日本放射線技術学会雑誌
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
検索
詳細検索
OR
閲覧
検索
64 巻, 5 号
選択された号の論文の14件中1～14を表示しています
すべての抄録を表示する
    • |<
    • <
    • 1
    • >
    • >|
巻頭言
原著
  • ガウス混合モデルに基づく適応的ウィナーフィルタによる胸部X線CT画像のノイズ除去
    田淵 真弘, 山根 延元, 森川 良孝
    2008 年 64 巻 5 号 p. 563-572
    発行日: 2008/05/20
    公開日: 2008/05/29
    DOIhttps://doi.org/10.6009/jjrt.64.563
    ジャーナル フリー
    抄録を表示する抄録を非表示にする
    In recent decades, X-ray CT imaging has become more important as a result of its high-resolution performance. However, it is well known that the X-ray dose is insufficient in the techniques that use low-dose imaging in health screening or thin-slice imaging in work-up. Therefore, the degradation of CT images caused by the streak artifact frequently becomes problematic. In this study, we applied a Wiener filter (WF) using the universal Gaussian mixture distribution model (UNI-GMM) as a statistical model to remove streak artifact. In designing the WF, it is necessary to estimate the statistical model and the precise co-variances of the original image. In the proposed method, we obtained a variety of chest X-ray CT images using a phantom simulating a chest organ, and we estimated the statistical information using the images for training. The results of simulation showed that it is possible to fit the UNI-GMM to the chest X-ray CT images and reduce the specific noise.
    抄録全体を表示
    PDF形式でダウンロード (1482K)
臨床技術
  • MRI Body Diffusion Weighted Image におけるクエン酸鉄アンモニウム水溶液を用いた消化管アーチファクト消去の試み
    高橋 俊行, 加藤 京一, 西澤 剛, 中澤 靖夫
    2008 年 64 巻 5 号 p. 573-578
    発行日: 2008/05/20
    公開日: 2008/05/29
    DOIhttps://doi.org/10.6009/jjrt.64.573
    ジャーナル フリー
    抄録を表示する抄録を非表示にする
    The clinical usefulness, as well as the advantages and limitations of DWI in the abdomen and pelvis, currently are under discussion. One of the limitations is the artifact from bowel fluid that may obscure lesion signals or make it difficult to detect them. The purpose of this study was to examine evidence as to whether an oral contrast agent of ferric ammonium citrate could eliminate this artifact from the bowel loop. The study consisted of a phantom study and clinical study. The density of the phantom compounded it to 1-6 times, 8 times and 12 times. We changed the density with ferric ammonium citrate to find the best density. The pulse sequence used SE-PEI and, variable parameter changed TE and b value. The signal intensity of the phantoms was visually analyzed. We took the results to an outside observer as a clinical study and confirmed the effect visually. When a signal of ferric ammonium citrate extended TE time and increased b value, it fell. As it thickened the density of phantom, it was the result that the signal deteriorated, and was good. However, an artifact from ferric ammonium citrate appeared when we exceeded 5× density. The signal of the bowel fluid artifact disappeared by having a normal person take the 4× density as in the clinical study. Elimination of bowel fluid artifact on abdominal DWI was able to suggest the possibility of taking the ferric ammonium citrate solution at 4× density.
    抄録全体を表示
    PDF形式でダウンロード (1016K)
  • 肺血流シンチグラフィにおけるダイナミック像を利用した右左シャント率測定法の検討
    市川 肇, 山田 さやか, 吉岡 千峰, 玉置 豊士, 三浦 俊一, 鈴木 資巳, 牧野 哲三
    2008 年 64 巻 5 号 p. 579-586
    発行日: 2008/05/20
    公開日: 2008/05/29
    DOIhttps://doi.org/10.6009/jjrt.64.579
    ジャーナル フリー
    抄録を表示する抄録を非表示にする
    Objective: We examined a method of quantitative analysis that used dynamic and static images to measure the Right-left (R-L) shunt ratio in lung perfusion scintigraphy. Methods: A total of 18 patients suspected of having R-L shunt brought on by congenital heart disease were referred for lung perfusion scintigraphy from November 2005 to February 2007 at our hospital. We acquired anterior dynamic images, set ROIs in all fields of view, and measured the highest count. We acquired anterior and posterior static images of the chest and measured lung counts. We considered the highest count on dynamic images to be the total injection dose per one second, normalized the acquisition time of static images, and calculated the R-L shunt ratio. We weighed the measurement results of the R-L shunt ratio obtained by the dynamic method against that of the whole-body method by t-test and the least-squares method. Results: When we used a posterior static image in the dynamic method, we found that the coefficient of correlation (r) was 0.9831. The result of the t-test was that there was no significant difference at a level of significance of 1%. Discussion: We think the use of the dynamic method is possible in R-L shunt ratio measurement and can shorten the examination time.
    抄録全体を表示
    PDF形式でダウンロード (1952K)
速報
  • MRIマグネットが刺青シールおよびアイメイクに及ぼす力学的作用の検討
    森下 雄太, 宮地 利明, 上田 丞政, 清水 満, 濱口 隆史, 藤原 康博, 林 弘之
    2008 年 64 巻 5 号 p. 587-590
    発行日: 2008/05/20
    公開日: 2008/05/29
    DOIhttps://doi.org/10.6009/jjrt.64.587
    ジャーナル フリー
    抄録を表示する抄録を非表示にする
    The purpose of our study was to assess the mechanical effect on tattoo seals and eye makeup caused by a spatial magnetic gradient in the magnetic resonance imaging (MRI) system. Seven kinds of tattoo seals and three kinds of eye makeup, i.e., mascara, eye shadow, and eyeliner were used. On a 3.0-Tesla MRI, we determined these deflection angles according to a method established by the American Society for Testing and Materials (ASTM) at the position that produced the greatest magnetically induced deflection. Eighty-five percent of the tattoo seals showed deflection angles greater than 45 degrees of the ASTM guidelines, and the mascara and eye shadow showed over 40 degrees. This was because these contained ferromagnetic pigments such as an iron oxide, but those translational forces were very small owing to slight mass. However, it is desirable that these should be removed before MRI examination to prevent secondary problems.
    抄録全体を表示
    PDF形式でダウンロード (320K)
第63回総会学術大会合同シンポジウム
第63回総会学術大会　モーニングセミナー
教育講座―技師が書く技師のための読影講座―
基礎講座―検査を実施する上で知っておきたい画像処理技術―
臨床技術講座
連載読み物―医療の周りの法律について（10）―
JIRAトピックス
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top