MDPI Acta Medica Okayama 2075-4418 15 6 2025 Robustness of Machine Learning Predictions for Determining Whether Deep Inspiration Breath-Hold Is Required in Breast Cancer Radiation Therapy 668 EN Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Jamal, Ghaida Al Jamal Department of Oral Medicine and Oral Surgery, Faculty of Dentistry, Jordan University of Science and Technology Mamiko Fujikura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Ryo Kamizaki Radiological Technology, Graduate School of Health Sciences, Okayama University Kazuhiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Suzuka Yoshida Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yoshihide Nakamura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Yoshinori Tanabe Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Sugimoto Radiological Technology, Graduate School of Health Sciences, Okayama University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Majd Barham Department of Dentistry and Dental Surgery, College of Medicine and Health Sciences, An-Najah National University Nouha Tekiki Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Miki Hisatomi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Junichi Asaumi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Background/Objectives: Deep inspiration breath-hold (DIBH) is a commonly used technique to reduce the mean heart dose (MHD), which is critical for minimizing late cardiac side effects in breast cancer patients undergoing radiation therapy (RT). Although previous studies have explored the potential of machine learning (ML) to predict which patients might benefit from DIBH, none have rigorously assessed ML model performance across various MHD thresholds and parameter settings. This study aims to evaluate the robustness of ML models in predicting the need for DIBH across different clinical scenarios. Methods: Using data from 207 breast cancer patients treated with RT, we developed and tested ML models at three MHD cut-off values (240, 270, and 300 cGy), considering variations in the number of independent variables (three vs. six) and folds in the cross-validation (three, four, and five). Robustness was defined as achieving high F2 scores and low instability in predictive performance. Results: Our findings indicate that the decision tree (DT) model demonstrated consistently high robustness at 240 and 270 cGy, while the random forest model performed optimally at 300 cGy. At 240 cGy, a threshold critical to minimize late cardiac risks, the DT model exhibited stable predictive power, reducing the risk of overestimating DIBH necessity. Conclusions: These results suggest that the DT model, particularly at lower MHD thresholds, may be the most reliable for clinical applications. By providing a tool for targeted DIBH implementation, this model has the potential to enhance patient-specific treatment planning and improve clinical outcomes in RT. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2075-4418 15 6 2025 Improving Diagnostic Performance for Head and Neck Tumors with Simple Diffusion Kurtosis Imaging and Machine Learning Bi-Parameter Analysis 790 EN Suzuka Yoshida Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Yoshihide Nakamura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yuka Fukumura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yuki Nakamitsu Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Kazuhiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Yudai Shimizu Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yoshinori Tanabe Radiological Technology, Graduate School of Health Sciences, Okayama University Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Majd Barham Department of Dentistry and Dental Surgery, College of Medicine and Health Sciences, An-Najah National University Nouha Tekiki Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Nurul N. Kamaruddin Department of Oral Rehabilitation and Regenerative Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Miki Hisatomi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yoshinobu Yanagi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Junichi Asaumi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Background/Objectives: Mean kurtosis (MK) values in simple diffusion kurtosis imaging (SDI)-a type of diffusion kurtosis imaging (DKI)-have been reported to be useful in the diagnosis of head and neck malignancies, for which pre-processing with smoothing filters has been reported to improve the diagnostic accuracy. Multi-parameter analysis using DKI in combination with other image types has recently been reported to improve the diagnostic performance. The purpose of this study was to evaluate the usefulness of machine learning (ML)-based multi-parameter analysis using the MK and apparent diffusion coefficient (ADC) values-which can be acquired simultaneously through SDI-for the differential diagnosis of benign and malignant head and neck tumors, which is important for determining the treatment strategy, as well as examining the usefulness of filter pre-processing. Methods: A total of 32 pathologically diagnosed head and neck tumors were included in the study, and a Gaussian filter was used for image pre-processing. MK and ADC values were extracted from pixels within the tumor area and used as explanatory variables. Five ML algorithms were used to create models for the prediction of tumor status (benign or malignant), which were evaluated through ROC analysis. Results: Bi-parameter analysis with gradient boosting achieved the best diagnostic performance, with an AUC of 0.81. Conclusions: The usefulness of bi-parameter analysis with ML methods for the differential diagnosis of benign and malignant head and neck tumors using SDI data were demonstrated. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2077-0383 13 6 2024 Enhancing Diagnostic Precision: Evaluation of Preprocessing Filters in Simple Diffusion Kurtosis Imaging for Head and Neck Tumors 1783 EN Yuki Nakamitsu Radiological Technology, Graduate School of Health Sciences, Okayama University Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Yudai Shimizu Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Kazuhiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Yuuki Yoshimura Radiological Technology, Graduate School of Health Sciences, Okayama University Suzuka Yoshida Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Yoshihide Nakamura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Yuka Fukumura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Ryo Kamizaki Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Yoshinori Tanabe Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Sugimoto Radiological Technology, Graduate School of Health Sciences, Okayama University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Majd Barham Department of Dentistry and Dental Surgery, College of Medicine and Health Sciences, An-Najah National University Nouha Tekiki Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Junichi Asaumi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Background: Our initial clinical study using simple diffusion kurtosis imaging (SDI), which simultaneously produces a diffusion kurtosis image (DKI) and an apparent diffusion coefficient map, confirmed the usefulness of SDI for tumor diagnosis. However, the obtained DKI had noticeable variability in the mean kurtosis (MK) values, which is inherent to SDI. We aimed to improve this variability in SDI by preprocessing with three different filters (Gaussian [G], median [M], and nonlocal mean) of the diffusion-weighted images used for SDI. Methods: The usefulness of filter parameters for diagnosis was examined in basic and clinical studies involving 13 patients with head and neck tumors. Results: The filter parameters, which did not change the median MK value, but reduced the variability and significantly homogenized the MK values in tumor and normal tissues in both basic and clinical studies, were identified. In the receiver operating characteristic curve analysis for distinguishing tumors from normal tissues using MK values, the area under curve values significantly improved from 0.627 without filters to 0.641 with G (sigma = 0.5) and 0.638 with M (radius = 0.5). Conclusions: Thus, image pretreatment with G and M for SDI was shown to be useful for improving tumor diagnosis in clinical practice. No potential conflict of interest relevant to this article was reported.

Springer Acta Medica Okayama 2090-4762 55 1 2024 Evaluating the index of panoramic X-ray image quality using K-means clustering method 4 EN Satoshi Imajo Division of Radiology, Medical Support Department, Okayama University Hospital Yoshinori Tanabe Faculty of Medicine, Graduate School of Health Sciences, Okayama University Nobue Nakamura Division of Radiology, Medical Support Department, Okayama University Hospital Mitsugi Honda Division of Radiology, Medical Support Department, Okayama University Hospital Masahiro Kuroda Faculty of Medicine, Graduate School of Health Sciences, Okayama University Background A panoramic X-ray image is generally considered optimal when the occlusal plane is slightly arched, presenting with a gentle curve. However, the ideal angle of the occlusal plane has not been determined. This study provides a simple evaluation index for panoramic X-ray image quality, built using various image and cluster analyzes, which can be used as a training tool for radiological technologists and as a reference for image quality improvement.<br> Results A reference panoramic X-ray image was acquired using a phantom with the Frankfurt plane positioned horizontally, centered in the middle, and frontal plane centered on the canine teeth. Other images with positioning errors were acquired with anteroposterior shifts, vertical rotations of the Frankfurt plane, and horizontal left/right rotations. The reference and positioning-error images were evaluated with the cross-correlation coefficients for the occlusal plane profile, left/right angle difference, peak signal-to-noise ratio (PSNR), and deformation vector fields (DVF). The results of the image analyzes were scored for positioning-error images using K-means clustering analysis. Next, we analyzed the correlations between the total score, cross-correlation analysis of the occlusal plane curves, left/right angle difference, PSNR, and DVF. In the scoring, the positioning-error images with the highest quality were the ones with posterior shifts of 1 mm. In the analysis of the correlations between each pair of results, the strongest correlations (r = 0.7–0.9) were between all combinations of PSNR, DVF, and total score.<br> Conclusions The scoring of positioning-error images using K-means clustering analysis is a valid evaluation indicator of correct patient positioning for technologists in training. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2075-4418 13 24 2023 Characteristic Mean Kurtosis Values in Simple Diffusion Kurtosis Imaging of Dentigerous Cysts 3619 EN Yuka Fukumura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Suzuka Yoshida Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yoshihide Nakamura Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yuki Nakamitsu Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla Al-Hammad Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Kazuhiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Ryo Kamizaki Radiological Technology, Graduate School of Health Sciences, Okayama University Yudai Shimizu Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yoshinori Tanabe Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Sugimoto Radiological Technology, Graduate School of Health Sciences, Okayama University Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Majd Barham Department of Dentistry and Dental Surgery, College of Medicine and Health Sciences, An-Najah National University Nouha Tekiki Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Nurul Kamaruddin Department of Oral Rehabilitation and Regenerative Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yoshinobu Yanagi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Junichi Asaumi Department of Oral and Maxillofacial Radiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University We evaluated the usefulness of simple diffusion kurtosis (SD) imaging, which was developed to generate diffusion kurtosis images simultaneously with an apparent diffusion coefficient (ADC) map for 27 cystic disease lesions in the head and neck region. The mean kurtosis (MK) and ADC values were calculated for the cystic space. The MK values were dentigerous cyst (DC): 0.74, odontogenic keratocyst (OKC): 0.86, ranula (R): 0.13, and mucous cyst (M): 0, and the ADC values were DC: 1364 × 10−6 mm2/s, OKC: 925 × 10−6 mm2/s, R: 2718 × 10−6 mm2/s, and M: 2686 × 10−6 mm2/s. The MK values of DC and OKC were significantly higher than those of R and M, whereas their ADC values were significantly lower. One reason for the characteristic signal values in diffusion-weighted images of DC may be related to content components such as fibrous tissue and exudate cells. When imaging cystic disease in the head and neck region using SD imaging, the maximum b-value setting at the time of imaging should be limited to approximately 1200 s/mm2 for accurate MK value calculation. This study is the first to show that the MK values of DC are characteristically higher than those of other cysts. No potential conflict of interest relevant to this article was reported.

Spandidos Publications Acta Medica Okayama 1792-0981 26 5 2023 Evaluation of the accuracy of heart dose prediction by machine learning for selecting patients not requiring deep inspiration breath‑hold radiotherapy after breast cancer surgery 536 EN Ryo Kamizaki Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla Al‑Hammad Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Nouha Tekiki Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hinata Ishizaka Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Kazuhiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Sugimoto Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Yoshinori Tanabe Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Majd Barham Department of Dentistry and Dental Surgery, College of Medicine and Health Sciences, An‑Najah National University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Yuki Nakamitsu Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Masaki Hirano Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Yuki Muto Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Hiroki Ihara Department of Radiology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Soichi Sugiyama Department of Proton Beam Therapy, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Increased heart dose during postoperative radiotherapy (RT) for left‑sided breast cancer (BC) can cause cardiac injury, which can decrease patient survival. The deep inspiration breath‑hold technique (DIBH) is becoming increasingly common for reducing the mean heart dose (MHD) in patients with left‑sided BC. However, treatment planning and DIBH for RT are laborious, time‑consuming and costly for patients and RT staff. In addition, the proportion of patients with left BC with low MHD is considerably higher among Asian women, mainly due to their smaller breast volume compared with that in Western countries. The present study aimed to determine the optimal machine learning (ML) model for predicting the MHD after RT to pre‑select patients with low MHD who will not require DIBH prior to RT planning. In total, 562 patients with BC who received postoperative RT were randomly divided into the trainval (n=449) and external (n=113) test datasets for ML using Python (version 3.8). Imbalanced data were corrected using synthetic minority oversampling with Gaussian noise. Specifically, right‑left, tumor site, chest wall thickness, irradiation method, body mass index and separation were the six explanatory variables used for ML, with four supervised ML algorithms used. Using the optimal value of hyperparameter tuning with root mean squared error (RMSE) as an indicator for the internal test data, the model yielding the best F2 score evaluation was selected for final validation using the external test data. The predictive ability of MHD for true MHD after RT was the highest among all algorithms for the deep neural network, with a RMSE of 77.4, F2 score of 0.80 and area under the curve‑receiver operating characteristic of 0.88, for a cut‑off value of 300 cGy. The present study suggested that ML can be used to pre‑select female Asian patients with low MHD who do not require DIBH for the postoperative RT of BC. No potential conflict of interest relevant to this article was reported.

Cell Press Acta Medica Okayama 2405-8440 9 8 2023 Bayesian statistical modeling to predict observer-specific optimal windowing parameters in magnetic resonance imaging e19038 EN Kohei Sugimoto Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University Masataka Oita Faculty of Interdisciplinary Science and Engineering in Health Systems, Okayama University Masahiro Kuroda Department of Radiological Technology, Faculty of Health Sciences, Okayama University Magnetic resonance (MR) images require a process known as windowing for optimizing the display conditions. However, the conventional windowing process often fails to achieve the preferred display conditions for observers due to various factors. This study proposes a novel framework for predicting the preferred windowing parameters for each observer using Bayesian statistical modeling. MR images obtained from 1000 patients were divided into training and test sets at a 7:3 ratio. The image intensity and windowing parameters were standardized using previously reported methods. Bayesian statistical modeling was utilized to predict the windowing parameters preferred by three MR imaging (MRI) operators. The performance of the proposed framework was evaluated by assessing the mean relative error (MRE), mean absolute error (MAE), and Pearson's correlation coefficient (ρ) of the test set. In addition, the naive method, which presumes that the average value of the windowing parameters for each acquisition sequence and body region in the training set is optimal, was also used for comparison. Three MRI operators and three radiologists conducted visual assessments. The mean MRE, MAE, and ρ values for the window level and width (WL/WW) in the proposed framework were 12.6 and 13.9, 42.9 and 85.4, and 0.98 and 0.98, respectively. These results outperformed those obtained using the naive method. The visual assessments revealed no significant differences between the original and predicted display conditions, indicating that the proposed framework accurately predicts individualized windowing parameters with the additional advantages of robustness and ease of use. Thus, the proposed framework can effectively predict the windowing parameters preferred by each observer. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1198-0052 30 8 2023 Mean Heart Dose Prediction Using Parameters of Single-Slice Computed Tomography and Body Mass Index: Machine Learning Approach for Radiotherapy of Left-Sided Breast Cancer of Asian Patients 7412 7424 EN Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Ryo Kamizaki Radiological Technology, Graduate School of Health Sciences, Okayama University Nouha Tekiki Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hinata Ishizaka Radiological Technology, Graduate School of Health Sciences, Okayama University Kazuhiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Sugimoto Radiological Technology, Graduate School of Health Sciences, Okayama University Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Yoshinori Tanabe Radiological Technology, Graduate School of Health Sciences, Okayama University Majd Barham Department of Dentistry and Dental Surgery, College of Medicine and Health Sciences, An-Najah National University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Yudai Shimizu Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki Nakamitsu Radiological Technology, Graduate School of Health Sciences, Okayama University Junichi Asaumi Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Deep inspiration breath-hold (DIBH) is an excellent technique to reduce the incidental radiation received by the heart during radiotherapy in patients with breast cancer. However, DIBH is costly and time-consuming for patients and radiotherapy staff. In Asian countries, the use of DIBH is restricted due to the limited number of patients with a high mean heart dose (MHD) and the shortage of radiotherapy personnel and equipment compared to that in the USA. This study aimed to develop, evaluate, and compare the performance of ten machine learning algorithms for predicting MHD using a patient's body mass index and single-slice CT parameters to identify patients who may not require DIBH. Machine learning models were built and tested using a dataset containing 207 patients with left-sided breast cancer who were treated with field-in-field radiotherapy with free breathing. The average MHD was 251 cGy. Stratified repeated four-fold cross-validation was used to build models using 165 training data. The models were compared internally using their average performance metrics: F2 score, AUC, recall, accuracy, Cohen's kappa, and Matthews correlation coefficient. The final performance evaluation for each model was further externally analyzed using 42 unseen test data. The performance of each model was evaluated as a binary classifier by setting the cut-off value of MHD & GE; 300 cGy. The deep neural network (DNN) achieved the highest F2 score (78.9%). Most models successfully classified all patients with high MHD as true positive. This study indicates that the ten models, especially the DNN, might have the potential to identify patients who may not require DIBH. No potential conflict of interest relevant to this article was reported.

Public Library of Science Acta Medica Okayama 1932-6203 18 2 2023 Evaluation of calculation processes of apparent diffusion coefficient subtraction method (ASM) imaging EN Majd Barham Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Yuuki Yoshimura Radiological Technology, Graduate School of Health Sciences, Okayama University Kentaro Hamada Radiological Technology, Graduate School of Health Sciences, Okayama University Abdullah Khasawneh Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kohei Sugimoto Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Konishi Radiological Technology, Graduate School of Health Sciences, Okayama University Nouha Tekiki Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Irfan Sugianto Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Babatunde O. Bamgbose Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hinata Ishizaka Radiological Technology, Graduate School of Health Sciences, Okayama University Yudai Shimizu Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki Nakamitsu Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Kamizaki Radiological Technology, Graduate School of Health Sciences, Okayama University Akira Kurozumi Central Division of Radiology, Okayama University Hospital Toshi Matsushita Central Division of Radiology, Okayama University Hospital Seiichiro Ohno Central Division of Radiology, Okayama University Hospital Junichi Asaumi Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences A number of restricted diffusion (RD) imaging techniques, such as diffusion kurtosis (DK) imaging and Q space imaging, have been developed and proven to be useful for the diagnosis of diseases, including cerebral gliomas and cerebrovascular infarction. In particular, apparent diffusion coefficient (ADC) subtraction method (ASM) imaging has become available recently as a novel RD imaging technique. ASM is based on the difference between the ADC values in an image pair of two ADC maps, ADC basic (ADCb) and ADC modify (ADCm), which are created from diffusion-weighted images taken using short and long effective diffusion times, respectively. The present study aimed to assess the potential of different types of ASM imaging by comparing them with DK imaging which is the gold-standard RD imaging technique. In the present basic study using both polyethylene glycol phantom and cell-containing bio-phantom, three different types of ASM images were created using different calculation processes. ASM/A is an image calculated by dividing the absolute difference between ADCb and ADCm by ADCb several times. By contrast, ASM/S is an image created by dividing the absolute difference between ADCb and ADCm by the standard deviation of ADCb several times. As for positive ASM/A image (PASM/A), the positive image, which was resultant after subtracting ADCb from ADCm, was divided by ADCb several times. A comparison was made between the types of ASM and DK images. The results showed the same tendency between ASM/A in addition to both ASM/S and PASM/A. By increasing the number of divisions by ADCb from three to five times, ASM/A images transformed from DK-mimicking to more RD-sensitive images compared with DK images. These observations suggest that ASM/A images may prove useful for future clinical applications in RD imaging protocols for the diagnosis of diseases. No potential conflict of interest relevant to this article was reported.

Sciendo Acta Medica Okayama 1898-0309 29 2 2023 Objective evaluation method using multiple image analyses for panoramic radiography improvement 85 91 EN Satoshi Imajo Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Yoshinori Tanabe Department of Radiological Technology, Faculty of Health Sciences, Okayama University Nobue Nakamura Division of Radiology, Medical Support Department, Okayama University Hospital Mitsugi Honda Division of Radiology, Medical Support Department, Okayama University Hospital Masahiro Kuroda Department of Radiological Technology, Faculty of Health Sciences, Okayama University Introduction: In the standardization of panoramic radiography quality, the education and training of beginners on panoramic radiographic imaging are important. We evaluated the relationship between positioning error factors and multiple image analysis results for reproducible panoramic radiography.<br> Material and methods: Using a panoramic radiography system and a dental phantom, reference images were acquired on the Frankfurt plane along the horizontal direction, midsagittal plane along the left-right direction, and for the canine on the forward-backward plane. Images with positioning errors were acquired with 1-5 mm shifts along the forward-backward direction and 2-10 degrees rotations along the horizontal (chin tipped high/low) and vertical (left-right side tilt) directions on the Frankfurt plane. The cross-correlation coefficient and angle difference of the occlusion congruent plane profile between the reference and positioning error images, peak signal-to-noise ratio (PSNR), and deformation vector value by deformable image registration were compared and evaluated.<br> Results: The cross-correlation coefficients of the occlusal plane profiles showed the greatest change in the chin tipped high images and became negatively correlated from 6 degrees image rotation (r = -0.29). The angle difference tended to shift substantially with increasing positioning error, with an angle difference of 8.9 degrees for the 10 degrees chin tipped low image. The PSNR was above 30 dB only for images with a 1-mm backward shift. The positioning error owing to the vertical rotation was the largest for the deformation vector value.<br> Conclusions: Multiple image analyses allow to determine factors contributing to positioning errors in panoramic radiography and may enable error correction. This study based on phantom imaging can support the education of beginners regarding panoramic radiography. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 77 3 2023 Usefulness of Simple Diffusion Kurtosis Imaging for Head and Neck Tumors: An Early Clinical Study 273 280 EN Yudai Shimizu Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Yuki Nakamitsu Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Suzuka Yoshida Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuka Fukumura Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshihide Nakamura Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazuhiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Ryo Kamizaki Radiological Technology, Graduate School of Health Sciences, Okayama University Satoshi Imajoh Radiological Technology, Graduate School of Health Sciences, Okayama University Yoshinori Tanabe Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Sugimoto Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Babatunde O. Bamgbose Department of Oral Diagnostic Sciences, Faculty of Dentistry, Bayero University Yoshinobu Yanagi Department of Dental Informatics, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Junichi Asaumi Department of Oral and Maxillofacial Radiology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Original Article 10.18926/AMO/65492 Diffusion kurtosis (DK) imaging (DKI), a type of restricted diffusion-weighted imaging, has been reported to be useful for tumor diagnoses in clinical studies. We developed a software program to simultaneously create DK images with apparent diffusion coefficient (ADC) maps and conducted an initial clinical study. Multi-shot echo-planar diffusion-weighted images were obtained at b-values of 0, 400, and 800 sec/mm2 for simple DKI, and DK images were created simultaneously with the ADC map. The usefulness of the DK image and ADC map was evaluated using a pixel analysis of all pixels and a median analysis of the pixels of each case. Tumor and normal tissues differed significantly in both pixel and median analyses. In the pixel analysis, the area under the curve was 0.64 for the mean kurtosis (MK) value and 0.77 for the ADC value. In the median analysis, the MK value was 0.74, and the ADC value was 0.75. The MK and ADC values correlated moderately in the pixel analysis and strongly in the median analysis. Our simple DKI system created DK images simultaneously with ADC maps, and the obtained MK and ADC values were useful for differentiating head and neck tumors from normal tissue. No potential conflict of interest relevant to this article was reported.

Spandidos Publications Acta Medica Okayama 1792-0981 25 3 2023 Quantitative evaluation of the reduction of distortion and metallic artifacts in magnetic resonance images using the multiacquisition variable‑resonance image combination selective sequence 109 EN Masaki Hirano Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Yuki Muto Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Yuta Fujiwara Division of Clinical Radiology Service, Okayama Central Hospital Tomoaki Sasaki Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Kazuhiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Ryo Kamizaki Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Satoshi Imajoh Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Yoshinori Tanabe Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki Nakamitsu Department of Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700‑8558, Japan Yudai Shimizu Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kohei Sugimoto Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University, Okayama, 770‑8558, Japan Masataka Oita Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Irfan Sugianto Department of Oral Radiology, Faculty of Dentistry, Hasanuddin University Babatunde O. Bamgbose Department of Oral Diagnostic Sciences, Faculty of Dentistry, Bayero University Magnetic resonance imaging (MRI) is superior to computed tomography (CT) in determining changes in tissue structure, such as those observed following inflammation and infection. However, when metal implants or other metal objects are present, MRI exhibits more distortion and artifacts compared with CT, which hinders the accurate measurement of the implants. A limited number of reports have examined whether the novel MRI sequence, multiacquisition variable-resonance image combination selective (MAVRIC SL), can accurately measure metal implants without distortion. Therefore, the present study aimed to demonstrate whether MAVRIC SL could accurately measure metal implants without distortion and whether the area around the metal implants could be well delineated without artifacts. An agar phantom containing a titanium alloy lumbar implant was used for the present study and was imaged using a 3.0 T MRI machine. A total of three imaging sequences, namely MAVRIC SL, CUBE and magnetic image compilation (MAGiC), were applied and the results were compared. Distortion was evaluated by measuring the screw diameter and distance between the screws multiple times in the phase and frequency directions by two different investigators. The artifact region around the implant was examined using a quantitative method following standardization of the phantom signal values. It was revealed that MAVRIC SL was a superior sequence compared with CUBE and MAGiC, as there was significantly less distortion, a lack of bias between the two different investigators and significantly reduced artifact regions. These results suggested the possibility of utilizing MAVRIC SL for follow-up to observe metal implant insertions. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 76 1 2022 Development and Evaluation of a Short-time Imaging Method for the Clinical Study of the Apparent Diffusion Coefficient Subtraction Method 25 32 EN Kohei Sugimoto Radiological Technology, Graduate School of Health Sciences, Okayama University Masahiro Kuroda Radiological Technology, Graduate School of Health Sciences, Okayama University Yuuki Yoshimura Radiological Technology, Graduate School of Health Sciences, Okayama University Kentaro Hamada Radiological Technology, Graduate School of Health Sciences, Okayama University Abdullah Khasawneh Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Majd Barham Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Nouha Tekiki Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kohei Konishi Radiological Technology, Graduate School of Health Sciences, Okayama University Hinata Ishizaka Radiological Technology, Graduate School of Health Sciences, Okayama University Yudai Shimizu Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuki Nakamitsu Radiological Technology, Graduate School of Health Sciences, Okayama University Wlla E. Al-Hammad Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Kamizaki Radiological Technology, Graduate School of Health Sciences, Okayama University Susumu Kanazawa Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Junichi Asaumi Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Original Article 10.18926/AMO/63205 The apparent diffusion coefficient subtraction method (ASM) was developed as a new restricted diffusionweighted imaging technique for magnetic resonance imaging (MRI). The usefulness of the ASM has been established by in vitro basic research using a bio-phantom, and clinical research on the application of the ASM for the human body is needed. Herein, we developed a short-time sequence for ASM imaging of the heads of healthy volunteers (n=2), and we investigated the similarity between the obtained ASM images and diffusion kurtosis (DK) images to determine the utility of the ASM for clinical uses. This study appears to be the first to report ASM images of the human head. We observed that the short-time sequence for the ASM imaging of the head can be scanned in approx. 3 min at 1.5T MRI. The noise reduction effect of median filter processing was confirmed on the ASM images scanned by this sequence. The obtained ASM images showed a weak correlation with the DK images, indicating that the ASM images are restricted diffusion-weighted images. The new shorttime imaging sequence could thus be used in clinical studies applying the ASM. No potential conflict of interest relevant to this article was reported.

Spandidos Publications Acta Medica Okayama 2049-9450 15 3 2021 New field‑in‑field with two reference points method for whole breast radiotherapy: Dosimetric analysis and radiation‑induced skin toxicities assessment EN Nouha Tekiki Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Hinata Ishizaka Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Abdullah Khasawneh Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Majd Barham Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kentaro Hamada Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Konishi Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Kohei Sugimoto Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Kuniaki Katsui Department of Proton Beam Therapy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Soichi Sugiyama Department of Radiology, Okayama University Hospital Kenta Watanabe Department of Radiology, Okayama University Hospital Kotaro Yoshio Department of Radiology, Okayama University Hospital Norihisa Katayama Department of Radiology, Kagawa Prefectural Central Hospital Takeshi Ogata Department of Radiology, Iwakuni Clinical Center Hiroki Ihara Department of Radiology, Tsuyama Chuo Hospital Susumu Kanazawa Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Junichi Asaumi Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences The usefulness of the field‑in‑field with two reference points (FIF w/ 2RP) method, in which the dose reference points are set simultaneously at two positions in the irradiation field and the high‑dose range is completely eliminated, was examined in the present study with the aim of decreasing acute skin toxicity in adjuvant breast radiotherapy (RT). A total of 573 patients with breast cancer who underwent postoperative whole breast RT were classified into 178 cases with wedge (W) method, 142 cases with field‑in‑field without 2 reference points (FIF w/o 2RP) method and 253 cases with FIF w/ 2RP method. Using the FIF w/ 2RP method, the high‑dose range was the lowest among the three irradiation methods. The planning target volume (PTV) V105% and the breast PTV for evaluation (BPe) V105% decreased to 0.09 and 0.10%, respectively. The FIF w/ 2RP method vs. the FIF w/o 2RP method had a strong association (η) with PTV V105% (η=0.79; P<0.001) and BPe V105% (η=0.76; P<0.001). The FIF w/ 2RP method had a significant impact on lowering the skin toxicity grade in weeks 3 and 4, and increasing the occurrence of skin toxicity grade 0. The FIF w/ 2RP method vs. the W method had a moderate association with skin toxicity grade at week 3 (η=0.49; P<0.001). Using the FIF w/ 2RP method, the high‑dose range V105% of the target decreased to 0%, and skin adverse events were decreased in conjunction. For patients with early‑stage breast cancer, particularly patients with relatively small‑sized breasts, the FIF w/ 2RP method may be an optimal irradiation method. No potential conflict of interest relevant to this article was reported.

Nature Research Acta Medica Okayama 2045-2322 11 1 2021 Sarcopenia is associated with poor prognosis after chemoradiotherapy in patients with stage III non-small-cell lung cancer: a retrospective analysis 11882 EN Kuniaki Katsui Department of Proton Beam Therapy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takeshi Ogata Department of Radiology, Iwakuni Clinical Center Soichi Sugiyama Department of Radiology, Okayama University Hospital Kotaro Yoshio Department of Radiology, Okayama University Hospital Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Takao Hiraki Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Katsuyuki Kiura Department of Allergy and Respiratory Medicine, Okayama University Hospital Yoshinobu Maeda Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Shinichi Toyooka Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Susumu Kanazawa Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences We intended to investigate whether muscle and adipose masses were associated with prognosis among patients with stage III non-small-cell lung cancer (NSCLC) who were undergoing chemoradiotherapy (CCRT). We retrospectively explored data of patients with stage III NSCLC who underwent definitive CCRT (>= 60 Gy) between January 2004 and March 2018 at our hospital. We examined the relationship of overall survival (OS) with body mass index (BMI), skeletal muscle index (SMI), psoas muscle index (PMI), visceral adipose tissue index (VAI), subcutaneous adipose tissue index (SAI), and visceral-to-subcutaneous adipose tissue area ratio (VSR) using log-rank tests for the univariate analysis and Cox proportional hazard models for the multivariate analysis. Overall, 16, 32, and 12 patients had stage IIIA, IIIB, and IIIC NSCLC, respectively. The total radiotherapy dose ranged from 60 Gy/30 fractions to 66 Gy/33 fractions. In the univariate analysis, the performance status (PS), BMI, and SMI were associated with OS, whereas the PMI, VAI, SAI, and VSR were not. In the multivariate analysis, the PS and SMI were associated with OS. The hazard ratios and 95% confidence intervals were 2.91 and 1.28-6.64 for PS, and 2.36 and 1.15-4.85 for SMI, respectively. The 1, 3, and 5-year OS rates were 92.1%, 59.6%, and 51.0% in patients with high SMI, and 63.6%, 53.8%, and 17.9% in patients with low SMI, respectively. The SMI correlated with prognosis in our study population, whereas adipose mass did not. Therefore, sarcopenia should be considered while predicting the OS in such patients. No potential conflict of interest relevant to this article was reported.

BMC Acta Medica Okayama 1748-717X 16 1 2021 Lung stereotactic body radiation therapy for elderly patients aged >= 80 years with pathologically proven early-stage non-small cell lung cancer: a retrospective cohort study 39 EN Kenta Watanabe Department of Radiology, Okayama University Hospital Kuniaki Katsui Department of Proton Beam Therapy, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Soichiro Sugiyama Department of Radiology, Okayama University Hospital Kotaro Yoshio Department of Radiology, Okayama University Hospital Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Takao Hiraki Department of Radiology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Katsuyuki Kiura Department of Allergy and Respiratory Medicine, Okayama University Hospital Yoshinobu Maeda Department of Hematology, Oncology, and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry,and Pharmaceutical Sciences Shinichi Toyooka Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Susumu Kanazawa Department of Radiology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Background</br> Stereotactic body radiation therapy (SBRT) is an established therapy for medically inoperable early-stage non-small cell lung cancer (NSCLC). Many elderly patients are medically inoperable owing to comorbidities. Therefore, SBRT may be a useful therapy for elderly patients. However, the application of SBRT for patients aged ≥ 80 years has not been completely elucidated. Therefore, this study aimed to assess the clinical utility of SBRT for elderly patients aged ≥ 80 years with pathologically proven early-stage NSCLC.</br> Methods</br> We retrospectively evaluated the data of patients aged ≥ 80 years with pathologically proven primary NSCLC who underwent SBRT at our institution between January 2009 and March 2020. Treatment outcomes and toxicities were analyzed. We used the Kaplan–Meier method to estimate survival curves and the log-rank test to compare the survival curves. We performed univariate and multivariate Cox regression analyses. p-values < 0.05 were regarded significant.</br> Results</br> Sixty-four patients (65 lesions) were included, and the median follow-up period was 38.7 (range 3.5–95.7) months. The median age was 82.9 (range 80.0–94.8) years. Sixteen patients were medically operable, and 48 patients were medically inoperable. The prescribed dose of SBRT was either 48 Gy in four fractions or 60 Gy in 10 fractions. The median survival time was 60.0 months (95% confidence interval, 43.5–71.1). The 1-, 3-, and 5-year local control, cancer-specific survival, progression-free survival, and overall survival rates were 98.4%, 98.4%, 81.0%, and 88.9%; 90.1%, 93.7%, 58.9%, and 68.3%; and 87.4%, 83.5%, 38.2%, and 47.5%, respectively. Multivariate analysis revealed that inoperability and solid nodules were the predictors of poor overall survival after SBRT in elderly patients. Two patients (3.1%) had grade 3 radiation pneumonitis, and one patient (1.6%) had grade 5 radiation pneumonitis.</br> Conclusions</br> SBRT was feasible in patients aged ≥ 80 years with NSCLC. It achieved good local control with minimal toxicity. SBRT may be beneficial in elderly patients with early-stage NSCLC. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 75 1 2021 Volumetric PET Parameters Predict Prognosis after Definitive Chemoradiotherapy with Cisplatin/Docetaxel for Stage III Non-Small Cell Lung Cancer 15 23 EN Kuniaki Katsui Department of Proton Beam Therapy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takeshi Ogata Department of Radiology, Iwakuni Clinical Center Akihiro Tada Department of Radiology, Okayama Diagnostic Imaging Center Soichi Sugiyama Department of Radiology, Okayama University Hospital Kotaro Yoshio Department of Radiology, Okayama University Hospital Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Katsuyuki Kiura Allergy and Respiratory Medicine, Okayama University Hospital Yoshinobu Maeda Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shinichi Toyooka General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takao Hiraki Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Susumu Kanazawa Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Original Article 10.18926/AMO/61429 The aim of this study was to investigate whether volumetric positron emission tomography (PET) parameters are prognostic predictors in stage III non-small cell lung cancer patients receiving definitive concurrent chemo-radiotherapy (CCRT) with cisplatin/docetaxel. Cases involving definitive CCRT were reviewed retrospectively, and the maximum standardized uptake value, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated. The relationships between these PET parameters and prognosis were analyzed. MTV and TLG were significant predictors of distant metastasis-free survival (DMFS) (p = 0.0003 and 0.0005, respectively) and progression-free survival (PFS) (p = 0.001 and 0.0007, respectively). The three-year DMFS rates in patients with low and high MTV were 13.3% and 64.6%, respectively, and the corresponding values in those with low and high TLG were 13.3% and 65.2%, respectively. The three-year PFS rates in patients with low and high MTV were 13.3% and 57.8%, respectively, and the corresponding values in patients with low and high TLG were 13.3% and 57.8%, respectively. However, MTV and TLG were not predictors of local control or overall sur-vival. We demonstrated that volumetric PET parameters were predictors of patients receiving definitive CCRT. Our findings contradict the findings of previous reports and warrant further research to validate them. No potential conflict of interest relevant to this article was reported.

Wiley Acta Medica Okayama 2045-7634 2020 Radiation pneumonitis after definitive concurrent chemoradiotherapy with cisplatin/docetaxel for non-small cell lung cancer: Analysis of dose-volume parameters EN Kuniaki Katsui Department of Proton Beam Therapy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Takeshi Ogata Department of Radiology, Iwakuni Clinical Center Kenta Watanabe Department of Radiology, Okayama University Hospital Norihisa Katayama Department of Radiology, Okayama University Hospital Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Katsuyuki Kiura Department of Allergy and Respiratory Medicine, Okayama University Hospital Takao Hiraki Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Yoshinobu Maeda Department of Hematology, Oncology, and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Shinichi Toyooka Departments of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Susumu Kanazawa Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Background: Radiation pneumonitis (RP) is a major pulmonary adverse event of chest radiotherapy. The PACIFIC trial that identified durvalumab as an effective subsequent-line therapy after concurrent chemoradiotherapy (CCRT) found that patients with grade 2 or higher RP may have to be excluded from treatment under certain criteria. The purpose of this study was to investigate the relationship between grade ≥2 RP and the parameters of dose-volume histograms after CCRT with cisplatin/docetaxel for stage III non-small cell lung cancer and conduct a subset analysis of severe RP that can lead to the permanent discontinuation of treatment per the PACIFIC trial criteria to help determine treatment strategy. <br/> Methods: We calculated the percentage of the lung volume received at least 5 Gy (V5) and 20 Gy (V20), the mean lung dose (MLD), and the lung volume spared from a 5 Gy dose (VS5) to the total lung volume. Factors affecting the incidence of grade ≥2 RP were identified; severe RP was defined as grade ≥3 as well as grade 2 RP that required ≥10 mg prednisolone for at least 12 weeks. <br/> Results: This study included 45 patients. On univariate analysis, all parameters and total lung volume were found to be significant predictors of grade ≥2 RP (P = .001, .003, .03, .004, and .02, respectively). On multivariate analysis, V20 was a significant predictive factor of grade ≥2 RP (P = .007). Severe RP developed in 6 of 37 patients (16.2%) whose V20 values were 35% or lower. On univariate analysis, only V20 was a significant predictor of severe RP in these patients (P = .01). <br/> Conclusions: The best approach to reduce the rate of grade ≥2 RP is to maintain the V5, V20, MLD, and VS5 as low as possible during radiotherapy planning in patients receiving definitive CCRT with cisplatin/docetaxel. No potential conflict of interest relevant to this article was reported.

Spandidos Publications Acta Medica Okayama 1791-2997 20 3 2019 Development of a novel method for visualizing restricted diffusion using subtraction of apparent diffusion coefficient values 2963 2969 EN Yuuki Yoshimura Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Masahiro Kuroda Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Irfan Sugianto Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Abdullah Khasawneh Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Babatunde O. Bamgbose Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kentaro Hamada Department of Radiological Technology, Graduate School of Health Sciences, Okayama University Majd Barham Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Nouha Tekiki Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Akira Kurozumi Central Division of Radiology, Okayama University Hospital Toshi Matsushita Central Division of Radiology, Okayama University Hospital Seiichiro Ohno Central Division of Radiology, Okayama University Hospital Susumu Kanazawa Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Junichi Asaumi Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences In order to visualize restricted diffusion, the present study developed a novel method called 'apparent diffusion coefficient (ADC) subtraction method (ASM)' and compared it with diffusion kurtosis imaging (DKI). The diffusion-weighted images of physiological saline, in addtion to bio-phatoms of low cell density and the highest cell density were obtained using two sequences with different effective diffusion times. Then, the calculated ADC values were subtracted. The mean values and standard deviations (SD) of the ADC values of physiological saline, low cell density and the highest cell density phantoms were 2.95 +/- 0.08x10(-3), 1.90 +/- 0.35x10(-3) and 0.79 +/- 0.05x10(-3) mm(2)/sec, respectively. The mean kurtosis values and SD of DKI were 0.04 +/- 0.01, 0.44 +/- 0.13 and 1.27 +/- 0.03, respectively. The ASM and SD values were 0.25 +/- 0.20x10(4), 0.51 +/- 0.41x10(4) and 4.80 +/- 4.51x10(4) (sec/mm(2))(2), respectively. Using bio-phantoms, the present study demonstrated that DKI exhibits restricted diffusion in the extracellular space. Similarly, ASM may reflect the extent of restricted diffusion in the extracellular space. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 67 6 2013 In Vitro Assessment of Factors Affecting the Apparent Diffusion Coefficient of Jurkat Cells Using Bio-phantoms 359 367 EN Kazunori Katashima Masahiro Kuroda Masakazu Ashida Takanori Sasaki Takehito Taguchi Hidenobu Matsuzaki Jun Murakami Yoshinobu Yanagi Miki Hisatomi Marina Hara Hirokazu Kato Yuichi Ohmura Tomoki Kobayashi Susumu Kanazawa Sosuke Harada Mitsuhiro Takemoto Seiichiro Ohno Seiichi Mimura Junichi Asaumi Original Article 10.18926/AMO/52009 It is well known that many tumor tissues show lower apparent diffusion coefficient (ADC) values, and that several factors are involved in the reduction of ADC values. The aim of this study was to clarify how much each factor contributes to decreases in ADC values. We investigate the roles of cell density, extracellular space, intracellular factors, apoptosis and necrosis in ADC values using bio-phantoms. The ADC values of bio-phantoms, in which Jurkat cells were encapsulated by gellan gum, were measured by a 1.5-Tesla magnetic resonance imaging device with constant diffusion time of 30sec. Heating at 42℃ was used to induce apoptosis while heating at 48℃ was used to induce necrosis. Cell death after heating was evaluated by flow cytometric analysis and electron microscopy. The ADC values of bio-phantoms including non-heated cells decreased linearly with increases in cell density, and showed a steep decline when the distance between cells became less than 3μm. The analysis of ADC values of cells after destruction of cellular structures by sonication suggested that approximately two-thirds of the ADC values of cells originate from their cellular structures. The ADC values of bio-phantoms including necrotic cells increased while those including apoptotic cells decreased. This study quantitatively clarified the role of the cellular factors and the extracellular space in determining the ADC values produced by tumor cells. The intermediate diffusion time of 30msec might be optimal to distinguish between apoptosis and necrosis. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 66 5 2012 HIF-1α Contributes to Hypoxia-induced Invasion and Metastasis of Esophageal Carcinoma via Inhibiting E-cadherin and Promoting MMP-2 Expression 399 407 EN Shao-Wu Jing Ya-Di Wang Masahiro Kuroda Jing-Wei Su Guo-Gui Sun Qing Liu Yun-Jie Cheng Cong-Rong Yang Original Article 10.18926/AMO/48964 Hypoxia-inducible factor-1α (HIF-1α) has been found to enhance tumor invasion and metastasis, but no study has reported its action in esophageal carcinoma. The goal of this study was to explore the probable mechanism of HIF-1α in the invasion and metastasis of esophageal carcinoma Eca109 cells in vitro and in vivo. mRNA and protein expression of HIF-1α, E-cadherin and matrix metalloproteinase-2 (MMP-2) under hypoxia were detected by RT-PCR and Western blotting. The effects of silencing HIF-1α on E-cadherin, MMP-2 mRNA and protein expression under hypoxia or normoxia were detected by RT-PCR and Western blotting, respectively. The invasive ability of Eca109 cells was tested using a transwell chambers. We established an Eca109-implanted tumor model and observed tumor growth and lymph node metastasis. The expression of HIF-1α, E-cadherin and MMP-2 in xenograft tumors was detected by Western blotting. After exposure to hypoxia, HIF-1α protein was up-regulated, both mRNA and protein levels of E-cadherin were down-regulated and MMP-2 was up-regulated, while HIF-1α mRNA showed no significant change. SiRNA could block HIF-1α effectively, increase E-cadherin expression and inhibit MMP-2 expression. The number of invading cells decreased after HIF-1α was silenced. Meanwhile, the tumor volume was much smaller, and the metastatic rate of lymph nodes and the positive rate were lower in vivo. Our observations suggest that HIF-1α inhibition might be an effective strategy to weaken invasion and metastasis in the esophageal carcinoma Eca109 cell line. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 66 3 2012 In Vitro Assessment of Factors Affecting the Apparent Diffusion Coefficient of Ramos Cells Using Bio-phantoms 263 270 EN Takanori Sasaki Masahiro Kuroda Kazunori Katashima Masakazu Ashida Hidenobu Matsuzaki Junichi Asaumi Jun Murakami Seiichiro Ohno Hirokazu Kato Susumu Kanazawa Original Article 10.18926/AMO/48566 The roles of cell density, extracellular space, intracellular factors, and apoptosis induced by the molecularly targeted drug rituximab on the apparent diffusion coefficient (ADC) values were investigated using bio-phantoms. In these bio-phantoms, Ramos cells (a human Burkittｾs lymphoma cell line) were encapsulated in gellan gum. The ADC values decreased linearly with the increase in cell density, and declined steeply when the extracellular space became less than 4 μm. The analysis of ADC values after destruction of the cellular membrane by sonication indicated that approximately 65% of the ADC values of normal cells originate from the cell structures made of membranes and that the remaining 35% originate from intracellular components. Microparticles, defined as particles smaller than the normal cells, increased in number after rituximab treatments, migrated to the extracellular space and significantly decreased the ADC values of bio-phantoms during apoptosis. An in vitro study using bio-phantoms was conducted to quantitatively clarify the roles of cellular factors and of extracellular space in determining the ADC values yielded by tumor cells and the mechanism by which apoptosis changes those values. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 66 3 2012 Visualization of Stent Lumen in MR Imaging: Relationship with Stent Design and RF Direction 203 211 EN Seiichiro Ohno Takashi Harimoto Miyuki Hirosue Masahiro Miyai Kengo Hattori Masahiro Kuroda Susumu Kanazawa Keiji Inamura Hirokazu Kato Original Article 10.18926/AMO/48559 Magnetic resonance imaging (MRI) visualization of metallic stent lumens is possible if the stent structure counteracts eddy currents in the lumen induced by the radio frequency magnetic field, B1. To examine the effectiveness of various stent designs in counteracting eddy currents, we anchored eight copper stent models and 2 commercially available nickel-titanium alloy (Nitinol) stents in a gel phantom, perpendicular or parallel to the direction of B1. A mesh stent lumen showed hypointensity irrespective of its alignment relative to B1. A solenoid stent lumen showed hypointensity with the stent axis parallel to B1, but it had the same signal intensity as outside the lumen when perpendicular to B1. A Moebius stent lumen showed no signal reduction, irrespective of alignment relative to B1. Lumens of the commercially available stents showed hypointensity regardless of alignment relative to B1. Computer simulation revealed that the signal intensities of the stents corresponded to magnetic flux densities of B1 in the stents, which are modified by the structure of the stent. While in vivo MRI viewing of a Moebius stent lumen is likely possible regardless of axis alignment, inherent structural weakness may be problematic. As a more practical choice, the solenoid stent is easier to manufacture and generates no hypointensive signal when the axis is parallel to B0. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 122 3 2010 脈絡膜血管腫に対する放射線治療 219 223 EN Sosuke Harada Mitsuhiro Takemoto Koutarou Yoshio Katsuhide Kojima Norihisa Katayama Kuniaki Katsui Masahiro Kuroda Toshihiko Matsuo Susumu Kanazawa PURPOSE: Circumscribed choroidal hemangioma is an uncommon, benign vascular tumor that typically appears in the posterior pole of the eye. Visual acuity loss typically results from its exudation, followed by serous retinal detachment. The purpose of the study was to evaluate the efficacy and the safety of external beam irradiation in treating circumscribed choroidal hemangioma. METHODS: We treated 4 eyes of 4 patients with circumscribed choroidal hemangioma with external beam irradiation at Okayama University Hospital from 2002 to 2009. A total absorbed dose of 20 Gy (beam energy, 4, 10 MV) was applied to each of the 4 patients. Each patient received a single 2-Gy daily fraction for five consecutive days in a week, for two consecutive weeks. RESULTS: In all cases, the retinal detachment showed complete resolution within 8 to 48 days after treatment. A decrease in tumor thickness was observed in all cases except one in which the follow-up period was rather short (3.7 months). The visual acuity improved in all 4 eyes. No eyes showed deterioration of visual acuity. During follow-up periods of 3.7 months to 58.5 months, there were no signs of radiation-induced cataract, retinopathy or optic neuropathy. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 41 10 2005 Role of O-6-methylguanine-DNA methyltransferase and effect of O-6-benzylguanine on the anti-tumor activity of cis-diaminedichloroplatinum(II) in oral cancer cell lines 984 993 EN Yu Maki Jun Murakami Jun-ichi Asaumi Hidetsugu Tsujigiwa Hitoshi Nagatsuka Susumu Kokeguchi Kazuhiro Fukui Noriko Kawai Yoshinobu Yanagi Masahiro Kuroda Noriaki Tanaka Nagahide Matsubara Kanji Kishi <p>The DNA repair enzyme, O-6-methylguanine-DNA methyltransferase (MGMT) modulates the effectiveness of alkylating agents. However, the relationship between MGMT and the sensitivities to other agents has not been explored. In the present study, the association between MGMT expression and the cellular sensitivity to the platinum agent, CDDP was examined in four human oral cancer cell tines. CDDP depleted MGMT protein and mRNA levels in all four cell tines. Two cell lines with low MGMT expression were sensitive to an alkylating agent, N-methyl-N'-nitro-N-nitrosoguanidine and CDDP, whereas two other cell tines with high MGMT expression were resistant to both agents. Furthermore, the addition of the MGMT inhibitor, O-6-benzylguanine (O-6-BG), invariably enhanced CDDP sensitivity. CDDP depleted MGMT expression, and CDDP sensitivity was enhanced by O-6-BG. These results provide valuable information about the relationship between MGMT expression and CDDP sensitivity in oral cancer chemotherapy. (c) 2005 Elsevier Ltd. All rights reserved. </p> No potential conflict of interest relevant to this article was reported.

Springer Acta Medica Okayama 0344-5704 56 1 2005 Effects of histone deacetylase inhibitor FR901228 on expression level of telomerase reverse transcriptase in oral cancer 22 28 EN Jun Murakami Jun-ichi Asaumi Noriko Kawai Hidetsugu Tsujigiwa Yoshinobu Yanagi Hitoshi Nagatsuka Tetsuyoshi Inoue Susumu Kokeguchi Shoji Kawasaki Masahiro Kuroda Noriaki Tanaka Nagahide Matsubara Kanji Kishi We speculated whether or not the expression level of telomerase reverse transcriptase (hTERT) would be modulated by agents targeting epigenetics in oral cancer cell lines. Although hTERT is known to be targeted by epigenetic changes, it remains unclear how chemoagents targeting epigenetics work on hTERT transcription. In the present study, the epigenetic effects of histone deacetylase (HDAC) inhibitor FR901228 on hTERT transcription were analysed by RT-PCR in oral cancer cell lines. The mRNA expression of hTERT was upregulated after exposure to FR901228 in hTERT-negative Hep2 cells, even in the hTERT highly expressed SAS and KB cells. Moreover, co-treatment of protein synthesis inhibitor cycloheximide (CHX) resulted in the induction of hTERT transcription by FR901228. This suggests that the induction of hTERT by FR901228 requires de novo protein synthesis to some extent and is more likely a direct than an indirect effect on epigenetic changes such as histone acetylation / deacetylation. We further examined the effect of FR901228 on c-myc protein, which is one of the main hTERT transcription activators. FR901228 repressed c-myc protein only in the absence of CHX, dependent of the enhancement of de novo protein synthesis. Our results indicate that c-myc protein is repressed indirectly by FR901228 but may not contribute FR901228-induced hTERT transcription. The present study showed that the HDAC inhibitor FR901228 induced the hTERT gene by a complex mechanism that involved other transcription factors except for c-myc, in addition to the inhibition of histone deacetylation. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 40 6 2004 Effects of demethylating agent 5-aza-2 '-deoxycytidine and histone deacetylase inhibitor FR901228 on maspin gene expression in oral cancer cell lines 597 603 EN Jun Murakami Jun-ichi Asaumi Yuu Maki Hidetsugu Tsujigiwa Masahiro Kuroda Noriyuki Nagai Yoshinobu Yanagi Tetsuyoshi Inoue Shoji Kawasaki Noriaki Tanaka Nagahide Matsubara Kanji Kishi <p>Maspin, which belongs to the serine protease inhibitor (serpin) superfamily, has been proposed as a potent tumor suppressor that inhibits cell motility, invasion, angiogenesis, and metastasis. In the present study, we examined the effects of 5-aza-2'-deoxycytidine (5-aza-dC), a demethylating agent, and FR901228, a histone deacetylase (HDAC) inhibitor, on maspin expression in oral cancer cell tines. The expression levels of maspin mRNA were divided into two groups, which was the maspin tow-expressed and high-expressed cell lines in the 12 oral cancer cell lines. The maspin promoter contained only a few methylated CpG sites in the maspin low-expressed cell lines. Moreover, the methylation status was not altered after 5-aza-dC treatment. However, the transcription of the maspin gene was clearly increased following 5-aza-dC treatment in a number of oral cancer cell tines. These results imply that an action of 5-aza-dC is separate from induction of promoter demethylation. Treatment with FR901228 resulted in a time-dependent stimulation of the re-expression of maspin mRNA as early as 4 h after treatment in the maspin downregulated cells. The re-expression of the maspin gene may contribute to the recuperation of biological functions linked to FR901228 such as an inhibitory effect on tumor angiogenesis and cell invasion. These results indicate that maspin and its target genes may be excellent leads for future studies on the potential benefits of FR901228, a HDAC inhibitor, in cancer therapy.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 46 3 1992 Cepharanthin Reduces Thermotolerance by Enhancing Thermosensitivity in NIH3T3 Cells 147 155 EN Masahiro Kuroda Shoji Kawasaki Yoshio Hiraki Article 10.18926/AMO/32672 <p>The effects of cepharanthin (Ce), glycyrrhizin (G), verapamil (V), and G plus V on induced thermotolerance in NIH3T3 cells were studied. Cells were heated with or without the drug at 45 degrees C for 20 min (the first heating), incubated at 37 degrees C for 12h (the incubation period), and heated again at 45 degrees C for 0-210 min (the second heating). G and V were added throughout the experiment, while Ce was added throughout the experiment or during only the first or second heating, or the incubation period. The cells were harvested after the second heating to evaluate cell survival. In control experiments without any drug, thermotolerance developed and reached the highest peak in the cells incubated for 12h at 37 degrees C. However, thermotolerance in the control cells was suppressed by incubating them at 0 degree C, but developed by subsequent incubation at 37 degrees C. This suggests that the acquisition of thermotolerance by the cells required metabolic processes during the incubation at 37 degrees C. When each drug was present throughout the experiment, only Ce or the combined use of G and V was effective in reducing thermotolerance. Thermotolerance was also suppressed in the presence of Ce during the second heating. These results indicate that Ce reduces thermotolerance by enhancing thermosensitivity rather than by inhibiting the development of thermotolerance.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 46 6 1992 Report of a study using phantom materials, and clinical experience with simultaneous radio-hyperthermotherapy. 417 426 EN Masahiro Kuroda Keiji Inamura Seiji Tahara Seiichi Mimura Yasutaka Mikami Shoji Kawasaki Yoshio Hiraki Article 10.18926/AMO/32638 <p>Simultaneous radiohyperthermotherapy (SRH) is a combined hyperthermia-radiation therapy in which irradiation is given during heating. Mutual interference between the high energy radiotherapy system (Toshiba LMR-15A) and the 13.56 MHz capacitive heating system (Omron HEH-500C) was tested with phantom materials prior to a clinical trial with SRH. The energy and flatness of irradiation were not affected by the heating system within the range of clinical use. The high energy radiotherapy system did not affect the increase or distribution of temperature during simultaneous treatment. The results of this phantom study indicated that these apparatuses would not produce clinically significant mutual interference during SRH. A clinical trial was performed on a 57-year-old woman with postoperative recurrence of rectal cancer. This is the first reported clinical case treated with true SRH in which external irradiation was administered during mid capacitive heating. Twelve SRH treatments were performed on the recurrent lesion at a frequency of twice a week for six weeks using the apparatuses described above. There was a significant reduction in pain after treatment. The tumor marker carcinoembryonic antigen (CEA) level decreased after treatment. On CT images taken after treatment, the tumor site became a low density area which indicated necrosis. There were no side effects. These results suggest that further clinical study of SRH should be performed to clarify its advantages.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 55 4 2001 Kinematic magnetic resonance imaging (MRI) of the normal shoulder: assessment of the shapes and signals of the superior and inferior labra with abductive movement using an open-type imager. 237 243 EN Izumi Togami Nobuya Sasai Masatoshi Tsunoda Tetsuro Sei Takayuki Yabuki Takahiro Kitagawa Masahiko Mitani Shiro Akaki Masahiro Kuroda Yoshio Hiraki Article 10.18926/AMO/31990 <p>A preliminary study was conducted to evaluate the superior and inferior glenoid labra with abductive movement using an open-type MR unit in asymptomatic healthy volunteers. Both fast low angle shot (FLASH) and turbo spin echo (TSE) images were obtained to evaluate the shapes of both the superior and inferior labra, as well as to assess changes in signal at these sites. As the abduction angle was increased, the shape of the superior labrum changed from round or triangular to crescentic and a higher signal was frequently seen. At an abduction angle of 150 degrees, an increase in signal was seen in one-half of the superior labra; this increase was noted more frequently in volunteers over 40 years of age. In some of the superior labra, the increase in signal seen at 150 degrees abduction disappeared on subsequent images obtained at 0 degrees abduction. Hence, the increase in signal was considered to be a reversible change. The shape of the inferior labrum tended to change from crescentic to triangular or round. An increase in signal in the inferior labrum was unrelated to the abduction angle. Abductive kinematic studies using an open-type MR unit provides information about the morphology of the superior and inferior labra, as well as information about signal changes occurring at these sites.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 53 3 1999 A new experimental system for irradiating tumors in mice using a linear accelerator under specific pathogen-free conditions. 111 118 EN Masahiro Kuroda Keiji Inamura Seiji Tahara Yuzuru Kurabayashi Tadaatsu Akagi Junichi Asaumi Izumi Togami Mitsuhiro Takemoto Osamu Honda Yasuki Morioka Shoji Kawasaki Yoshio Hiraki Article 10.18926/AMO/31638 <p>We developed a reliable system for the irradiation of xenografted tumors in mice which allows for accurate local irradiation under specific pathogen-free conditions. The system presented here consists of acrylic supports for mice and an acrylic box connected to a pump through 0.22 microns pore-sized filters. Mice with xenotransplanted tumors growing on their right hind legs were set on the supports and put into the box in a laminar flow hood. The tumors of 7 mice were irradiated simultaneously with X-rays of 6 and 10 MV generated by a linear accelerator at a dose rate of 3.1-4.7 Gy/min. The air was ventilated through filters during irradiation in the closed box. Microorganism tests confirmed that no bacteria entered or left the box. One of the significant characteristics of this setup is that it allows for irradiation under conditions of acute hypoxia, which is obtained using an integrated tourniquet. The dose variation among 7 tumors was less than 1%. The rest of the mouse's body was shielded effectively by a half-field technique and a lead block. As a result, the whole body dose for the mice was 0-4% of the total dose absorbed by the tumor. Due to the high dose rate and the ability to irradiate 7 mice simultaneously under specific pathogen-free conditions, this new system can be considered a time-saving and valuable tool for radiation oncology research.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 53 2 1999 The Results of Radiotherapy for T1 Glottic Cancers: Influence of Radiation Beam Energy 91 94 EN Michinori Yamamoto Ikuo Joja Mitsuhiro Takemoto Masahiro Kuroda Yoshio Hiraki Article 10.18926/AMO/31630 We analyzed the influence of various parameters on the results of radiotherapy for T1 glottic cancer by assessing the outcomes of 60 patients with this cancer who received definitive radiotherapy between 1985 and 1994. Seven patients were treated with a cobalt-60 unit, and the other 53 with a linear accelerator (26 patients at 3-MV, 10 at 6-MV, and 17 at 10-MV). Of the 17 patients treated at 10-MV, 4 also received part of their treatment with a cobalt-60 unit. The total radiation dose ranged from 56 Gy to 70 Gy (mean, 61 Gy). The total radiation dose of 51 patients (85%) was 60 Gy. The factors found to influence local control were the strength of the radiation beam energy and whether or not there was gross tumor invasion of the anterior commissure. The local control rate was 71% in the patients treated with a 10-MV linear accelerator, 56% in those treated with a 6-MV linear accelerator and, 97% in those treated with a cobalt-60 unit or a 3-MV linear accelerator (P = 0.0173). The local control rate was 43% in the patients with gross anterior commissure invasion and 88% in those without (P = 0.0075). We conclude that low energy photon beams are more suitable for the treatment of early glottic cancers, especially if the lesion grossly invades the anterior commissure. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 47 3 1993 Hyperthermotherapy added to the multidisciplinary therapy for penile cancer. 169 174 EN Masahiro Kuroda Tomoyasu Tsushima Yasutomo Nasu Junichi Asaumi Koji Nishikawa Xian Shu Gao Ikuo Joja Yoshihiro Takeda Izumi Togami Eiichi Makihata Shoji Kawasaki Hiroyuki Ohmori Yoshio Hiraki Article 10.18926/AMO/31599 <p>We performed a long-term follow-up of 4 patients with penile cancer who underwent hyperthermotherapy from August 1985 until August 1992. Hyperthermia was applied using a frequency of 350 MHz with a waveguide applicator twice a week for 60 min each for an average of 9.5 times (varying from 6 to 13 times). The total heating time that the temperature of urethra could be kept above 42 degrees C, was 166 min on the average (ranging from 0 to 463 min). Two patients classified as stage I according to the Jackson classification and 1 patient classified as stage IV underwent combined radiotherapy and received an average radiation dose of 53 Gy (range, 40-70 Gy). Among these patients 2 underwent combined chemotherapy with bleomycin or peplomycin. Malignant cells disappeared posttherapeutically and in August 1992, after an average of 5 years and 9 months (varying from 4 years 6 months to 6 years 10 months), the patients were free of recurrences. The one patient on stage IV had extensive invasion of the abdominal wall, but still recovered completely. One patient on stage III underwent combined chemotherapy and hyperthermotherapy, but heating had obviously been insufficient. There was a residue of malignant cells after the treatment and we performed a penectomy. Regarding functional preservation of the penis a multidisciplinary therapy incorporating hyperthermotherapy can be expected to increase the curativity. This indicates that it could induce in an advanced case, where an operation would be difficult, complete remission.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 47 4 1993 Hyperthermotherapy for postoperative local recurrences of rectal cancer. 249 254 EN Masahiro Kuroda Akio Hizuta Hiromi Iwagaki Eiichi Makihata Junichi Asaumi Koji Nishikawa Xian Shu Gao Tomio Nakagawa Izumi Togami Yoshihiro Takeda Ikuo Joja Shoji Kawasaki Kunzo Orita Yoshio Hiraki Article 10.18926/AMO/31557 <p>Between November 1984 and August 1992 we used hyperthermotherapy in six cases of local recurrence of rectal cancer. Hyperthermotherapy was performed on the average 8.7 times (range: 3-18) for each patient for 60 min each. All patients underwent combined radiotherapy and received a mean radiation dose of 42.5 Gy (range: 9-60 Gy). Five patients underwent heating within 1 h after irradiation and one patient simultaneously with the irradiation. Four patients underwent combined chemotherapy and two patients immunotherapy. Before the treatment all patients had painful lesions, but pain decreased posttherapeutically in five patients. Performance status improved in two patients. High carcinoembryonic antigen levels prior to the therapy in four patients decreased in all cases after treatment. Posttherapeutical computed tomograms revealed only minor response or no changes. After the treatment, four patients died of exacerbations of recurrent tumors and one patient of distant metastases. The patient who underwent simultaneous radiohyperthermotherapy is presently alive, in August 1992, 38 months after initiation of the treatment. The 50% survival time after initiation of the treatment was 25 months (range: 10-38 months). Hyperthermotherapy combined with radiotherapy, chemotherapy and/or immunotherapy was useful for the alleviation of pain in patients who developed local recurrence after surgery, and improved survival after recurrences can be expected.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 48 4 1994 A new capacitive heating applicator for the simultaneous radiohyperthermotherapy of superficial and shallow-seated tumors. 211 216 EN Akio Tanaka Masahiro Kuroda Keiji Inamura Shouji Kawasaki Yoshio Hiraki Article 10.18926/AMO/31087 <p>External capacitive heating is the usual method of electromagnetic wave heating, in which the tumor is caught and heated between two opposite applicators. Using a phantom, the authors developed and evaluated the performance of a new capacitive heating applicator designed for simultaneous radiohyperthermotherapy (SRH) in which the electron beam irradiation is provided from above an external capacitive heating applicator for the treatment of superficial and shallow-seated tumors. The trial applicator was constructed to fulfill the following conditions: 1. use of an electrode plate which does not affect the electron beam depth dose, 2. a uniform thickness to maintain flatness of the electron beam, and 3. a cooling function to prevent damage to normal skin tissue and enhance the therapeutic gain factor. This applicator was comprised of a 0.1-mm-thick copper electrode and a 5-mm-thick cooling chamber. The depth of the 80% dose of the new applicator was 21 mm with a 9-MeV electron beam and 36mm with a 15-MeV electron beam, which was comparable to the effect of a conventional irradiation bolus. The temperature distribution produced by the trial applicator was symmetrical on both sides from the center of the applicator. The 50% specific absorption rate region was 6.4 cm wide at a depth of 1 cm from the phantom surface and 2.8 cm wide at a depth of 3 cm. There have been no previous reports on the development of an external capacitive heating applicator designed for the SRH of superficial and shallow-seated tumors; this is the first such report.(ABSTRACT TRUNCATED AT 250 WORDS)</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 51 2 1997 Preoperative multidisciplinary treatment with hyperthermia for soft tissue sarcoma 93 99 EN Eiichi Makihata Masahiro Kuroda Akira Kawai Toshifumi Ozaki Shinsuke Sugihara Hajime Inoue Ikuo Joja Junichi Asaumi Shoji Kawasaki Yoshio Hiraki Article 10.18926/AMO/30776 <p>We report the results of phase I/II studies of preoperative multidisciplinary treatment of 14 patients with soft tissue sarcoma using hyperthermia from November 1990 to April 1995. The preoperative treatment was conducted with thermo-radio-chemotherapy in 11 cases of stage III, and with thermo-radiotherapy as well as thermo-chemotherapy in three cases of stages I and II. Hyperthermia was carried out twice a week with totals ranging from 4 to 14 times (average: 8.4 times); each session lasted 60min. Radiotherapy was administered four or five times per week, and the dose was 1.8 2Gy/fraction, with a total of 30-40Gy in a four week period. Chemotherapy was mainly in the form of MAID regimen (2-mercaptoethanesulphonic acid (mesna), adriamycin, ifosfamide and dacarbazine). The tumors were surgically resected in all patients after completing the preoperative treatment. The efficacy rate, as expressed by the percentage of either tumors in which reduction rate was 50% or more, or tumors for which post-treatment contrast enhanced CT image revealed low density volumes occupying 50% or more of the total mass, was 71 % (ten of the 14 tumors). The mean tumor necrosis rate in the resected specimens was 78%. The tumor necrosis rate was significantly high (P &#60; 0.05) in patients whose Time &#8805; 42°C was of long duration. Postoperative complications were observed in six patients; among these, two patients developed wound infection that required surgical treatment as a complication of surgery performed in the early stage following the preoperative treatment. After a mean postoperative follow-up of 27 months, distant metastasis occurred in four patients resulting in three fatalities. The three-year cumulative survival rate was 64.3%. No local recurrence was observed in any patient during the follow-up, thus confirming our hypothesis that preoperative multidisciplinary treatment has an excellent local efficacy. We think that it would be valuable to conduct, at many facilities, phase III studies on the treatment of soft tissue sarcoma by a combination of surgery and preoperative multidisciplinary treatment using hyperthermia, paying close attention to the interval between these two modalities.</p> No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 99 7-8 1987 転移性骨腫瘍の臨床症状 1013 1016 EN Nobuo Satoh Hiroyuki Ueda Tetsuya Nakamura Masahiro Kuroda Noriko Kanzaki Akihumi Mizuta Kiminori Murakami Ikuo Joja Keiji Hashimoto Yoshio Hiraki Kaname Aono The study included 40 cases of bone metastasis experienced from January 1982 to August 1986 at the Department of Radiology, Okayama University Hospital. The rate of pain Remission was 89.6% in 29 patients given radiotherapy. Increases in serum ALP and LDH were found in a few patients and a quarter of these patients improved after radiotherapy. Serum Ca increased in 5 patients with multiple bone metastases. No potential conflict of interest relevant to this article was reported.

岡山大学医療技術短期大学部 Acta Medica Okayama 0917-4494 9 2 1999 重粒子線の生物学的効果比と潜在性致死損傷からの回復 75 81 EN Shoji Kawasaki Koichi Shibuya Junichi Asaumi Masahiro Kuroda Yoshio Hiraki Yoshiya Furusawa 10.18926/15251 150KV X線,中性子線及び炭素(LET13, 20, 50, 90, 140, 150, 153, 200keV/μm)を照射したマウスNIH3T3細胞の生存率曲線のLD(10)から(60)Coγ線に対する生物学的効果比(RBE)を求めた｡RBEは150KV X線では1.26,中性子線では2.44,炭素線(LET13, 20, 50, 90, 140, 150, 153, 200keV/μm)ではそれぞれ1.41, 1.47, 2.22, 2.61, 1.61, 2.05, 1.57であった｡LETとRBEの関係では100keV/μm付近にピークを認めた｡150KVX線のLETは13keV/μm,中性子線のLETは70keVμmに相当した｡(60)Co γ線の潜在性致死損傷からの回復(PLDR)は大きかった｡炭素線(13keV/μm)照射でもPLDRが観察されるがLETが大きくなるとPLDRは減少したが,LET90keV/μmの炭素線でもPLDRが認められた｡照射時の細胞状態の検討では増殖期の細胞の感受性は定常期細胞に比し僅かに高かった｡ No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 12 2 2002 Cell cycle of tsAF8 after heating 101 106 EN Koichi Shibuya Shoji Kawasaki Masahiro Kuroda Jun-ichi Asaumi Hirokazu Kato Yoshio Hiraki 10.18926/15229 Thermotolerance in tsAF8 cells develops during incubation at 34℃ after heating at 45℃, while it is suppressed by the following incubation at a non-permissive temperature of 39.7℃ after the same heating. The incubation temperature after heating may affect the cell cycle and consequently thermotolerance. In the present study, a relationship between the thermotolerance and the cell cycle of tsAF8 was investigated. The cell cycle fractions and DNA synthesis were measured by flow cytometry using double staining with propidium iodide and bromodeoxyuridine. When the tsAF8 cells were heated at 45℃ for 20 min, and thereafter incubated at 34℃, bromodeoxyuridine uptake in the S phase cells (DNA synthesis) was recovered to 65.1% 6 h after the heating, and the cells showed gradual accumulation in the G(2)/M phase. When the cells were incubated at 39.7℃ after heating at 45℃ for 20 min, then showed inhibition of thermotolerance development, the DNA synthesis was recovered to 15.1% temporarily 6 h after the heating, but it became 0% after 12 h, and the cells did not remarkably accumulate in any phases of the cell cycle. This inhibition of DNA synthesis at 39.7℃ was considered to be the result of cell survival decreasing by a step-down heating. However, the relationship between the thermotolerance and the cell cycle was not found out in tsAF8 cells, because the cells did not accumulate in any phases of the cell cycle under the inhibitory condition of thermotolerance. No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 13 2 2003 MRIにおける画像の再構成 77 82 EN Hirokazu Kato Katsumi Hanamoto Masahiro Kuroda Koichi Shibuya Shoji Kawasaki 10.18926/15215 磁気共鳴は医学におけるイメージングにおいて重要なモダリティーであり,高度な数学的手法が画像の再構成に取り入れられている｡画像再構成の数学的手法および画像再構成にいたるまでの数学的な過程を理解するこは,MRIを学ぶものにとって非常に重要であるが,成書において明確な説明はなされていない｡ここでは,MR画像の再構成法を,複素関数と複素フ-リェ係数を用いて導いたので報告する｡ No potential conflict of interest relevant to this article was reported.

岡山大学医学部保健学科 Acta Medica Okayama 1345-0948 14 2 2004 MRIにおけるサンプリング時間の測定と画像の再構成 121 128 EN Hirokazu Kato Katsumi Hanamoto Shoji Kawasaki Koichi Shibuya Masahiro Kuroda Tadashi Koyama 10.18926/15198 MRIにおいてk-spaceを構築するためにはエコー信号をサンプリング時間に従って採取する必要がある.このサンプリング時間を測定するために,FOV(field of view)の左半分にファントムを置くことにより階段関数となるスピン分布を生成した｡得られたエコー信号を,階段関数をフ-リェ変換したときに得られるフ-リェ係数と比較することによりサンプリング時間を求めた｡得られたサンプリング時間を用いて,MRI MULTI-TEST PHANTOMをMRI装置でスキャンすることにより得られたエコー信号をサンプリングしk-spaceを構築した。このk-spaceをフ-リェ逆変換することによりMRI MULTI-TEST PHANTOMの画像を再構成することができた。 No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 103 7-8 1991 NIH 3T3 細胞の温熱耐性に対するケルセチンの作用　第1編　細胞の生存率からみたケルセチンの作用 973 981 EN Masahiro Kuroda Yoshio Hiraki Shouji Kawasaki The inhibition of thermotolerance development by quercetin was examined in NIH 3T3 cells. The cytotoxicity of quercetin increased with the increase in the concentration (10,100μg/ml) and duration (12,48,72 hours) of treatment. The cell killing effect of heat was not enhanced by quercetin (10μg/ml) itself. Quercetin (10μg/ml) inhibited the proliferation of cells for about 72 hours. Quercetin (10μg/ml) delayed the development of thermotolerance, but did not decrease the degree of maximum thermotolerance. Quercetin (10μg/ml) exibited no effect on the decay of thermotolerance. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 105 1-2 1993 塩化ベンザルコニウムによる温熱耐性の誘導 43 48 EN Masahiro Kuroda Junichi Asaumi Koji Nishikawa Seiryo Tanaka Xian Shu Gao Michinori Yamamoto Eiichi Makihata Yoshio Hiraki Shoji Kawasaki The ability of benzalkonium chloride to induce thermotolerance was examined in NIH3T3 cells. Benzalkonium chloride enhanced cytotoxicity as its concentration and administration period increased. The cell survival decreased to 50% of that in the non-treated group by 20min of treatment in 0.002% benzalkonium chloride. Thermotolerance developed during the culture after 20min of treatment with 0.002% benzalkonium chloride. Thermotolerance reached its peak at 15h after treatment and decreased subsequently. At 15h after treatment, the Do value at 45℃ heating, a parameter of thermotolerance was 3.8-fold higher than that of the non-treated group. The thermotolerance induced by 0.002% benzalkonium chloride increased as its treatment period was prolonged. These findings suggested a relationship between thermotolerance induction and the cell membrane damage by benzalkonium chloride. No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 108 3-6 1996 マウス口腔粘膜および頭部皮膚に対する血管収縮剤エピネフリンの放射線防護効果の検討 139 144 EN Xianshu Gao Tomio Nakagawa Michinori Yamamoto Masahiro Kuroda Katsuyoshi Sakae Mitsuharu Shimizu Harutaka Niiya Yoshihiro Takeda Ikuo Joja Yoshio Hiraki Shoji Kawasaki Epinephrine is the most widely used vasoconstrictive drug. However, its radioprotective potential has not yet been studied for radiation-induced mucositis and dermatitis. Other vasoconstrictive drugs induce a radioprotective effect, but are not used because of their severe side effects. We studied the radioprotective effect of epinephrine on the oral mucosa and scalp of the mice. The radiation dose was 20Gy in a single fraction to the head of the mouse. In the group treated with epinephrine ointment, secretion from the oral cavity was slight, body wieght loss was less and hair loss was observed in fewer cases compared to those in the group without of epinephrine ointment. The mechanism is thought to be related to oxygenation. Epinephrine causes vasoconstriction, therefore the blood supply is lowered and the oxygen concentration in the tissue decline. In conclusion, epinephrine is considered to have potential as a radioprotective ointment for mucous membranes and skin. No potential conflict of interest relevant to this article was reported.

岡山大学医療技術短期大学部 Acta Medica Okayama 0917-4494 3 1993 薬剤耐性細胞におけるアドリアマイシンの細胞内取り込みと細胞膜電位差の相関 81 85 EN Jun-ichi Asaumi Shoji Kawasaki Koji Nishikawa Xian Shu Gao Masahiro Kuroda Yoshio Hiraki 10.18926/11843 We observed adiamycin (ADR) uptake and cellular transmembrane potential [amount of intracellular fluorescence of 3,3'- (Di-n-hexyl)- 2,2'- oxacarbocyanine iodide (NK-2280)] in ADR-resistant cells established from Ehrlich ascites tumor cells (EATC) and wild type EATC. In ADR-resistant cells, ADR uptake and the cellular transmembrane potential decreased as the degree of resistance increased. 4,4'- diisothiocyanatostilbene- 2,2'- disulfonic acid (DIDS) induced markedly decreases of ADR uptake and the cellular transmembrane potential. A good correlation was observed between ADR uptake and transmembrane potential in cultured cells. No potential conflict of interest relevant to this article was reported.

岡山大学医療技術短期大学部 Acta Medica Okayama 0917-4494 6 1996 蛍光pH指示薬を用いたフローサイトメトリーによる細胞内pHの測定と温熱およびアミロライド誘導体の細胞内pHへの影響 1 5 EN Jun-ichi Asaumi Shoji Kawasaki Masahiro Kuroda Yoshihiro Takeda Yoshio Hiraki 10.18926/11730 エールリッヒ腹水癌細胞とそのアドリアマイシン耐性細胞において蛍光pH指示薬2'、7'-bis-(2-carboxyethyl) carboxyfluorescein] (BCECF) の蛍光量をフローサイトメトリーで測定することによって細胞内pHの検量曲線を作成することができた。このことより、これらの細胞においてBCECFの蛍光量で細胞内pHの変化を簡易に比較できることを示唆した。さらに、温熱、Na(+)/H(+) exchanger の阻害例であるアミロライド[3,5-diamino-6-chloro-N-(diaminomethylene) pyrazinecarboxamide]、およびアミロライド誘導隊MH-12-43[N-amidino-3-amino-6-chloro-5-(N-ethyliso-propylamino) pyrazinecarboxyamide] の細胞内pHへの影響をエールリッヒ腹水癌細胞で観察した。37℃では、0.5mMアミロライド、0.05mM　MH-12-43により細胞内pHは減少し、42℃処理によりさらに減少した。42℃において、0.05mM　MH-12-43による細胞内pHの減少は、0.5mMアミロライドによる減少より大きかった。 No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 1993 Cepharanthin Reduces Thermotolerance by Enhancing Thermosensitivity in NIH3T3 Cells EN No potential conflict of interest relevant to this article was reported.