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Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation

PURPOSE: The aim of this study was to investigate dosimetric effects of scattering filter on the stand‐up technique for total skin irradiation (TSI) with a single electron field by Monte Carlo (MC) simulation. METHODS: MC simulations were performed with BEAMnrc and DOSXYZnrc packages under EGSnrc en...

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Autores principales: Tseng, Wenchih, Li, Ruiqi, Wu, Qiuwen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7856491/
https://www.ncbi.nlm.nih.gov/pubmed/33314659
http://dx.doi.org/10.1002/acm2.13119
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author Tseng, Wenchih
Li, Ruiqi
Wu, Qiuwen
author_facet Tseng, Wenchih
Li, Ruiqi
Wu, Qiuwen
author_sort Tseng, Wenchih
collection PubMed
description PURPOSE: The aim of this study was to investigate dosimetric effects of scattering filter on the stand‐up technique for total skin irradiation (TSI) with a single electron field by Monte Carlo (MC) simulation. METHODS: MC simulations were performed with BEAMnrc and DOSXYZnrc packages under EGSnrc environment. Scattering filter of a metal disc was mounted in the accessory slot. The filter materials (Cu, Fe, Au, Zn, Ag) were investigated, with thickness ranging from 0.05 to 0.55 mm, depending on material. The extended source to skin distance (SSD) ranging from 250 to 350 cm was studied. The following dosimetric quantities were evaluated: percent depth dose (PDD), profiles and output factor at depth of maximum, and composite dose distribution on a 30‐cm diameter cylindrical phantom. They were compared with the standard dual beam technique used at our clinic. The effects on different patient sizes were also studied. RESULTS: No filter produced acceptable profile flatness (±10% within the central 160 cm) at 250 cm SSD. At 300 cm SSD, Au (0.1 mm), Ag (0.25 mm), Cu (0.5 mm) produced acceptable flatness while Zn (0.45 mm) required 325 cm SSD. For these four configurations, the d(max) was 0.90–0.99 cm, similar to dual beam (0.97 cm); R(50) was 1.85–1.91 cm, compared with dual beam of 2.06 cm; the output factor ranged from 0.025 to 0.029, lower than the dual beam (0.080). With the composite fields for four configurations, the d(max) was 0.10 cm, compared with dual beam (0.16 cm). The surface dose was 97%, similar to dual beam (96%). B‐factor was 3.3–3.4, compared with dual beam of 3.1. The maximum X‐ray contamination was 3%, higher than dual beam (1%). CONCLUSIONS: The investigation suggests the TSI stand‐up technique can be implemented using a single electron beam if a customized filter is used. More dosimetric measurements are needed to validate the MC results and clinical implementation.
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spelling pubmed-78564912021-02-05 Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation Tseng, Wenchih Li, Ruiqi Wu, Qiuwen J Appl Clin Med Phys Radiation Oncology Physics PURPOSE: The aim of this study was to investigate dosimetric effects of scattering filter on the stand‐up technique for total skin irradiation (TSI) with a single electron field by Monte Carlo (MC) simulation. METHODS: MC simulations were performed with BEAMnrc and DOSXYZnrc packages under EGSnrc environment. Scattering filter of a metal disc was mounted in the accessory slot. The filter materials (Cu, Fe, Au, Zn, Ag) were investigated, with thickness ranging from 0.05 to 0.55 mm, depending on material. The extended source to skin distance (SSD) ranging from 250 to 350 cm was studied. The following dosimetric quantities were evaluated: percent depth dose (PDD), profiles and output factor at depth of maximum, and composite dose distribution on a 30‐cm diameter cylindrical phantom. They were compared with the standard dual beam technique used at our clinic. The effects on different patient sizes were also studied. RESULTS: No filter produced acceptable profile flatness (±10% within the central 160 cm) at 250 cm SSD. At 300 cm SSD, Au (0.1 mm), Ag (0.25 mm), Cu (0.5 mm) produced acceptable flatness while Zn (0.45 mm) required 325 cm SSD. For these four configurations, the d(max) was 0.90–0.99 cm, similar to dual beam (0.97 cm); R(50) was 1.85–1.91 cm, compared with dual beam of 2.06 cm; the output factor ranged from 0.025 to 0.029, lower than the dual beam (0.080). With the composite fields for four configurations, the d(max) was 0.10 cm, compared with dual beam (0.16 cm). The surface dose was 97%, similar to dual beam (96%). B‐factor was 3.3–3.4, compared with dual beam of 3.1. The maximum X‐ray contamination was 3%, higher than dual beam (1%). CONCLUSIONS: The investigation suggests the TSI stand‐up technique can be implemented using a single electron beam if a customized filter is used. More dosimetric measurements are needed to validate the MC results and clinical implementation. John Wiley and Sons Inc. 2020-12-12 /pmc/articles/PMC7856491/ /pubmed/33314659 http://dx.doi.org/10.1002/acm2.13119 Text en © 2020 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. This is an open access article under the terms of the http://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
Tseng, Wenchih
Li, Ruiqi
Wu, Qiuwen
Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation
title Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation
title_full Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation
title_fullStr Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation
title_full_unstemmed Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation
title_short Investigation of effect of filter on the stand‐up technique for total skin irradiation by Monte Carlo simulation
title_sort investigation of effect of filter on the stand‐up technique for total skin irradiation by monte carlo simulation
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7856491/
https://www.ncbi.nlm.nih.gov/pubmed/33314659
http://dx.doi.org/10.1002/acm2.13119
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