Commissioning and comprehensive evaluation of the ArcCHECK cylindrical diode array for VMAT pretreatment delivery QA

Vibha Chaswal, Michael Weldon, Nilendu Gupta, Arnab Chakravarti, Yi Rong

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


We present commissioning and comprehensive evaluation for ArcCHECK as a QA equipment for volumetric-modulated arc therapy (VMAT), using the 6 MV photon beam with and without the flattening filter, and the SNC patient software (version 6.2). In addition to commissioning involving absolute dose calibration, array calibration, and PMMA density verification, ArcCHECK was evaluated for its response dependency on linac dose rate, instantaneous dose rate, radiation field size, beam angle, and couch insertion. Scatter dose characterization, consistency and symmetry of response, and dosimetry accuracy evaluation for fixed aperture arcs and clinical VMAT patient plans were also investigated. All the evaluation tests were performed with the central plug inserted and the homogeneous PMMA density value. Results of gamma analysis demonstrated an overall agreement between ArcCHECK-measured and TPS-calculated reference doses. The diode based field size dependency was found to be within 0.5% of the reference. The dose rate-based dependency was well within 1% of the TPS reference, and the angular dependency was found to be ± 3% of the reference, as tested for BEV angles, for both beams. Dosimetry of fixed arcs, using both narrow and wide field widths, resulted in clinically acceptable global gamma passing rates on the 3%/3mm level and 10% threshold. Dosimetry of narrow arcs showed an improvement over published literature. The clinical VMAT cases demonstrated high level of dosimetry accuracy in gamma passing rates.

Original languageEnglish (US)
Pages (from-to)212-225
Number of pages14
JournalJournal of Applied Clinical Medical Physics
Issue number4
StatePublished - Jan 1 2014
Externally publishedYes


  • Angular dependence
  • ArcCHECK commissioning
  • ArcCHECK diode array
  • ArcCHECK evaluation
  • Quality assurance
  • Volumetric-modulated arc therapy

ASJC Scopus subject areas

  • Radiation
  • Instrumentation
  • Radiology Nuclear Medicine and imaging


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