A Monte Carlo‐based analytic model of neutron dose equivalent for a mevion gantry‐mounted passively scattered proton system for craniospinal irradiation.
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| Title: | A Monte Carlo‐based analytic model of neutron dose equivalent for a mevion gantry‐mounted passively scattered proton system for craniospinal irradiation. |
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| Authors: | Baradaran‐Ghahfarokhi, Milad1 (AUTHOR), Reynoso, Francisco1 (AUTHOR), Sun, Baozhou1 (AUTHOR), Darafsheh, Arash1 (AUTHOR), Prusator, Michael T.1 (AUTHOR), Mutic, Sasa1 (AUTHOR), Zhao, Tianyu1 (AUTHOR) tzhao@wustl.edu |
| Source: | Medical Physics. Sep2020, Vol. 47 Issue 9, p4509-4521. 13p. |
| Subjects: | Monte Carlo method, Neutrons, Protons, Neutron irradiation, Irradiation, Depth profiling, Correction factors |
| Abstract: | Purpose: To calculate in‐ and out‐of‐field neutron spectra and dose equivalent, using Monte Carlo (MC) simulation, for a Mevion gantry‐mounted passively scattered proton system in craniospinal irradiation. An analytical model based on the MC calculations that estimates in‐ and out‐of‐field neutron dose equivalent from proton Craniospinal irradiation (CSI) was also developed. Methods: The MCNPX MC code was used to simulate a Mevion S250 proton therapy system. The simulated proton depth doses and profiles for pristine and spread‐out Bragg peaks were benchmarked against the measured data. Previous measurements using extended‐range Bonner spheres were used to verify the calculated neutron spectra and dose equivalent. Using the benchmarked results as a reference condition, a correction‐based analytical model was reconstructed by fitting the data to derive model parameters at 95% confidence interval. Sensitivity analysis of brass aperture opening, thickness of the Lucite (PMMA) range compensator, and modulation width was performed to obtain correction parameters for nonreference conditions. Results: For the neutron dose equivalent per therapeutic proton dose, the MCNPX calculated dose equivalent matched the measured values to within 8%. The benchmarked neutron dose equivalent at the isocenter was 41.2 and 20.8 mSv/Gy, for cranial and spinal fields, respectively. For in‐ and out‐of‐field neutron dose calculations, the correction‐based analytical model showed up to 17% discrepancy compared to the MC calculations. The correction factors may provide a conservative estimation of neutron dose, especially for depth ≤ 5 cm and regions underneath the brass aperture. Conclusion: The proposed analytical model can be used to estimate the contribution of the neutron dose to the overall CSI treatment dose. Moreover, the model can be employed to estimate the neutron dose to the implantable cardiac electronic devices. [ABSTRACT FROM AUTHOR] |
| Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: egs DbLabel: Engineering Source An: 146080875 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: A Monte Carlo‐based analytic model of neutron dose equivalent for a mevion gantry‐mounted passively scattered proton system for craniospinal irradiation. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Baradaran‐Ghahfarokhi%2C+Milad%22">Baradaran‐Ghahfarokhi, Milad</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Reynoso%2C+Francisco%22">Reynoso, Francisco</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Sun%2C+Baozhou%22">Sun, Baozhou</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Darafsheh%2C+Arash%22">Darafsheh, Arash</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Prusator%2C+Michael+T%2E%22">Prusator, Michael T.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Mutic%2C+Sasa%22">Mutic, Sasa</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Zhao%2C+Tianyu%22">Zhao, Tianyu</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> tzhao@wustl.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Sep2020, Vol. 47 Issue 9, p4509-4521. 13p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Monte+Carlo+method%22">Monte Carlo method</searchLink><br /><searchLink fieldCode="DE" term="%22Neutrons%22">Neutrons</searchLink><br /><searchLink fieldCode="DE" term="%22Protons%22">Protons</searchLink><br /><searchLink fieldCode="DE" term="%22Neutron+irradiation%22">Neutron irradiation</searchLink><br /><searchLink fieldCode="DE" term="%22Irradiation%22">Irradiation</searchLink><br /><searchLink fieldCode="DE" term="%22Depth+profiling%22">Depth profiling</searchLink><br /><searchLink fieldCode="DE" term="%22Correction+factors%22">Correction factors</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Purpose: To calculate in‐ and out‐of‐field neutron spectra and dose equivalent, using Monte Carlo (MC) simulation, for a Mevion gantry‐mounted passively scattered proton system in craniospinal irradiation. An analytical model based on the MC calculations that estimates in‐ and out‐of‐field neutron dose equivalent from proton Craniospinal irradiation (CSI) was also developed. Methods: The MCNPX MC code was used to simulate a Mevion S250 proton therapy system. The simulated proton depth doses and profiles for pristine and spread‐out Bragg peaks were benchmarked against the measured data. Previous measurements using extended‐range Bonner spheres were used to verify the calculated neutron spectra and dose equivalent. Using the benchmarked results as a reference condition, a correction‐based analytical model was reconstructed by fitting the data to derive model parameters at 95% confidence interval. Sensitivity analysis of brass aperture opening, thickness of the Lucite (PMMA) range compensator, and modulation width was performed to obtain correction parameters for nonreference conditions. Results: For the neutron dose equivalent per therapeutic proton dose, the MCNPX calculated dose equivalent matched the measured values to within 8%. The benchmarked neutron dose equivalent at the isocenter was 41.2 and 20.8 mSv/Gy, for cranial and spinal fields, respectively. For in‐ and out‐of‐field neutron dose calculations, the correction‐based analytical model showed up to 17% discrepancy compared to the MC calculations. The correction factors may provide a conservative estimation of neutron dose, especially for depth ≤ 5 cm and regions underneath the brass aperture. Conclusion: The proposed analytical model can be used to estimate the contribution of the neutron dose to the overall CSI treatment dose. Moreover, the model can be employed to estimate the neutron dose to the implantable cardiac electronic devices. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1002/mp.14299 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 4509 Subjects: – SubjectFull: Monte Carlo method Type: general – SubjectFull: Neutrons Type: general – SubjectFull: Protons Type: general – SubjectFull: Neutron irradiation Type: general – SubjectFull: Irradiation Type: general – SubjectFull: Depth profiling Type: general – SubjectFull: Correction factors Type: general Titles: – TitleFull: A Monte Carlo‐based analytic model of neutron dose equivalent for a mevion gantry‐mounted passively scattered proton system for craniospinal irradiation. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Baradaran‐Ghahfarokhi, Milad – PersonEntity: Name: NameFull: Reynoso, Francisco – PersonEntity: Name: NameFull: Sun, Baozhou – PersonEntity: Name: NameFull: Darafsheh, Arash – PersonEntity: Name: NameFull: Prusator, Michael T. – PersonEntity: Name: NameFull: Mutic, Sasa – PersonEntity: Name: NameFull: Zhao, Tianyu IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 09 Text: Sep2020 Type: published Y: 2020 Identifiers: – Type: issn-print Value: 00942405 Numbering: – Type: volume Value: 47 – Type: issue Value: 9 Titles: – TitleFull: Medical Physics Type: main |
| ResultId | 1 |
