The Elekta Unity magnetic resonance (MR) linac is limited to longitudinal couch motion and a sagittal-only laser, which restricts the ability to perform patient-specific quality assurance (PSQA) intensity-modulated radiotherapy (IMRT) measurements for very lateral targets. This work introduces a simple method to perform PSQA using the Sun Nuclear ArcCheck-MR phantom at left and right lateral positions without additional equipment or in-house construction. The proposed setup places the center of the phantom 1.3 cm vertical and 12.9 cm lateral to isocenter in either the left or right direction. Computed tomography (CT) scans are used to simulate the setup and create a QA plan template in the Monaco treatment planning system (TPS). The workflow is demonstrated for four patients, with an average axial distance from the center of the bore to the planning target volume (PTV) of 12.4 cm. Gamma pass rates were above 94% for all plans using global 3%/2 mm gamma criterion with a 10% threshold. Setup uncertainties are slightly larger for the proposed lateral setup compared to the centered setup on the Elekta platform (∼1 mm compared to ∼0.5 mm), but acceptable pass rates are achievable without optimizing shifts in the gamma analysis software. In general, adding the left and right lateral positions increases the axial area in the bore encompassed by the cylindrical measurement array by 147%, substantially increasing the flexibility of measurements for offset targets. Based on this work, we propose using the lateral QA setup if the closest distance to the PTV edge from isocenter is larger than the array radius (10.5 cm) or the percent of the PTV encompassed by the diode array would be increased with the lateral setup compared to the centered setup.
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http://dx.doi.org/10.1002/acm2.14323 | DOI Listing |
J Radiol Prot
January 2025
Radiation Protection Dosimetry (6.3), Physikalisch-Technische Bundesanstalt, Braunschweig, NDS, GERMANY.
With the International Commission on Radiological Protection (ICRP) lowering the annual dose limit for the eye lens to 20 mSv, precise monitoring of eye lens exposure has become essential. The personal dose equivalent at a depth of 3 mm, Hp(3), is the measurement method for monitoring the dose to the lens of the eye. Traditional dosimetry methods primarily address lateral radiation exposure scenarios, where radiation approaches from the left or right, necessitating the rotation of the phantom during type testing around the vertical axis.
View Article and Find Full Text PDFMed Phys
January 2025
Department of Radiation Oncology, Stanford University, Palo Alto, California, USA.
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View Article and Find Full Text PDFBiomed Phys Eng Express
January 2025
Mindanao Radiation Physics Center, MSU-Iligan Institute of Technology, Andres Bonifacio Street Tibanga, Iligan City, Lanao Norte, 9200, PHILIPPINES.
To accurately model and validate the 6 MV Elekta Compactlinear accelerator using the Geant4 Application for Tomographic Emission (GATE). In particular, this study focuses on the precise calibration and validation of critical parameters, including jaw collimator positioning, electron source nominal energy, flattening filter geometry, and electron source spot size, which are often not provided in technical documentation. Methods: Simulation of the Elekta Compact6 MV linear accelerator was performed using the Geant4 Application for Tomographic Emission (GATE) v.
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View Article and Find Full Text PDFPoult Sci
December 2024
Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands.
Impaired walking ability and leg health are commonly seen in broilers and can negatively impact their welfare. Commonly, walking ability and leg health are assessed manually, but this is time consuming and can be subjective. Automated approaches for scoring walking ability and leg health at the individual level could therefore have great added value.
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