Highlights
- •The use of Compass as model-based QA tool for stereotactic VMAT plans was analyzed.
- •Evaluation of DVH parameters together with 2D and 3D gamma analysis was executed.
- •Moderate correlation between gamma-index pass-rates for CCD and CRD existed.
- •In addition to model-based QA measurements are needed to verify treatment plans.
Abstract
Purpose
To use Compass as a model-based quality assurance (QA) tool for stereotactic body
radiation therapy (SBRT) and stereotactic radiation therapy (SRT) volumetric modulated
arc therapy (VMAT) treatment plans calculated with Eclipse treatment planning system
(TPS).
Materials and methods
Twenty clinical stereotactic VMAT SBRT and SRT treatment plans were blindly selected
for evaluation. Those plans included four different treatment sites: prostate, brain,
lung and body. The plans were evaluated against dose-volume histogram (DVH) parameters
and 2D and 3D gamma analysis. The dose calculated with Eclipse treatment planning
system (TPS) was compared to Compass calculated dose (CCD) and Compass reconstructed
dose (CRD).
Results
The maximum differences in mean dose of planning target volume (PTV) were 2.7 ± 1.0%
between AAA and Acuros XB calculation algorithm TPS dose, −7.6 ± 3.5% between Eclipse
TPS dose and CCD dose and −5.9 ± 3.7% between Eclipse TPS dose and CRD dose for both
Eclipse calculation algorithms, respectively. 2D gamma analysis was not able to identify
all the cases that 3D gamma analysis specified for further verification.
Conclusions
Compass is suitable for QA of SBRT and SRT treatment plans. However, the QA process
should include wide set of DVH-based dose parameters and 3D gamma analysis should
be the preferred method when performing clinical patient QA. The results suggest that
the Compass should not be used for smaller field sizes than 3 × 3 cm2 or the beam model should be adjusted separately for both small (FS ≤ 3 cm) and large
(FS > 3 cm) field sizes.
Keywords
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Article info
Publication history
Accepted:
November 9,
2017
Received in revised form:
October 22,
2017
Received:
May 14,
2017
Identification
Copyright
© 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
