View in EDS HTML Full Text PDF Full Text

LET measurements in proton and helium‐ion beams of therapeutic energies using a silicon pixel detector towards a tool for quality assurance.

Saved in:
Bibliographic Details
Title: LET measurements in proton and helium‐ion beams of therapeutic energies using a silicon pixel detector towards a tool for quality assurance.
Authors: Hamad, Yasmin1,2,3,4 (AUTHOR) yasmin.hamad@dkfz-heidelberg.de, Sari, Ferisya Kusuma2,5 (AUTHOR), Félix‐Bautista, Renato1,2 (AUTHOR), Martišíková, Mária1,2 (AUTHOR), Mairani, Andrea1,4 (AUTHOR), Gehrke, Tim1,2,6 (AUTHOR)
Source: Medical Physics. Sep2025, Vol. 52 Issue 9, p1-15. 15p.
Subjects: Proton beams, Silicon detectors, Treatment effectiveness, Radiation absorption, Ion beams, Measurement, Quality assurance
Abstract: Background: As advanced treatment plans increasingly include optimizing both dose and linear energy transfer (LET), there is a growing demand for tools to measure LET in clinical settings. Although various detection systems have been investigated in this pursuit, the scarcity of detectors capable of providing per‐ion data for a fast and streamlined verification of LET distributions remains an issue. Silicon pixel detector technology bridges this gap by enabling rapid tracking of single‐ion energy deposition. Purpose: This study proposes a methodology for assessing LET and relative biological effectiveness (RBE) in mixed radiation fields produced by clinical proton and helium ion beams, using a hybrid silicon pixel detector equipped with a Timepix3 chip. Methods: The Timepix3 detector was placed behind PMMA slabs of different thicknesses and exposed to initially monoenergetic proton and helium‐ion beams. The detector featured a 300 µm‐thick silicon sensor operated in partial depletion. Silicon‐based LET spectra were derived from single‐ion deposited energy across the sensor and subsequently converted to water‐equivalent spectra. Track‐ and dose‐averaged LET (LETt and LETd) were calculated from these spectra. LET measurements were used as input to estimate the RBE via the modified microdosimetric kinetic model (mMKM) assuming an (α/β)γ value of 2 Gy. Measurements were compared with simulations performed using the FLUKA Monte Carlo code. Energy deposition spectra, LETt and LETd values were simulated at various depths in PMMA for the radiation fields used, by considering the contribution from the secondary particles generated in the ion interaction processes as well. Results: Energy deposition spectra were validated against Monte Carlo simulations, showing good agreement in both spectral shapes and positions. However, a depth uncertainty of less than 1 mm and other potential differences between measurements and simulations led to deviations, particularly in the distal region of the Bragg curve. Relative differences of LETd between measurements and simulations were within 3% for protons and 10% for helium ions upstream of the Bragg curves. Notably, larger discrepancies were observed in the distal part of the Bragg curve, with maximum relative differences of 7% for protons and 17% for helium ions. Average differences between RBE predictions from measured and simulated LET spectra were within 1% and 6% for protons and helium, respectively. Nevertheless, for both particle types, most measurements agreed with simulations within 1σ experimental uncertainty across the measured depths, with deviations beyond 1σ generally remaining within 3σ. Conclusions: This study demonstrates the performance of silicon pixel detectors with respect to LET measurements and RBE estimation in clinical proton and helium‐ion beams. The streamlined and accessible outline of the proposed methodology supports easy implementation into clinical routines, promising a viable and sound quality assurance tool for particle 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.)
Database: Engineering Source
Full text is not displayed to guests.
FullText Links:
  – Type: pdflink
Text:
  Availability: 1
Header DbId: egs
DbLabel: Engineering Source
An: 187979064
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: LET measurements in proton and helium‐ion beams of therapeutic energies using a silicon pixel detector towards a tool for quality assurance.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Hamad%2C+Yasmin%22">Hamad, Yasmin</searchLink><relatesTo>1,2,3,4</relatesTo> (AUTHOR)<i> yasmin.hamad@dkfz-heidelberg.de</i><br /><searchLink fieldCode="AR" term="%22Sari%2C+Ferisya+Kusuma%22">Sari, Ferisya Kusuma</searchLink><relatesTo>2,5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Félix‐Bautista%2C+Renato%22">Félix‐Bautista, Renato</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Martišíková%2C+Mária%22">Martišíková, Mária</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Mairani%2C+Andrea%22">Mairani, Andrea</searchLink><relatesTo>1,4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Gehrke%2C+Tim%22">Gehrke, Tim</searchLink><relatesTo>1,2,6</relatesTo> (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Sep2025, Vol. 52 Issue 9, p1-15. 15p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Proton+beams%22">Proton beams</searchLink><br /><searchLink fieldCode="DE" term="%22Silicon+detectors%22">Silicon detectors</searchLink><br /><searchLink fieldCode="DE" term="%22Treatment+effectiveness%22">Treatment effectiveness</searchLink><br /><searchLink fieldCode="DE" term="%22Radiation+absorption%22">Radiation absorption</searchLink><br /><searchLink fieldCode="DE" term="%22Ion+beams%22">Ion beams</searchLink><br /><searchLink fieldCode="DE" term="%22Measurement%22">Measurement</searchLink><br /><searchLink fieldCode="DE" term="%22Quality+assurance%22">Quality assurance</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Background: As advanced treatment plans increasingly include optimizing both dose and linear energy transfer (LET), there is a growing demand for tools to measure LET in clinical settings. Although various detection systems have been investigated in this pursuit, the scarcity of detectors capable of providing per‐ion data for a fast and streamlined verification of LET distributions remains an issue. Silicon pixel detector technology bridges this gap by enabling rapid tracking of single‐ion energy deposition. Purpose: This study proposes a methodology for assessing LET and relative biological effectiveness (RBE) in mixed radiation fields produced by clinical proton and helium ion beams, using a hybrid silicon pixel detector equipped with a Timepix3 chip. Methods: The Timepix3 detector was placed behind PMMA slabs of different thicknesses and exposed to initially monoenergetic proton and helium‐ion beams. The detector featured a 300 µm‐thick silicon sensor operated in partial depletion. Silicon‐based LET spectra were derived from single‐ion deposited energy across the sensor and subsequently converted to water‐equivalent spectra. Track‐ and dose‐averaged LET (LETt and LETd) were calculated from these spectra. LET measurements were used as input to estimate the RBE via the modified microdosimetric kinetic model (mMKM) assuming an (α/β)γ value of 2 Gy. Measurements were compared with simulations performed using the FLUKA Monte Carlo code. Energy deposition spectra, LETt and LETd values were simulated at various depths in PMMA for the radiation fields used, by considering the contribution from the secondary particles generated in the ion interaction processes as well. Results: Energy deposition spectra were validated against Monte Carlo simulations, showing good agreement in both spectral shapes and positions. However, a depth uncertainty of less than 1 mm and other potential differences between measurements and simulations led to deviations, particularly in the distal region of the Bragg curve. Relative differences of LETd between measurements and simulations were within 3% for protons and 10% for helium ions upstream of the Bragg curves. Notably, larger discrepancies were observed in the distal part of the Bragg curve, with maximum relative differences of 7% for protons and 17% for helium ions. Average differences between RBE predictions from measured and simulated LET spectra were within 1% and 6% for protons and helium, respectively. Nevertheless, for both particle types, most measurements agreed with simulations within 1σ experimental uncertainty across the measured depths, with deviations beyond 1σ generally remaining within 3σ. Conclusions: This study demonstrates the performance of silicon pixel detectors with respect to LET measurements and RBE estimation in clinical proton and helium‐ion beams. The streamlined and accessible outline of the proposed methodology supports easy implementation into clinical routines, promising a viable and sound quality assurance tool for particle 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.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=187979064
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1002/mp.18085
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 15
        StartPage: 1
    Subjects:
      – SubjectFull: Proton beams
        Type: general
      – SubjectFull: Silicon detectors
        Type: general
      – SubjectFull: Treatment effectiveness
        Type: general
      – SubjectFull: Radiation absorption
        Type: general
      – SubjectFull: Ion beams
        Type: general
      – SubjectFull: Measurement
        Type: general
      – SubjectFull: Quality assurance
        Type: general
    Titles:
      – TitleFull: LET measurements in proton and helium‐ion beams of therapeutic energies using a silicon pixel detector towards a tool for quality assurance.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Hamad, Yasmin
      – PersonEntity:
          Name:
            NameFull: Sari, Ferisya Kusuma
      – PersonEntity:
          Name:
            NameFull: Félix‐Bautista, Renato
      – PersonEntity:
          Name:
            NameFull: Martišíková, Mária
      – PersonEntity:
          Name:
            NameFull: Mairani, Andrea
      – PersonEntity:
          Name:
            NameFull: Gehrke, Tim
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 09
              Text: Sep2025
              Type: published
              Y: 2025
          Identifiers:
            – Type: issn-print
              Value: 00942405
          Numbering:
            – Type: volume
              Value: 52
            – Type: issue
              Value: 9
          Titles:
            – TitleFull: Medical Physics
              Type: main
ResultId 1