グリッドコンピューティングを用いたボリュームレンダリング手法の開発

平成18年度電気・情報関連学会中国支部第57回連合大会資料 岡山理科大学, 岡山 (2006 10

Visualization Technique based on Grid Computing for Large-scale Volume-data

情報処理学会研究報告 グラフィクスとCAD研究会 2007.0

Visualization Technique based on Grid Computing for Large-scale Volume-data

近年, 高解像度化の進むCTやMRIから出力されるボリュームデータを,高精度にかつ高速に可視化するため,本研究ではグリッドコンピューティングを用いてボリュームレンダリングを行う手法を提案する.医療施設や研究機関に多数導入されている計算機を計算資源とするグリッドコンピューティングを用いる.計算能力の不均一な環境下において,可視性に基づき動的にタスクの投入を行うための手法を提案し,シミュレーションによりその有用性を確認した.提案手法をインプリメントし,グリッドコンピューティングを用いて大規模ボリュームデータのレンダリングを行った.To visualize high-resolution volumedata acquired from a recent CT or MRI, we propose a method for rendering the large-scale volume data using a grid computing. We use existing computers with non-homogeneous computing tasks to agent machines based on the visibility of divided volume data in a grid computing environment. Simulation results demonstrate the usefulness of the propose method. A large scale volumedata is rendered using our grid computing system

A New Secured Technique for Suprahepatic Vena Caval Anastomosis in Porcine Liver Transplantation

It is well recognized that hemorrhage or kinking of the suprahepatic vena caval anastomosis is the most fatal complication apparent within 24 hr after orthotopic liver transplantation in the pig. A secured technique for suprahepatic vena caval anastomosis is described in detail herein. Our technique include (1) the use of a diaphragmatic cuff, (2) the closure of phrenic vein orifices using transfixation technique, and (3) the application of "stay-suture" in the orifice of right phrenic vein. This technique has added significantly to the strength of the suprahepatic vena caval anastomosis, and there has been no experiences of uncontrollable bleeding and kinking of suprahepatic vena caval anastomosis in 48 porcine orthotopic transplants of the liver. In conclusion, we believe that this technique described herein is a simplified and secured method to avoid the hemorrhage and kinking of suprahepatic anastomosis in porcine liver transplantation

Volume rendering using grid computing for large-scale volume data

In this paper, we propose a volume rendering method using grid computing for large-scale volume data. Grid computing is attractive because medical institutions and research facilities often have a large number of idle computers. A large-scale volume data is divided into sub-volumes and the sub-volumes are rendered using grid computing. When using grid computing, different computers rarely have the same processor speeds. Thus the return order of results rarely matches the sending order. However order is vital when combining results to create a final image. Job-Scheduling is important in grid computing for volume rendering, so we use an obstacle-flag which changes priorities dynamically to manage sub-volume results. Obstacle-Flags manage visibility of each sub-volume when line of sight from the view point is obscured by other sub-volumes. The proposed Dynamic Job-Scheduling based on visibility substantially increases efficiency. Our Dynamic Job-Scheduling method was implemented on our university's campus grid and we conducted comparative experiments, which showed that the proposed method provides significant improvements in efficiency for large-scale volume rendering

Improved Techniques for Orthotopic Liver Transplantation in Pigs: A preliminary study

Orthotopic liver transplantations were performed on 12 pigs between November, 1986 and February, 1987. Survivals and causes of death were assessed according to the type of surgical procedure employed. Six operations were carried out according to the original procedure of Terblanche et al, whereas for other six animals, the transplantation was conducted by our modified procedure in which cannulation was made into the splenic vein without splenectomy at the veno-venous (v-v) bypass and a diaphragmatic cuff was used for the anastomosis of suprahepatic vena cava. 1/6 animals with original procedure and 5/6 with our modified procedure survived for more than 7 days. The total ischemic time was significantly short in the group subjected to the modified procedure. The major cause of death in the group on which the original procedure was conducted was gastric ulceration, accounting for 67% of the mortality, whereas in the modified procedure group, the mortality rate was reduced significantly to 17%. This operative technique has provided excellent survival rates in our transplanted animals

Neoadjuvant Chemotherapy with or without Concurrent Hormone Therapy in Estrogen Receptor-Positive Breast Cancer:NACED-Randomized Multicenter Phase II Trial

Although in the neoadjuvant setting for estrogen receptor (ER)-positive breast cancers, chemotherapy or hormone therapy alone does not result in satisfactory tumor response, it is unknown whether concurrent chemo-endocrine therapy is superior to chemotherapy alone in clinical outcomes. We conducted a randomized phase II trial to test the responses of ER-positive patients to concurrent administration of chemo-endocrine therapy in the neoadjuvant setting. Women with stage II-III, ER-positive, invasive breast cancer (n=28) received paclitaxel followed by fluorouracil, epirubicin, cyclophosphamide (T-FEC) and were randomized to receive concurrent chemo-endocrine therapy consisting of goserelin administered subcutaneously for premenopausal women or an aromatase inhibitor for postmenopausal women. The primary endpoint was the pathological complete response (pCR) rate after neoadjuvant therapy. Twenty-eight patients were randomized. There were no significant differences in pCR rate between the concurrent group (12.5%;2/16) and the chemotherapy alone group (8.3%;1/12). Tumor size after therapy was significantly reduced in the concurrent therapy group (p=0.035), but not in the chemotherapy-alone group (p=0.622). Neoadjuvant chemotherapy with concurrent hormone therapy provided no significant improvement in pCR rate in ER-positive breast cancers. These preliminary results should be followed up by further studies

Estrogen receptor (ER) mRNA expression and molecular subtype distribution in ER-negative/progesterone receptor-positive breast cancers

We examined estrogen receptor (ER) mRNA expression and molecular subtypes in stage I-III breast cancers that are progesterone receptor (PR) positive but ER and HER2 negative by immunohistochemistry (IHC) or fluorescent in situ hybridization. The ER, PR, and HER2 status was determined by IHC as part of routine clinical assessment (N = 501). Gene expression profiling was done with the Affymetrix U133A gene chip. We compared expressions of ESR1 and MKI67 mRNA, distribution of molecular subtypes by the PAM50 classifier, the sensitivity to endocrine therapy index, and the DLDA30 chemotherapy response predictor signature among ER/PR-positive (n = 223), ER-positive/PR-negative (n = 73), ER-negative/PR-positive (n = 20), and triple-negative (n = 185) cancers. All patients received neoadjuvant chemotherapy with an anthracycline and taxane and had adjuvant endocrine therapy only if ER or PR > 10 % positive. ESR1 expression was high in 25 % of ER-negative/PR-positive, in 79 % of ER-positive/PR-negative, in 96 % of ER/PR-positive, and in 12 % of triple-negative cancers by IHC. The average MKI67 expression was significantly higher in the ER-negative/PR-positive and triple-negative cohorts. Among the ER-negative/PR-positive patients, 15 % were luminal A, 5 % were Luminal B, and 65 % were basal like. The relapse-free survival rate of ER-negative/PR-positive patients was equivalent to ER-positive cancers and better than the triple-negative cohort. Only 20-25 % of the ER-negative/PR-positive tumors show molecular features of ER-positive cancers. In this rare subset of patients (i) a second RNA-based assessment may help identifying the minority of ESR1 mRNA-positive, luminal-type cancers and (ii) the safest clinical approach may be to consider both adjuvant endocrine and chemotherapy

Effect of the interaction between physical activity and estimated macronutrient intake on HbA1c : population-based cross-sectional and longitudinal studies

Introduction Healthy diet and physical activity (PA) are essential for preventing type 2 diabetes, particularly, a combination of diet and PA. However, reports on interaction between PA and diet, especially from large epidemiological studies, are limited. We investigated the effect of interaction between PA and macronutrient intake on hemoglobin A1c (HbA1c) levels in the general population. Research design and methods We conducted a cross-sectional study of 55 469 men and women without diabetes who participated in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study. A self-administered questionnaire ascertained PA and macronutrient intake (carbohydrate, fat, and protein). Multiple linear regression analyses were performed to adjust for confounding variables and examine the interactions. In addition, we conducted a longitudinal study during a 5-year period within a subcohort (n=6881) with accelerometer-assessed PA data. Results Overall, PA had a weak inverse association (β=−0.00033, p=0.049) and carbohydrate intake had a strong positive association (β=0.00393, p<0.001) with HbA1c. We observed a tendency of interactions between PA and carbohydrate or fat intake, but not protein intake, on HbA1c levels after adjusting for age, sex, study area, total energy intake, alcohol consumption, smoking, and medication for hypertension or hypercholesterolemia (Pinteraction=0.054, 0.006, and 0.156, respectively). The inverse associations between PA and HbA1c level were more evident in participants with high-carbohydrate (or low-fat) intake than in participants with low-carbohydrate (or high-fat) intake. Although further adjustment for body mass index slightly attenuated the above interactions (Pinteraction=0.098 for carbohydrate and 0.068 for fat), the associations between PA and HbA1c level in stratified analyses remained unchanged. Similar associations and interactions were reproduced in the longitudinal study. Conclusions The present results suggest that the effect of PA on HbA1c levels is modified by intake of macronutrient composition