TITLE:
DICOM-RT Plan Complexity Verification for Volumetric Modulated Arc Therapy
AUTHORS:
Hideharu Miura, Masao Tanooka, Hiroyuki Inoue, Masayuki Fujiwara, Kengo Kosaka, Hiroshi Doi, Yasuhiro Takada, Soichi Odawara, Norihiko Kamikonya, Shozo Hirota
KEYWORDS:
Volumetric Modulated Arc Therapy, Quality Assurance, Radiation Treatment Planning, Radiation Dosimetry
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.3 No.3,
June
12,
2014
ABSTRACT:
The
purpose of this study was to investigate the relationship between plan
parameters verified with DICOM-RT and dosimetric results for volumetric
modulated arc therapy (VMAT). We investigated three
treatment locations: prostate cancer (ten cases), maxillary sinus cancer (four
cases), and malignant pleura mesothelioma (four cases) with treatment plans
generated by a MonacoTM treatment planning system (TPS), and
delivered with an Elekta SynergyTM linear accelerator. We calculated
plan parameters, including gantry and multileaf collimator (MLC) positions,
Monitor Units (MU), and millimeters of MLC motion per degree of gantry rotation
(mm/degree), and performed
quality assurance (QA) with a DICOM-RT plan verification system. We measured
the VMAT dose with a two-dimensional diode array detector. The average gamma
passing rate with percent dose acceptance criteria and distance to agreement
criteria of 2 mm and 2% (2 mm/2%) were 97.4%, 97.8% and 92.0% for prostate
cancer, maxillary sinus cancer, and malignant pleural mesothelioma, respectively. The mean 95th
percentile value for DICOM-calculated mm/degree was 4.0, 5.2, and 11.1 for
prostate cancer, maxillary sinus cancer, and malignant pleural mesothelioma,
respectively. The gamma passing rate showed a correlation with calculated
mm/degree, with a coefficient of determination (R2) of 0.60. Higher
calculated mm/degree values led to increased dosimetric
errors. We conclude that dose distribution calculated by a TPS is more reliable
at smaller mm/degree.