray tube currents and voltages with experimental data at different positions in the phantom. The results obtained for all conditions applied show a difference less than 2.6% and 4.3% for head and body phantom, respectively. It was demonstrated that GATE is a good tool to simulate CTDIw values and to study of the influence of tube current and voltage on the absorbed dose.

Research paper thumbnail of Validation of the GATE Monte Carlo code for radiation therapy: Varian Clinac2300C/D

2018 4th International Conference on Optimization and Applications (ICOA), 2018

Our work aimed to validate a GATE Modeled of a linear accelerator Clinac2300C/D using GATE 8.0 fo... more Our work aimed to validate a GATE Modeled of a linear accelerator Clinac2300C/D using GATE 8.0 for 6MV photon beam. The reference measurements were determined by ionization chambers (PTW 31014) and were compared with GATE results. To reduce the computing time, the simulation tasks were splitted into several jobs to run simultaneously in our local cluster. The simulation parameters of GATE were adjusted to validate the accelerator modeling from percentage depth dose and profiles in the reference conditions. Good agreement between simulations and measurements in water was observed. A gamma index comparison was performed, and more than 97% of the points for all simulations passed the 2%/2 mm gamma criterion.

Research paper thumbnail of Monte Carlo Estimation of Dose in Heterogeneous Phantom Around 6MV Medical Linear Accelerator

Advances in Science, Technology and Engineering Systems Journal

In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition... more In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition Multi-Leaf Collimator (HD 120 MLC) instead of the removable jaws, using GATE Monte Carlo Platform version 8.2. We validated the multileaf collimator (MLC) geometry by simulating two dosimetric functions (Percentage Depth Dose (PDD) and Dose Profile (DP)), for 6MV photon beam energy and different field sizes (3x3, 4x4, 6x6, 8x8, 10x10, 12x12, 15x15, and 20x20 cm²). We then compared the results with measurements realized with two detectors, namely the cylindrical ionization chamber and the micro-diode PTW silicon. By applying the Relative Dose Difference method (RDD), we noted a less than 2% and 1% agreement for the field sizes (10x10, 12x12, 15x15, 20x20 cm²) and (3x3, 4x4, 6x6, 8x8 cm²) respectively. Moreover, to evaluate the relevance of Monte Carlo method in a heterogeneous media, particularly in small field sizes (1x1, 2x2, 3x3 cm²), we have simulated three clinical studies based on the Physical Test Objects (PTOs) that are the equivalent slabs of lung and bone included in a water phantom. We noticed that the simulated PDDs exhibit two significant irregularities in the interface between water and lung. To eliminate these phenomena, we have used the "setMaxStepSizeInRegion" parameter implemented in GATE. We also noticed an important difference of 5% corresponding to the small field sizes, between homogeneous and heterogeneous simulated PDDs. We used the RDD method in this case as well. Moreover, we observed a difference between 1-4% between the simulated PDDs and the calculated ones by ECLIPSE Treatment Planning System (TPS). These results indicate that GATE (8.2) is useful in dosimetry with heterogeneous situations as well such as bone and lung.

Research paper thumbnail of Monte Carlo Estimation of Dose in Heterogeneous Phantom Around 6MV Medical Linear Accelerator

Advances in Science, Technology and Engineering Systems Journal

In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition... more In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition Multi-Leaf Collimator (HD 120 MLC) instead of the removable jaws, using GATE Monte Carlo Platform version 8.2. We validated the multileaf collimator (MLC) geometry by simulating two dosimetric functions (Percentage Depth Dose (PDD) and Dose Profile (DP)), for 6MV photon beam energy and different field sizes (3x3, 4x4, 6x6, 8x8, 10x10, 12x12, 15x15, and 20x20 cm²). We then compared the results with measurements realized with two detectors, namely the cylindrical ionization chamber and the micro-diode PTW silicon. By applying the Relative Dose Difference method (RDD), we noted a less than 2% and 1% agreement for the field sizes (10x10, 12x12, 15x15, 20x20 cm²) and (3x3, 4x4, 6x6, 8x8 cm²) respectively. Moreover, to evaluate the relevance of Monte Carlo method in a heterogeneous media, particularly in small field sizes (1x1, 2x2, 3x3 cm²), we have simulated three clinical studies based on the Physical Test Objects (PTOs) that are the equivalent slabs of lung and bone included in a water phantom. We noticed that the simulated PDDs exhibit two significant irregularities in the interface between water and lung. To eliminate these phenomena, we have used the "setMaxStepSizeInRegion" parameter implemented in GATE. We also noticed an important difference of 5% corresponding to the small field sizes, between homogeneous and heterogeneous simulated PDDs. We used the RDD method in this case as well. Moreover, we observed a difference between 1-4% between the simulated PDDs and the calculated ones by ECLIPSE Treatment Planning System (TPS). These results indicate that GATE (8.2) is useful in dosimetry with heterogeneous situations as well such as bone and lung.

Research paper thumbnail of Assessment of computed tomography dose index (CTDI) using the platform GEANT4/GATE

Perspectives in Science, 2019

Absorbed dose during a CT exam can be estimated by the computed tomography dose index (CTDI). The... more Absorbed dose during a CT exam can be estimated by the computed tomography dose index (CTDI). The aim of this study is to validate a simulated CTDI with measured data for a 16-slice CT system. To measure the CTDI we have used an ion chamber, electrometer and two Polymethylmethacrylate (PMMA) phantoms (head and body). GATE (GEANT4 Application for Tomographic Emission) platform is a Monte Carlo code for medical physics applications, especially dosimetry studies. CTDI and CTDIw were recorded to compare simulated results for different x-ray tube currents and voltages with experimental data at different positions in the phantom. The results obtained for all conditions applied show a difference less than 2.6% and 4.3% for head and body phantom, respectively. It was demonstrated that GATE is a good tool to simulate CTDIw values and to study of the influence of tube current and voltage on the absorbed dose.

Research paper thumbnail of Validation of the GATE Monte Carlo code for radiation therapy: Varian Clinac2300C/D

2018 4th International Conference on Optimization and Applications (ICOA), 2018

Our work aimed to validate a GATE Modeled of a linear accelerator Clinac2300C/D using GATE 8.0 fo... more Our work aimed to validate a GATE Modeled of a linear accelerator Clinac2300C/D using GATE 8.0 for 6MV photon beam. The reference measurements were determined by ionization chambers (PTW 31014) and were compared with GATE results. To reduce the computing time, the simulation tasks were splitted into several jobs to run simultaneously in our local cluster. The simulation parameters of GATE were adjusted to validate the accelerator modeling from percentage depth dose and profiles in the reference conditions. Good agreement between simulations and measurements in water was observed. A gamma index comparison was performed, and more than 97% of the points for all simulations passed the 2%/2 mm gamma criterion.

Research paper thumbnail of Monte Carlo Estimation of Dose in Heterogeneous Phantom Around 6MV Medical Linear Accelerator

Advances in Science, Technology and Engineering Systems Journal

In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition... more In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition Multi-Leaf Collimator (HD 120 MLC) instead of the removable jaws, using GATE Monte Carlo Platform version 8.2. We validated the multileaf collimator (MLC) geometry by simulating two dosimetric functions (Percentage Depth Dose (PDD) and Dose Profile (DP)), for 6MV photon beam energy and different field sizes (3x3, 4x4, 6x6, 8x8, 10x10, 12x12, 15x15, and 20x20 cm²). We then compared the results with measurements realized with two detectors, namely the cylindrical ionization chamber and the micro-diode PTW silicon. By applying the Relative Dose Difference method (RDD), we noted a less than 2% and 1% agreement for the field sizes (10x10, 12x12, 15x15, 20x20 cm²) and (3x3, 4x4, 6x6, 8x8 cm²) respectively. Moreover, to evaluate the relevance of Monte Carlo method in a heterogeneous media, particularly in small field sizes (1x1, 2x2, 3x3 cm²), we have simulated three clinical studies based on the Physical Test Objects (PTOs) that are the equivalent slabs of lung and bone included in a water phantom. We noticed that the simulated PDDs exhibit two significant irregularities in the interface between water and lung. To eliminate these phenomena, we have used the "setMaxStepSizeInRegion" parameter implemented in GATE. We also noticed an important difference of 5% corresponding to the small field sizes, between homogeneous and heterogeneous simulated PDDs. We used the RDD method in this case as well. Moreover, we observed a difference between 1-4% between the simulated PDDs and the calculated ones by ECLIPSE Treatment Planning System (TPS). These results indicate that GATE (8.2) is useful in dosimetry with heterogeneous situations as well such as bone and lung.

Research paper thumbnail of Monte Carlo Estimation of Dose in Heterogeneous Phantom Around 6MV Medical Linear Accelerator

Advances in Science, Technology and Engineering Systems Journal

In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition... more In this work, we completed a validation of the Varian Clinac IX equipped with the High Definition Multi-Leaf Collimator (HD 120 MLC) instead of the removable jaws, using GATE Monte Carlo Platform version 8.2. We validated the multileaf collimator (MLC) geometry by simulating two dosimetric functions (Percentage Depth Dose (PDD) and Dose Profile (DP)), for 6MV photon beam energy and different field sizes (3x3, 4x4, 6x6, 8x8, 10x10, 12x12, 15x15, and 20x20 cm²). We then compared the results with measurements realized with two detectors, namely the cylindrical ionization chamber and the micro-diode PTW silicon. By applying the Relative Dose Difference method (RDD), we noted a less than 2% and 1% agreement for the field sizes (10x10, 12x12, 15x15, 20x20 cm²) and (3x3, 4x4, 6x6, 8x8 cm²) respectively. Moreover, to evaluate the relevance of Monte Carlo method in a heterogeneous media, particularly in small field sizes (1x1, 2x2, 3x3 cm²), we have simulated three clinical studies based on the Physical Test Objects (PTOs) that are the equivalent slabs of lung and bone included in a water phantom. We noticed that the simulated PDDs exhibit two significant irregularities in the interface between water and lung. To eliminate these phenomena, we have used the "setMaxStepSizeInRegion" parameter implemented in GATE. We also noticed an important difference of 5% corresponding to the small field sizes, between homogeneous and heterogeneous simulated PDDs. We used the RDD method in this case as well. Moreover, we observed a difference between 1-4% between the simulated PDDs and the calculated ones by ECLIPSE Treatment Planning System (TPS). These results indicate that GATE (8.2) is useful in dosimetry with heterogeneous situations as well such as bone and lung.