Impact of nuclear fragmentation and irradiation scenarios on the dose‐averaged LET, the RBE, and their relationship for H, He, C, O, and Ne ions.
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| Title: | Impact of nuclear fragmentation and irradiation scenarios on the dose‐averaged LET, the RBE, and their relationship for H, He, C, O, and Ne ions. |
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| Authors: | Parisi, Alessio1 (AUTHOR) parisi.alessio@mayo.edu, Furutani, Keith M.1 (AUTHOR), Beltran, Chris J.1 (AUTHOR) |
| Source: | Medical Physics. May2025, Vol. 52 Issue 5, p3450-3460. 11p. |
| Subjects: | Linear energy transfer, Nuclear fragmentation, Irradiation, Hydrogen ions, Ions, Microdosimetry, Physiological effects of radiation, Isotopes |
| Abstract: | Background: Projectile and target fragmentation are nuclear phenomena that can influence the computation of the linear energy transfer (LET) and the relative biological effectiveness (RBE) in external radiotherapy with accelerated ions. Correlations between these two quantities are routinely established during radiobiological experiments to interpret the results and to develop and calibrate RBE models. Purpose: This study systematically evaluates the impact of secondary fragments and irradiation scenarios on the dose‐averaged LET, the RBE, and their correlation in the case of exposures to clinically relevant ion beams. Methods: 57 600 microdosimetric lineal energy spectra and corresponding LET distributions were simulated with the Monte Carlo code PHITS across different scenarios, including track segment calculations, pristine, and spread‐out Bragg peaks of 1H, 4He, 12C, 16O, and 20Ne ions within water phantoms. The LET distributions were analyzed to calculate the dose‐average LET, both including or excluding the contribution of secondary ions of an element different from the primary beam. Similarly, the lineal energy distributions were processed in conjunction with the Mayo Clinic Florida microdosimetric kinetic model to compute the RBE for two theoretical cell lines (α/β = 2 and 10 Gy in the case of 6 MV x‐rays). Correlations between the RBE and dose‐averaged LET were established by analyzing the simulation results within water phantoms and then compared to the corresponding trends from the track segment calculations. Results: Excluding secondary fragments had a pronounced impact on the dose‐averaged LET and the RBE, particularly in the entrance regions of proton beams and close to the distal edge of heavier ions. The correlations between the RBE and the dose‐averaged LET were not universal, but highly dependent on the irradiation scenario. For proton beams only, the dose‐averaged LET of hydrogen ions served as a practical first‐order descriptor of the RBE. Track segment simulations, commonly used for calibrating and benchmarking RBE models, provided a reasonable approximation for low‐energy beams but failed to fully capture the complexity of polyenergetic radiation fields. Conclusions: Secondary fragments can substantially affect the dose‐averaged LET and the RBE, even in proton beams. The dose‐averaged LET, including or not the contributions from secondary fragments, was generally unable to adequately capture RBE variations across different scenarios. A more comprehensive approach, considering microdosimetric distributions, is necessary to accurately describe RBE variations in ion therapy. [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: 185030458 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Impact of nuclear fragmentation and irradiation scenarios on the dose‐averaged LET, the RBE, and their relationship for H, He, C, O, and Ne ions. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Parisi%2C+Alessio%22">Parisi, Alessio</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> parisi.alessio@mayo.edu</i><br /><searchLink fieldCode="AR" term="%22Furutani%2C+Keith+M%2E%22">Furutani, Keith M.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Beltran%2C+Chris+J%2E%22">Beltran, Chris J.</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. May2025, Vol. 52 Issue 5, p3450-3460. 11p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Linear+energy+transfer%22">Linear energy transfer</searchLink><br /><searchLink fieldCode="DE" term="%22Nuclear+fragmentation%22">Nuclear fragmentation</searchLink><br /><searchLink fieldCode="DE" term="%22Irradiation%22">Irradiation</searchLink><br /><searchLink fieldCode="DE" term="%22Hydrogen+ions%22">Hydrogen ions</searchLink><br /><searchLink fieldCode="DE" term="%22Ions%22">Ions</searchLink><br /><searchLink fieldCode="DE" term="%22Microdosimetry%22">Microdosimetry</searchLink><br /><searchLink fieldCode="DE" term="%22Physiological+effects+of+radiation%22">Physiological effects of radiation</searchLink><br /><searchLink fieldCode="DE" term="%22Isotopes%22">Isotopes</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Background: Projectile and target fragmentation are nuclear phenomena that can influence the computation of the linear energy transfer (LET) and the relative biological effectiveness (RBE) in external radiotherapy with accelerated ions. Correlations between these two quantities are routinely established during radiobiological experiments to interpret the results and to develop and calibrate RBE models. Purpose: This study systematically evaluates the impact of secondary fragments and irradiation scenarios on the dose‐averaged LET, the RBE, and their correlation in the case of exposures to clinically relevant ion beams. Methods: 57 600 microdosimetric lineal energy spectra and corresponding LET distributions were simulated with the Monte Carlo code PHITS across different scenarios, including track segment calculations, pristine, and spread‐out Bragg peaks of 1H, 4He, 12C, 16O, and 20Ne ions within water phantoms. The LET distributions were analyzed to calculate the dose‐average LET, both including or excluding the contribution of secondary ions of an element different from the primary beam. Similarly, the lineal energy distributions were processed in conjunction with the Mayo Clinic Florida microdosimetric kinetic model to compute the RBE for two theoretical cell lines (α/β = 2 and 10 Gy in the case of 6 MV x‐rays). Correlations between the RBE and dose‐averaged LET were established by analyzing the simulation results within water phantoms and then compared to the corresponding trends from the track segment calculations. Results: Excluding secondary fragments had a pronounced impact on the dose‐averaged LET and the RBE, particularly in the entrance regions of proton beams and close to the distal edge of heavier ions. The correlations between the RBE and the dose‐averaged LET were not universal, but highly dependent on the irradiation scenario. For proton beams only, the dose‐averaged LET of hydrogen ions served as a practical first‐order descriptor of the RBE. Track segment simulations, commonly used for calibrating and benchmarking RBE models, provided a reasonable approximation for low‐energy beams but failed to fully capture the complexity of polyenergetic radiation fields. Conclusions: Secondary fragments can substantially affect the dose‐averaged LET and the RBE, even in proton beams. The dose‐averaged LET, including or not the contributions from secondary fragments, was generally unable to adequately capture RBE variations across different scenarios. A more comprehensive approach, considering microdosimetric distributions, is necessary to accurately describe RBE variations in ion therapy. [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.17755 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 11 StartPage: 3450 Subjects: – SubjectFull: Linear energy transfer Type: general – SubjectFull: Nuclear fragmentation Type: general – SubjectFull: Irradiation Type: general – SubjectFull: Hydrogen ions Type: general – SubjectFull: Ions Type: general – SubjectFull: Microdosimetry Type: general – SubjectFull: Physiological effects of radiation Type: general – SubjectFull: Isotopes Type: general Titles: – TitleFull: Impact of nuclear fragmentation and irradiation scenarios on the dose‐averaged LET, the RBE, and their relationship for H, He, C, O, and Ne ions. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Parisi, Alessio – PersonEntity: Name: NameFull: Furutani, Keith M. – PersonEntity: Name: NameFull: Beltran, Chris J. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 05 Text: May2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 00942405 Numbering: – Type: volume Value: 52 – Type: issue Value: 5 Titles: – TitleFull: Medical Physics Type: main |
| ResultId | 1 |
