Sum signal dosimetry: A new approach for high dose quality assurance with Gafchromic EBT3

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Abstract

© 2017 American Association of Physicists in Medicine. Gafchromic EBT3 film dosimetry in radiosurgery (RS) and hypofractionated radiotherapy (HRT) is complicated by the limited film accuracy at high fractional doses. The aim of this study is to develop and evaluate sum signal (SS) film dosimetry to increase dose resolution at high fractional doses, thus allowing for use of EBT3 for dose distribution verification of RS/HRT treatments. To characterize EBT3 dose-response, a calibration was performed in the dose range 0.44-26.43 Gy. Red (RC) and green (GC) channel net optical densities were linearly added to produce the SS. Dose resolution and overall accuracy of the dosimetric protocol were estimated and compared for SS,RC, and GC. A homemade Matlab software was developed to compare, in terms of gamma analysis, dose distributions delivered by a Cyberknife on EBT3 films to dose distributions calculated by the treatment planning system. The new SS and conventional single channel (SC) methods were compared, using 3%/1 and 4%/1 mm acceptance criteria, for 20 patient plans. Our analysis shows that the SS dose-response curve is characterized by a steeper trend in comparison with SC, with SS providing a higher dose resolution in the whole dose range investigated. Gamma analysis confirms that the percentage of points satisfying the agreement criteria is significantly higher for SS compared to SC: 95.03% vs. 88.41% (P = 0.014) for 3%/1 mm acceptance criteria and 97.24% vs. 93.58% (P = 0.048) for 4%/1 mm acceptance criteria. This study demonstrates that the SS approach is a new and effective method to improve dosimetric accuracy in the framework of the RS-HRT patient-specific quality assurance protocol.
Original languageEnglish
Pages (from-to)181-190
Number of pages10
JournalJournal of Applied Clinical Medical Physics
Volume18
Issue number2
DOIs
Publication statusPublished - Mar 1 2017

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Radiosurgery
assurance
Quality assurance
Film Dosimetry
Dosimetry
dosimeters
Radiotherapy
dosage
Calibration
Software
Medicine
acceptability
Network protocols
radiation therapy
Density (optical)
Therapeutics
Planning
optical density
medicine
planning

Keywords

  • Dosimetric verification
  • Gafchromic EBT3
  • Radiosurgery/hypofractioned radiotherapy

Cite this

@article{16e26759155645688fe3b8e0e6ae4cca,
title = "Sum signal dosimetry: A new approach for high dose quality assurance with Gafchromic EBT3",
abstract = "{\circledC} 2017 American Association of Physicists in Medicine. Gafchromic EBT3 film dosimetry in radiosurgery (RS) and hypofractionated radiotherapy (HRT) is complicated by the limited film accuracy at high fractional doses. The aim of this study is to develop and evaluate sum signal (SS) film dosimetry to increase dose resolution at high fractional doses, thus allowing for use of EBT3 for dose distribution verification of RS/HRT treatments. To characterize EBT3 dose-response, a calibration was performed in the dose range 0.44-26.43 Gy. Red (RC) and green (GC) channel net optical densities were linearly added to produce the SS. Dose resolution and overall accuracy of the dosimetric protocol were estimated and compared for SS,RC, and GC. A homemade Matlab software was developed to compare, in terms of gamma analysis, dose distributions delivered by a Cyberknife on EBT3 films to dose distributions calculated by the treatment planning system. The new SS and conventional single channel (SC) methods were compared, using 3{\%}/1 and 4{\%}/1 mm acceptance criteria, for 20 patient plans. Our analysis shows that the SS dose-response curve is characterized by a steeper trend in comparison with SC, with SS providing a higher dose resolution in the whole dose range investigated. Gamma analysis confirms that the percentage of points satisfying the agreement criteria is significantly higher for SS compared to SC: 95.03{\%} vs. 88.41{\%} (P = 0.014) for 3{\%}/1 mm acceptance criteria and 97.24{\%} vs. 93.58{\%} (P = 0.048) for 4{\%}/1 mm acceptance criteria. This study demonstrates that the SS approach is a new and effective method to improve dosimetric accuracy in the framework of the RS-HRT patient-specific quality assurance protocol.",
keywords = "Dosimetric verification, Gafchromic EBT3, Radiosurgery/hypofractioned radiotherapy",
author = "Davide Cusumano and Davide Cusumano and Fumagalli, {Maria Luisa} and Francesco Ghielmetti and Linda Rossi and Giuliano Grossi and Raffaella Lanzarotti and Laura Fariselli and {De Martin}, Elena",
year = "2017",
month = "3",
day = "1",
doi = "10.1002/acm2.12045",
language = "English",
volume = "18",
pages = "181--190",
journal = "Journal of Applied Clinical Medical Physics",
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T1 - Sum signal dosimetry: A new approach for high dose quality assurance with Gafchromic EBT3

AU - Cusumano, Davide

AU - Cusumano, Davide

AU - Fumagalli, Maria Luisa

AU - Ghielmetti, Francesco

AU - Rossi, Linda

AU - Grossi, Giuliano

AU - Lanzarotti, Raffaella

AU - Fariselli, Laura

AU - De Martin, Elena

PY - 2017/3/1

Y1 - 2017/3/1

N2 - © 2017 American Association of Physicists in Medicine. Gafchromic EBT3 film dosimetry in radiosurgery (RS) and hypofractionated radiotherapy (HRT) is complicated by the limited film accuracy at high fractional doses. The aim of this study is to develop and evaluate sum signal (SS) film dosimetry to increase dose resolution at high fractional doses, thus allowing for use of EBT3 for dose distribution verification of RS/HRT treatments. To characterize EBT3 dose-response, a calibration was performed in the dose range 0.44-26.43 Gy. Red (RC) and green (GC) channel net optical densities were linearly added to produce the SS. Dose resolution and overall accuracy of the dosimetric protocol were estimated and compared for SS,RC, and GC. A homemade Matlab software was developed to compare, in terms of gamma analysis, dose distributions delivered by a Cyberknife on EBT3 films to dose distributions calculated by the treatment planning system. The new SS and conventional single channel (SC) methods were compared, using 3%/1 and 4%/1 mm acceptance criteria, for 20 patient plans. Our analysis shows that the SS dose-response curve is characterized by a steeper trend in comparison with SC, with SS providing a higher dose resolution in the whole dose range investigated. Gamma analysis confirms that the percentage of points satisfying the agreement criteria is significantly higher for SS compared to SC: 95.03% vs. 88.41% (P = 0.014) for 3%/1 mm acceptance criteria and 97.24% vs. 93.58% (P = 0.048) for 4%/1 mm acceptance criteria. This study demonstrates that the SS approach is a new and effective method to improve dosimetric accuracy in the framework of the RS-HRT patient-specific quality assurance protocol.

AB - © 2017 American Association of Physicists in Medicine. Gafchromic EBT3 film dosimetry in radiosurgery (RS) and hypofractionated radiotherapy (HRT) is complicated by the limited film accuracy at high fractional doses. The aim of this study is to develop and evaluate sum signal (SS) film dosimetry to increase dose resolution at high fractional doses, thus allowing for use of EBT3 for dose distribution verification of RS/HRT treatments. To characterize EBT3 dose-response, a calibration was performed in the dose range 0.44-26.43 Gy. Red (RC) and green (GC) channel net optical densities were linearly added to produce the SS. Dose resolution and overall accuracy of the dosimetric protocol were estimated and compared for SS,RC, and GC. A homemade Matlab software was developed to compare, in terms of gamma analysis, dose distributions delivered by a Cyberknife on EBT3 films to dose distributions calculated by the treatment planning system. The new SS and conventional single channel (SC) methods were compared, using 3%/1 and 4%/1 mm acceptance criteria, for 20 patient plans. Our analysis shows that the SS dose-response curve is characterized by a steeper trend in comparison with SC, with SS providing a higher dose resolution in the whole dose range investigated. Gamma analysis confirms that the percentage of points satisfying the agreement criteria is significantly higher for SS compared to SC: 95.03% vs. 88.41% (P = 0.014) for 3%/1 mm acceptance criteria and 97.24% vs. 93.58% (P = 0.048) for 4%/1 mm acceptance criteria. This study demonstrates that the SS approach is a new and effective method to improve dosimetric accuracy in the framework of the RS-HRT patient-specific quality assurance protocol.

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KW - Gafchromic EBT3

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