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Evaluation of Patient-Specific Quality Assurance for Carbon Ion Radiotherapy Using Full Energy Scanning Method at QST Hospital

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2022年第4期11卷 200-209页

作者： Asami Inomata Masashi Katsumata Sung Hyun Lee Yui Suzuki Takeo Nakajima Wataru Furuichi Keishi Yamaoka Atsushi Yamamoto Hideyuki Mizuno ryosuke kohno Accelerator Engineering Corporation Chiba Japan Department of Accelerator and Medical Physics National Institutes for Quantum and Radiological Science and Technology Chiba Japan Department of Heavy Particle Medical Science Graduate School of Medical Science Yamagata University Yamagata Japan QST Hospital National Institutes for Quantum and Radiological Science and Technology Chiba Japan Department of Radiological Sciences International University of Health and Welfare Tochigi Japan

Purpose: Patient-specific QA (PSQA) measurements for carbon ion radiotherapy (CIRT) are critical components of processes designed to identify discrepancies between calculated and delivered doses. We report the results of PSQA conducted at the QST Hospital during the period from September 2017 to March 2018. Methods: We analyzed PSQA results for 1448 fields for 10 disease sites with various target volumes, target depths and number of energy layers. For the PSQA, all the planned beams were recalculated on a water phantom with treatment planning software. The recalculated dose distributions were compared with the measured distributions using a 2D ionization chamber array at three depths, including 95% of the area of the prescription dose. These recalculated dose distributions were evaluated using the 3%/3mm gamma index with a passing threshold of 90%. Results: The passing rates for prostate, head and neck, and bone and soft tissue were 96.8%, 99.3%, and 91.7%, respectively. Additionally, 94.7% of lung plans with low energy beams passed. Overall, the CIRT in the QST Hospital reached a high passing rate of more than 95%. Although the remaining 5% failed to pass, there was no dependence between measurement depth and disease sites in these failures. Conclusion: Using PSQA measurements, we confirmed consistency between the planned and delivered doses for CIRT using the full energy scanning method.

关键词： Carbon Ion Radiotherapy Full Energy Scanning Patient-Specific Quality Assurance Gamma Index

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In Vivo Dosimetry of an Anthropomorphic Phantom Using the RADPOS for Proton Beam Therapy

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2016年第3期5卷 177-183页

作者： ryosuke kohno Hidenori Yamaguchi Kana Motegi Kenji Hotta Shie Nishioka Tetsuo Akimoto National Cancer Center Hospital East Kashiwa Japan Graduate School of Pure and Applied Sciences University of Tsukuba Tsukuba Japan National Cancer Center Hospital Tokyo Japan

The radiation positioning system (RADPOS) combines an electromagnetic positioning sensor with metal oxide semiconductor field-effect transistor (MOSFET) dosimetry, enabling simultaneous online measurement of dose and spatial position. Evaluation points can be determined with the RADPOS. The accuracy of in-vivo proton dosimetry was evaluated using the RADPOS and an anthropomorphic head and neck phantom. MOSFET doses measured at 3D positions obtained with the RADPOS were compared with treatment plan values calculated using a simplified Monte Carlo (SMC) method. MOSFET responses, which depend strongly on the linear energy transfer of the proton beam, were corrected using the SMC method. The SMC method was used to calculate only dose deposition determined by the experimental depth-dose distribution and lateral displacement of protons due to the multiple scattering effect in materials and incident angle. This method thus enabled rapid calculation of accurate doses in even heterogeneities. In vivo dosimetry using the RADPOS, as well as MOSFET doses, agreed with SMC calculations in the range of ?3.0% to 8.3%. Most measurement errors occurred because of uncertainties in dose calculations due to the 1-mm position error. The results indicate that uncertainties in measurement position can be controlled successfully within 1 mm when using the RADPOS with in-vivo proton dosimetry.

关键词： RADPOS MOSFET In Vivo Dosimetry Position Sensor Proton Beam Therapy

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Experimental Evaluation of CT Number Changes in 320-Row CBCT Volume Scan for Proton Range Calculation

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2018年第2期7卷 141-150页

作者： Ryuta Hirai ryosuke kohno Yu Kumazaki Tetsuo Akimoto Hidetoshi Saitoh Shingo Kato Department of Radiation Oncology Saitama Medical University Saitama Japan Department of Radiation Oncology Saitama Medical University International Medical Center Saitama Japan The University of Texas MD Anderson Cancer Center Houston TX USA Division of Particle Therapy National Cancer Center Hospital East Chiba Japan Division of Radiological Sciences Faculty of Health Sciences Tokyo Metropolitan University Tokyo Japan

We investigated the longitudinal positional dependence of CT number in 320-row Cone Beam Computed Tomography (CBCT) volume scan (320-row volume scan) using a simple geometric phantom (SGP) and a chest simulation phantom (CSP) in order to evaluate its effect on proton range calculation. The SGP consisted of lung substitute material (LSM) and a cylindrical phantom (CP) made of high-density polyethylene. The CSP was an anthropomorphic phantom similar to the human chest. The two phantoms were scanned using 320-row volume scan in various longitudinal positions from the central beam axis. In experiments using the SGP, an image blur at the boundary of the two materials became gradually evident when the LSM was placed far away from the beam central axis. The image blur of the phantom was consistent with the gradation in CT number. The maximum difference in CT numbers between the 64-row helical scan and 320-row volume scan at the boundary of the two materials was consistent with approximately 50% of the relative proton stopping power. In contrast, the CT number profile in each longitudinal position was fairly consistent and longitudinal positional dependence rarely occurred in the CSP experiments. Pass lengths of CT beams through areas with widely different electron densities were shorter, and thus did not significantly impact CT numbers. Based on findings from the CSP experiments, we considered 320-row volume scan to be feasible for proton range calculation in clinical settings, although the relatively large longitudinal positional dependence of CT number should be accounted for when doing so.

关键词： 320-Row CBCT Volume Scan CT Number Proton Range Relative Stopping Power

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Biological Dose Comparison between a Fixed RBE and a Variable RBE in SFO and MFO IMPT with Various Multi-Beams for Brain Cancer

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2019年第1期8卷 32-45页

作者： ryosuke kohno Wenhua Cao Pablo Yepes Xuemin Bai Falk Poenisch David R. Grosshans Tetsuo Akimoto Radhe Mohan Medical Physics Section National Institute of Radiological Sciences Chiba Japan Department of Radiation Physics University of Texas MD Anderson Cancer Center Houston USA Division of Radiation Oncology and Particle Therapy Exploratory Oncology Research & Clinical Trial Center National Cancer Center Hospital East Chiba Japan

IMPT plans with various multi-angle beams were planned by the Varian Eclipse treatment planning system for one case of brain cancer. Dose distributions for each plan, along with the associated linear energy transfer distributions, were recomputed using an in-house fast Monte Carlo dose calculator with a FRBE of 1.1 or with a previously published VRBE model. We then compared dosimetric parameters obtained by the VRBE with those obtained by the FRBE. Biological doses obtained by the VRBE for the clinical target volume in all plans were 1% - 2% larger than those obtained by the FRBE. The minimum dose obtained by the VRBE for the right optic nerve in the MFO IMPT with 4 fields was 70% larger than that obtained by the FRBE, but the difference was only 18.1 cGy (RBE). The difference in maximum dose for the right optic nerve in the MFO IMPT with 5 fields was less than 10.4%, but the difference was 131.8 cGy (RBE). The mean difference in maximum dose was less than 2% for all other organs at risk. We found that biological dose with the FRBE had any dose errors in IMPT with various multi-angle beams.

关键词： IMPT Monte Carlo Biological Dose Variable RBE

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Dose Comparison between Eclipse Dose Calculation and Fast Dose Calculator in Single- and Multi-Field Optimization Intensity-Modulated Proton Therapy Plans with Various Multi-Beams for Brain Cancer

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2017年第4期6卷 421-432页

作者： ryosuke kohno Wenhua Cao Pablo Yepes Xuemin Bai Falk Poenisch David R. Grosshans Tetsuo Akimoto Radhe Mohan Department of Radiation Physics The University of Texas MD Anderson Cancer Center Houston TX USA Division of Radiation Oncology and Particle Therapy Exploratory Oncology Research & Clinical Trial Center National Cancer Center Hospital East Kashiwa Japan Department of Radiation Oncology The University of Texas MD Anderson Cancer Center Houston TX USA

The purpose of this study was to grasp current potential problems of dose error in intensity-modulated proton therapy (IMPT) plans. We were interested in dose differences of the Varian Eclipse treatment planning system (TPS) and the fast dose calculation method (FDC) for single-field optimization (SFO) and multi-field optimization (MFO) IMPT plans. In addition, because some authors have reported dosimetric benefit of a proton arc therapy with ultimate multi-fields in recent years, we wanted to evaluate how the number of fields and beam angles affect the differences for IMPT plans. Therefore, for one brain cancer patient with a large heterogeneity, SFO and MFO IMPT plans with various multi-angle beams were planned by the TPS. Dose distributions for each IMPT plan were calculated by both the TPS’s conventional pencil beam algorithm and the FDC. The dosimetric parameters were compared between the two algorithms. The TPS overestimated 400 - 500 cGy (RBE) for minimum dose to the CTV relative to the dose calculated by the FDC. These differences indicate clinically relevant effect on clinical results. In addition, we observed that the maximum difference in dose calculated between the TPS and the FDC was about 900 cGy (RBE) for the right optic nerve, and this quantity also has a possibility to have a clinical effect. The major difference was not seen in calculations for SFO IMPT planning and those for MFO IMPT planning. Differences between the TPS and the FDC in SFO and MFO IMPT plans depend strongly on beam arrangement and the presence of a heterogeneous body. We advocate use of a Monte Carlo method in proton treatment planning to deliver the most precise proton dose in IMPT.

关键词： Fast Dose Calculator Monte Carlo Intensity-Modulated Proton Therapy Single-Field Optimization (SFO) Multi-Field Optimization (MFO)

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Position Verification of the RADPOS 4-D <i>In-Vivo</i>Dosimetry System

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2015年第4期4卷 318-325页

作者： ryosuke kohno Hidenori Yamaguchi Kana Motegi Fumiya Tanaka Tsunemichi Akita Yuki Nagata Kenji Hotta Tomoko Miyagishi Shie Nishioka Takeshi Dohmae Tetsuo Akimoto Particle Therapy Division National Cancer Center Hospital East Kashiwa Japan Graduate School of Pure and Applied Sciences University of Tsukuba Tsukuba Japan

The accuracy of the position measurements obtained by the radiation positioning system (RADPOS) was evaluated under static and dynamic conditions. In the static verifications, the RADPOS was fixed to the treatment couch in a photon treatment room and a proton treatment room, and was translocated with the treatment couch in x, y and z directions. Because the presence of magnetic and/or electrically conductive materials can cause a systematic shift in the measured position by distorting the RADPOS transmitted field, the effect of metals on the performance of the positioning system was also investigated. Dynamic verification was performed using the couch drive and a dynamic anthropomorphic thorax phantom. We thus confirmed the utility of RADPOS as a position sensor to perform in vivo dosimetry.

关键词： RADPOS MOSFET In-Vivo Dosimetry Position Sensor Photon Therapy Proton Beam Therapy

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Plasma leptin and ghrelin concentrations in patients with Crohn's disease

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World Journal of Gastroenterology 2005年第46期11卷 7314-7317页

作者： Yoshito Nishi Hajime Isomoto Hiroaki Ueno Ken Ohnita Chun Yang Wen Fuminao Takeshima ryosuke Mishima Masamitsu Nakazato Shigeru kohno Second Department of Internal Medicine Nagasaki University School of Medicine Sakamoto 1-7-1 Nagasaki Japan Department of Endoscopy Nagasaki University School of Medicine Sakamoto 1-7-1Nagasaki Japan Department of Molecular Pathology Atomic Bomb Disease Institute Nagasaki University School of MedicineSakamoto 12-4 Nagasaki Japan Third Departmentof Internal Medicine Miyazaki Medical College KiyotakeMiyazaki Japan

AIM: To determine the concentrations of leptin and ghrelin, which have opposite effects on appetite,energy expenditure, and weight control, in the plasma of patients with Crohn's disease (CD), which is often associated with weight loss and malnutrition.METHODS: Plasma leptin and ghrelin concentrations were determined in 28 outpatients with CD by radioimmunoassay. Age- and sex-matched controls with and without Helicobacter pylori(H pylori) infection (28for each) were enrolled in the study. Circulating levels of these hormones were assessed with respect to CD activity, disease localization and medical treatment.RESULTS: There were no significant differences in ghrelin levels between CD patients and H pylorinegative controls. However, circulating ghrelin levels were significantly lower in H pylori-infected subjects than in CD patients and uninfected controls. Plasma leptin levels were comparable among the groups. Localization and medication profile had no significant impact on circulating ghrelin and leptin levels.CONCLUSION: Apart from H pyloriinfection, CD itself has no significant influence on circulating ghrelin and leptin levels in the outpatients who were mostly in inactive state.

关键词：等离子体结肠疾病临床表现治疗

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