Clinical reference dosimetry for the 0.5 T inline rotating biplanar Linac‐MR.
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| Title: | Clinical reference dosimetry for the 0.5 T inline rotating biplanar Linac‐MR. |
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| Authors: | Yip, Eugene1,2 (AUTHOR) eyip@ualberta.ca, Tari, Shima Y1,2 (AUTHOR), Reynolds, Michael W2,3 (AUTHOR), Sinn, David2,4 (AUTHOR), Murray, Brad R5 (AUTHOR), Fallone, B Gino1,2,5 (AUTHOR), Oliver, Patricia AK1,2,6 (AUTHOR) |
| Source: | Medical Physics. Apr2024, Vol. 51 Issue 4, p2933-2940. 8p. |
| Subjects: | Dosimeters, Radiation dosimetry, Ionization chambers, Magnetic field effects, Magnetic fields, Correction factors |
| Abstract: | Background: The world's first clinical 0.5 T inline rotating biplanar Linac‐MR system is commissioned for clinical use. For reference dosimetry, unique features to device, including an SAD = 120 cm, bore clearance of 60 cm × 110 cm, as well as 0.5 T inline magnetic field, provide some challenges to applying a standard dosimetry protocol (i.e., TG‐51). Purpose: In this work, we propose a simple and practical clinical reference dosimetry protocol for the 0.5T biplanar Linac‐MR and validated its results. Methods: Our dosimetry protocol for this system is as follows: tissue phantom ratios at 20 and 10 cm are first measured and converted into %dd10x beam quality specifier using equations provided and Kalach and Rogers. The converted %dd10x is used to determine the ion chamber correction factor, using the equations in the TG‐51 addendum for the Exradin A12 farmer chamber used, which is cross‐calibrated with one calibrated at a standards laboratory. For a 0.5 T parallel field, magnetic field effect on chamber response is assumed to have no effect and is not explicitly corrected for. Once the ion chamber correction factor for a non‐standard SAD (kQ,msr) is determined, TG‐51 is performed to obtain dose at a depth of 10 cm at SAD = 120 cm. The dosimetry protocol is repeated with the magnetic field ramped down. To validate our dosimetry protocol, Monte Carlo (EGSnrc) simulations are performed to confirm the determined kQ,msr values. MC Simulations and magnetic Field On versus Field Off measurements are performed to confirm that the magnetic field has no effect. To validate our overall dosimetry protocol, external dose audits, based on optical simulated luminescent dosimeters, thermal luminescent dosimeters, and alanine dosimeters are performed on the 0.5 T Linac‐MR system. Results: Our EGSnrc results confirm our protocol‐determined kQ,msr values, as well as our assumptions about magnetic field effects (kB = 1) within statistical uncertainty for the A‐12 chamber. Our external dosimetry procedures also validated our overall dosimetry protocol for the 0.5 T biplanar Linac‐MR hybrid. Ramping down the magnetic field has resulted in a dosimetric difference of 0.1%, well within experimental uncertainty. Conclusion: With the 0.5 T parallel magnetic field having minimal effect on the ion chamber response, a TPR20,10 approach to determine beam quality provides an accurate method to perform clinical dosimetry for the 0.5 T biplanar Linac‐MR. [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 |
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| Header | DbId: egs DbLabel: Engineering Source An: 176451125 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Clinical reference dosimetry for the 0.5 T inline rotating biplanar Linac‐MR. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Yip%2C+Eugene%22">Yip, Eugene</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> eyip@ualberta.ca</i><br /><searchLink fieldCode="AR" term="%22Tari%2C+Shima+Y%22">Tari, Shima Y</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Reynolds%2C+Michael+W%22">Reynolds, Michael W</searchLink><relatesTo>2,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Sinn%2C+David%22">Sinn, David</searchLink><relatesTo>2,4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Murray%2C+Brad+R%22">Murray, Brad R</searchLink><relatesTo>5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Fallone%2C+B+Gino%22">Fallone, B Gino</searchLink><relatesTo>1,2,5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Oliver%2C+Patricia+AK%22">Oliver, Patricia AK</searchLink><relatesTo>1,2,6</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Apr2024, Vol. 51 Issue 4, p2933-2940. 8p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Dosimeters%22">Dosimeters</searchLink><br /><searchLink fieldCode="DE" term="%22Radiation+dosimetry%22">Radiation dosimetry</searchLink><br /><searchLink fieldCode="DE" term="%22Ionization+chambers%22">Ionization chambers</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetic+field+effects%22">Magnetic field effects</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetic+fields%22">Magnetic fields</searchLink><br /><searchLink fieldCode="DE" term="%22Correction+factors%22">Correction factors</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Background: The world's first clinical 0.5 T inline rotating biplanar Linac‐MR system is commissioned for clinical use. For reference dosimetry, unique features to device, including an SAD = 120 cm, bore clearance of 60 cm × 110 cm, as well as 0.5 T inline magnetic field, provide some challenges to applying a standard dosimetry protocol (i.e., TG‐51). Purpose: In this work, we propose a simple and practical clinical reference dosimetry protocol for the 0.5T biplanar Linac‐MR and validated its results. Methods: Our dosimetry protocol for this system is as follows: tissue phantom ratios at 20 and 10 cm are first measured and converted into %dd10x beam quality specifier using equations provided and Kalach and Rogers. The converted %dd10x is used to determine the ion chamber correction factor, using the equations in the TG‐51 addendum for the Exradin A12 farmer chamber used, which is cross‐calibrated with one calibrated at a standards laboratory. For a 0.5 T parallel field, magnetic field effect on chamber response is assumed to have no effect and is not explicitly corrected for. Once the ion chamber correction factor for a non‐standard SAD (kQ,msr) is determined, TG‐51 is performed to obtain dose at a depth of 10 cm at SAD = 120 cm. The dosimetry protocol is repeated with the magnetic field ramped down. To validate our dosimetry protocol, Monte Carlo (EGSnrc) simulations are performed to confirm the determined kQ,msr values. MC Simulations and magnetic Field On versus Field Off measurements are performed to confirm that the magnetic field has no effect. To validate our overall dosimetry protocol, external dose audits, based on optical simulated luminescent dosimeters, thermal luminescent dosimeters, and alanine dosimeters are performed on the 0.5 T Linac‐MR system. Results: Our EGSnrc results confirm our protocol‐determined kQ,msr values, as well as our assumptions about magnetic field effects (kB = 1) within statistical uncertainty for the A‐12 chamber. Our external dosimetry procedures also validated our overall dosimetry protocol for the 0.5 T biplanar Linac‐MR hybrid. Ramping down the magnetic field has resulted in a dosimetric difference of 0.1%, well within experimental uncertainty. Conclusion: With the 0.5 T parallel magnetic field having minimal effect on the ion chamber response, a TPR20,10 approach to determine beam quality provides an accurate method to perform clinical dosimetry for the 0.5 T biplanar Linac‐MR. [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.16951 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 8 StartPage: 2933 Subjects: – SubjectFull: Dosimeters Type: general – SubjectFull: Radiation dosimetry Type: general – SubjectFull: Ionization chambers Type: general – SubjectFull: Magnetic field effects Type: general – SubjectFull: Magnetic fields Type: general – SubjectFull: Correction factors Type: general Titles: – TitleFull: Clinical reference dosimetry for the 0.5 T inline rotating biplanar Linac‐MR. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Yip, Eugene – PersonEntity: Name: NameFull: Tari, Shima Y – PersonEntity: Name: NameFull: Reynolds, Michael W – PersonEntity: Name: NameFull: Sinn, David – PersonEntity: Name: NameFull: Murray, Brad R – PersonEntity: Name: NameFull: Fallone, B Gino – PersonEntity: Name: NameFull: Oliver, Patricia AK IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 04 Text: Apr2024 Type: published Y: 2024 Identifiers: – Type: issn-print Value: 00942405 Numbering: – Type: volume Value: 51 – Type: issue Value: 4 Titles: – TitleFull: Medical Physics Type: main |
| ResultId | 1 |
