Megumi Nakao

The reduction of metal artifacts in computed tomography (CT) images, specifically for strong artifacts generated from multiple metal objects, is a challenging issue in medical imaging research. Although there have been some studies on supervised metal artifact reduction through the learning of synthesized artifacts, it is difficult for simulated artifacts to cover the complexity of the real physical phenomena that may be observed in X-ray propagation. In this paper, we introduce metal artifact r

This paper presents a new set of techniques by which surgeons can interactively manipulate patient-specific volumetric models for sharing surgical process. To handle physical interaction between the surgical tools and organs, we propose a simple surface-constraint-based manipulation algorithm to consistently simulate common surgical manipulations such as grasping, holding and retraction. Our computation model is capable of simulating soft-tissue deformation and incision in real time. We also pre

The proposed methods address problems with the matching of surfaces with large curvatures and deformations and achieved smaller registration errors than existing shape matching methods, even at the tip and ridge regions. The findings and inter-subject statistical representation are directly available for further research on pneumothorax deformation modeling.

Organ shape reconstruction based on a single-projection image during treatment has wide clinical scope, e.g., in image-guided radiotherapy and surgical guidance. We propose an image-to-graph convolutional network that achieves deformable registration of a three-dimensional (3D) organ mesh for a low-contrast two-dimensional (2D) projection image. This framework enables simultaneous training of two types of transformation: from the 2D projection image to a displacement map, and from the sampled pe

Previous studies demonstrated that the adjuvant-free form of a fusion protein consisting of a truncated herpes simplex virus type 1 (HSV-1) glycoprotein D and human interleukin-2 (tgD-IL-2) elicited superior protective immunity in mice. In this study, the immunotherapeutic efficacy of tgD-IL-2 against vaginal HSV-2 infection was investigated using a guinea pig model. Footpad injections of tgD-IL-2 (12.5 micrograms/dose) after the onset of primary lesions strongly suppressed recurrence in the chr

This method addresses tradeoff problems between symmetric reconstruction and restoration of the native contour of the mandible.

The mode of action of bulgecin was investigated by examining its bactericidal and bacteriolytic activities, its effect on bacterial morphology, and its interaction with penicillin-binding proteins (PBPs). Bulgecin alone did not show any antibacterial activity against Escherichia coli and Serratia marcescens, but in concert with cefmenoxime, it induced potent growth-inhibitory and bactericidal activities. Electron microscopic examination of E. coli cells exposed to bulgecin combined with cefmenox

This study presents a haptic simulator for learning palpation of aorta in cardiovascular surgery and performs quantitative evaluation in educational use through some user study. The simulator implements physics-based methods that enable VR simulation of soft organs with autonomous motion like a beating heart or an aorta. The developed model simulates real-time deformation and force feedback during surgical palpation based on finite element methods. The evaluation with cardiovascular surgeons and

In preoperative planning for mandibular reconstructive surgery, it is necessary to determine the osteotomy lines for fibular shaping and the proper placement of fibular segments in the mandible. Although virtual surgical planning has been utilized in preoperative decision making, current software designs require manual operation and a trial-and-error process to refine the reconstruction plan. We have developed volumetric fibular transfer simulation software that can quickly design a preoperative

This study establishes a practical environment for transferring knowledge on bioelasticity between expert and trainee medical practitioners. Through haptic interaction with a deformable virtual anatomical model, experts set the model's elasticity conditions by simulating a surgical procedure. Trainees experience the elasticity by attempting the same surgical manipulation

The effect of cefotiam and cefazolin on the ultrastructure of Klebsiella pneumoniae DT-S in vitro and in experimental pneumonia in mice was examined by electron microscopy. The action of both cephalosporins against K. pneumoniae DT-S was bactericidal, and a dose response in the action was definite. At the minimal inhibitory concentration of each cephalosporin, filamentation of the cells was induced and the cytoplasm became sparse during the course of incubation. With elevation of the concentrati

This study proposes methods for the support of radiotherapy planning for dynamic tumor-tracking irradiation for lung tumors. It aims to simulate the deformation of the lung caused by respiration and to visualize the result as DRRs (Digitally Reconstructed Radiographs) in real time. Our lung- deformation model treats the lung as an elastic object and analyzes the deformation based on linear FEM (the Finite Element Method). The simulation models the lung using CT volume data and generates a model