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Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System.

Publication ,  Journal Article
Rankine, LJ; Mein, S; Cai, B; Curcuru, A; Juang, T; Miles, D; Mutic, S; Wang, Y; Oldham, M; Li, HH
Published in: Int J Radiat Oncol Biol Phys
April 1, 2017

PURPOSE: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. METHODS AND MATERIALS: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data. Preliminary tests ("AP" and "3D-Bands") were delivered to 9.5-cm usable diameter cylindrical PRESAGE dosimeters to validate the treatment planning system (TPS) for nonmodulated deliveries; assess the sensitivity, uniformity, and rotational symmetry of the PRESAGE dosimeters; and test the robustness of the remote dosimetry protocol. Following this, 4 clinical MRgIMRT plans ("MultiTarget," "Prostate," "Head/Neck," and "C-Shape") were measured using 13-cm usable diameter PRESAGE dosimeters. For all plans, 3D-γ (3% or 3 mm global, 10% threshold) passing rates were calculated and 3D-γ maps were examined. Point doses were measured with an IBA-CC01 ionization chamber for validation of absolute dose. Finally, by use of an in-house-developed, GPU-accelerated Monte Carlo algorithm (gPENELOPE), we independently calculated dose for all 6 Task Group 119 plans and compared against the TPS. RESULTS: For PRESAGE measurements, 3D-γ analysis yielded passing rates of 98.7%, 99.2%, 98.5%, 98.0%, 99.2%, and 90.7% for AP, 3D-Bands, MultiTarget, Prostate, Head/Neck, and C-Shape, respectively. Ion chamber measurements were within an average of 0.5% (±1.1%) from the TPS dose. Monte Carlo calculations demonstrated good agreement with the TPS, with a mean 3D-γ passing rate of 98.5% ± 1.9% using a stricter 2%/2-mm criterion. CONCLUSIONS: We have validated the dosimetric accuracy of a commercial MRgIMRT system using high-resolution 3D techniques. We have demonstrated for the first time that hybrid 3D remote dosimetry is a comprehensive and feasible approach to commissioning MRgIMRT. This may provide better sensitivity in error detection compared with standard 2-dimensional measurements and could be used when implementing complex new magnetic resonance guided radiation therapy technologies.

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Published In

Int J Radiat Oncol Biol Phys

DOI

EISSN

1879-355X

Publication Date

April 1, 2017

Volume

97

Issue

5

Start / End Page

1095 / 1104

Location

United States

Related Subject Headings

  • Sensitivity and Specificity
  • Scattering, Radiation
  • Reproducibility of Results
  • Radiotherapy, Image-Guided
  • Radiotherapy, Conformal
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Oncology & Carcinogenesis
  • Neoplasms
 

Citation

APA
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ICMJE
MLA
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Rankine, L. J., Mein, S., Cai, B., Curcuru, A., Juang, T., Miles, D., … Li, H. H. (2017). Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System. Int J Radiat Oncol Biol Phys, 97(5), 1095–1104. https://doi.org/10.1016/j.ijrobp.2017.01.223
Rankine, Leith J., Stewart Mein, Bin Cai, Austen Curcuru, Titania Juang, Devin Miles, Sasa Mutic, Yuhe Wang, Mark Oldham, and H Harold Li. “Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System.Int J Radiat Oncol Biol Phys 97, no. 5 (April 1, 2017): 1095–1104. https://doi.org/10.1016/j.ijrobp.2017.01.223.
Rankine LJ, Mein S, Cai B, Curcuru A, Juang T, Miles D, et al. Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System. Int J Radiat Oncol Biol Phys. 2017 Apr 1;97(5):1095–104.
Rankine, Leith J., et al. “Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System.Int J Radiat Oncol Biol Phys, vol. 97, no. 5, Apr. 2017, pp. 1095–104. Pubmed, doi:10.1016/j.ijrobp.2017.01.223.
Rankine LJ, Mein S, Cai B, Curcuru A, Juang T, Miles D, Mutic S, Wang Y, Oldham M, Li HH. Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System. Int J Radiat Oncol Biol Phys. 2017 Apr 1;97(5):1095–1104.
Journal cover image

Published In

Int J Radiat Oncol Biol Phys

DOI

EISSN

1879-355X

Publication Date

April 1, 2017

Volume

97

Issue

5

Start / End Page

1095 / 1104

Location

United States

Related Subject Headings

  • Sensitivity and Specificity
  • Scattering, Radiation
  • Reproducibility of Results
  • Radiotherapy, Image-Guided
  • Radiotherapy, Conformal
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Oncology & Carcinogenesis
  • Neoplasms