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| Title | ガンマ・カメラ - 電子計算機システムにおける分解時間とその補正法 II. ガンマ・カメラ動態システムの分解時間補正 |
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| Subtitle | 原著 |
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| Authors | 飯沼武*, 福久健二郎**, 松本徹* |
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| Organization | *放射線医学総合研究所 臨床研究部, **技術部 |
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| Journal | 核医学 |
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| Volume | 12 |
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| Number | 1 |
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| Page | 25-32 |
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| Year/Month | 1975/2 |
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| Article | 原著 |
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| Publisher | 日本核医学会 |
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| Abstract | 「1. はじめに」前報において遅延線型シンチレーション・カメラとオン・ライン計算機システムの計数率特性と分解時間について論じた. 本報ではカメラから出力されるdisplay event rateがディジタル動態画像として収集される際に生ずる計数損失とその補正法および収集可能な限界について報告する. 現在, シンチレーション・カメラ動態システムのデータ収集法として, (1)リスト・モード(Lモードと略)と, (2)ヒストグラム・モード(Hモードと略)の2種が用いられている. また両モードにおいて具体的なハードウェアの構成が異なり, それによって計数率特性が異なるので, システム毎に検討を加える. 「2. シンチレーション・カメラ動態システムの分類」近年, 利用されている動態システムを分類するとFig. 1のようになる. 同図はVTRやMTを用いたデータ・ストア・プレイバック・システムで, カメラのX, Y信号がA-D変換され, ディジタル量としてVTRやMTに記録され, データ収集後, プレイバックすることによってディジタル像が得られるものである. |
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| Practice | 臨床医学：一般 |
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| English |
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| Title | Resolving Time of Scintillation Camera-Computer System and Methods of Correction for Counting Loss II. On the Dynamic Performance of various Types of Camera-Computer Systems |
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| Subtitle | original |
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| Authors | Takeshi IINUMA, Kenjiro FUKUHISA, Toru MATSUMOTO |
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| Authors(kana) | |
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| Organization | National Institute of Radiological Sciences |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 12 |
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| Number | 1 |
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| Page | 25-32 |
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| Year/Month | 1975/2 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary] Following the previous work, counting-rate performance of camera-computer systems is investigated for two modes of data acquisition. The first is "LIST" mode in which image data and timing signal are sequentially stored onto magnetic disk or tape via buffer memory. The second is "HISTOGRAM" mode in which image data are stored into core memory as a digital image and then the image are transfered to magnetic disk or tape by the signal of frame timing. Firstly, the counting-rates stored in the buffer memory was measured as a function of display event-rates of scintillation camera for the two modes. For the both modes, stored counting-rates (M) are expressed by the following formula: M=N/(1-Nτ) where N is the display event-rates of the camera and τ is the resolving time including analog-to-digital conversion time and memory cycle time. The resolving time for each mode may be different, but it is about 10 μsec for the both mode in our computer system (TOSBAC 3400 model 31). Secondly, the data transfer speed from the buffer memory to external memory such as magnetic disk or tape was considered for the two modes. For the "LIST" mode, the maximum value of stored counting-rates from the camera is expressed in terms of size of buffer memory, access time and data transfer-rate of the external memory. For the "HISTOGRAM" mode, the minimum time of the frame is determined by size of buffer memory, access time and transfer rate of the external memory. In our system, maximum value of stored counting-rates is about 17,000 counts/sec. with the buffer size of 2,000 words, and minimum frame time is about 130 msec. with the buffer size of 1024 words. These values agree well with the calculated ones. From the present analysis, design of the camera-computer system becomes possible for the qauntitative dynamic imaging and future improvements are suggested. |
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| Practice | Clinical medicine |
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