Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
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Volume 54, Issue 10
Displaying 1-28 of 28 articles from this issue
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  • [title in Japanese]
    Article type: Cover
    1998 Volume 54 Issue 10 Pages Cover4-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351897
    JOURNAL FREE ACCESS
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  • [title in Japanese]
    Article type: Cover
    1998 Volume 54 Issue 10 Pages Cover5-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351898
    JOURNAL FREE ACCESS
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  • [title in Japanese]
    Article type: Index
    1998 Volume 54 Issue 10 Pages Toc3-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351899
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  • [title in Japanese]
    Article type: Index
    1998 Volume 54 Issue 10 Pages Toc4-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351900
    JOURNAL FREE ACCESS
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  • [title in Japanese]
    [in Japanese]
    Article type: Article
    1998 Volume 54 Issue 10 Pages I-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351901
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages II-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351902
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages III-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351903
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages IV-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351904
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages V-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351905
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages VI-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351906
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages VI-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351907
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  • Examination of Presampling MTF Measurement Method in CT
    SATORU MATSUO, MITSURU KOMIZU, TETSUO KIDA, KAZUO NOMA, KAZUTAKA MASUD ...
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1191-1199
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351908
    JOURNAL FREE ACCESS
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    The presampling modulation transfer function(MTF) of digital images generaly uses a profile curve obtained in the direction perpendicular to the slit. There are two methods of obtaining the profile curve in the perpendicular direction, one that uses the line spread functions(LSFs) of the center and half-pixel-shifted alignments, and one that obtains the curve from a composite LSF calculated from the profile curves of many alignments. Although the presampling MTF-calculated composite LSF is more accurate, it takes longer to obtain. Therefore, we used a presampling MTF calculated from a profile curve of the slit image obtained in the parallel direction instead of the perpendicular direction. Because the LSF calculated from the profile curves of the parallel direction corresponds closely to the composite LSF, we can obtain an accurate curve by a much simpler method. The presampling MTF calculated from the composite LSF and the LSF obtained in the direction parallel to the slit image showed a deviation of less than 0.013.
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  • Signal Intensity and Partial Volume Effect in MRI
    TSUKASA DOI, YOSHIMASA MIZUNO
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1200-1206
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351909
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    The signal intensity obtained from an organism is determined by its tissue composition, the scanning technique, parameters of the apparatus, and other factors. We examined the influence of the partial volume effect on signal intensity and vision in the relation between voxel and photographic subject. We studied the influence that the photographic subject and slice thickness(slice face)exterted on signal intensity, and measured changes in signal intensity according to the positional relation between pixels and the photographic subject. From the results, we clarified the mechanism by which signal is given out from the voxel and examined the relation between the partial volume effect and signal intensity(contrast to noise ratio). We found that signal intensity is determined by the partial volume effect as determined by the radio between the signal body and a substance set in the surroundings using a macro target and micro target. Moreover, the stimulation given to vision has the relation of a logarithm in contrast. We clarified that the CNR is applied as an approximate value.
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  • X-ray Output and Percentage Ripple in X-ray Tube Voltage : X-ray Generators for Mammography
    SHIGERU MIYAZAKI, YOH KATOH, TORU NEGISHI, SHINJI ABE, IZUMI OGURA
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1207-1215
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351910
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    Various characteristics of x-ray generators used for mammography(tube voltage, tube current, percentage average error of irradiation time, percentage ripple of the tube voltage waveform, linearity, and reproducibility of the photographic effect)have already been clarified by the authors. In our more recent investigations, x-ray output and radiation quality as percentage ripple of the tube voltage waveform were evaluated using the dynamic study method with the aluminum filter specified in the International Electrotechnical Commission(IEC) standard. In addition, we also assessed the effects of fluctuation in percentage ripple of the tube voltage waveform on the x-ray spectrum. Based on the results obtained, the characteristics of an ideal x-ray generator for mammography are discussed. The results of this study showed that x-ray output differences in terms of percentage ripple ranged from 45% to 82% compared with that of a constant-potential high-voltage generator. With regard to radiation quality, differences of 0.01 to 0.02 mm were found in the half value layer using an aluminum filter. The thicker the x-ray absorber, the more marked the effects of percentage ripple. In terms of the x-ray spectrum, moreover, characteristic x-rays(at 17.4 and 19.5 keV)cannot be effectively used, although a molybdenum target or molybdenum filter is used. Based on these results, a constant potential high-voltage generator with percentage ripple of 4% or less in the tube voltage waveform should be employed for mammography.
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  • Acoustic Noise Analysis of Echo Planar Imaging : Multi-center Trial and Comparison with Other Pulse Sequences
    TOSHIAKI MIYATI, HIROYUKI NARITA, NORITAKE AKAIWA, SHIGERU ISHIHARA, H ...
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1216-1225
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351911
    JOURNAL FREE ACCESS
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    The purpose of this study was to evaluate acoustic noise in echo plannar imaging(EPI) at various magnetic resonance imaging(MRI) centers, and to compare EPI acoustic noise with that in other principal pulse sequences. We measured the maximum clinical acoustic noise[A-weighted root-mean-square sound pressure levels(Leq)and peak impulse sound pressure levels(Lpeak)]for FPI under the same conditions in five clinical superconducting MRI systems(0.5-1.5T). We also compared the sound pressure levels for EPI and nine different pulse sequences, and analyzed the acoustic noise spectra. There was no signification difference between acoustic noise levels in EPI and other pulse sequences, and these values were within Occupational Safety and Health Administration guidelines at all centers. However, of all the pulse sequences, EPI has the greatest proportion of high-frequency acoustic noise(>1,000 Hz). Single-shot EPI was subject to higher-pitched noise than multi-shot EPI. Even among centers using the same magnet and gradient coil systems, there was considerable difference in acoustic noise levels(maximum differences in Leq and Lpeak were 7.0 dBA and 7.7 dB, respectively).
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  • Immobilization Device for Head and Neck Region in Radiotherapy
    JUNICHI SASAKI, KAZUO IZAWA, KIYOTO KAWANABE, YUUKO SEGUCHI, AKITOSHI ...
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1226-1233
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351912
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    We developed two new kinds of immobilization devices for the head and neck region, one for a treatment couch and the other for a simulator couch. These new devices are made of carbon resin and are composed of a head rest, shell(cast)mounting portion, and accessory mounting portion. The "simulator couch" type is convenient for treatment planning, CT, and MR examinations, and can be used as a treatment couch. The "treatment couch" type is used in the greatment room. A special exclusive interface is used as an attachment for the treatment couch. Three immobilization methods, i.e., bite, shell(cast), and a device for stereotactic radiotherapy are available. We examined the bending of the immobilization device with the arm-type interface. When 5 kg is loaded, the average amount of bending is 1.1 mm. This immobilization device is useful for small treatment fields in the head and neck region, multiple portal treatment, and fractionated stereotactic radiotherapy.
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  • Reduction of CSF Flow Artifact in Fast Fluid Attenuated Inversion Recovery MR Imaging : Study of Excitation Width in 180゜ Inversion Pulse
    TOSHIO TSUCHIHASHI, ISAO FUJITA, SATOSHI YOSHIZAWA, TOSHIO MAKI, MATSU ...
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1234-1240
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351913
    JOURNAL FREE ACCESS
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    A technique that increases slice thickness so that it becomes wider than the excitation width of the 180゜ inversion pulse and in which TR is partitioned twice has been investigated with regard to fast FLAIR. This is a technique that reduces the flow artifact of CSF. It is thought that, with this technique, the flow artifact is reduced because the CSF that flows onto the slice reaches the null point. The cross talk effect of the 180゜ inversion pulse appears as a high CSF signal. As a result, the number of slices needs to be partitioned two or three times before imaging. Thus the imaging time is doubled or tripled. Considering the cross talk effect of the 180゜ inversion pulse and the imaging time needed for this technique, the optimal imaging technique would be one that uses an inversion pulse that is four times slice thickness plus slice space and for which the number of slices is partitioned twice. Furthermore, the null point of CSF was dependent on dividing TR in half.
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  • Electromagnetic Compatibility in Medicine
    Makoto Kikuchi
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1241-1246
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351914
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  • Frequency Analysis of SPECT Images
    Hideo Ohnishi
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1247-1252
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351915
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  • Technical Study for the Improvement of the Detectability of Abdominal Lesions : Low Contrast Resolution and Exposure Dose
    KYOJI HIGASHIMURA
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1253-1257
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351916
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  • [title in Japanese]
    [in Japanese]
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1258-1259
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351917
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  • [title in Japanese]
    [in Japanese]
    Article type: Article
    1998 Volume 54 Issue 10 Pages 1260-1263
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351918
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  • [title in Japanese]
    Article type: Bibliography
    1998 Volume 54 Issue 10 Pages 1264-1265
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351919
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages 1266-1267
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351920
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages 1268-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351921
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  • New Member List
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages 1269-1270
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351922
    JOURNAL RESTRICTED ACCESS
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  • [title in Japanese]
    Article type: Appendix
    1998 Volume 54 Issue 10 Pages 1271-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351923
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  • [title in Japanese]
    Article type: Cover
    1998 Volume 54 Issue 10 Pages Cover6-
    Published: October 20, 1998
    Released on J-STAGE: June 29, 2017
    DOIhttps://doi.org/10.6009/jjrt.KJ00001351924
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