Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
Volume 65 , Issue 2
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  • Seiichiro Miyakawa, Masayuki Akiyama, Yasuo Nakazawa, Akira Shinozuka
    2009 Volume 65 Issue 2 Pages 239-244
    Published: February 20, 2009
    Released: February 26, 2009
    JOURNALS FREE ACCESS
    99mTc-GSA hepatic scintigraphy can evaluate the physiopathology and hepatic functions in liver diseases. The procedure usually proceeds by placing a gamma camera in the anterior and frontal positions parallel to the frontal cross section of the patient. However, because the liver is situated from the front towards the right side of the body, the distance between the liver and the gamma camera can attenuate the isotope count. The present study examines the notion that placing the gamma camera at a RAO position for imaging will augment the counts from the liver, thus enabling a more accurate evaluation of hepatic function. We analyzed the Time Activity Curve on a RAO image selected from raw data acquired using dynamic SPECT. A comparison of images obtained in this manner with analytical data from frontal images indicated that positioning the gamma camera at 30° at RAO, can capture more radioisotope counts than the frontal view, thus enabling a more accurate evaluation of hepatic function.
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  • Ryo Higashide, Katsuhiro Ichikawa, Hiroshi Kunitomo, Kazuya Ohashi, Ma ...
    2009 Volume 65 Issue 2 Pages 245-253
    Published: February 20, 2009
    Released: February 26, 2009
    JOURNALS FREE ACCESS
    The presampled modulation transfer function (MTF) is recognized as the established metric for characterizing the resolution performance of a digital imaging system. In the past, the three general approaches for assessing the presampled MTF were using the angulated slit, angulated edge, and angulated square-wave test pattern all of which are tilted slightly against the column direction of the detector. In all methods, it is important to determine the exact angle of the respective test devices. In this study, we examined the influence of angle-measurement error in three test devices and the optimal technique of angle measurement. These results demonstrated that the influences of angle-measurement error in each method were equal. We also investigated three angle-measurement techniques using trace of objects, Hough transfer, and comparative observation of synthetic profiles. These results suggested that the technique using synthetic profiles was the most optimal technique in the angle measurement. Through use of the technique, angle-measurement error was completely overcome. This technique will contribute to improved accuracy of presampled MTF measurements.
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  • Satsuki Tsuji, Reiko Kanda
    2009 Volume 65 Issue 2 Pages 254-262
    Published: February 20, 2009
    Released: February 26, 2009
    JOURNALS FREE ACCESS
    We undertook a survey to determine the public acceptance of medical radiation exposure throughout Japan, and 1,357 responses (67.9% response rate) were obtained using a two-stage systematic stratified random sampling method. The acceptance of exposure of children was generally similar to that of adults. For each of the attributes, 45–60% of the participants were accepting of exposure for cancer treatment and diagnosis, but only 30% were accepting of exposure for X-ray diagnoses of bone fractures and dental caries. In general, the presence of a child did not markedly affect women’s acceptance of exposure. Factor analyses identified 3 factors influencing the acceptance of child exposure: symptomatic diseases to determine treatment, the possibility of high-risk diseases (or major organ diseases), and the association with cancer. Cluster analysis showed 4 clusters: a positive group regarding children’s exposure for the diagnosis of bone fractures and dental caries (12.9% of all participants), a positive group for major organ disease and cancer (15.5%), a negative group excluding cancer (55.2%), and a positive group for all cases (16.4%). The cluster distributions revealed that mothers with 10-to 18-year-old firstborn children showed a tendency to accept the medical radiation exposure of their children in all cases.
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Note
  • Mitsuyoshi Yasuda, Kyouichi Kato, Toshiyuki Takahashi, Shougo Sai, Kaz ...
    2009 Volume 65 Issue 2 Pages 263-269
    Published: January 20, 2009
    Released: February 26, 2009
    JOURNALS FREE ACCESS
    It is difficult to obtain body diffusion weighted images (BDWI) using MRI that does not support parallel imaging and multi-NEX in clinical usage. Therefore, we evaluated whether a multiple image additions technique on the workstation could improve BDWI image quality and be good for clinical use by considering SNR and image distortion. We added 2 to 5 images on the same slice location with changing FOV, slice thickness, or reconstruction matrix in the phantom studies, and confirmed SNR improvement under all conditions. We also confirmed that this addition technique did not affect image distortion. We found that in 16 of the 18 clinical cases, BDWI with 5 images addition match pathology and T2 weighted images. We believe that this addition technique in available in the clinical practice.
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