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The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy

PURPOSE: Proton treatment plan perturbation by common dental fixtures such as amalgams (Am) and porcelain‐fused‐to‐metal (PFM) crowns has, to date, been uncharacterized. Previous studies have been conducted to determine the physical effect of these materials within the beam path for single spots, bu...

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Autores principales: Hu, Yue‐Houng, Seum, Wan Chan Tseung Hok, Hunzeker, Ashley, Muller, Olivia, Foote, Robert L., Mundy, Daniel W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10338740/
https://www.ncbi.nlm.nih.gov/pubmed/36972299
http://dx.doi.org/10.1002/acm2.13973
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author Hu, Yue‐Houng
Seum, Wan Chan Tseung Hok
Hunzeker, Ashley
Muller, Olivia
Foote, Robert L.
Mundy, Daniel W.
author_facet Hu, Yue‐Houng
Seum, Wan Chan Tseung Hok
Hunzeker, Ashley
Muller, Olivia
Foote, Robert L.
Mundy, Daniel W.
author_sort Hu, Yue‐Houng
collection PubMed
description PURPOSE: Proton treatment plan perturbation by common dental fixtures such as amalgams (Am) and porcelain‐fused‐to‐metal (PFM) crowns has, to date, been uncharacterized. Previous studies have been conducted to determine the physical effect of these materials within the beam path for single spots, but their effects on complex treatment plans and clinical anatomy have not yet been quantified. The present manuscript aims to study the effect of Am and PFM fixtures on proton treatment planning in a clinical setting. METHODS: An anthropomorphic phantom with removable tongue, maxilla, and mandible modules was simulated on a clinical computed tomography (CT) scanner. Spare maxilla modules were modified to include either a 1.5 mm depth central groove occlusal amalgam (Am) or a porcelain‐fused‐to‐metal (PFM) crown, implanted on the first right molar. Modified tongue modules were 3D printed to accommodate several axial or sagittal oriented pieces of EBT‐3 film. Clinically representative spot‐scanning proton plans were generated in Eclipse v.15.6 using the proton convolution superposition (PCS) algorithm v.15.6.06 using a multi‐field optimization (MFO) technique with the goal of delivering a uniform 54 Gy dose to a clinical target volume (CTV) typical of a base‐of‐tongue (BoT) treatment. A typical geometric beam arrangement of two anterior oblique (AO) beams and a posterior beam was employed. Plans optimized without any material overrides were delivered to the phantom A) without implants; B) with Am fixture; or C) with PFM crown. Plans were also reoptimized and delivered with inclusion of material overrides to equate relative stopping power of the fixture with that of a previously measured result. RESULTS: Plans exhibit slightly greater dose weight towards AO beams. The optimizer accounted for inclusion of fixture overrides by increasing beam weights to the beam closest to the implant. Film measurements exhibited cold spots directly within the beam path through the fixture in plans with and without overridden materials. Cold spots were somewhat mitigated in plans including overridden materials in the structure set but were not entirely eliminated. Cold spots associated with Am and PFM fixtures were quantified at 17% and 14% for plans without overrides, respectively, and 11% and 9% with using Monte Carlo simulation. Compared with film measurements and Monte Carlo simulation, the treatment planning system underestimates the dose shadowing effect in plans including material overrides. CONCLUSIONS: Dental fixtures create a dose shadowing effect directly in line with the beam path through the material. This cold spot is partially mitigated by overriding the material to measured relative stopping powers. Due to uncertainties in modeling perturbation through the fixture, the magnitude of the cold spot is underestimated using the institutional TPS when compared to measurement and MC simulation.
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spelling pubmed-103387402023-07-14 The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy Hu, Yue‐Houng Seum, Wan Chan Tseung Hok Hunzeker, Ashley Muller, Olivia Foote, Robert L. Mundy, Daniel W. J Appl Clin Med Phys Radiation Oncology Physics PURPOSE: Proton treatment plan perturbation by common dental fixtures such as amalgams (Am) and porcelain‐fused‐to‐metal (PFM) crowns has, to date, been uncharacterized. Previous studies have been conducted to determine the physical effect of these materials within the beam path for single spots, but their effects on complex treatment plans and clinical anatomy have not yet been quantified. The present manuscript aims to study the effect of Am and PFM fixtures on proton treatment planning in a clinical setting. METHODS: An anthropomorphic phantom with removable tongue, maxilla, and mandible modules was simulated on a clinical computed tomography (CT) scanner. Spare maxilla modules were modified to include either a 1.5 mm depth central groove occlusal amalgam (Am) or a porcelain‐fused‐to‐metal (PFM) crown, implanted on the first right molar. Modified tongue modules were 3D printed to accommodate several axial or sagittal oriented pieces of EBT‐3 film. Clinically representative spot‐scanning proton plans were generated in Eclipse v.15.6 using the proton convolution superposition (PCS) algorithm v.15.6.06 using a multi‐field optimization (MFO) technique with the goal of delivering a uniform 54 Gy dose to a clinical target volume (CTV) typical of a base‐of‐tongue (BoT) treatment. A typical geometric beam arrangement of two anterior oblique (AO) beams and a posterior beam was employed. Plans optimized without any material overrides were delivered to the phantom A) without implants; B) with Am fixture; or C) with PFM crown. Plans were also reoptimized and delivered with inclusion of material overrides to equate relative stopping power of the fixture with that of a previously measured result. RESULTS: Plans exhibit slightly greater dose weight towards AO beams. The optimizer accounted for inclusion of fixture overrides by increasing beam weights to the beam closest to the implant. Film measurements exhibited cold spots directly within the beam path through the fixture in plans with and without overridden materials. Cold spots were somewhat mitigated in plans including overridden materials in the structure set but were not entirely eliminated. Cold spots associated with Am and PFM fixtures were quantified at 17% and 14% for plans without overrides, respectively, and 11% and 9% with using Monte Carlo simulation. Compared with film measurements and Monte Carlo simulation, the treatment planning system underestimates the dose shadowing effect in plans including material overrides. CONCLUSIONS: Dental fixtures create a dose shadowing effect directly in line with the beam path through the material. This cold spot is partially mitigated by overriding the material to measured relative stopping powers. Due to uncertainties in modeling perturbation through the fixture, the magnitude of the cold spot is underestimated using the institutional TPS when compared to measurement and MC simulation. John Wiley and Sons Inc. 2023-03-27 /pmc/articles/PMC10338740/ /pubmed/36972299 http://dx.doi.org/10.1002/acm2.13973 Text en © 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Oncology Physics
Hu, Yue‐Houng
Seum, Wan Chan Tseung Hok
Hunzeker, Ashley
Muller, Olivia
Foote, Robert L.
Mundy, Daniel W.
The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy
title The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy
title_full The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy
title_fullStr The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy
title_full_unstemmed The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy
title_short The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy
title_sort effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10338740/
https://www.ncbi.nlm.nih.gov/pubmed/36972299
http://dx.doi.org/10.1002/acm2.13973
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