Author, as appears in the article.: Hernandez, V; Vera-Sánchez, JA; Vieillevigne, L; Khamphan, C; Saez, J
Department: Ciències Mèdiques Bàsiques
URV's Author/s: Hernandez Masgrau, Victor
Keywords: Dose calculation Fields Impact Mlc Mlc modelling Tongue and groove Tps modelling
Abstract: Commercial TPSs typically model the tongue-and-groove (TG) by extending the projections of the leaf sides by a certain constant width. However, this model may produce discrepancies of as much as 7%-10% in the calculated average doses, especially for the High Definition multi-leaf collimator (MLC) (Hernandez et al 2017 Phys. Med. Biol. 62 6688-707). The purpose of the present study is to introduce and validate a new method for modelling the TG that uses a non constant TG width. We provide the theoretical background and a detailed methodology to determine the optimal shape of this TG width from measurements and we fit an empirical function to the TG width that depended on two parameters a(1) and a(2). Parameter a(1) represents the TG width and a(2) introduces a curvature correction in the width near the leaf tip end. The new TG model was implemented in MATLAB and when the curvature correction was zero (a(2) = 0) it caused the same discrepancies as the constant width model used by the Eclipse TPS. On the other hand, when the experimentally determined a(2) was used the new model's calculations were in close agreement with measurements, with all differences in average doses <1%. Additionally, film dosimetry was used to successfully validate the potential of the new TG model to recreate the fine spatial details associated to TG effects. We also showed that the parameters a(1), a(2) depend solely on the MLC design by evaluating three different linear accelerators for each MLC model considered, namely Varian's High Definition and Millennium120 MLCs. In conclusion, a new method was presented that greatly improves the TG modelling. The present method can be easily implemented in commercial TPSs and has the potential to further increase their accuracy, especially for MLCs with rounded leaf ends.
Thematic Areas: Astronomia / física Ciência da computação Ciências biológicas i Ciências biológicas ii Engenharias ii Engenharias iii Engenharias iv Engineering, biomedical General medicine Interdisciplinar Matemática / probabilidade e estatística Medicina i Medicina ii Odontología Psicología Radiological and ultrasound technology Radiology, nuclear medicine & medical imaging Radiology, nuclear medicine and imaging Saúde coletiva
licence for use: https://creativecommons.org/licenses/by/3.0/es/
Author's mail: victor.hernandez@urv.cat
Author identifier: 0000-0003-3770-8486
Record's date: 2024-01-16
Papper version: info:eu-repo/semantics/acceptedVersion
Link to the original source: https://iopscience.iop.org/article/10.1088/1361-6560/aaf098
Papper original source: Physics In Medicine And Biology. 63 (24):
APA: Hernandez, V; Vera-Sánchez, JA; Vieillevigne, L; Khamphan, C; Saez, J (2018). A new method for modelling the tongue-and-groove in treatment planning systems. Physics In Medicine And Biology, 63(24), -. DOI: 10.1088/1361-6560/aaf098
Licence document URL: http://repositori.urv.cat/ca/proteccio-de-dades/
Article's DOI: 10.1088/1361-6560/aaf098
Entity: Universitat Rovira i Virgili
Journal publication year: 2018
Publication Type: Journal Publications
Repositori URV