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Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments

BACKGROUND: The use of small fields has increased by the emergence of advanced radiotherapy. Dose calculations of these fields are complex and challenging for many reasons such as lack of electrical equilibrium even in homogeneous environments, and this complexity will increase in presence of hetero...

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Autores principales: Zaghian, Razieh, Sedighi Pashaki, Abdolazim, Haghparast, Abbas, Gholami, Mohammad Hadi, Mohammadi, Mahdi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Shiraz University of Medical Sciences 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8064127/
https://www.ncbi.nlm.nih.gov/pubmed/33937122
http://dx.doi.org/10.31661/jbpe.v0i0.1121
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author Zaghian, Razieh
Sedighi Pashaki, Abdolazim
Haghparast, Abbas
Gholami, Mohammad Hadi
Mohammadi, Mahdi
author_facet Zaghian, Razieh
Sedighi Pashaki, Abdolazim
Haghparast, Abbas
Gholami, Mohammad Hadi
Mohammadi, Mahdi
author_sort Zaghian, Razieh
collection PubMed
description BACKGROUND: The use of small fields has increased by the emergence of advanced radiotherapy. Dose calculations of these fields are complex and challenging for many reasons such as lack of electrical equilibrium even in homogeneous environments, and this complexity will increase in presence of heterogeneity. According to the importance of delivery the accurate prescription dose to the target volume in the patient’s body, the dose calculation accuracy of used commercial algorithms in clinical treatment planning systems (TPS) should be evaluated. OBJECTIVE: The present study aims to evaluate the accuracy of Collapsed-cone dose measurement algorithm in Isogray treatment planning system. MATERIAL AND METHODS: In this analytical study, the measurements were made in tissue equivalent solid water phantom with lung and bone heterogeneities by Pinpoint dosimeter (0.015 cm(3) sensitive volume) in several radiation fields (1×1 to 5×5 cm(2)). The phantoms were irradiated with 6, 10 and 18 MV photon beams and finally, the results of experimental calculations were compared with treatment planning outputs. RESULTS: In all setups, the maximum deviation occurred in the field of 1×1 cm(2). Then, the maximum deviation was observed for 2×2 cm(2) field size; however, it was up to 5% for homogeneous water phantom and lung heterogeneity. In 3×3 cm(2) and larger fields, there was a good agreement between the results of the TPS and experimental dosimetry. The maximum deviation was observed in water-bone heterogeneity. CONCLUSION: This algorithm was able to pass the standard audit criteria, but it is better to be used more cautiously in bone heterogeneity, especially in low energies.
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spelling pubmed-80641272021-04-30 Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments Zaghian, Razieh Sedighi Pashaki, Abdolazim Haghparast, Abbas Gholami, Mohammad Hadi Mohammadi, Mahdi J Biomed Phys Eng Original Article BACKGROUND: The use of small fields has increased by the emergence of advanced radiotherapy. Dose calculations of these fields are complex and challenging for many reasons such as lack of electrical equilibrium even in homogeneous environments, and this complexity will increase in presence of heterogeneity. According to the importance of delivery the accurate prescription dose to the target volume in the patient’s body, the dose calculation accuracy of used commercial algorithms in clinical treatment planning systems (TPS) should be evaluated. OBJECTIVE: The present study aims to evaluate the accuracy of Collapsed-cone dose measurement algorithm in Isogray treatment planning system. MATERIAL AND METHODS: In this analytical study, the measurements were made in tissue equivalent solid water phantom with lung and bone heterogeneities by Pinpoint dosimeter (0.015 cm(3) sensitive volume) in several radiation fields (1×1 to 5×5 cm(2)). The phantoms were irradiated with 6, 10 and 18 MV photon beams and finally, the results of experimental calculations were compared with treatment planning outputs. RESULTS: In all setups, the maximum deviation occurred in the field of 1×1 cm(2). Then, the maximum deviation was observed for 2×2 cm(2) field size; however, it was up to 5% for homogeneous water phantom and lung heterogeneity. In 3×3 cm(2) and larger fields, there was a good agreement between the results of the TPS and experimental dosimetry. The maximum deviation was observed in water-bone heterogeneity. CONCLUSION: This algorithm was able to pass the standard audit criteria, but it is better to be used more cautiously in bone heterogeneity, especially in low energies. Shiraz University of Medical Sciences 2021-04-01 /pmc/articles/PMC8064127/ /pubmed/33937122 http://dx.doi.org/10.31661/jbpe.v0i0.1121 Text en Copyright: © Journal of Biomedical Physics and Engineering https://creativecommons.org/licenses/by-nc/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 Unported License, ( http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) ) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Article
Zaghian, Razieh
Sedighi Pashaki, Abdolazim
Haghparast, Abbas
Gholami, Mohammad Hadi
Mohammadi, Mahdi
Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments
title Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments
title_full Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments
title_fullStr Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments
title_full_unstemmed Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments
title_short Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments
title_sort investigation of collapsed-cone algorithm accuracy in small fields and heterogeneous environments
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8064127/
https://www.ncbi.nlm.nih.gov/pubmed/33937122
http://dx.doi.org/10.31661/jbpe.v0i0.1121
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