A new component module (CM) named mini multileaf collimator (mMLC) was developed for the Monte Carlo code BEAMnrc. It models the geometry of the add-on miniature multileaf collimator ModuLeaf (MRC Systems GmbH, Heidelberg, Germany, now part of Siemens, Erlangen, Germany). The new CM is partly based on the existing CM called DYNVMLC. The development was performed using a modified EGSnrc platform which enables us to work in the Microsoft Visual Studio environment. In order to validate the new CM, the PRIMUS linac with 6 MV x-rays (Siemens OCS, Concord, CA, USA) equipped with the ModuLeaf mMLC was modelled. Validation was performed by two methods: (a) a ray-tracing method to check the correct geometry of the multileaf collimator (MLC) and (b) a comparison of calculated and measured results of the following dosimetrical parameters: output factors, dose profiles, field edge position penumbra, MLC interleaf leakage and transmission values. Excellent agreement was found for all parameters. It was, in particular, found that the relationship between leaf position and field edge depending on the shape of the leaf ends can be investigated with a higher accuracy by this new CM than by measurements demonstrating the usefulness of the new CM.
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http://dx.doi.org/10.1088/0031-9155/57/10/3093 | DOI Listing |
Front Oncol
January 2025
Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Purpose: This study aimed to provide quantitative information for implementing Lattice radiotherapy (LRT) using a medical linear accelerator equipped with the Millennium 120 multi-leaf collimator (MLC). The research systematically evaluated the impact of varying vertex diameters and separations on dose distribution, peak-to-valley dose ratio (PVDR), and normal tissue dose.
Methods: A cylindrical Virtual Water™ phantom was used to create LRT treatments using the Eclipse version 16.
Phys Med
January 2025
Centre for Medical and Radiation Physics, University of Wollongong, NSW, Australia; St George Cancer Care Centre, St George Hospital, Kogarah, NSW, Australia; School of Physics, University of Sydney, Camperdown, NSW, Australia.
Purpose: Even with modern immobilisation devices, some amount of intrafraction patient motion is likely to occur during stereotactic radiosurgery (SRS) delivery. The aim of this work was to investigate how robustness of plans to intrafraction motion is affected by plan geometry and complexity.
Methods: In 2018, the Trans-Tasman Radiation Oncology Group conducted a multiple-target SRS international planning challenge, the data from which was utilised in this study.
Cureus
December 2024
Department of Radiology, Aichi Medical University, Nagakute, JPN.
Purpose In linac-based stereotactic radiosurgery (SRS) utilizing a multileaf collimator (MLC) for brain metastases (BMs), a volumetric-modulated arc (VMA) technique is indispensable for generating a suitable dose distribution with efficient planning and delivery. However, the optimal calculation grid spacing (GS) and statistical uncertainty (SU) of the Monte Carlo algorithm for VMA optimization have yet to be determined. This planning study aimed to examine the impacts of GS and GU settings on VMA-based SRS planning and to find the optimal combination for templating.
View Article and Find Full Text PDFMed Phys
January 2025
Department of Medical Physics, Nova Scotia Health, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada.
intra-arc binary collimation (iABC) is a novel treatment technique in which dynamic conformal arcs are periodically interrupted with binary collimation. It has demonstrated its utility through planning studies for the treatment of multiple metastases. However, the binary collimation approach is idealized in the planning system, while the treatment deliveries must adhere to the physical limitations of the mechanical systems involved [e.
View Article and Find Full Text PDFHealth Phys
January 2025
Department of Radiation Oncology, Medicine Faculty of Van Yüzüncü Yıl University, Van, Turkey.
Quality assurance practices performed before treatment are believed to identify various potential errors. In this study, 2-dimensional (2D) dosimetric results were analyzed by making some intentional mistakes in six different treatment plans. In this way, the detectability of errors was investigated.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!