Masayuki Nishiki
Toshiba
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Featured researches published by Masayuki Nishiki.
Medical Imaging 1998: Physics of Medical Imaging | 1998
Akira Tsukamoto; Shinichi Yamada; Takayuki Tomisaki; Manabu Tanaka; Takuya Sakaguchi; Hiroshi Asahina; Masayuki Nishiki
Flat-panel detector (FPD) is the driving force for realizing the next generation of x-ray systems. The purpose of this study was to develop a selenium-based FPD for both radiography and fluoroscopy. The detector uses amorphous selenium (a-Se) and a thin-film transistor (TFT) array. The simple construction of the a-Se layer permits real-time readout. The unique response characteristics of the FPD, which can be saturated over permitted x-ray doses, are provided by the TFT structure. Our prototype FPD was designed to acquire images at 30 frames per second (fps). A high modulation transfer factor was obtained: 0.63 at 2.0 Lp/mm. Sequential fluoroscopic images were acquired at up to 30 fps. The linear characteristics of the detector covered the commonly employed range of clinical exposure dose. Less than 1.5% image lag was measured at 30 fps.
Medical Imaging 2002: Physics of Medical Imaging | 2002
Olivier Tousignant; Martin Choquette; Yves Demers; Luc Laperriere; Jonathan Leboeuf; Michitaka Honda; Masayuki Nishiki; Akihito Takahashi; Akira Tsukamoto
Real time flat panel detectors based on amorphous selenium (a-Se) have demonstrated to be the most advanced technology for direct conversion X-ray imaging in various medical applications. In continuation of real time detector development, ANRAD Corporation introduce in this paper a large size 14 inches X 14 inches active area detector built with an amorphous selenium (a-Se) converter coated on a TFT array. This new detector is a scaled up version of the 9 inches X 9 inches presented last year based on a TFT array with 150 um x 150 um pixel and a 1000 mm thick a-Se PIN structure operated at 10V/um. DQE(f=0) measurements were performed in low dose range and demonstrated to be in agreement with a linear model including 2500e of electronic noise. It is also shown that the spatial resolution (MTF) could be controlled by selenium coating process and can almost reach the theoretical limit defined by the pixel pitch. Finally, the first 14 inches X 14 inches chest image is presented.
Journal of Orthopaedic Trauma | 1997
Takashi Ohe; Kozo Nakamura; Takashi Matsushita; Masayuki Nishiki; Naoto Watanabe; Kunitoshi Matsumoto
A simulation study of distal interlocking of an intramedullary nail was performed using newly devised, portable stereo fluoroscopy. Two intramedullary nails in which ten holes were drilled perpendicular to the long axis and at various angles to the diameter were inserted into a femoral and a tibial bone model. Ten drill bits were drilled freehand into the holes in the nail with the aid of the stereo fluoroscope. All twenty drill bits were seated in the holes in the first attempt. This instrument provides a three-dimensional view in real time, which enables the surgeon to appreciate the three-dimensional relationship between the drill bit and the hole in the nail in the bone model. Distal interlocking of the intramedullary nail is facilitated with the aid of this stereo fluoroscope.
Medical Imaging 2003: Physics of Medical Imaging | 2003
Olivier Tousignant; Yves Demers; Luc Laperriere; Masayuki Nishiki; Seiichirou Nagai; Takayuki Tomisaki; Akihito Takahashi; Kunio Aoki
Clinical evaluation results are presented using a large area, real time, amorphous selenium (a:Se), flat panel detector (FPD). The detector comprises of 1 mm thick amorphous selenium layer deposited onto a TFT panel that has a pixel pitch of .15 mm. The field of view of the detector is about 14” x 14” that is large enough to be used in R/F as well as general angiography application including digital subtraction angiography (DSA). Due to its high spatial resolution and low noise performance, it is shown that the detector is well suited to replace conventional image intensifier systems as well as film-screen systems.
Medical Imaging 1996: Image Display | 1996
Satoru Oishi; Masayuki Nishiki; Hiroshi Asahina; Chiharu Tanabe; Kunihiro Yasunaga; Hiroharu Nakamura
In pediatric cardiac angiography, there are several peculiarities such as limitation of both x-ray dose and the amount of contrast medium in comparison with conventional angiography. Due to these peculiarities, the catheter examinations are accomplished in a short time with biplane x- ray apparatus. Thus, it is often difficult to determine 3D structures of blood vessels, especially those of pediatric anomalies. Then a new 3D reconstruction method based on selective biplane angiography was developed in order to support diagnosis and surgical planning. The method was composed of particular reconstruction and composition. Individual 3D image is reconstructed with the particular reconstruction, and all 3D images are composed into standard coordinate system in the composition. This method was applied to phantom images and clinical images for evaluation of the method. The 3D image of the clinical data was reconstructed accurately as its structures were compared with the real structures described in the operative findings. The 3D visualization based on the method is helpful for diagnosis and surgical planning of complicated anomalies in pediatric cardiology.
Archive | 1992
Masayuki Nishiki; Shigemi Fujiwara; Mikihito Hayashi; Akira Tsukamoto; Kinya Takamizawa; Masayuki Takano; Seiichiro Nagai
Archive | 1992
Hiroshi Asahina; Masayuki Nishiki
Archive | 1996
Akira Tsukamoto; Masayuki Nishiki; Seiichiro Nagai; Koichiro Nabuchi; Tohru Saisu; Shinichi Yamada; Takayuki Tomisaki; Manabu Tanaka
Archive | 1985
Masayuki Nishiki; Kazuhiro Iinuma
Archive | 1999
Takuya Sakaguchi; Akira Tsukamoto; Masayuki Nishiki; Naoto Watanabe