Haruhi Tsuru1,2, Yoshihiro Ueda3, Mikoto Tamura4, Hajime Monzen4, Shingo Ohira1, Akira Masaoka1, Shouki Inui1,2, Koji Konishi1, Junichi Fukunaga5, Hirokazu Mizuno6, Masayoshi Miyazaki1, Masahiko Koizumi2. 1. Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan. 2. Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Osaka, Japan. 3. Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan; ueda-yo@mc.pref.osaka.jp. 4. Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan. 5. Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan. 6. Division of central radiology, Osaka Rosai Hospital, Osaka, Japan.
Abstract
BACKGROUND/AIM: The aim of this study was to evaluate the mechanical performance and the effect on dose distribution and deliverability of volumetric modulated arc therapy (VMAT) plans for prostate cancer created with the commercial knowledge-based planning (KBP) system (RapidPlan™). MATERIALS AND METHODS: Three institutions, A, B, and C were enrolled in this study. Each institution established and trained a KBP model with their own cases. CT data and structures for 45 patients at institution B were utilized to validate the dose-volume parameters (D2(%), D95(%), and D98(%) for target, and V50(%), V75(%), and V90(%) for rectum and bladder), and the following mechanical performance parameters and gamma passing rates of each KBP model: leaf sequence variability (LSV), aperture area variability (AAV), total monitor unit (MU), modulation complexity score for VMAT (MCSv), MU/control point (CP), aperture area (AA)/CP, and MU×AA/CP. RESULTS: Significant differences (p<0.01) in dosimetric parameters such as D2 and D98 for target and V50, V75, and V90 for bladder were observed among the three institutions. The means and standard deviations of MCSv were 0.31±0.03, 0.29±0.02, and 0.32±0.03, and the angles of maximum and minimum MU×AA/CP were 269° and 13°, 269° and 13°, and 273° and 153° at institutions A, B, and C, respectively. The mean gamma passing rate (1%/1 mm.) was >95% for all cases in each institution. Dose distribution and mechanical performance significantly differed between the three models. CONCLUSION: Each KBP model had different dose distributions and mechanical performance but could create an acceptable plan for deliverability regardless of mechanical performance. Copyright
BACKGROUND/AIM: The aim of this study was to evaluate the mechanical performance and the effect on dose distribution and deliverability of volumetric modulated arc therapy (VMAT) plans for prostate cancer created with the commercial knowledge-based planning (KBP) system (RapidPlan™). MATERIALS AND METHODS: Three institutions, A, B, and C were enrolled in this study. Each institution established and trained a KBP model with their own cases. CT data and structures for 45 patients at institution B were utilized to validate the dose-volume parameters (D2(%), D95(%), and D98(%) for target, and V50(%), V75(%), and V90(%) for rectum and bladder), and the following mechanical performance parameters and gamma passing rates of each KBP model: leaf sequence variability (LSV), aperture area variability (AAV), total monitor unit (MU), modulation complexity score for VMAT (MCSv), MU/control point (CP), aperture area (AA)/CP, and MU×AA/CP. RESULTS: Significant differences (p<0.01) in dosimetric parameters such as D2 and D98 for target and V50, V75, and V90 for bladder were observed among the three institutions. The means and standard deviations of MCSv were 0.31±0.03, 0.29±0.02, and 0.32±0.03, and the angles of maximum and minimum MU×AA/CP were 269° and 13°, 269° and 13°, and 273° and 153° at institutions A, B, and C, respectively. The mean gamma passing rate (1%/1 mm.) was >95% for all cases in each institution. Dose distribution and mechanical performance significantly differed between the three models. CONCLUSION: Each KBP model had different dose distributions and mechanical performance but could create an acceptable plan for deliverability regardless of mechanical performance. Copyright
Authors: Matthew T Studenski; Voichita Bar-Ad; Joshua Siglin; David Cognetti; Joseph Curry; Madalina Tuluc; Amy S Harrison Journal: Med Dosim Date: 2012-12-14 Impact factor: 1.482