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Volumetric-modulated arc therapy: effective and efficient end-to-end patient-specific quality assurance.

Publication ,  Journal Article
O'Daniel, J; Das, S; Wu, QJ; Yin, F-F
Published in: Int J Radiat Oncol Biol Phys
April 1, 2012

PURPOSE: To explore an effective and efficient end-to-end patient-specific quality-assurance (QA) protocol for volumetric modulated arc radiotherapy (VMAT) and to evaluate the suitability of a stationary radiotherapy QA device (two-dimensional [2D] ion chamber array) for VMAT QA. METHODS AND MATERIALS: Three methods were used to analyze 39 VMAT treatment plans for brain, spine, and prostate: ion chamber (one-dimensional absolute, n = 39), film (2D relative, coronal/sagittal, n = 8), and 2D ion chamber array (ICA, 2D absolute, coronal/sagittal, n = 39) measurements. All measurements were compared with the treatment planning system dose calculation either via gamma analysis (3%, 3- to 4-mm distance-to-agreement criteria) or absolute point dose comparison. The film and ion chamber results were similarly compared with the ICA measurements. RESULTS: Absolute point dose measurements agreed well with treatment planning system computed doses (ion chamber: median deviation, 1.2%, range, -0.6% to 3.3%; ICA: median deviation, 0.6%, range, -1.8% to 2.9%). The relative 2D dose measurements also showed good agreement with computed doses (>93% of pixels in all films passing gamma, >90% of pixels in all ICA measurements passing gamma). The ICA relative dose results were highly similar to those of film (>90% of pixels passing gamma). The coronal and sagittal ICA measurements were statistically indistinguishable by the paired t test with a hypothesized mean difference of 0.1%. The ion chamber and ICA absolute dose measurements showed a similar trend but had disparities of 2-3% in 18% of plans. CONCLUSIONS: After validating the new VMAT implementation with ion chamber, film, and ICA, we were able to maintain an effective yet efficient patient-specific VMAT QA protocol by reducing from five (ion chamber, film, and ICA) to two measurements (ion chamber and single ICA) per plan. The ICA (Matrixx®, IBA Dosimetry) was validated for VMAT QA, but ion chamber measurements are recommended for absolute dose comparison until future developments correct the ICA angular dependence.

Duke Scholars

Published In

Int J Radiat Oncol Biol Phys

DOI

EISSN

1879-355X

Publication Date

April 1, 2012

Volume

82

Issue

5

Start / End Page

1567 / 1574

Location

United States

Related Subject Headings

  • Spinal Neoplasms
  • Radiotherapy, Intensity-Modulated
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Quality Control
  • Quality Assurance, Health Care
  • Prostatic Neoplasms
  • Oncology & Carcinogenesis
  • Male
 

Citation

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O’Daniel, J., Das, S., Wu, Q. J., & Yin, F.-F. (2012). Volumetric-modulated arc therapy: effective and efficient end-to-end patient-specific quality assurance. Int J Radiat Oncol Biol Phys, 82(5), 1567–1574. https://doi.org/10.1016/j.ijrobp.2011.01.018
O’Daniel, Jennifer, Shiva Das, Q Jackie Wu, and Fang-Fang Yin. “Volumetric-modulated arc therapy: effective and efficient end-to-end patient-specific quality assurance.Int J Radiat Oncol Biol Phys 82, no. 5 (April 1, 2012): 1567–74. https://doi.org/10.1016/j.ijrobp.2011.01.018.
O’Daniel J, Das S, Wu QJ, Yin F-F. Volumetric-modulated arc therapy: effective and efficient end-to-end patient-specific quality assurance. Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1567–74.
O’Daniel, Jennifer, et al. “Volumetric-modulated arc therapy: effective and efficient end-to-end patient-specific quality assurance.Int J Radiat Oncol Biol Phys, vol. 82, no. 5, Apr. 2012, pp. 1567–74. Pubmed, doi:10.1016/j.ijrobp.2011.01.018.
O’Daniel J, Das S, Wu QJ, Yin F-F. Volumetric-modulated arc therapy: effective and efficient end-to-end patient-specific quality assurance. Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1567–1574.
Journal cover image

Published In

Int J Radiat Oncol Biol Phys

DOI

EISSN

1879-355X

Publication Date

April 1, 2012

Volume

82

Issue

5

Start / End Page

1567 / 1574

Location

United States

Related Subject Headings

  • Spinal Neoplasms
  • Radiotherapy, Intensity-Modulated
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Quality Control
  • Quality Assurance, Health Care
  • Prostatic Neoplasms
  • Oncology & Carcinogenesis
  • Male