著者
花井 耕造 井原 文子 勝田 昭一 村松 禎久 村上 勉 井原 完有 藤田 智之 川合 英夫 田仲 隆 森山 紀之
出版者
公益社団法人日本放射線技術学会
雑誌
日本放射線技術學會雜誌 (ISSN:03694305)
巻号頁・発行日
vol.50, no.12, pp.1950-1959, 1994-12-01
被引用文献数
10

本研究ではAxial像を中心に, ヘリカルCTにおける再構成間隔と腫瘤性陰影の描出能の関係をコントラスト分解能の違いから述べた.ヘリカルCTでは, 検査目的に応じて最適な再構成間隔を定めることで, 体軸方向に対する情報量をいかに効率良く, かつ最大限に得るかが重要なスキャン条件の選択となる.今後, 3次元画像表示への対応も含めて最適再構成間隔の設定基準を定めて行きたい.
著者
川下 郁生 石田 隆行 桂川 茂彦 有村 秀孝 土井 邦雄
出版者
公益社団法人日本放射線技術学会
雑誌
日本放射線技術學會雜誌 (ISSN:03694305)
巻号頁・発行日
vol.56, no.3, pp.443-448, 2000-03-20
被引用文献数
1

Computer-aided diagnosis(CAD)system has been developing in the field of medical imaging. As CAD becomes more common in diagnostic radiology, it is expected that diagnostic performance will be improved. In actual use, however, the results of CAD might be affected by the quality of images, which are obtained under different exposure conditions and / or with differing devices. In this study, we investigated the effect of varied image quality on the results of texture analysis, a method developed by Katsuragawa, et al. and used in CAD for the detection of interstitial lung desease. To provide samples of varying image quality, we obtained images using various exposure doses and scatterer thicknesses. It was found that texture analysis was affected by differences in scatterer thickness.
著者
長岡 宏明 永峰 正幸 嶽間澤 博 松田 稔 鈴木 義久
出版者
公益社団法人日本放射線技術学会
雑誌
日本放射線技術學會雜誌 (ISSN:03694305)
巻号頁・発行日
vol.50, no.8, 1994-08-01

センサー自体に厚みがあるため、被写体に密着しての撮像が不可能となった。検知感度については光センサータイプが優れ、空気圧センサータイプは特に感度が鈍かった。しかし、感度が良すぎても、髪の毛や衣服などで検知する等、取扱上で不便な点もあった。外周センサータイプでは危険なほど圧迫してもセンサーが感知しないこともあった。
著者
畑川 政勝 井上 誠 庄垣 雅史 岸本 健治 吉田 梨影
出版者
公益社団法人日本放射線技術学会
雑誌
日本放射線技術學會雜誌 (ISSN:03694305)
巻号頁・発行日
vol.48, no.11, pp.1932-1938, 1992-11-01
被引用文献数
13

The modulation transfer function (MTF) has been used for evaluation of radiographic image quality. However, in digital radiographic system such as a computed radiography (CR), the MTF can not be used in the same way of an analog system for evaluation because digital system is not shift-invaliant system. Then, we suggest the "MTF_<final>" which includes geometric unsharpness, detector unsharpness, unsharpness of the sampling aperture and unsharpness of the display (Laser-printer). It is an analog component in the digital system and in agreement with the definition of the MTF. Furthermore, an overall aliasing has to be used with MTF_<final> for evaluating the digital system because it is one of the important factors of the digital system. The MTF_<final> and the overall aliasing can be obtained from the overall MTFs of the center alignment and the shifted alignment.
著者
高木 昭浩 吉岡 克則 寺岡 悟見 相馬 努 矢野 今朝人 宮坂 正 横井 孝司 村瀬 研也
出版者
公益社団法人日本放射線技術学会
雑誌
日本放射線技術學會雜誌 (ISSN:03694305)
巻号頁・発行日
vol.62, no.5, pp.729-733, 2006-05-20
被引用文献数
6 6

The following process conventionally has been followed to develop quantitative images of cerebral blood flow: (1) mean cerebral blood flow (mCBF) is calculated by the Patlak plot method; (2) a SPECT slice that includes the basal ganglia is selected; and (3) based on the value of mCBF calculated by the Patlak plot method, the SPECT slice is corrected by the Lassen method and developed into a SPECT image of quantitative regional cerebral blood flow. However, this process is complicated, and the values of rCBF have been reported to fluctuate because selection of the SPECT slice and the ROI setting are in the hands of the operator. We have developed new software that automates this analysis. This software enables automatic processing simply by inputting the value of mCBF in the normal hemisphere. Since there is no need for manual operations such as setting the ROI, reproducibility is improved as well. Regional cerebral blood flow as determined by this software is quite similar to that calculated by the conventional method, so the existing clinical evaluation does not need to be changed. This software is considered to be useful.