SU-E-T-118: Dose Verification for Accuboost Applicators Using TLD, Ion Chamber and Gafchromic Film Measurements

Chisela, W; Yao, R; Dorbu, G

doi:10.1118/1.4888448

Title: SU-E-T-118: Dose Verification for Accuboost Applicators Using TLD, Ion Chamber and Gafchromic Film Measurements

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Abstract

Purpose: To verify dose delivered with HDR Accuboost applicators using TLD, ion chamber and Gafchromic film measurements and to examine applicator leakage. Methods: A microSelectron HDR unit was used to deliver a dose of 50cGy to the mid-plane of a 62mm thick solid water phantom using dwell times from Monte Carlo pre-calculated nomograms for a 60mm, 70mm Round and 60mm Skin-Dose Optimized (SDO) applicators respectively. GafChromic EBT3+ film was embedded in the phantom midplane horizontally to measure dose distribution. Absolute dose was also measured with TLDs and an ADCL calibrated parallel-plate ion chamber placed in the film plane at field center for each applicator. The film was calibrated using 6MV x-ray beam. TLDs were calibrated in a Cs-137 source at UW-Madison calibration laboratory. Radiation leakage through the tungsten alloy shell was measured with a film wrapped around outside surface of a 60mm Round applicator. Results: Measured maximum doses at field center are consistently lower than predicated by 5.8% for TLD, 8.8% for ion chamber, and 2.6% for EBT3+ film on average, with measurement uncertainties of 2.2%, 0.3%, and 2.9% for TLD, chamber, film respectively. The total standard uncertainties for ion chamber and Gafchromic film measurement are 4.9% and 4.6% respectively[1].more »« less

Authors:

Chisela, W; Yao, R; Dorbu, G ^[1]

Columbus Regional Healthcare, Columbus, GA (United States)

Publication Date:: Sun Jun 01 00:00:00 EDT 2014

OSTI Identifier:: 22339873

Resource Type:: Journal Article

Journal Name:: Medical Physics

Additional Journal Information:: Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405

Country of Publication:: United States

Language:: English

Subject:: 07 ISOTOPES AND RADIATION SOURCES; 60 APPLIED LIFE SCIENCES; CESIUM 137; FILM DOSIMETRY; IONIZATION CHAMBERS; MONTE CARLO METHOD; NOMOGRAMS; PHANTOMS; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; THICKNESS; TUNGSTEN ALLOYS

Citation Formats


                    Chisela, W, Yao, R, and Dorbu, G. SU-E-T-118: Dose Verification for Accuboost Applicators Using TLD, Ion Chamber and Gafchromic Film Measurements.  United States: N. p., 2014. 
        Web.  doi:10.1118/1.4888448.

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                    Chisela, W, Yao, R, & Dorbu, G. SU-E-T-118: Dose Verification for Accuboost Applicators Using TLD, Ion Chamber and Gafchromic Film Measurements.  United States.  https://doi.org/10.1118/1.4888448

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                    Chisela, W, Yao, R, and Dorbu, G. 2014.  
        "SU-E-T-118: Dose Verification for Accuboost Applicators Using TLD, Ion Chamber and Gafchromic Film Measurements".  United States.  https://doi.org/10.1118/1.4888448.

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@article{osti_22339873,

  title        = {SU-E-T-118: Dose Verification for Accuboost Applicators Using TLD, Ion Chamber and Gafchromic Film Measurements},

  author       = {Chisela, W and Yao, R and Dorbu, G},

  abstractNote = {Purpose: To verify dose delivered with HDR Accuboost applicators using TLD, ion chamber and Gafchromic film measurements and to examine applicator leakage. Methods: A microSelectron HDR unit was used to deliver a dose of 50cGy to the mid-plane of a 62mm thick solid water phantom using dwell times from Monte Carlo pre-calculated nomograms for a 60mm, 70mm Round and 60mm Skin-Dose Optimized (SDO) applicators respectively. GafChromic EBT3+ film was embedded in the phantom midplane horizontally to measure dose distribution. Absolute dose was also measured with TLDs and an ADCL calibrated parallel-plate ion chamber placed in the film plane at field center for each applicator. The film was calibrated using 6MV x-ray beam. TLDs were calibrated in a Cs-137 source at UW-Madison calibration laboratory. Radiation leakage through the tungsten alloy shell was measured with a film wrapped around outside surface of a 60mm Round applicator. Results: Measured maximum doses at field center are consistently lower than predicated by 5.8% for TLD, 8.8% for ion chamber, and 2.6% for EBT3+ film on average, with measurement uncertainties of 2.2%, 0.3%, and 2.9% for TLD, chamber, film respectively. The total standard uncertainties for ion chamber and Gafchromic film measurement are 4.9% and 4.6% respectively[1]. The area defined by the applicator aperture was covered by 80% of maximum dose for 62mm compression thickness. When 100cGy is delivered to mid-plane with a 60mm Round applicator, surface dose ranges from 60cGy to a maximum of 145cGy, which occurs at source entrance to the applicator. Conclusion: Measured doses by all three techniques are consistently lower than predicted in our measurements. For a compression thickness of 62 mm, the field size defined by the applicator is only covered by 80% of prescribed dose. Radiation leakage of up to 145cGy was found at the source entrance of applicators.},

  doi          = {10.1118/1.4888448},

  url          = {https://www.osti.gov/biblio/22339873},
  journal      = {Medical Physics},

  issn         = {0094-2405},

  number       = 6,

  volume       = 41,

  place        = {United States},

  year         = {Sun Jun 01 00:00:00 EDT 2014},

  month        = {Sun Jun 01 00:00:00 EDT 2014}

}

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