Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
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Volume 64, Issue 7
Displaying 1-20 of 20 articles from this issue
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Opening Article
Original
  • Pilot Study of Domain-specific Terminology Adaptation for Morphological Analysis: Research on Unknown Terms in National Examination Documents of Radiological Technologists
    Shintarou Tsuji, Naoki Nishimoto, Katsuhiko Ogasawara
    2008 Volume 64 Issue 7 Pages 791-794
    Published: July 20, 2008
    Released on J-STAGE: August 22, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.791
    JOURNAL FREE ACCESS
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    Although large medical texts are stored in electronic format, they are seldom reused because of the difficulty of processing narrative texts by computer. Morphological analysis is a key technology for extracting medical terms correctly and automatically. This process parses a sentence into its smallest unit, the morpheme. Phrases consisting of two or more technical terms, however, cause morphological analysis software to fail in parsing the sentence and output unprocessed terms as "unknown words." The purpose of this study was to reduce the number of unknown words in medical narrative text processing. The results of parsing the text with additional dictionaries were compared with the analysis of the number of unknown words in the national examination for radiologists. The ratio of unknown words was reduced 1.0% to 0.36% by adding terminologies of radiological technology, MeSH, and ICD-10 labels. The terminology of radiological technology was the most effective resource, being reduced by 0.62%. This result clearly showed the necessity of additional dictionary selection and trends in unknown words. The potential for this investigation is to make available a large body of clinical information that would otherwise be inaccessible for applications other than manual health care review by personnel.
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Note
  • Verification of Irradiation Conditions of X-rays That Influence Implantable Cardiac Pacemakers
    Naoki Umezawa, Minoru Hirose, Toshihiro Shinbo
    2008 Volume 64 Issue 7 Pages 795-804
    Published: July 20, 2008
    Released on J-STAGE: August 22, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.795
    JOURNAL FREE ACCESS
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    Originally, it was thought that X-rays did not influence implantable cardiac pacemakers. In general, radiological technologists did not take proper care of these devises at the time of X-Ray examinations. However, 11 cases in which pacemakers malfunctioned (for example partial electrical reset) during CT examinations have been reported in recent years. At the time, we tended to attribute such problems to the peculiarities of multi-detector CT (MDCT). However, on logical grounds this explanation seemed weak. To better explain the problem, we attempted various tests in which pacemakers were exposed to CT and X-ray photography equipment. We analyzed some ECG results to clarify the matter and took measurements to examine these problems.
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Clinical Technology
  • Effect of Diagnostic X-rays on Implantable Cardiac Pacemakers and Implantable Cardioverter Defibrillators, and Its Management
    Nobuhiro Oda, Hiroshi Nakajima, Haruhiko Abe, Syuji Koyama, Shingo Kak ...
    2008 Volume 64 Issue 7 Pages 805-813
    Published: July 20, 2008
    Released on J-STAGE: August 22, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.805
    JOURNAL FREE ACCESS
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    The effects of diagnostic X-rays on implantable cardiac pacemakers and implantable cardioverter defibrillators (ICDs) were investigated. A total of 33 pacemakers from six manufacturers and nine ICDs from four manufacturers were irradiated using several X-ray units (plain X-ray diagnostic unit, under-table system fluoroscopy unit, over-table system fluoroscopy unit, biplane cardiac digital angiography unit, DSA unit and cone-beam CT unit). No systematic reset phenomena were observed in any pacemakers and ICDs under the X-ray irradiation. Nevertheless, over-sensing associated with the lack of a few pulses was observed in three of 33 pacemakers under radiation exposure. It has been proven that diagnostic X-rays might affect pacemaker function. Since the duration of the over-sensing under the radiation was very short and included transient episodes, this sensing failure, therefore, induced by radiation exposure would not affect the health of pacemaker recipients. ICDs were not affected by radiation exposure at a clinical dose. It is recommended that caution be exercised in direct irradiation to the pacemaker. Using a copper sheet of 2.0 mm thickness or more prevented over-sensing of pacemakers in the present study, especially when serial X-ray exposures were used with an over-table fluoroscopy system or cone-beam CT unit.
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  • Quantitative Assessment of Wall Motion in Gated SPECT Using the Centerline Method
    Toshikazu Imae, Keita Fujii, Masaaki Takano, Junichi Yamazaki, Kyohito ...
    2008 Volume 64 Issue 7 Pages 814-821
    Published: July 20, 2008
    Released on J-STAGE: August 22, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.814
    JOURNAL FREE ACCESS
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    Evaluation of myocardial wall motion is an important assessment of heart function. Specific analysis programs in nuclear medicine, such as QGS (quantitative gated SPECT) analysis and p-FAST (perfusion-function assessment for myocardial SPECT), have been used to assess wall motion, but they have not evaluated it through a comparison of normal data. The centerline method, using left ventriculograms (LVG), evaluates regional wall motion quantitatively through a comparison of normal data and patient data, and abnormality of wall motion is expressed in units of standard deviation (SD) s from the mean motion in a reference population. However, angiography is an invasive inspection, wall motion analysis is usually in one direction, and the conventional centerline method is not a three-dimensional analysis. The purpose of this study was to apply the centerline method to nuclear medicine and examine the wall motion of subjects through a comparison of normal wall motion non-invasively and in a three-dimensional way. We arranged the analysis program using C language and inspected it using a dynamic cardiac phantom and computed tomography (CT) scanner. We made a polar map that indicated the mean and SD of normal wall motion. Our proposed method was able to assess the wall motion of subjects quantitatively through a comparison of normal wall motion in nuclear medicine.
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  • Evaluation of the OS-EM Parameter with Automatic Quantitative Analysis for Cerebral Blood Flow of the ECD Tool
    Kimie Asao, Hitomi Takeda, Akihiro Takaki, Kazunori Kawakami, Satomi T ...
    2008 Volume 64 Issue 7 Pages 822-831
    Published: July 20, 2008
    Released on J-STAGE: August 22, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.822
    JOURNAL FREE ACCESS
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    The parameters of reconstruction iteration and subset of the ordered subset expectation maximization (OS-EM) method have a great impact on image quality. In a cerebral blood flow (CBF) examination, it is critical to produce consistent results when analyzing clinical data. We evaluated the number of iterations and subset of the OS-EM method to stabilize image quality using a normal case and an infarction case. In the maximum likelihood expectation maximization (ML-EM) method, it was confirmed that the convergence of an infarction case was somewhat delayed compared with a normal case. With the OS-EM method, we have obtained the same results. Based on the rCBF values, we postulate that the iteration value is more than 8 and the subset value is less than 10. Furthermore, multiplying the iteration by a subset value ranging from 50 to 60 helps in stabilizing the quality of CBF imaging.
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Educational Lecture—Interpreting Medical Images for Radiological Technologists—
Basic Lecture—The Image Processing Technology that You Should Learn on Examination—
Clinical Technology Cource
Science Exchanges Committee Report
Committee News
JIRA Topics
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