scholarly journals MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Lucia Paganini ◽  
Giacomo Reggiori ◽  
Antonella Stravato ◽  
Valentina Palumbo ◽  
Pietro Mancosu ◽  
...  
Keyword(s):  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Output Factor ◽  
Water Phantom ◽  
Graphical Environment ◽  
Clinical Complexity ◽  
Output Factors ◽  
Dosimetric Leaf Gap ◽  
Clinical Cases

Abstract Background PRIMO is a graphical environment based on PENELOPE Monte Carlo (MC) simulation of radiotherapy beams able to compute dose distribution in patients, from plans with different techniques. The dosimetric characteristics of an HD-120 MLC (Varian), simulated using PRIMO, were here compared with measurements, and also with Acuros calculations (in the Eclipse treatment planning system, Varian). Materials and methods A 10 MV FFF beam from a Varian EDGE linac equipped with the HD-120 MLC was used for this work. Initially, the linac head was simulated inside PRIMO, and validated against measurements in a water phantom. Then, a series of different MLC patterns were established to assess the MLC dosimetric characteristics. Those tests included: i) static fields: output factors from MLC shaped fields (2 × 2 to 10 × 10 cm2), alternate open and closed leaf pattern, MLC transmitted dose; ii) dynamic fields: dosimetric leaf gap (DLG) evaluated with sweeping gaps, tongue and groove (TG) effect assessed with profiles across alternate open and closed leaves moving across the field. The doses in the different tests were simulated in PRIMO and then compared with EBT3 film measurements in solid water phantom, as well as with Acuros calculations. Finally, MC in PRIMO and Acuros were compared in some clinical cases, summarizing the clinical complexity in view of a possible use of PRIMO as an independent dose calculation check. Results Static output factor MLC tests showed an agreement between MC calculated and measured OF of 0.5%. The dynamic tests presented DLG values of 0.033 ± 0.003 cm and 0.032 ± 0.006 cm for MC and measurements, respectively. Regarding the TG tests, a general agreement between the dose distributions of 1–2% was achieved, except for the extreme patterns (very small gaps/field sizes and high TG effect) were the agreement was about 4–5%. The analysis of the clinical cases, the Gamma agreement between MC in PRIMO and Acuros dose calculation in Eclipse was of 99.5 ± 0.2% for 3%/2 mm criteria of dose difference/distance to agreement. Conclusions MC simulations in the PRIMO environment were in agreement with measurements for the HD-120 MLC in a 10 MV FFF beam from a Varian EDGE linac. This result allowed to consistently compare clinical cases, showing the possible use of PRIMO as an independent dose calculation check tool.

scholarly journals Performance of a Commercial Macro Monte Carlo Dose Calculation Algorithm for Determining Output Factors of Clinical Electron Fields

2009 ◽  
Vol 8 (4) ◽  
pp. 307-314 ◽  
Author(s):  
Richard A. Popple ◽  
Ivan A. Brezovich ◽  
Prem N. Pareek ◽  
Jun Duan ◽  
Sui Shen ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Strong Dependence ◽  
Dose Calculation ◽  
Monte Carlo Algorithm ◽  
Planning System ◽  
Treatment Planning System ◽  
Large Field ◽  
Calculation Algorithm ◽  
Output Factors ◽  
The Difference

We compare measured output factors of clinical electron fields to those calculated by a commercial treatment planning system based on an electron Monte Carlo algorithm. The measured data is comprised of 195 fields with energies 6 to 18 MeV, applicator sizes 6 × 6 cm2 to 25 × 25 cm2, and source to surface distances (SSDs) of 97 to 107 cm. Due to a scarcity of clinical fields for the highest energies and the largest applicator sizes, additional measurements were made at arbitrarily chosen large field sizes at previously not used energies, for a total of 223 output factors. The difference between calculation and measurement ranged from −2.9% to 3.9%, with a mean difference of −0.2%. Half of the field shapes had a difference with magnitude less than 0.8%. Only 7 (3%) of the field shapes were outliers, having differences greater than 2%. All outliers had field widths at the normalization point < 3.5 cm, were applied at SSDs > 100 cm, were inserts for the 25 × 25 cm2 applicator, or had more than one of these characteristics. For narrow and elongated fields the TPS slightly overestimated output factors, whereas for field shapes with aspect ratio close to 1 the TPS slightly underestimated the output factors. No strong dependence of the difference on energy was observed.

scholarly journals Relative output factors of different collimation systems in truebeam STx medical linear accelerator

2021 ◽  
Vol 9 (4) ◽  
pp. 48-55
Author(s):  
Duc Chi Do ◽  
Ngoc Toan Tran ◽  
Robin Hill ◽  
Do Kien Nguyen
Keyword(s):  
Linear Accelerator ◽  
Planning System ◽  
Treatment Planning System ◽  
Medical Systems ◽  
High Definition ◽  
Computational Accuracy ◽  
Output Factor ◽  
Medical Linear Accelerator ◽  
Small Fields ◽  
Output Factors

The IAEA TRS483 and TRS398 Code of Practices (CoP) were used to calculate relative output factors for small photon beams of 6X, 6XFFF energies shaped by High Definition Multileaf Collimator (HDMLC), jaws and cones mounted on TrueBeam STx medical linear accelerator (Varian Medical Systems), respectively. A comparison between these results were made. The results show a large discrepancy in relative output factor curves found among different collimation systems of the same equivalent field sizes and between the CoPs. Therefore, the specific beam modelling in treatment planning system for each type of the collimation system to be used for small fields maybe required for better computational accuracy.

scholarly journals Assessment of CT Imaging Protocols Impacts on Calculation of Point Dose in Water Phantom Using Radiotherapy Treatment Planning System

2020 ◽  
Author(s):  
Gholamreza Fallah Mohammadi ◽  
Ehsan Mihandoost
Keyword(s):  
Treatment Planning ◽  
Photon Energy ◽  
Dose Calculation ◽  
Ct Images ◽  
Ct Imaging ◽  
Planning System ◽  
Treatment Planning System ◽  
Ct Image ◽  
Water Phantom ◽  
Imaging Protocols

Purpose: Point dose calculation in the Treatment Planning System (TPS) is performed using Computed Tomography (CT) images because CT images data have the tissue electron density information. The effect of CT imaging protocols on the calculation of point doses in TPS is one of the most important subjects that was evaluated in this study. Materials and Methods: CT scan imaging was performed from cylindrical water phantom using three scanner systems and different imaging technical parameters. The CT images data were irradiated in TPS to delivering a 200 cGy radiation dose to the center of the phantom with 6 and 15MV X-Ray photon energy with multiple radiation fields and Monitor Unit (MU) were separately calculated. In the TPS, a virtual water phantom with the same characteristic as CT image phantom was simulated and irradiated with similar conditions. The difference in MU values obtained from two irradiation methods in TPS was compared with Wilcoxon nonparametric test.   Results: Variations of mA, kV, Pitch, slice thickness, and kernel as CT imaging parameters have not significantly affected radiotherapy point dose calculation (<2%). CT imaging protocols as a thin slice, 80 kV, and sharp kernel have the greatest difference between CT image-based calculation and designed phantom calculation in TPS where wedge field and 6 MV photon energy were used. Conclusion: The use of CT images obtained with multiple protocols can be used without having a significant effect on the dose calculations of the treatment planning system.

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.

scholarly journals Fast MCsquare-Based Independent Dose Verification Platform for Pencil Beam Scanning Proton Therapy

2021 ◽  
Vol 20 ◽  
pp. 153303382110330
Author(s):  
Chunbo Liu ◽  
Meng Wei Ho ◽  
Jiyeon Park ◽  
Wen Chien Hsi ◽  
Xiaoying Liang ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Treatment Plan ◽  
Dose Calculation ◽  
Pencil Beam ◽  
Dose Verification ◽  
Beam Scanning ◽  
Water Phantom ◽  
Pencil Beam Scanning ◽  
The Absolute ◽  
Clinical Cases

Purpose: To commission MCsquare (a multi-cores CPU-based dose calculation engine) for pencil beam scanning (PBS) proton therapy, integrate it into RayStation treatment plan system (TPS) to create a dedicated platform for fast independent dose verification. Method: A MCsquare-based independent dose verification platform (MC2InRS) was developed to realize automatic dose re-calculation for clinical use, including data preparation, dose calculation, 2D/3D gamma analysis. MCsquare was commissioned based on in-air lateral dose profiles, integrated depth dose, and the absolute dose of different beam energies for Proteus®ONE. MC2InRS was validated with measurement data using various targets and depths in a water phantom. This study also investigated 15 clinical cases to demonstrate the feasibility and effectiveness of MC2InRS platform in clinic practice. Results: Between simulation and measurement, the distal range differences at 80% (R80) and 20% (R20) dose levels for each energy were below 0.05 mm, and 0.1 mm, respectively, and the absolute dose differences were below 0.5%. 29 out of 36 QA planes reached a 100% gamma passing rate (GPR) for 2%/2mm criteria, and a minimum of 98.3% gamma was obtained in water phantom between simulation and measurement. For the 15 clinical cases investigated, the average 2D GPR (2%/2mm) was 95.4%, 99.3% for MCsquare vs. measurement, MCsquare vs. TPS, respectively. The average 3D GPR (2%/2mm) was 98.9%, 95.3% for MCsquare vs. TPS in water, and computed tomography (CT), respectively. Conclusion: MC2InRS, a fast, independent dose verification platform, has been developed to perform dose verification with high accuracy and efficiency for Pencil Bream Scanning (PBS). Its potential to be applied in routine clinical practice has also been discussed.

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