Yoshitaka Sato

University of Fukui, Hukui, Fukui, Japan

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Publications (4)10.04 Total impact

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    ABSTRACT: Purpose: The aim of this study was to investigate the potential of PET imaging with a hypoxia-selective tracer ⁶²Cu-diacetyl-bis(N⁴-methylthiosemicarbazone) (⁶²Cu-ATSM) for evaluating the prognosis of patients with head and neck cancer (HNC). Methods: Twenty-five patients with HNC including stage II to IV underwent both ⁶²Cu-ATSM and ¹⁸F-FDG PET before the initiation of treatment. Volumes of interest were placed on the tumor and sternocleidomastoid muscles to obtain SUVmax and to calculate the tumor-to-muscle activity ratio (TMR). The PET results were correlated with clinical follow-up, and the receiver operating characteristic analysis was used to determine the optimal cutoff values. Progression-free survival (PFS) and cause-specific survival (CSS) were statistically analyzed. Results: Patients were followed up for periods ranging from 4 to 32 months. Twelve patients died from local recurrence or metastasis of a primary cancer, and 2 had recurrence of the 13 remaining patients. Mean (SD) periods of PFS and CSS were 15.5 (12.5) and 18.6 (11.0) months, respectively. Optimal cutoff values for each PET index were as follows: SUVs of ⁶²Cu-ATSM (SUVATSM) and FDG were 3.6 and 7.9; TMRs of ATSM (TMRATSM) and FDG were 3.2 and 5.6. When the cutoff for TMRATSM was set at 3.2, patients with a greater TMRATSM had significantly worse PFS (P = 0.014) and CSS (P = 0.031). Two-year PFS and CSS rates were 73% and 80% for patients with a lower TMRATSM (≤3.2); however, they were 20% and 33% for those with hypoxic tumors (TMRATSM, >3.2), respectively. F-FDG-related indices did not show any significant difference in either PFS or CSS. Conclusions: Pretreatment ⁶²Cu-ATSM PET is useful for predicting the prognosis of patients with HNC.
    Clinical Nuclear Medicine 08/2014; 39(12). DOI:10.1097/RLU.0000000000000537 · 3.93 Impact Factor
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    ABSTRACT: Purpose. To assess changes in lower urinary tract symptoms (LUTS) within 1 year after brachytherapy in patients receiving alpha 1-adrenoceptor antagonists. Methods. We retrospectively evaluated 116 patients who underwent (125)I prostate brachytherapy in our institute. Seventy-one patients were treated with a combination of external beam radiation therapy and brachytherapy. Alpha 1-adrenoceptor antagonists were prescribed to all patients after brachytherapy. International Prostate Symptom Score (IPSS) forms and postvoid residual urine volume were recorded at all follow-up visits. Results. Forty-nine patients were given tamsulosin hydrochloride, 32 were given silodosin hydrochloride, and 35 were given naftopidil for up to 6 months after seed implantation. Patients given tamsulosin or naftopidil tended to show a higher peak IPSS and slower recovery to baseline values than those given silodosin. The patients given naftopidil showed an insufficient recovery in storage symptoms in naftopidil group in comparison with tamsulosin group at 3 months and with silodosin group at 6 and 9 months. Conclusions. In the management of LUT after brachytherapy, silodosin may provide a more favorable improvement. Silodosin and tamsulosin may have an advantage in improving not only voiding but also storage lower urinary tract symptoms after brachytherapy.
    03/2014; 2014(2):140654. DOI:10.1155/2014/140654
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    ABSTRACT: Technological developments have increased the ease of performing perfusion MRI by arterial spin labeling (ASL) in clinical settings. The objective of this study was to evaluate the effects of radiotherapy on extra-axial brain tumors by using MR perfusion images obtained using the pseudo-continuous arterial spin labeling (pcASL) method. Six consecutive patients (nine lesions) with extra-axial brain tumors treated only with radiotherapy were enrolled in this study. MR examinations, including pcASL imaging, were performed before and after radiotherapy. Cerebral blood flow, maximum tumor blood flow (mTBF), tumor volume and the ratio of signal enhancement by contrast material (enhancement ratio) were evaluated in serial examinations during the course of radiotherapy. Both the percentage change in mTBF (mTBF ratio) and the percentage change in volume (volume ratio) were calculated using values obtained before and after radiotherapy. The correlation between the volume ratio and the mTBF ratio was assessed using linear regression analysis and Spearman's rank correlation coefficient (rs). A strong correlation was demonstrated between the tumor volume ratio and the mTBF ratio before and after radiotherapy (rs=0.93, P<.01). However, no significant correlation was identified between changes in enhancement and volume ratio (rs=0.20) or between changes in enhancement and mTBF ratio (rs=0.30) before and after radiotherapy. The mTBF measured using pcASL may serve as an additive index for tumor volume when determining tumor response to radiotherapy even in the absence of contrast material.
    Magnetic Resonance Imaging 06/2013; 31(8). DOI:10.1016/j.mri.2013.04.011 · 2.09 Impact Factor
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    ABSTRACT: Without Abstract
    European Radiology 02/2006; 16(1):242-3. DOI:10.1007/s00330-005-2803-0 · 4.01 Impact Factor