Commissioning and quality assurance of RapidArc radiotherapy delivery system Journal Article


Authors: Ling, C. C.; Zhang, P.; Archambault, Y.; Bocanek, J.; Tang, G.; LoSasso, T.
Article Title: Commissioning and quality assurance of RapidArc radiotherapy delivery system
Abstract: Purpose: The Varian RapidArc is a system for intensity-modulated radiotherapy (IMRT) treatment planning and delivery. RapidArc incorporates capabilities such as variable dose-rate, variable gantry speed, and accurate and fast dynamic multileaf collimators (DMLC), to optimize dose conformality, delivery efficiency, accuracy and reliability. We developed RapidArc system commissioning and quality assurance (QA) procedures. Methods and Materials: Tests have been designed that evaluate RapidArc performance in a stepwise manner. First, the accuracy of DMLC position during gantry rotation is examined. Second, the ability to vary and control the dose-rate and gantry speed is evaluated. Third, the combined use of variable DMLC speed and dose-rate is studied. Results: Adapting the picket fence test for RapidArc, we compared the patterns obtained with stationary gantry and in RapidArc mode, and showed that the effect of gantry rotation on leaf accuracy was minimal (≤0.2 mm). We then combine different dose-rates (111-600 MU/min), gantry speeds (5.5-4.3°/s), and gantry range (Δθ = 90-12.9°) to give the same dose to seven parts of a film. When normalized to a corresponding open field (to account for flatness and asymmetry), the dose of the seven portions show good agreement, with a mean deviation of 0.7%. In assessing DMLC speed (0.46, 0.92, 1.84, and 2.76 cm/s) during RapidArc, the analysis of designed radiation pattern indicates good agreement, with a mean deviation of 0.4%. Conclusions: The results of these tests provide strong evidence that DMLC movement, variable dose-rates and gantry speeds can be precisely controlled during RapidArc. © 2008 Elsevier Inc. All rights reserved.
Keywords: intensity modulated radiation therapy; treatment planning; radiation dose; accuracy; quality control; radiotherapy dosage; radiotherapy; calibration; radiotherapy, intensity-modulated; dosimetry; quality assurance; total quality management; radiosensitivity; radiometry; radiotherapy planning, computer-assisted; film dosimetry; commissioning; particle accelerators; rapidarc; rotation; speed; computer networks; qa; dose rates
Journal Title: International Journal of Radiation Oncology, Biology, Physics
Volume: 72
Issue: 2
ISSN: 0360-3016
Publisher: Elsevier Inc.  
Date Published: 2008-10-01
Start Page: 575
End Page: 581
Language: English
DOI: 10.1016/j.ijrobp.2008.05.060
PUBMED: 18793960
PROVIDER: scopus
DOI/URL:
Notes: --- - "Cited By (since 1996): 61" - "Export Date: 17 November 2011" - "CODEN: IOBPD" - "Source: Scopus"
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MSK Authors
  1. Pengpeng Zhang
    175 Zhang
  2. C Clifton Ling
    331 Ling
  3. Thomas J LoSasso
    99 LoSasso