Shinichi Ueda
Kanazawa University
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Publication
Featured researches published by Shinichi Ueda.
Journal of Radiotherapy | 2014
Kimiya Noto; Shinichi Ueda; Hironori Kojima; Naoki Isomura; Akihiro Takemura; Shigeyuki Takamatsu; Tomoyasu Kumano; Tsuyoshi Takanaka
Purpose. Accuracy of dose delivery in multiple breath-hold segmented volumetric modulated arc therapy (VMAT) was evaluated in comparison to noninterrupted VMAT using a static phantom. Material and Methods. Five VMAT plans were evaluated. A Synergy linear accelerator (Elekta AB, Stockholm, Sweden) was employed. A VMAT delivery sequence was divided into multiple segments according to each of the predefined breath-hold periods (10, 15, 20, 30, and 40 seconds). The segmented VMAT delivery was compared to noninterrupted VMAT delivery in terms of the isocenter dose and pass rates of a dose difference of 1% with a dose threshold of 10% of the maximum dose on a central coronal plane using a two-dimensional dosimeter, MatriXX Evolution (IBA Dosimetry, Schwarzenbruck, Germany). Results. Means of the isocenter dose differences were 0.5%, 0.2%, 0.2%, 0.0%, and 0.0% for the beam-on-times between interrupts of 10, 15, 20, 30, and 40 seconds, respectively. Means of the pass rates were 85%, 99.9%, 100%, 100%, and 100% in the same order as the above. Conclusion. Our static phantom study indicated that the multiple breath-hold segmented VMAT maintains stable and accurate dose delivery when the beam-on-time between interrupts is 15 seconds or greater.
Archive | 2019
Noriomi Yokoyama; Akihiro Takemura; Hironori Kojima; Kousuke Tsukamoto; Shinichi Ueda; Kimiya Noto
High risk prostate cancer is treated with a combination of intensity-modulated radiation therapy (IMRT) and high dose rate brachytherapy (HDR-BT). Deformable image registration (DIR) techniques used for dose accumulation sums dose distributions. The accuracy of DIR would get worse when density of an organ in a pair of registering two images differs greatly each other. Needles and contrast medium are used in HDR-BT. In this study, the effect of needles and contrast medium for DIR accuracy was evaluated. Six patients with prostate cancer were enrolled, who were treated with the combination of HDR-BT and IMRT. In the HDR-BT plan, needleless image (NI) and needleless and no-contrast medium image (NCI) were created from the original HDR-BT plan image (OI) to investigate the influence of needles and contrast medium. Both DIR and rigid registration (RR) were performed on the OI, NIs and NCIs by using MIM Maestro ver. 6.7.6 (MIM software Inc, Cleveland, USA) and after that the dose distribution of HDR-BT (used as the reference image) and IMRT were accumulated. The Dice Similarity coefficient (DSC) between DIR and RR were analyzed and compared each other. The mean DSC values of the prostate with DIR on OI, NI and NCI were 0.51, 0.57 and 0.73, respectively. The DSC with DIR on NCI was higher than DSC with DIR on OI and NI. The DSC values improved by removing the contrast medium.
Physics and Imaging in Radiation Oncology | 2018
Akihiro Takemura; Akira Nagano; Hironori Kojima; Tomohiro Ikeda; Noriomi Yokoyama; Kosuke Tsukamoto; Kimiya Noto; Naoki Isomura; Shinichi Ueda; Hiroki Kawashima
Background and purpose In adaptive radiotherapy, deformable image registration (DIR) is used to propagate delineations of tumors and organs into a new therapy plan and to calculate the accumulated total dose. Many DIR accuracy metrics have been proposed. An alternative proposed here could be a local uncertainty (LU) metric for DIR results. Materials and methods The LU represented the uncertainty of each DIR position and was focused on deformation evaluation in uniformly-dense regions. Four cases demonstrated LU calculations: two head and neck cancer cases, a lung cancer case, and a prostate cancer case. Each underwent two CT examinations for radiotherapy planning. Results LU maps were calculated from each DIR of the clinical cases. Reduced fat regions had LUs of 4.6 ± 0.9 mm, 4.8 ± 1.0 mm, and 4.5 ± 0.7 mm, while the shrunken left parotid gland had a LU of 4.1 ± 0.8 mm and the shrunken lung tumor had a LU of 3.7 ± 0.7 mm. The bowels in the pelvic region had a LU of 10.2 ± 3.7 mm. LU histograms for the cases were similar and 99% of the voxels had a LU < 3 mm. Conclusions LU is a new uncertainty metric for DIR that was demonstrated for clinical cases. It had a tolerance of <3 mm.
Japanese Journal of Radiological Technology | 2000
Hiroji Iida; Shinichi Ueda; Mitsuru Shimizu; Sakio Tamura; Kixhiro Koshida
Japanese Journal of Radiology | 2013
Shigeyuki Takamatsu; Tsuyoshi Takanaka; Tomoyasu Kumano; Eiichi Mizuno; Satoshi Shibata; Shizuko Ohashi; Y. Kurata; Shinichi Ueda; Naoki Hori; Saori Shouji; Kimiya Noto; Hironori Kojima; Osamu Matsui
Radiological Physics and Technology | 2009
Akihiro Takemura; Saori Shoji; Shinichi Ueda; Y. Kurata; Tomoyasu Kumano; Shigeyuki Takamatsu; Masayuki Suzuki
Radiological Physics and Technology | 2016
Akihiro Takemura; Kumiko Togawa; Tomohiro Yokoi; Shinichi Ueda; Kimiya Noto; Hironori Kojima; Naoki Isomura; Tomoyasu Kumano
Journal of Radiotherapy in Practice | 2015
Akihiro Takemura; Shogo Tanabe; Mei Tokai; Shinichi Ueda; Kimiya Noto; Naoki Isomura; Hironori Kojima
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology | 2013
Akihiro Takemura; Shinichi Ueda; Kimiya Noto; Hironori Kojima; Naoki Isomura
International Journal of Radiation Oncology Biology Physics | 2012
T. Yokoi; Shinichi Ueda; Akihiro Takemura; Kimiya Noto; Naoki Isomura; K. Togawa; Tsuyoshi Takanaka; Tomoyasu Kumano; Eiichi Mizuno