Author(s)

Hideharu Miura, Masao Tanooka, Hiroyuki Inoue, Masayuki Fujiwara, Kengo Kosaka, Hiroshi Doi, Yasuhiro Takada, Soichi Odawara, Norihiko Kamikonya, Shozo Hirota

Department of Radiological Technology, Hyogo College of Medicine College Hospital, Nishinomiya City, Japan.
Department of Radiology, Hyogo College of Medicine, Nishinomiya City, Japan.

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 Monaco^TM treatment planning system (TPS), and delivered with an Elekta Synergy^TM 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.

Volumetric Modulated Arc Therapy, Quality Assurance, Radiation Treatment Planning, Radiation Dosimetry

Miura, H. , Tanooka, M. , Inoue, H. , Fujiwara, M. , Kosaka, K. , Doi, H. , Takada, Y. , Odawara, S. , Kamikonya, N. and Hirota, S. (2014) DICOM-RT Plan Complexity Verification for Volumetric Modulated Arc Therapy. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 3, 117-124. doi: 10.4236/ijmpcero.2014.33017.