Publications by authors named "Yoshikazu Maeda"

Background: Intrahepatic cholangiocarcinoma (ICC) is a challenging primary liver cancer with a poor prognosis, especially in unresectable cases. Traditional palliative irradiation is limited in reducing liver doses. This study aimed to evaluate the efficacy and toxicity of respiratory-gated proton beam therapy without fiducial markers for intrahepatic cholangiocarcinoma.

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Purpose: In concurrent chemoradiotherapy for advanced esophageal cancer, a 2-phase method consisting of initial irradiation of a wide elective nodal region and boost irradiation of the primary lesion is commonly employed. Although dose escalation to the primary lesion may be required to achieve higher local control rates, the radiation dose to critical organs must not exceed dose constraints. To achieve an optimum balance of dose prescription and dose reduction to surrounding organs, such as the lungs and heart, we compared hybrid dose distributions and investigated the best combination of the following recent irradiation techniques: volumetric modulation arc therapy (VMAT), proton broad-beam irradiation, and intensity-modulated proton beam therapy (IMPT).

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Background: Proton beam therapy (PBT) has been recently reported to achieve excellent tumor control with minimal toxicity in patients with unresectable hepatocellular carcinoma (HCC). Radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) was investigated for larger HCC. This study was designed to evaluate the therapeutic effect of PBT on unresectable HCC in comparison with TACE combined with RFA.

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Background: It is important to have precise image guidance throughout proton therapy in order to take advantage of the therapy's physical selectivity.

Purpose: We evaluated the effectiveness of computed tomography (CT)-image guidance in proton therapy for patients with hepatocellular carcinoma (HCC) by assessing daily proton dose distributions. The importance of daily CT image-guided registration and daily proton dose monitoring for tumors and organs at risk (OARs) was investigated.

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We evaluated elective nodal irradiation (ENI) doses during radical chemoradiotherapy (CRT) for esophageal cancer (EC). A total of 79 patients (65 men and 14 women) aged 52-80 years with T1-3, N0-3, and M0 (including M1ly) who underwent CRT for EC during November 2012-September 2019 were eligible for this retrospective analysis. Patients were divided into two groups: the high-dose group (HG), including 38 patients who received ≥40 Gy as ENI; and the low-dose group (LG), including 41 patients who received <40 Gy.

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We report here the long-term results of marker-less respiratory-gated proton therapy (PT), without fiducial markers for hepatocellular carcinoma (HCC), which was planned using a four-dimensional computed tomography technique. Local tumor control (LTC) and overall survival (OS) were estimated using the Kaplan-Meier method. Toxicity was graded per CTCAE v5.

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Purpose: To evaluate the dosimetric advantages of daily adaptive radiotherapy (DART) in intensity-modulated proton therapy (IMPT) for high-risk prostate cancer by comparing estimated doses of the conventional non-adaptive radiotherapy (NART) that irradiates according to an original treatment plan through the entire treatment and the DART that uses an adaptive treatment plan generated by using daily CT images acquired before each treatment.

Methods: Twenty-three patients with prostate cancer were included. A treatment plan with 63 Gy (relative biological effectiveness (RBE)) in 21 fractions was generated using treatment planning computed tomography (CT) images assuming that all patients had high-risk prostate cancer for which the clinical target volume (CTV) needs to include prostate and the seminal vesicle (SV) in our treatment protocol.

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Objective: In cases of head and neck cancer treated with intra-arterial chemotherapy, no objective indices are available for determining the distribution of anticancer drugs administered to multiple arteries. To establish such indices, noninvasive measurements of drug concentrations are required in the arterial perfusion area of each artery. In MRI, changes in 1/T (Δ1/T) are correlated with the contrast agent concentration.

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Purpose: To evaluate the optimal period of replanning to spare the rectal dose by investigating daily rectal movements during computed tomography (CT) image-guided proton therapy for prostate cancer.

Materials And Methods: To evaluate the optimum reference period for replanning, we analyzed 1483 sets of daily CT (dCT) images acquired from 40 prostate cancer patients and measured the daily rectal movement along the anterior-posterior direction based on the simulator CT (sCT) images and dCT images. We calculated daily dose distributions based on initial plans on the sCT images and replans on the dCT images for 13 representative patients, and evaluated daily dose volume histograms (DVHs) for the prostate, seminal vesicles, and rectum.

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The layer-stacking method can provide three-dimensional conformal dose distributions to the target based on a passive scattering method using mini-spread-out Bragg peak (SOBP). The purpose of this work is to demonstrate the effectiveness of a new weight optimization algorithm that can enhance the robustness of dose distributions against layer depth variation in layer-stacking proton beam therapy. In the robustness algorithm, the upper limit of the layer's weight was adapted to the conventional algorithm and varied for 620 weight set evaluations.

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Introduction: A post-marketing surveillance (PMS) study was conducted to confirm the long-term risk-benefit profile of sitagliptin administered to Japanese patients with type 2 diabetes mellitus (T2DM) under real-world conditions.

Methods: This prospective, multicentre, open-label PMS collected data from 3326 patients receiving sitagliptin according to the approved indication during the case registration period (July 2010-June 2012; observation period, 3 years). Safety was assessed via collection of data on adverse drug reactions (ADRs), estimated glomerular filtration rate (eGFR) and cardiovascular events whereas efficacy was assessed via changes in glycated hemoglobin (HbA1c).

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Global Phase III trials of suvorexant showed no obvious differences in the safety and efficacy profile of suvorexant between elderly and non-elderly patients. However, the clinical profile of suvorexant in elderly patients with comorbidities in a real-world setting was not evaluated. To further understand the safety and efficacy profile of suvorexant in elderly patients with insomnia in a daily clinical practice setting, we conducted a sub-group analysis of the post-marketing drug-use results survey.

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: Suvorexant is a dual orexin receptor antagonist used for treating insomnia. The authors elucidated the safety profiles and clinical course of insomnia therapy with suvorexant under different initial treatment status seen in daily routine practice. : Subgroup analysis of a post-marketing survey (PMS; 2015-2017) divided patients based on their initial treatment status with suvorexant into 'hypnotic-naïve (Group N)', 'switching from a prior sleep medication (Group S),' 'add-on therapy (Group A),' and 'others (Group O).

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Background: We report on the results of a Japanese postmarketing drug-use survey of suvorexant (Belsomra) tablets.

Methods: A survey with a ≤ 6-month observation period after the start of administration was conducted, targeting insomnia patients who were treated with suvorexant for the first time in Japan. Information on the safety and efficacy of the drug product was collected.

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To evaluate the safety and effectiveness of the long-term administration of diazoxide in patients with hyperinsulinemic hypoglycemia, a post-marketing surveillance study was conducted. Between 2008 and 2015, with a maximum observation period of 7 yr, 384 patients were monitored; 117 (30.5%) experienced at least one adverse drug reaction (ADR).

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Purpose: The purpose of this study was to analyze the respiratory motion of each segment of the liver in patients with or without a history of abdominal surgery using four-dimensional computed tomography.

Materials And Methods: In total, 57 patients treated for abdominal tumors using proton beam therapy were enrolled. Eighteen patients had a history of abdominal surgery and 39 did not.

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Purpose: We quantified interfractional movements of the prostate, seminal vesicles (SVs), and rectum during computed tomography (CT) image-guided proton therapy for prostate cancer and studied the range variation in opposed lateral proton beams.

Materials/methods: We analyzed 375 sets of daily CT images acquired throughout the proton therapy treatment of ten patients. We analyzed daily movements of the prostate, SVs, and rectum by simulating three image-matching strategies: bone matching, prostate center (PC) matching, and prostate-rectum boundary (PRB) matching.

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We evaluated the effectiveness and toxicity of proton beam therapy (PBT) for hepatocellular carcinomas (HCC) >5 cm without fiducial markers using four-dimensional CT (4D-CT) planning. The subjects were 29 patients treated at our hospital between March 2011 and March 2015. The median total dose was 76 Cobalt Gray Equivalents (CGE) in 20 fractions (range; 66-80.

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Purpose: To evaluate the effectiveness of CT image-guided proton radiotherapy for prostate cancer by analyzing the positioning uncertainty and assessing daily dose change due to anatomical variations.

Materials And Methods: Patients with prostate cancer were treated by opposed lateral proton beams based on a passive scattering method using an in-room CT image-guided system. The system employs a single couch for both CT scanning and beam delivery.

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The efficacy of proton beam therapy (PBT) for hepatocellular carcinoma (HCC) has been reported, but insertion of fiducial markers in the liver is usually required. We evaluated the efficacy and toxicity of respiratory-gated PBT without fiducial markers for HCC located within 2 cm of the gastrointestinal tract. From March 2011 to December 2015 at our institution, 40 patients were evaluated (median age, 72 years; range, 38-87 years).

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Purpose/objective(s): Accurate and reproducible positioning of the breast is difficult due to its deformability and softness; thus, targeting a breast tumor or tumor bed with fractionated radiotherapy using external beam radiation is difficult. The aim of this study was to develop a novel bra to aid in breast immobilization in the prone position.

Materials & Methods: To assess the accuracy of prone position fixation of breast tumors, 33 breast cancer patients with 34 lesions were recruited.

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Background: Proton beam therapy (PBT) achieves good local control for hepatocellular carcinoma (HCC), and toxicity tends to be lower than for photon radiotherapy. Focal liver parenchymal damage in radiotherapy is described as the focal liver reaction (FLR); the threshold doses (TDs) for FLR in the background liver have been analyzed in stereotactic ablative body radiotherapy and brachytherapy. To develop a safer approach for PBT, both TD and liver volume changes are considered clinically important in predicting the extent of damage before treatment, and subsequently in reducing background liver damage.

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Objective: Paliperidone palmitate once-monthly injectable (PP1M) is approved in Japan and other countries for the treatment of schizophrenia. During the 6 month Japanese early postmarketing phase vigilance (EPPV) period, 32 deaths were reported. This report reviews potential contributing factors to the fatal outcomes in the PP1M-treated population.

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In the development of an external radiotherapy treatment planning system, the output factor (OPF) is an important value for the monitor unit calculations. We developed a proton OPF calculation model with consideration for the collimator aperture edge to account for the dependence of the OPF on the collimator aperture and distance in proton beam therapy. Five parameters in the model were obtained by fitting with OPFs measured by a pinpoint chamber with the circular radiation fields of various field radii and collimator distances.

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