| Japanese |
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| Title | シンチレーションカメラの感度不均一性に関する研究 第2報 各種因子による不均一性の変化の定量的評価 |
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| Subtitle | 原著 |
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| Authors | 松本徹* |
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| Organization | *放射線医学総合研究所 臨床研究部 |
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| Journal | 核医学 |
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| Volume | 15 |
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| Number | 1 |
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| Page | 1-8 |
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| Year/Month | 1978/2 |
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| Article | 原著 |
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| Publisher | 日本核医学会 |
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| Abstract | 「I. 緒言」前報告では, カメラの感度不均一性は不均一性の程度と不均一性パターンの変化をあらわす2つの指標を用いて定量的に評価できることを示した. 本報ではデジタル電子計算機による不均一性補正法を確立するため, 各種の不均一性因子の関数としてカメラの感度不均一性をあらわすflood像を測定し, これより不均一度と不均一性パターンの変化を計算した. 次にその結果から不均一性補正の精度に重大な影響を与える因子は何か, 不均一性補正を行うにはどんな条件のflood像を測定しておけばよいか, 補正用マトリックスの交換はいつ, いかなる基準で行うべきか, 等について検討した.「II. 方法」アンガー型シンチレーションカメラの感度不均一性を, カメラ, コリメータ, 線源の3つに分割して考えることにし, 次のような測定を行った. [ (a) カメラ自体の不均一性] 本報では, まず不均一性に関してもっとも基本的な情報を与えると思われる, カメラ自体の不均一性を次のようなgeometryで測定した. |
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| Practice | 臨床医学：一般 |
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| English |
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| Title | Non-Uniform Sensitivity of Delay-Line Scintillation Camera (No.2) ; Quantitative Assessment of the Non-uniformity of the camera under the Various Conditions |
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| Subtitle | Original Articles |
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| Authors | Toru MATUMOTO |
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| Organization | Clinical Division, National Institute of Radiological Sciences |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 15 |
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| Number | 1 |
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| Page | 1-8 |
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| Year/Month | 1978/2 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | [Summary] In order to establish a useful method of correcting non-uniform sensitivity of the camera by a digital computer system, non-uniformity measurements were performed under the various conditions and the non-uniformity of the flood images obtained was evaluated quantitatively. The output from a commercial delay-line type camera (TOSHIBA GCA 202) was analyzed using the NIRS on-line computer system (TOSBAC-3400 MODEL 31 DAC system) . The flood image data were collected in a 64×64 matrix without a collimator and with two collimators with respect to the point or the plane sources of 99mTc and 57Co in air. Number of collected data was about 4×10 6 counts/total area. By parameters expressing the extent of non-uniformity of a flood image and the differences in the non-uniformity pattern among the images, changes in non-uniformity with time, and the effects of varying window settings and counting rates were detected and evaluated with or without a collimator. As results of the above analysis, changes in non-uniformity with time (for three months) and with counting rates from 10 3 to 2.5×10 4 cps are found to be insignificant. It is confirmed that non-uniformity of the two parallel hole collimators (1600 hole and 40000 hole) are insignificant. With energy window width of less than 20% and gain-variations varying from-10% to 10% of peak centering, changes of the extent of the non-uniformity pattern are very sensitive. |
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| Practice | Clinical medicine |
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