Dosimetry in MRgPT: Impact of magnetic fields on TLD dose response during proton irradiation.
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| Title: | Dosimetry in MRgPT: Impact of magnetic fields on TLD dose response during proton irradiation. |
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| Authors: | Fuchs, Hermann1 (AUTHOR) hermann.fuchs@meduniwien.ac.at, Palmans, Hugo2,3 (AUTHOR), Heilemann, Gerd1 (AUTHOR), Zuschlag, Dominik1 (AUTHOR), Georg, Dietmar1 (AUTHOR), Kuess, Peter1 (AUTHOR) |
| Source: | Medical Physics. Jan2025, Vol. 52 Issue 1, p633-639. 7p. |
| Subjects: | Magnetic flux density, Thermoluminescence dosimetry, Magnetotherapy, Proton therapy, Magnetic fields, Proton beams |
| Abstract: | Background: Proton beam therapy, when integrated with MRI guidance, presents complex dosimetric challenges due to interactions with magnetic fields. Prior research has emphasized the nuanced impact of magnetic fields on dosimetry. For thermoluminescent dosimeters (TLDs) the electron‐return effect, alongside small air cavities surrounding the pellets, can lead to nonuniform dose distributions. Future MR‐guided proton therapy will require reliable methods for end‐to‐end tests and dosimetric audits, which so far are often performed using TLDs equipped with phantoms. This implicates the necessity of accounting for these interactions. Purpose: This study investigates the influence of magnetic fields on TLDs at two proton energies, using magnetic field strengths of 0, 0.25, and 1T$1 \,\mathrm{T}$, aiming to clarify their impact on dose measurement accuracy. Methods: The study was conducted at a synchrotron‐based ion beam therapy beam line, enhanced by a resistive dipole magnet for creating magnetic fields up to 1T$1 \,\mathrm{T}$ to simulate MR‐guided proton therapy. Individual correction factors were applied for TLD measurements. The impact of air gaps on the TLD signal was evaluated using three dedicated TLD holders with air gaps of 0.1, 0.25, and 0.5 mm surrounding the TLD pellets using the highest available proton energy of 252.7MeV$252.7 \,\mathrm{M}\mathrm{e\mathrm{V}}$. Additionally, the influence of the magnetic field strength on the TLD response was evaluated for two proton energies of 97.4MeV$97.4 \,\mathrm{M}\mathrm{e\mathrm{V}}$ and 252.7MeV$252.7 \,\mathrm{M}\mathrm{e\mathrm{V}}$. Results: The study found no statistically significant variation in TLD dose response attributable to changes in the air gap or the presence of magnetic fields. A power analysis indicated an upper limit on a potential change in dose‐response as small as 1.5%. Conclusions: The findings suggested that the impact of air gap variations and magnetic field strengths on the TLD response was below the detection threshold of TLD sensitivity. This emphasizes the suitability of TLDs for dose measurement in MR‐guided proton therapy, indicating that additional correction factors may not be necessary despite the influence of magnetic fields. [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: 182048843 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Dosimetry in MRgPT: Impact of magnetic fields on TLD dose response during proton irradiation. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Fuchs%2C+Hermann%22">Fuchs, Hermann</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> hermann.fuchs@meduniwien.ac.at</i><br /><searchLink fieldCode="AR" term="%22Palmans%2C+Hugo%22">Palmans, Hugo</searchLink><relatesTo>2,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Heilemann%2C+Gerd%22">Heilemann, Gerd</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Zuschlag%2C+Dominik%22">Zuschlag, Dominik</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Georg%2C+Dietmar%22">Georg, Dietmar</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Kuess%2C+Peter%22">Kuess, Peter</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Jan2025, Vol. 52 Issue 1, p633-639. 7p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Magnetic+flux+density%22">Magnetic flux density</searchLink><br /><searchLink fieldCode="DE" term="%22Thermoluminescence+dosimetry%22">Thermoluminescence dosimetry</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetotherapy%22">Magnetotherapy</searchLink><br /><searchLink fieldCode="DE" term="%22Proton+therapy%22">Proton therapy</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetic+fields%22">Magnetic fields</searchLink><br /><searchLink fieldCode="DE" term="%22Proton+beams%22">Proton beams</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Background: Proton beam therapy, when integrated with MRI guidance, presents complex dosimetric challenges due to interactions with magnetic fields. Prior research has emphasized the nuanced impact of magnetic fields on dosimetry. For thermoluminescent dosimeters (TLDs) the electron‐return effect, alongside small air cavities surrounding the pellets, can lead to nonuniform dose distributions. Future MR‐guided proton therapy will require reliable methods for end‐to‐end tests and dosimetric audits, which so far are often performed using TLDs equipped with phantoms. This implicates the necessity of accounting for these interactions. Purpose: This study investigates the influence of magnetic fields on TLDs at two proton energies, using magnetic field strengths of 0, 0.25, and 1T$1 \,\mathrm{T}$, aiming to clarify their impact on dose measurement accuracy. Methods: The study was conducted at a synchrotron‐based ion beam therapy beam line, enhanced by a resistive dipole magnet for creating magnetic fields up to 1T$1 \,\mathrm{T}$ to simulate MR‐guided proton therapy. Individual correction factors were applied for TLD measurements. The impact of air gaps on the TLD signal was evaluated using three dedicated TLD holders with air gaps of 0.1, 0.25, and 0.5 mm surrounding the TLD pellets using the highest available proton energy of 252.7MeV$252.7 \,\mathrm{M}\mathrm{e\mathrm{V}}$. Additionally, the influence of the magnetic field strength on the TLD response was evaluated for two proton energies of 97.4MeV$97.4 \,\mathrm{M}\mathrm{e\mathrm{V}}$ and 252.7MeV$252.7 \,\mathrm{M}\mathrm{e\mathrm{V}}$. Results: The study found no statistically significant variation in TLD dose response attributable to changes in the air gap or the presence of magnetic fields. A power analysis indicated an upper limit on a potential change in dose‐response as small as 1.5%. Conclusions: The findings suggested that the impact of air gap variations and magnetic field strengths on the TLD response was below the detection threshold of TLD sensitivity. This emphasizes the suitability of TLDs for dose measurement in MR‐guided proton therapy, indicating that additional correction factors may not be necessary despite the influence of magnetic fields. [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.17454 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 7 StartPage: 633 Subjects: – SubjectFull: Magnetic flux density Type: general – SubjectFull: Thermoluminescence dosimetry Type: general – SubjectFull: Magnetotherapy Type: general – SubjectFull: Proton therapy Type: general – SubjectFull: Magnetic fields Type: general – SubjectFull: Proton beams Type: general Titles: – TitleFull: Dosimetry in MRgPT: Impact of magnetic fields on TLD dose response during proton irradiation. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Fuchs, Hermann – PersonEntity: Name: NameFull: Palmans, Hugo – PersonEntity: Name: NameFull: Heilemann, Gerd – PersonEntity: Name: NameFull: Zuschlag, Dominik – PersonEntity: Name: NameFull: Georg, Dietmar – PersonEntity: Name: NameFull: Kuess, Peter IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 01 Text: Jan2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 00942405 Numbering: – Type: volume Value: 52 – Type: issue Value: 1 Titles: – TitleFull: Medical Physics Type: main |
| ResultId | 1 |
