Highlights
- •Monitor unit verification is essential to confirm the accuracy and effectiveness.
- •Verification of lung SBRT plans was performed using a secondary independent TPS.
- •Dosimetric performance of the AXB was almost equal to that of XVMC.
- •The AXB serves as an independent verification method for XVMC.
Abstract
Purpose
To verify lung stereotactic body radiotherapy (SBRT) plans using a secondary treatment
planning system (TPS) as an independent method of verification and to define tolerance
levels (TLs) in lung SBRT between the primary and secondary TPSs.
Methods
A total of 147 lung SBRT plans calculated using X-ray voxel Monte Carlo (XVMC) were
exported from iPlan to Eclipse in DICOM format. Dose distributions were recalculated
using the Acuros XB (AXB) and the anisotropic analytical algorithm (AAA), while maintaining
monitor units (MUs) and the beam arrangement. Dose to isocenter and dose-volumetric
parameters, such as D2, D50, D95 and D98, were evaluated for each patient. The TLs of all parameters between XVMC and AXB
(TLAXB) and between XVMC and AAA (TLAAA) were calculated as the mean ± 1.96 standard deviations.
Results
AXB values agreed with XVMC values within 3.5% for all dosimetric parameters in all
patients. By contrast, AAA sometimes calculated a 10% higher dose in PTV D95 and D98 than XVMC. The TLAXB and TLAAA of the dose to isocenter were −0.3 ± 1.4% and 0.6 ± 2.9%, respectively. Those of D95 were 1.3 ± 1.8% and 1.7 ± 3.6%, respectively.
Conclusions
This study quantitatively demonstrated that the dosimetric performance of AXB is almost
equal to that of XVMC, compared with that of AAA. Therefore, AXB is a more appropriate
algorithm for an independent verification method for XVMC.
Keywords
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Article info
Publication history
Published online: July 28, 2017
Accepted:
July 22,
2017
Received in revised form:
July 6,
2017
Received:
February 10,
2017
Identification
Copyright
© 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
