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A quality assurance method that utilizes 3D dosimetry and facilitates clinical interpretation.

Publication ,  Journal Article
Oldham, M; Thomas, A; O'Daniel, J; Juang, T; Ibbott, G; Adamovics, J; Kirkpatrick, JP
Published in: Int J Radiat Oncol Biol Phys
October 1, 2012

PURPOSE: To demonstrate a new three-dimensional (3D) quality assurance (QA) method that provides comprehensive dosimetry verification and facilitates evaluation of the clinical significance of QA data acquired in a phantom. Also to apply the method to investigate the dosimetric efficacy of base-of-skull (BOS) intensity-modulated radiotherapy (IMRT) treatment. METHODS AND MATERIALS: Two types of IMRT QA verification plans were created for 6 patients who received BOS IMRT. The first plan enabled conventional 2D planar IMRT QA using the Varian portal dosimetry system. The second plan enabled 3D verification using an anthropomorphic head phantom. In the latter, the 3D dose distribution was measured using the DLOS/Presage dosimetry system (DLOS = Duke Large-field-of-view Optical-CT System, Presage Heuris Pharma, Skillman, NJ), which yielded isotropic 2-mm data throughout the treated volume. In a novel step, measured 3D dose distributions were transformed back to the patient's CT to enable calculation of dose-volume histograms (DVH) and dose overlays. Measured and planned patient DVHs were compared to investigate clinical significance. RESULTS: Close agreement between measured and calculated dose distributions was observed for all 6 cases. For gamma criteria of 3%, 2 mm, the mean passing rate for portal dosimetry was 96.8% (range, 92.0%-98.9%), compared to 94.9% (range, 90.1%-98.9%) for 3D. There was no clear correlation between 2D and 3D passing rates. Planned and measured dose distributions were evaluated on the patient's anatomy, using DVH and dose overlays. Minor deviations were detected, and the clinical significance of these are presented and discussed. CONCLUSIONS: Two advantages accrue to the methods presented here. First, treatment accuracy is evaluated throughout the whole treated volume, yielding comprehensive verification. Second, the clinical significance of any deviations can be assessed through the generation of DVH curves and dose overlays on the patient's anatomy. The latter step represents an important development that advances the clinical relevance of complex treatment QA.

Duke Scholars

Published In

Int J Radiat Oncol Biol Phys

DOI

EISSN

1879-355X

Publication Date

October 1, 2012

Volume

84

Issue

2

Start / End Page

540 / 546

Location

United States

Related Subject Headings

  • Skull Base Neoplasms
  • Radiotherapy, Intensity-Modulated
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Radiography
  • Quality Assurance, Health Care
  • Phantoms, Imaging
  • Organs at Risk
  • Oncology & Carcinogenesis
 

Citation

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ICMJE
MLA
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Oldham, M., Thomas, A., O’Daniel, J., Juang, T., Ibbott, G., Adamovics, J., & Kirkpatrick, J. P. (2012). A quality assurance method that utilizes 3D dosimetry and facilitates clinical interpretation. Int J Radiat Oncol Biol Phys, 84(2), 540–546. https://doi.org/10.1016/j.ijrobp.2011.12.015
Oldham, Mark, Andrew Thomas, Jennifer O’Daniel, Titania Juang, Geoffrey Ibbott, John Adamovics, and John P. Kirkpatrick. “A quality assurance method that utilizes 3D dosimetry and facilitates clinical interpretation.Int J Radiat Oncol Biol Phys 84, no. 2 (October 1, 2012): 540–46. https://doi.org/10.1016/j.ijrobp.2011.12.015.
Oldham M, Thomas A, O’Daniel J, Juang T, Ibbott G, Adamovics J, et al. A quality assurance method that utilizes 3D dosimetry and facilitates clinical interpretation. Int J Radiat Oncol Biol Phys. 2012 Oct 1;84(2):540–6.
Oldham, Mark, et al. “A quality assurance method that utilizes 3D dosimetry and facilitates clinical interpretation.Int J Radiat Oncol Biol Phys, vol. 84, no. 2, Oct. 2012, pp. 540–46. Pubmed, doi:10.1016/j.ijrobp.2011.12.015.
Oldham M, Thomas A, O’Daniel J, Juang T, Ibbott G, Adamovics J, Kirkpatrick JP. A quality assurance method that utilizes 3D dosimetry and facilitates clinical interpretation. Int J Radiat Oncol Biol Phys. 2012 Oct 1;84(2):540–546.
Journal cover image

Published In

Int J Radiat Oncol Biol Phys

DOI

EISSN

1879-355X

Publication Date

October 1, 2012

Volume

84

Issue

2

Start / End Page

540 / 546

Location

United States

Related Subject Headings

  • Skull Base Neoplasms
  • Radiotherapy, Intensity-Modulated
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Radiography
  • Quality Assurance, Health Care
  • Phantoms, Imaging
  • Organs at Risk
  • Oncology & Carcinogenesis