2021/12/04 更新

写真a

オオタ アツシ
太田 篤
OHTA Atsushi
所属
医歯学総合病院 放射線治療科 助教
職名
助教
外部リンク

学位

  • 博士(医学) ( 2017年3月   新潟大学 )

研究キーワード

  • 放射線治療

研究分野

  • ライフサイエンス / 放射線科学

経歴

  • 新潟大学   医歯学総合病院 放射線治療科   助教

    2017年4月 - 現在

  • 新潟大学   医歯学総合病院 放射線治療科   特任助教

    2016年8月 - 2017年3月

学歴

  • 新潟大学   医学部   医学科

    2000年4月 - 2006年3月

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    国名: 日本国

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所属学協会

  • 日本放射線腫瘍学会

    2011年6月 - 現在

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  • 日本医学放射線学会

    2008年4月 - 現在

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論文

  • Radiobiological evaluation considering setup error on single‐isocenter irradiation in stereotactic radiosurgery

    Hisashi Nakano, Satoshi Tanabe, Ryuta Sasamoto, Takeshi Takizawa, Satoru Utsunomiya, Madoka Sakai, Toshimichi Nakano, Atsushi Ohta, Motoki Kaidu, Hiroyuki Ishikawa

    Journal of Applied Clinical Medical Physics   2021年6月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley  

    DOI: 10.1002/acm2.13322

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    その他リンク: https://onlinelibrary.wiley.com/doi/full-xml/10.1002/acm2.13322

  • A comparative study of high-dose-rate brachytherapy boost combined with external beam radiation therapy versus external beam radiation therapy alone for high-risk prostate cancer. 国際誌

    Tomoya Oshikane, Motoki Kaidu, Eisuke Abe, Atsushi Ohta, Hirotake Saito, Toshimichi Nakano, Moe Honda, Satoshi Tanabe, Satoru Utsunomiya, Ryuta Sasamoto, Fumio Ishizaki, Takashi Kasahara, Tsutomu Nishiyama, Yoshihiko Tomita, Hidefumi Aoyama, Hiroyuki Ishikawa

    Journal of radiation research   2021年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We aimed to compare the outcomes of high-dose-rate brachytherapy (HDR-BT) boost and external beam radiation therapy (EBRT) alone for high-risk prostate cancer. This was a single-center, retrospective and observational study. Consecutive patients who underwent initial radical treatment by HDR-BT boost or EBRT alone from June 2009 to May 2016 at the Niigata University Medical and Dental Hospital, Japan were included. A total of 96 patients underwent HDR-BT boost, and 61 underwent EBRT alone. The prescription dose of HDR-BT boost was set to 18 Gy twice a day with EBRT 39 Gy/13 fractions. The dose for EBRT alone was mostly 70 Gy/28 fractions. The high-risk group received >6 months of prior androgen deprivation therapy. Overall survival, biochemical-free survival, local control and distant metastasis-free survival rates at 5 years were analyzed. The incidence of urological and gastrointestinal late adverse events of Grade 2 and above was also summarized. In the National Comprehensive Cancer Network (NCCN) high-risk calssification, HDR-BT boost had a significantly higher biochemical-free survival rate at 5 years (98.9% versus 90.7%, P = 0.04). Urethral strictures were more common in the HDR-BT boost group. We will continuously observe the progress of the study patients and determine the longer term results.

    DOI: 10.1093/jrr/rrab006

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  • Maximum distance in single-isocenter technique of stereotactic radiosurgery with rotational error using margin-based analysis.

    Hisashi Nakano, Satoshi Tanabe, Takumi Yamada, Satoru Utsunomiya, Takeshi Takizawa, Madoka Sakai, Ryuta Sasamoto, Hironori Sakai, Toshimichi Nakano, Hirotake Saito, Atsushi Ohta, Motoki Kaidu, Hiroyuki Ishikawa

    Radiological physics and technology   14 ( 1 )   57 - 63   2021年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Through geometrical simulation, we evaluated the effect of rotational error in patient setup on geometrical coverage and calculated the maximum distance between the isocenter and target, where the clinical PTV margin secures geometrical coverage with a single-isocenter technique. We used simulated spherical GTVs with diameters of 1.0 (GTV 1), 1.5 (GTV 2), 2.0 (GTV 3), and 3.0 cm (GTV 4). The location of the target center was set such that the distance between the target and isocenter ranged from 0 to 15 cm. We created geometrical coverage vectors so that each target was entirely covered by 100% of the prescribed dose. The vectors of the target positions were simultaneously rotated within a range of 0°-2.0° around the x-, y-, and z-axes. For each rotational error, the reduction in geometrical coverage of the targets was calculated and compared with that obtained for a rotational error of 0°. The tolerance value of the geometrical coverage reduction was defined as 5% of the GTV. The maximum distance that satisfied the 5% tolerance value for different values of rotational error at a clinical PTV margin of 0.1 cm was calculated. When the rotational errors were 0.5° for a 0.1 cm PTV margin, the maximum distances were as follows: GTV 1: 7.6 cm; GTV 2: 10.9 cm; GTV 3: 14.3 cm; and GTV 4: 21.4 cm. It might be advisable to exclude targets that are > 7.6 cm away from the isocenter with a single-isocenter technique to satisfy the tolerance value for all GTVs.

    DOI: 10.1007/s12194-020-00602-2

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  • Calculated relative biological effectiveness (RBE) for initial DNA double-strand breaks (DSB) from flattening filter and flattening filter-free 6 MV X-ray fields

    Hisashi Nakano, Daisuke Kawahara, Satoshi Tanabe, Satoru Utsunomiya, Takeshi Takizawa, Madoka Sakai, Toshimichi Nakano, Atsushi Ohta, Motoki Kaidu, Hiroyuki Ishikawa

    BJR|Open   3 ( 1 )   20200072 - 20200072   2021年1月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:British Institute of Radiology  

    <sec><title>Objectives:</title> We evaluated the radiobiological effectiveness based on the yields of DNA double-strand breaks (DSBs) of field induction with flattening filter (FF) and FF-free (FFF) photon beams.

    </sec><sec><title>Methods:</title> We used the particle and heavy ion transport system (PHITS) and a water equivalent phantom (30 × 30 × 30 cm<sup>3</sup>) to calculate the physical qualities of the dose-mean lineal energy (y<sub>D</sub>) with 6 MV FF and FFF. The relative biological effectiveness based on the yields of DNA-DSBs (RBE<sub>DSB</sub>) was calculated for standard radiation such as 220 kVp X-rays by using the estimating yields of SSBs and DSBs. The measurement points used to calculate the in-field y<sub>D</sub> and RBE<sub>DSB</sub> were located at a depth of 3, 5, and 10 cm in the water equivalent phantom on the central axis. Measurement points at 6, 8, and 10 cm in the lateral direction of each of the three depths from the central axis were set to calculate the out-of-field y<sub>D</sub> and RBE<sub>DSB</sub>.

    </sec><sec><title>Results:</title> The RBE<sub>DSB</sub> of FFF in-field was 1.7% higher than FF at each measurement depth. The RBE<sub>DSB</sub> of FFF out-of-field was 1.9 to 6.4% higher than FF at each depth measurement point. As the distance to out-of-field increased, the RBE<sub>DSB</sub> of FFF rose higher than those of FF. FFF has a larger RBE<sub>DSB</sub> than FF based on the yields of DNA-DSBs as the distance to out-of-field increased.

    </sec><sec><title>Conclusions:</title> The out-of-field radiobiological effect of FFF could thus be greater than that of FF since the spreading of the radiation dose out-of-field with FFF could be a concern compared to the FF.

    </sec><sec><title>Advances in knowledge:</title> The RBE<sub>DSB</sub> of FFF of out-of-field might be larger than FF.

    </sec>

    DOI: 10.1259/bjro.20200072

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  • Effect of setup error in the single-isocenter technique on stereotactic radiosurgery for multiple brain metastases. 国際誌

    Hisashi Nakano, Satoshi Tanabe, Satoru Utsunomiya, Takumi Yamada, Ryuta Sasamoto, Toshimichi Nakano, Hirotake Saito, Takeshi Takizawa, Hironori Sakai, Atsushi Ohta, Eisuke Abe, Motoki Kaidu, Hidefumi Aoyama

    Journal of applied clinical medical physics   21 ( 12 )   155 - 165   2020年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In conventional stereotactic radiosurgery (SRS), treatment of multiple brain metastases using multiple isocenters is time-consuming resulting in long dose delivery times for patients. A single-isocenter technique has been developed which enables the simultaneous irradiation of multiple targets at one isocenter. This technique requires accurate positioning of the patient to ensure optimal dose coverage. We evaluated the effect of six degrees of freedom (6DoF) setup errors in patient setups on SRS dose distributions for multiple brain metastases using a single-isocenter technique. We used simulated spherical gross tumor volumes (GTVs) with diameters ranging from 1.0 to 3.0 cm. The distance from the isocenter to the target's center was varied from 0 to 15 cm. We created dose distributions so that each target was entirely covered by 100% of the prescribed dose. The target's position vectors were rotated from 0°-2.0° and translated from 0-1.0 mm with respect to the three axes in space. The reduction in dose coverage for the targets for each setup error was calculated and compared with zero setup error. The calculated margins for the GTV necessary to satisfy the tolerance values for loss of GTV coverage of 3% to 10% were defined as coverage-based margins. In addition, the maximum isocenter to target distance for different 6DoF setup errors was calculated to satisfy the tolerance values. The dose coverage reduction and coverage-based margins increased as the target diameter decreased, and the distance and 6DoF setup error increased. An increase in setup error when a single-isocenter technique is used may increase the risk of missing the tumor; this risk increases with increasing distance from the isocenter and decreasing tumor size.

    DOI: 10.1002/acm2.13081

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  • Radiobiological effects of the interruption time with Monte Carlo Simulation on multiple fields in photon beams. 国際誌

    Hisashi Nakano, Daisuke Kawahara, Satoshi Tanabe, Satoru Utsunomiya, Takeshi Takizawa, Madoka Sakai, Hirotake Saito, Atsushi Ohta, Motoki Kaidu, Hiroyuki Ishikawa

    Journal of applied clinical medical physics   21 ( 12 )   288 - 294   2020年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: The interruption time is the irradiation interruption that occurs at sites and operations such as the gantry, collimator, couch rotation, and patient setup within the field in radiotherapy. However, the radiobiological effect of prolonging the treatment time by the interruption time for tumor cells is little evaluated. We investigated the effect of the interruption time on the radiobiological effectiveness with photon beams based on a modified microdosimetric kinetic (mMK) model. METHODS: The dose-mean lineal energy yD (keV/µm) of 6-MV photon beams was calculated by the particle and heavy ion transport system (PHITS). We set the absorbed dose to 2 or 8 Gy, and the interruption time (τ) was set to 1, 3, 5, 10, 30, and 60 min. The biological parameters such as α0, β0, and DNA repair constant rate (a + c) values were acquired from a human non-small-cell lung cancer cell line (NCI-H460) for the mMK model. We used two-field and four-field irradiation with a constant dose rate (3 Gy/min); the photon beams were paused for interruption time τ. We calculated the relative biological effectiveness (RBE) to evaluate the interruption time's effect compared with no interrupted as a reference. RESULTS: The yD of 6-MV photon beams was 2.32 (keV/µm), and there was little effect by changing the water depth (standard deviation was 0.01). The RBE with four-field irradiation for 8 Gy was decreased to 0.997, 0.975, 0.900, and 0.836 τ = 1, 10, 30, 60 min, respectively. In addition, the RBE was affected by the repair constant rate (a + c) value, the greater the decrease in RBE with the longer the interruption time when the (a + c) value was large. CONCLUSION: The ~10-min interruption of 6-MV photon beams did not significantly impact the radiobiological effectiveness, since the RBE decrease was <3%. Nevertheless, the RBE's effect on tumor cells was decreased about 30% by increasing the 60 min interruption time at 8 Gy with four-field irradiation. It is thus necessary to make the interruption time as short as possible.

    DOI: 10.1002/acm2.13110

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  • Dosimetric comparison of analytic anisotropic algorithm and Acuros XB algorithm in VMAT plans for high-grade glioma. 国際誌

    Takeshi Takizawa, Satoshi Tanabe, Satoru Utsunomiya, Hisashi Nakano, Takumi Yamada, Hironori Sakai, Atsushi Ohta, Hirotake Saito, Toshimichi Nakano, Eisuke Abe, Motoki Kaidu, Hidefumi Aoyama

    Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)   73   73 - 82   2020年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: To investigate the dosimetric impact between the anisotropic analytical algorithm (AAA) and the Acuros XB (AXB) algorithm in volumetric-modulated arc therapy (VMAT) plans for high-grade glioma (HGG). METHODS: We used a heterogeneous phantom to quantify the agreement between the measured and calculated doses from the AAA and from the AXB. We then analyzed 14 patients with HGG treated by VMAT, using the AAA. We newly created AXB plans for each corresponding AAA plan under the following conditions: (1) re-calculation for the same number of monitor units with an identical beam and leaf setup, and (2) re-optimization under the same conditions of dose constraints. The dose coverage for the planning target volume (PTV) was evaluated by dividing the coverage into the skull, air, and soft-tissue regions. RESULTS: Compared to the results obtained with the AAA, the AXB results were in good agreement with the measured profiles. The dose differences in the PTV between the AAA and re-calculated AXB plans were large in the skull region contained in the target. The dose difference in the PTV in both types of plan was significantly correlated with the volume of the skull contained in the target (r = 0.71, p = 0.0042). A re-optimized AXB plan's dose difference was lower vs. the re-calculated AXB plan's. CONCLUSIONS: We observed dose differences between the AAA and AXB plans, in particular in the cases in which the skull region of the target was large. Considering the phantom measurement results, the AXB algorithm should be used in VMAT plans for HGG.

    DOI: 10.1016/j.ejmp.2020.04.007

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  • The neurocognitive function change criteria after whole-brain radiation therapy for brain metastasis, in reference to health-related quality of life changes: a prospective observation study. 国際誌

    Toshimichi Nakano, Hidefumi Aoyama, Hirotake Saito, Satoshi Tanabe, Kensuke Tanaka, Katsuya Maruyama, Tomoya Oshikane, Atsushi Ohta, Eisuke Abe, Motoki Kaidu

    BMC cancer   20 ( 1 )   66 - 66   2020年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: We sought to construct the optimal neurocognitive function (NCF) change criteria sensitive to health-related quality of life (HR-QOL) in patients who have undergone whole-brain radiation therapy (WBRT) for brain metastasis. METHODS: We categorized the patients by the changes of NCF into groups of improvement versus deterioration if at least one domain showed changes that exceeded the cut-off while other domains remained stable. The remaining patients were categorized as stable, and the patients who showed both significant improvement and deterioration were categorized as 'both.' We examined the clinical meaning of NCF changes using the cut-off values 1.0, 1.5, and 2.0 SD based on the percentage of patients whose HR-QOL changes were ≥ 10 points. RESULTS: Baseline, 4-month and 8-month data were available in 78, 41 (compliance; 85%), and 29 (81%) patients, respectively. At 4 months, improvement/stable/deterioration/both was seen in 15%/12%/41%/32% of the patients when 1.0 SD was used; 19%/22%/37%/22% with 1.5 SD, and 17%/37%/37%/9% with 2.0 SD. The HR-QOL scores on the QLQ-C30 functional scale were significantly worse in the deterioration group versus the others with 1.0 SD (p = 0.013) and 1.5 SD (p = 0.015). With 1.5 SD, the HR-QOL scores on the QLQ-BN20 was significantly better in the improvement group versus the others (p = 0.033). However, when 'both' was included in 'improvement' or 'deterioration,' no significant difference in HR-QOL was detected. CONCLUSIONS: The NCF cut-off of 1.5 SD and the exclusion of 'both' patients from the 'deterioration' and 'improvement' groups best reflects HR-QOL changes.

    DOI: 10.1186/s12885-020-6559-3

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  • The association between oral candidiasis and severity of chemoradiotherapy-induced dysphagia in head and neck cancer patients: A retrospective cohort study. 国際誌

    Hirotake Saito, Ryusuke Shodo, Keisuke Yamazaki, Kouji Katsura, Yushi Ueki, Toshimichi Nakano, Tomoya Oshikane, Nobuko Yamana, Satoshi Tanabe, Satoru Utsunomiya, Atsushi Ohta, Eisuke Abe, Motoki Kaidu, Ryuta Sasamoto, Hidefumi Aoyama

    Clinical and translational radiation oncology   20   13 - 18   2020年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Background and purpose: Concurrent chemoradiotherapy (CCRT) for head and neck cancer (HNC) is a risk factor for oral candidiasis (OC). As Candida spp. are highly virulent, we conducted a retrospective study to determine whether OC increases the severity of dysphagia related to mucositis in HNC patients. Patients and methods: We retrospectively analyzed the cases of consecutive patients with carcinomas of the oral cavity, pharynx, and larynx who underwent CCRT containing cisplatin (CDDP) at our hospital. The diagnosis of OC was based on gross mucosal appearance. We performed a multivariate analysis to determine whether OC was associated with the development of grade 3 dysphagia in the Radiation Therapy Oncology Group (RTOG) Acute Toxicity Criteria. The maximum of the daily opioid doses was compared between the patients with and without OC. Results: We identified 138 HNC patients. OC was observed in 51 patients (37%). By the time of their OC diagnosis, 19 (37%) had already developed grade 3 dysphagia. Among the 30 patients receiving antifungal therapy, 12 (40%) showed clinical deterioration. In the multivariate analysis, OC was independently associated with grade 3 dysphagia (OR 2.75; 95%CI 1.22-6.23; p = 0.015). The patients with OC required significantly higher morphine-equivalent doses of opioids (45 vs. 30 mg/day; p = 0.029). Conclusion: Candida infection causes refractory dysphagia. It is worth investigating whether antifungal prophylaxis reduces severe dysphagia related to candidiasis.

    DOI: 10.1016/j.ctro.2019.10.006

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  • 多発脳転移に対する単一アイソセンタ照射法における患者セットアップの並進誤差が線量不確かさに及ぼす影響

    中野 永, 棚邊 哲史, 宇都宮 悟, 中野 智成, 斎藤 紘丈, 滝澤 健司, 山田 巧, 坂井 裕則, 太田 篤, 阿部 英輔, 海津 元樹, 青山 英史

    定位的放射線治療   24   81 - 89   2020年1月

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    記述言語:日本語   出版者・発行元:日本定位放射線治療学会  

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  • The impact of the three degrees-of-freedom fiducial marker-based setup compared to soft tissue-based setup in hypofractionated intensity-modulated radiotherapy for prostate cancer. 国際誌

    Satoshi Tanabe, Satoru Utsunomiya, Eisuke Abe, Hiraku Sato, Atsushi Ohta, Hironori Sakai, Takumi Yamada, Motoki Kaidu, Hidefumi Aoyama

    Journal of applied clinical medical physics   20 ( 6 )   53 - 59   2019年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: We evaluated the setup accuracy of a three-degree-of-freedom fiducial marker (3DOF-FM)-based setup compared to a soft tissue (ST)-based setup in hypofractionated intensity-modulated radiotherapy (IMRT) for prostate cancer. MATERIALS AND METHODS: We analyzed the setup accuracy for 17 consecutive prostate cancer patients with three implanted FMs who underwent hypofractionated IMRT. The 3DOF-ST-based setup using cone-beam computed tomography (CT) was performed after a six DOF-bony structure (BS)-based setup using an ExacTrac x-ray system. The 3DOF-FM-based matching using the ExacTrac x-ray system was done during the BS- and ST-based setups. We determined the mean absolute differences and the correlation between the FM- and ST-based translational shifts relative to the BS-based setup position. The rotational mean shifts detected by the ExacTrac x-ray system were also evaluated. RESULTS: The mean differences in the anterior-posterior (AP), superior-inferior (SI), and left-right (LR) dimensions were 0.69, 0.0, and 0.30 mm, respectively. The Pearson correlation coefficients for both shifts were 0.92 for AP, 0.91 for SI, and 0.68 for LR. The percentages of shift agreements within 2 mm were 85% for AP, 93% for SI, and 99% for LR. The absolute values of rotational shifts were 0.1° for AP, 0.3°, and 1.2° for LR. CONCLUSIONS: The setup accuracy of the 3DOF-FM-based setup has the potential to be interchangeable with a ST-based setup. Our data are likely to be useful in clinical practice along with the popularization of the hypofractionated IMRT in prostate cancer.

    DOI: 10.1002/acm2.12603

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  • Complementary Relation Between the Improvement of Dose Delivery Technique and PTV Margin Reduction in Dose-Escalated Radiation Therapy for Prostate Cancer. 国際誌

    Satoru Utsunomiya, Jun Yamamoto, Satoshi Tanabe, Mayu Oishi, Aruha Satsuma, Motoki Kaidu, Eisuke Abe, Atsushi Ohta, Naotaka Kushima, Hidefumi Aoyama

    Practical radiation oncology   9 ( 3 )   172 - 178   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: The purpose of this study is to demonstrate quantitatively the complementary relationship between the introduction of intensity modulated radiation therapy (IMRT) and planning target volume (PTV) margin reduction with an image guided technique in reducing the risk of rectal toxicity in dose-escalating prostate radiation therapy. METHODS AND MATERIALS: Three-dimensional conformal radiation therapy (CRT) and IMRT plans were generated for 10 patients with prostate cancer based on 2 PTV margin protocols (10/8 mm and 6/5 mm) and 2 dose prescriptions (70 Gy and 78 Gy). The normal tissue complication probability (NTCP) for each of the 8 scenarios was calculated using the Lyman-Kutcher-Burman model to estimate the risk of rectal and bladder late toxicity. The conformity and homogeneity indices of PTVs were calculated for each plan. RESULTS: The IMRT plans showed superiority in conformity and inferiority in homogeneity over 3-dimensional CRT plans. The rectal NTCPs were increased 3.5 to 4.1 times when the prescribed total dose was changed from 70 Gy to 78 Gy and the dose delivery and the image guided radiation therapy techniques remained unchanged. PTV margin reduction was shown to reduce the value of rectal NTCP significantly. Overall, implementing the IMRT technique alone could reduce the NTCP values only by 2.1% to 7.3% from those of 3-dimensional CRT. The introduction of both IMRT and PTV margin reduction was found to be necessary for rectal NTCP to remain <5% in the dose escalation from 70 to 78 Gy. CONCLUSIONS: The complementary relationship between the introduction of IMRT and PTV margin reduction was proven. We found that both approaches need to be implemented to safely deliver a curative dose in dose-escalating prostate radiation therapy.

    DOI: 10.1016/j.prro.2019.02.001

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  • Selection criteria for 3D conformal radiotherapy versus volumetric-modulated arc therapy in high-grade glioma based on normal tissue complication probability of brain. 国際誌

    Satoshi Tanabe, Haruna Takahashi, Hirotake Saito, Atsushi Ohta, Toshimichi Nakano, Ryuta Sasamoto, Miki Shioi, Satoru Utsunomiya, Eisuke Abe, Motoki Kaidu, Hidefumi Aoyama

    Journal of radiation research   60 ( 2 )   249 - 256   2019年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    There are no quantitative selection criteria for identifying high-grade glioma (HGG) patients who are suited for volumetric-modulated arc therapy (VMAT). This study aimed to develop selection criteria that can be used for the selection of the optimal treatment modality in HGG. We analyzed 20 patients with HGG treated by 3D conformal radiotherapy (3DCRT). First, VMAT plans were created for each patient retrospectively. For each plan, the normal tissue complication probability (NTCP) for normal brain was calculated. We then divided the patients based on the NTCPs of the 3DCRT plans for normal brain, using the threshold of 5%. We compared the NTCPs of the two plans and the gross tumor volumes (GTVs) of the two groups. For the GTVs, we used receiver operating characteristic curves to identify the cut-off value for predicting NTCP < 5%. We determined the respective correlations between the GTV and the GTV's largest cross-sectional diameter and largest cross-sectional area. In the NTCP ≥ 5% group, the NTCPs for the VMAT plans were significantly lower than those for the 3DCRT plans (P = 0.0011). The NTCP ≥ 5% group's GTV was significantly larger than that of the NTCP < 5% group (P = 0.0016), and the cut-off value of the GTV was 130.5 cm3. The GTV was strongly correlated with the GTV's largest cross-sectional diameter (R2 = 0.82) and largest cross-sectional area (R2 = 0.94), which produced the cut-off values of 7.5 cm and 41 cm2, respectively. It was concluded that VMAT is more appropriate than 3DCRT in cases in which the GTV is ≥130.5 cm3.

    DOI: 10.1093/jrr/rry106

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  • Effects of Catheter Tip Location on the Spread of Sensory Block Caused by a Continuous Thoracic Paravertebral Block: A Prospective, Randomized, Controlled, Double-Blind Study. 国際誌

    Takayuki Yoshida, Yoshiko Watanabe, Takeshi Hashimoto, Atsushi Ohta, Tatsuo Nakamoto

    BioMed research international   2019   1051629 - 1051629   2019年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Single injections in the anterior region of the thoracic paravertebral space (TPVS) have been reported to generate a multisegmental longitudinal spreading pattern more frequently than those in the posterior region of the TPVS. In this trial, we examined the hypothesis that a continuous thoracic paravertebral block (TPVB) administered through a catheter inserted into the anterior region of the TPVS allows a wider sensory block dispersion. Fifty consecutive patients undergoing video-assisted thoracic surgery were enrolled. Before the surgery, an infusion catheter was inserted into the TPVS through a needle placed adjacent to either the parietal pleura (group A) or internal intercostal membrane (group P) using an ultrasound-guided intercostal transverse approach according to a randomized allocation schedule. A chest radiograph was obtained postoperatively after injection of 10 mL of radiopaque dye through the catheter. Thereafter, 20 mL of 0.375% levobupivacaine was injected via the catheter, followed by commencement of continuous TPVB with 0.25% levobupivacaine at 8 mL/h. The primary outcome was the number of blocked dermatomes at 24 h after surgery. The secondary outcomes included radiopaque dye spreading patterns, the number of segments reached by the radiopaque dye, the number of blocked dermatomes at 2 h after surgery, and pain scores. The median (interquartile range [range]) number of blocked dermatomes 24 h after surgery was 3 (2.75-4 [1-6]) in group A (n = 22) and 2 (1.5-3 [0-7]) in group P (n = 25; p = 0.037). No significant differences in the other outcomes were found between the groups. In conclusion, a continuous TPVB administered using a catheter supposedly inserted into the anterior region of the TPVS allows a wider sensory block dispersion than a catheter inserted into the posterior region of the TPVS. This trial is registered with the UMIN Clinical Trials Registry (UMIN000018578).

    DOI: 10.1155/2019/1051629

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  • Definitive chemoradiotherapy with low-dose continuous 5-fluorouracil reduces hematological toxicity without compromising survival in esophageal squamous cell carcinoma patients. 国際誌

    Hirotake Saito, Atsushi Ohta, Eisuke Abe, Motoki Kaidu, Miki Shioi, Toshimichi Nakano, Tomoya Oshikane, Kensuke Tanaka, Katsuya Maruyama, Naotaka Kushima, Satoshi Tanabe, Satoru Utsunomiya, Ryuta Sasamoto, Hidefumi Aoyama

    Clinical and translational radiation oncology   9   12 - 17   2018年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Background and purpose: To compare chemoradiotherapy (CRT) with low-dose continuous 5-fluorouracil (5FU) to CRT with 5FU+cisplatin (CDDP) for esophageal squamous cell carcinoma (ESCC) in a retrospective cohort study. Methods and materials: We reviewed the cases of Stage I-IV ESCC patients who underwent definitive CRT in 2000-2014. Concomitant chemotherapy was one of the three regimens: (1) high-dose intermittent 5FU and CDDP (standard-dose FP: SDFP), (2) low-dose continuous 5FU and CDDP (LDFP), or (3) low-dose continuous 5FU (LD5FU). The general selection criteria for chemotherapy were: SDFP for patients aged <70 yrs; LDFP for those aged 70-74 yrs; LD5FU for those aged ≥75 yrs or with performance status (PS) ≥3. Propensity scores were derived with chemotherapy (LD5FU vs. 5FU+CDDP) as the dependent variable. Results: In a multivariate analysis, chemotherapy (LD5FU vs. SDFP, p = .24; LDFP vs. SDFP, p = .52) did not affect the overall survival (OS). LD5FU caused significantly less grade 3-4 leukopenia (9%) compared to SDFP (47%) and LDFP (44%) (p < .001). In a propensity-matched analysis, LD5FU affected neither OS (HR 1.06; 95%CI 0.55-2.05; p = .87) nor progression-free survival (HR 0.95, 95%CI 0.50-1.81; p = .87). Conclusion: CRT with low-dose continuous 5FU may be a less toxic option for elderly ESCC patients.

    DOI: 10.1016/j.ctro.2017.12.003

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  • Respiratory gating and multifield technique radiotherapy for esophageal cancer.

    Atsushi Ohta, Motoki Kaidu, Satoshi Tanabe, Satoru Utsunomiya, Ryuta Sasamoto, Katsuya Maruyama, Kensuke Tanaka, Hirotake Saito, Toshimichi Nakano, Miki Shioi, Haruna Takahashi, Naotaka Kushima, Eisuke Abe, Hidefumi Aoyama

    Japanese journal of radiology   35 ( 3 )   95 - 100   2017年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: To investigate the effects of a respiratory gating and multifield technique on the dose-volume histogram (DVH) in radiotherapy for esophageal cancer. METHODS AND MATERIALS: Twenty patients who underwent four-dimensional computed tomography for esophageal cancer were included. We retrospectively created the four treatment plans for each patient, with or without the respiratory gating and multifield technique: No gating-2-field, No gating-4-field, Gating-2-field, and Gating-4-field plans. We compared the DVH parameters of the lung and heart in the No gating-2-field plan with the other three plans. RESULT: In the comparison of the parameters in the No gating-2-field plan, there are significant differences in the Lung V5Gy, V20Gy, mean dose with all three plans and the Heart V25Gy-V40Gy with Gating-2-field plan, V35Gy, V40Gy, mean dose with No Gating-4-field plan and V30Gy-V40Gy, and mean dose with Gating-4-field plan. The lung parameters were smaller in the Gating-2-field plan and larger in the No gating-4-field and Gating-4-field plans. The heart parameters were all larger in the No gating-2-field plan. CONCLUSION: The lung parameters were reduced by the respiratory gating technique and increased by the multifield technique. The heart parameters were reduced by both techniques. It is important to select the optimal technique according to the risk of complications.

    DOI: 10.1007/s11604-016-0606-7

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  • Two-fraction high-dose-rate brachytherapy within a single day combined with external beam radiotherapy for prostate cancer: single institution experience and outcomes. 国際誌

    Junyang Liu, Motoki Kaidu, Ryuta Sasamoto, Fumio Ayukawa, Nobuko Yamana, Hiraku Sato, Kensuke Tanaka, Gen Kawaguchi, Atsushi Ohta, Katsuya Maruyama, Eisuke Abe, Takashi Kasahara, Tsutomu Nishiyama, Yoshihiko Tomita, Hidefumi Aoyama

    Journal of radiation research   57 ( 3 )   280 - 7   2016年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We investigated the outcomes of treatment for patients with localized prostate cancer (PCa) treated with 3D conformal radiation therapy (3D-CRT) followed by two-fraction high-dose-rate brachytherapy within a single day (2-fr.-HDR-BT/day) at a single institution. A total of 156 consecutive Asian males (median age, 67 years) were enrolled. To compare our findings with those of other studies, we analyzed our results using the D'Amico classification, assigning the patients to low- ( N =: 5; 3.2%), intermediate- ( N =: 36; 23.1%) and high-risk ( N =: 115; 73.7%) groups (Stage T3 PCa patients were classified as high-risk). One patient in the D'Amico low-risk group (20%), 13 intermediate-risk patients (36.1%) and 99 high-risk patients (86.1%) underwent androgen deprivation therapy. We administered a prescription dose of 39 Gy in 13 fractions of 3D-CRT combined with 18 Gy of HDR-BT in two 9-Gy fractions delivered within a single day. We did not distinguish between risk groups in determining the prescription dose. The median follow-up period was 38 months. Of the 156 patients, one died from primary disease and five died from other diseases. The 3-year overall survival (OS) rates were 100%, 100% and 93.7%, and the 3-year 'biochemical no evidence of disease (bNED)' rates were 100%, 100% and 96.9% for the D'Amico low-, intermediate- and high-risk groups, respectively. No patient developed ≥ Grade 3 early toxicity. The Grade 3 late genitourinary toxicity rate was 2.6%, and no ≥ Grade 3 late gastrointestinal toxicity occurred. The efficacy and safety of this study were satisfactory, and longer-term follow-up is necessary.

    DOI: 10.1093/jrr/rrw003

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  • Superiority of a soft tissue-based setup using cone-beam computed tomography over a bony structure-based setup in intensity-modulated radiotherapy for prostate cancer. 国際誌

    Hiraku Sato, Eisuke Abe, Satoru Utsunomiya, Motoki Kaidu, Nobuko Yamana, Kensuke Tanaka, Atsushi Ohta, Mika Obinata, Junyang Liu, Gen Kawaguchi, Katsuya Maruyama, Fumio Ayukawa, Hidefumi Aoyama

    Journal of applied clinical medical physics   16 ( 5 )   239–245   2015年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The purpose of this study was to test the superiority of a soft tissue-based setup using cone-beam computed tomography (CBCT) to a bony structure-based setup using the ExacTrac system in intensity-modulated radiotherapy (IMRT) for prostate cancer. We studied 20 patients with localized prostate cancer who received IMRT between November 2010 and February 2012. After the initial setup, the pelvic bony structure-based setup and ExacTrac system were applied. After that, CBCT and a soft tissue-based setup were used. A shift in the isocenter between the ExacTrac-based and CBCT-based setup was recorded in the anterior-posterior (AP), superior-inferior (SI), and left-right (LR) axes. The shift was considered an interfractional prostate shift. Post-treatment CBCT was also taken once a week to measure the intrafractional prostate shift, based on the coordinates of the isocenter between pre- and post-treatment CBCT. The planning target volume (PTV) margins were determined using van Herk's method. We measured the elapsed time required for soft tissue matching and the entire treatment time using CBCT. The means ± standard deviation (SD) of the inter- and intrafractional shifts were 0.9 ± 2.8 mm and -0.3 ± 1.4 mm in the AP, 0.9 ± 2.2 mm and -0.1 ± 1.2 mm in the SI, and 0.1 ± 0.7 mm and -0.1 ± 0.7 mm in the LR directions. The PTV margins in the cases of bony structure-based and soft tissue-based setups were 7.3 mm and 2.7 mm in the AP, 5.8 mm and 2.3 mm in the SI, and 1.9 mm and 1.2 mm in the LR directions. Even though the median elapsed time using CBCT was expanded in 5.9 min, the PTV margins were significantly reduced. We found the calculated PTV margins in the soft tissue-based setup using CBCT were small, and this arrangement was superior to the bony structure-based setup in prostate IMRT.

    DOI: 10.1120/jacmp.v16i5.5448

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  • The effectiveness of endoscopic submucosal dissection followed by chemoradiotherapy for superficial esophageal cancer. 国際誌

    Gen Kawaguchi, Ryuta Sasamoto, Eisuke Abe, Atsushi Ohta, Hiraku Sato, Kensuke Tanaka, Katsuya Maruyama, Motoki Kaizu, Fumio Ayukawa, Nobuko Yamana, Junyang Liu, Manabu Takeuchi, Masaaki Kobayashi, Hidefumi Aoyama

    Radiation oncology (London, England)   10   31 - 31   2015年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: To evaluate the risks and benefits of endoscopic submucosal dissection (ESD) in addition to chemoradiotherapy (CRT) for the treatment of superficial esophageal squamous cell carcinoma (SESCC). METHODS AND MATERIALS: We retrospectively reviewed the treatment outcomes of 47 patients with SESCC treated between October 2000 and December 2011. Sixteen patients with invasion into the submucosal layer (T1b) or the muscularis mucosa (m3) with positive vascular invasion were treated with CRT after ESD (ESD-CRT group). The lymph node area was irradiated to a total dose of 40-44 Gy and a boost radiation was administered if PET-positive lymph nodes or positive margins were observed. The remaining 31 patients received definitive CRT only (dCRT group). RESULTS: The radiation field was significantly larger in the ESD-CRT group; the "long T" was used in 11 patients (35.4%) in the dCRT group and 15 (93.7%) in the ESD-CRT group (p = 0.0001). The total radiation dose was smaller in the ESD-CRT group; 40 Gy was used in 10 patients (62.5%) in the ESD-CRT group and all but one patient in the dCRT group received ≥60 Gy (p = 0.00001). The 3-year overall survival rates in the dCRT and ESD-CRT groups were 63.2% and 90.0% respectively (p = 0.118). Recurrence developed in nine patients (29.0%) in the dCRT group and one (6.3%) in the ESD-CRT group. Local recurrence was observed in six patients (19%) in the dCRT group and none in the ESD-CRT-group (p = 0.029). Pericardial effusion (≥Grade 3) occurred in three patients (9.7%) in the dCRT group and none in the ESD-CRT group. CONCLUSIONS: ESD followed by CRT is an effective and safe approach for SESCC at m3 or T1b. This combination of ESD and CRT improves the local control rate, and it could decrease the number of cardiac toxicities due to a radiation-dose reduction relative to CRT alone.

    DOI: 10.1186/s13014-015-0337-4

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  • Main bronchial diverticula in the subcarinal region: their relation to airflow limitations. 国際誌

    Takeshi Higuchi, Naoya Takahashi, Motoi Shiotani, Suguru Sato, Atsushi Ohta, Haruo Maeda, Haruhiko Nakajima, Kazuhiko Itoh, Hiroki Tsukada

    Acta radiologica (Stockholm, Sweden : 1987)   53 ( 1 )   44 - 8   2012年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: To date, bronchial diverticula have generally been treated as a pathological condition associated with chronic obstructive pulmonary disease (COPD), although only a limited amount of published information is available on the relationship between bronchial diverticula as depicted by multidetector computed tomography (MDCT) and airflow limitations. PURPOSE: To evaluate the relationship between airflow limitations and main bronchial diverticula in the subcarinal region using spirometry and thin-section MDCT. MATERIAL AND METHODS: A total of 189 consecutive adult patients were retrospectively evaluated based on spirometry and thin-section MDCT of the chest. All examinations were performed at our institution between June and October 2008. The study group included 70 women and 119 men with a mean age of 65 years (range 19-86 years). The relationship between the FEV(1)% and bronchial diverticula in the subcarinal region was analyzed (Student's t-test). RESULTS: The indications for conducting the examinations were pulmonary diseases (82 patients), cardiovascular diseases (22), extrapulmonary malignancies (74), and other conditions (11). A total of 84/189 (44.4%) patients showed bronchial diverticula, and the FEV(1)% of 70/84 (83.3%) patients was above 70. The FEV(1)% of patients with lesions ranged from 26.0 to 97.8 (mean 76.8), whereas the range was 28.1-94.4 (mean 73.7) in those without lesions. There was no significant association between the FEV(1)% and the presence of subcarinal bronchial diverticula (P > 0.05). CONCLUSION: Our data demonstrate that thin-section chest CT commonly demonstrates main bronchial diverticula in the subcarinal region in patients without airflow limitations. We propose that the presence of a small number of tiny bronchial diverticula under the carina may not be a criterion for the diagnosis of COPD.

    DOI: 10.1258/ar.2011.110222

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