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Evaluation of a 2D diode array for IMRT quality assurance.

Publication ,  Journal Article
Létourneau, D; Gulam, M; Yan, D; Oldham, M; Wong, JW
Published in: Radiother Oncol
February 2004

BACKGROUND AND PURPOSE: The QA of intensity modulated radiotherapy (IMRT) dosimetry is a laborious task. The goal of this work is to evaluate the dosimetric characteristics of a new 2D diode array (MapCheck from Sun Nuclear Corporation, Melbourne, Florida) and assess the role it can play in routine IMRT QA. MATERIAL AND METHODS: Fundamental properties of the MapCheck such as reproducibility, linearity and temperature dependence are studied for high-energy photon beams. The accuracy of the correction for difference of diode sensitivity is also assessed. The diode array is benchmarked against film and ion chambers for conventional and IMRT treatments. The MapCheck sensitivity to multileaf collimator position errors is determined. RESULTS: The diode array response is linear with dose up to 295 cGy. All diodes are calibrated to within +/-1% of each other, and mostly within +/-0.5%. The MapCheck readings are reproducible to within a maximum SD of +/-0.15%. A temperature dependence of 0.57%/ degrees C was noted and should be taken into account for absolute dosimetric measurement. Clinical performance of the MapCheck for relative and absolute dosimetry is demonstrated with seven beam (6 MV) head and neck IMRT plans, and compares well with film and ion chamber measurements. Comparison to calculated dose maps demonstrates that the planning system model underestimates the dose gradients in the penumbra region. CONCLUSIONS: The MapCheck offers the dosimetric characteristics required for performing both relative and absolute dose measurements. Its use in the clinic can simplify and reduce the IMRT QA workload.

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Published In

Radiother Oncol

DOI

ISSN

0167-8140

Publication Date

February 2004

Volume

70

Issue

2

Start / End Page

199 / 206

Location

Ireland

Related Subject Headings

  • Sensitivity and Specificity
  • Risk Factors
  • Radiotherapy, High-Energy
  • Radiotherapy, Conformal
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Quality Control
  • Phantoms, Imaging
  • Oncology & Carcinogenesis
 

Citation

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Létourneau, D., Gulam, M., Yan, D., Oldham, M., & Wong, J. W. (2004). Evaluation of a 2D diode array for IMRT quality assurance. Radiother Oncol, 70(2), 199–206. https://doi.org/10.1016/j.radonc.2003.10.014
Létourneau, Daniel, Misbah Gulam, Di Yan, Mark Oldham, and John W. Wong. “Evaluation of a 2D diode array for IMRT quality assurance.Radiother Oncol 70, no. 2 (February 2004): 199–206. https://doi.org/10.1016/j.radonc.2003.10.014.
Létourneau D, Gulam M, Yan D, Oldham M, Wong JW. Evaluation of a 2D diode array for IMRT quality assurance. Radiother Oncol. 2004 Feb;70(2):199–206.
Létourneau, Daniel, et al. “Evaluation of a 2D diode array for IMRT quality assurance.Radiother Oncol, vol. 70, no. 2, Feb. 2004, pp. 199–206. Pubmed, doi:10.1016/j.radonc.2003.10.014.
Létourneau D, Gulam M, Yan D, Oldham M, Wong JW. Evaluation of a 2D diode array for IMRT quality assurance. Radiother Oncol. 2004 Feb;70(2):199–206.
Journal cover image

Published In

Radiother Oncol

DOI

ISSN

0167-8140

Publication Date

February 2004

Volume

70

Issue

2

Start / End Page

199 / 206

Location

Ireland

Related Subject Headings

  • Sensitivity and Specificity
  • Risk Factors
  • Radiotherapy, High-Energy
  • Radiotherapy, Conformal
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiometry
  • Quality Control
  • Phantoms, Imaging
  • Oncology & Carcinogenesis