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Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma

OBJECTIVES: Proton therapy has a theoretical dosimetric advantage due to the Bragg peak, but the linear energy transfer (LET), and therefore the relative biological effectiveness (RBE), increase at the end of range. For patients with Hodgkin lymphoma, the distal edge of beam is often located within...

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Autores principales: Rechner, Laura Ann, Maraldo, Maja V, Smith, Edward AK, Lundgaard, Anni Y., Hjalgrim, Lisa L., MacKay, Ranald I., Aitkenhead, Adam H., Aznar, Marianne C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The British Institute of Radiology. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10077416/
https://www.ncbi.nlm.nih.gov/pubmed/37035769
http://dx.doi.org/10.1259/bjro.20230012
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author Rechner, Laura Ann
Maraldo, Maja V
Smith, Edward AK
Lundgaard, Anni Y.
Hjalgrim, Lisa L.
MacKay, Ranald I.
Aitkenhead, Adam H.
Aznar, Marianne C.
author_facet Rechner, Laura Ann
Maraldo, Maja V
Smith, Edward AK
Lundgaard, Anni Y.
Hjalgrim, Lisa L.
MacKay, Ranald I.
Aitkenhead, Adam H.
Aznar, Marianne C.
author_sort Rechner, Laura Ann
collection PubMed
description OBJECTIVES: Proton therapy has a theoretical dosimetric advantage due to the Bragg peak, but the linear energy transfer (LET), and therefore the relative biological effectiveness (RBE), increase at the end of range. For patients with Hodgkin lymphoma, the distal edge of beam is often located within or close to the heart, where elevated RBE would be of potential concern. The purpose of this study was to investigate the impact of RBE and the choice of beam arrangement for adolescent patients with mediastinal Hodgkin lymphoma. METHODS: For three previously treated adolescent patients, proton plans with 1–3 fields were created to a prescribed dose of 19.8 Gy (RBE) in 11 fractions (Varian Eclipse v13.7), assuming an RBE of 1.1. Plans were recalculated using Monte-Carlo (Geant4 v10.3.3/Gate v8.1) to calculate dose-averaged LET. Variable RBE-weighted dose was calculated using the McNamara model, assuming an α/β ratio of 2 Gy for organs-at-risk. RESULTS: Although the LET decreased as the number of fields increased, the difference in RBE-weighted dose (Δdose) to organs-at-risk did not consistently decrease. Δdose values varied by patient and organ and were mostly of the order of 0–3 Gy (RBE), with a worst-case of 4.75 Gy (RBE) in near-maximum dose to the left atrium for one plan. CONCLUSIONS: RBE-weighted doses to organs-at-risk are sensitive to the choice of RBE model, which is of particular concern for the heart. ADVANCES IN KNOWLEDGE: There is a need to remain cautious when evaluating proton plans for Hodgkin lymphoma, especially when near-maximum doses to organs-at-risk are considered.
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spelling pubmed-100774162023-04-07 Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma Rechner, Laura Ann Maraldo, Maja V Smith, Edward AK Lundgaard, Anni Y. Hjalgrim, Lisa L. MacKay, Ranald I. Aitkenhead, Adam H. Aznar, Marianne C. BJR Open Original Research OBJECTIVES: Proton therapy has a theoretical dosimetric advantage due to the Bragg peak, but the linear energy transfer (LET), and therefore the relative biological effectiveness (RBE), increase at the end of range. For patients with Hodgkin lymphoma, the distal edge of beam is often located within or close to the heart, where elevated RBE would be of potential concern. The purpose of this study was to investigate the impact of RBE and the choice of beam arrangement for adolescent patients with mediastinal Hodgkin lymphoma. METHODS: For three previously treated adolescent patients, proton plans with 1–3 fields were created to a prescribed dose of 19.8 Gy (RBE) in 11 fractions (Varian Eclipse v13.7), assuming an RBE of 1.1. Plans were recalculated using Monte-Carlo (Geant4 v10.3.3/Gate v8.1) to calculate dose-averaged LET. Variable RBE-weighted dose was calculated using the McNamara model, assuming an α/β ratio of 2 Gy for organs-at-risk. RESULTS: Although the LET decreased as the number of fields increased, the difference in RBE-weighted dose (Δdose) to organs-at-risk did not consistently decrease. Δdose values varied by patient and organ and were mostly of the order of 0–3 Gy (RBE), with a worst-case of 4.75 Gy (RBE) in near-maximum dose to the left atrium for one plan. CONCLUSIONS: RBE-weighted doses to organs-at-risk are sensitive to the choice of RBE model, which is of particular concern for the heart. ADVANCES IN KNOWLEDGE: There is a need to remain cautious when evaluating proton plans for Hodgkin lymphoma, especially when near-maximum doses to organs-at-risk are considered. The British Institute of Radiology. 2023-02-15 /pmc/articles/PMC10077416/ /pubmed/37035769 http://dx.doi.org/10.1259/bjro.20230012 Text en © 2023 The Authors. Published by the British Institute of Radiology https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
spellingShingle Original Research
Rechner, Laura Ann
Maraldo, Maja V
Smith, Edward AK
Lundgaard, Anni Y.
Hjalgrim, Lisa L.
MacKay, Ranald I.
Aitkenhead, Adam H.
Aznar, Marianne C.
Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma
title Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma
title_full Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma
title_fullStr Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma
title_full_unstemmed Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma
title_short Proton linear energy transfer and variable relative biological effectiveness for adolescent patients with Hodgkin lymphoma
title_sort proton linear energy transfer and variable relative biological effectiveness for adolescent patients with hodgkin lymphoma
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10077416/
https://www.ncbi.nlm.nih.gov/pubmed/37035769
http://dx.doi.org/10.1259/bjro.20230012
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