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 Evaluation of two-dimensional dose distributions for pre-treatment patient-specific IMRT dosimetry

2018 ◽  
Vol 52 (3) ◽  
pp. 346-352
Author(s):  
Đeni Smilovic Radojcic ◽  
David Rajlic ◽  
Bozidar Casar ◽  
Manda Svabic Kolacio ◽  
Nevena Obajdin ◽  
...  
Keyword(s):  
Dose Distribution ◽  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Equivalent Material ◽  
Current Standard ◽  
Dose Distributions ◽  
Passing Rates ◽  
Anthropomorphic Phantoms

Abstract Background The accuracy of dose calculation is crucial for success of the radiotherapy treatment. One of the methods that represent the current standard for patient-specific dosimetry is the evaluation of dose distributions measured with an ionization chamber array inside a homogeneous phantom using gamma method. Nevertheless, this method does not replicate the realistic conditions present when a patient is undergoing therapy. Therefore, to more accurately evaluate the treatment planning system (TPS) capabilities, gamma passing rates were examined for beams of different complexity passing through inhomogeneous phantoms. Materials and methods The research was performed using Siemens Oncor Expression linear accelerator, Siemens Somatom Open CT simulator and Elekta Monaco TPS. A 2D detector array was used to evaluate dose distribution accuracy in homogeneous, semi-anthropomorphic and anthropomorphic phantoms. Validation was based on gamma analysis with 3%/3mm and 2%/2mm criteria, respectively. Results Passing rates of the complex dose distributions degrade depending on the thickness of non-water equivalent material. They also depend on dose reporting mode used. It is observed that the passing rate decreases with plan complexity. Comparison of the data for all set-ups of semi-anthropomorphic and anthropomorphic phantoms shows that passing rates are higher in the anthropomorphic phantom. Conclusions Presented results raise a question of possible limits of dose distribution verification in assessment of plan delivery quality. Consequently, good results obtained using standard patient specific dosimetry methodology do not guarantee the accuracy of delivered dose distribution in real clinical cases.

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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