Medical Imaging Technology
Online ISSN : 2185-3193
Print ISSN : 0288-450X
ISSN-L : 0288-450X
Volume 36, Issue 1
Displaying 1-10 of 10 articles from this issue
Main Topics / Management of Radiation Dose in Medical Imaging
  • Hidenobu SUZUKI, Yoshihisa MURAMATSU
    2018 Volume 36 Issue 1 Pages 1-2
    Published: 2018
    Released on J-STAGE: January 31, 2018
    JOURNAL FREE ACCESS
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  • Tomokazu SHOHJI
    2018 Volume 36 Issue 1 Pages 3-8
    Published: 2018
    Released on J-STAGE: January 31, 2018
    JOURNAL FREE ACCESS
    Recently a computed tomography (CT) unit plays an important role in a diagnosis and treatment plan. Generally, the principle of as low as reasonably achievable radiation exposure was proposed, which recommended that, for all radiographic examinations, including those involving children, radiologists should prioritize the use of the lowest achievable radiation dose that would not compromise the diagnostic capabilities of the examinations. However, medical radiation exposure of Japanese CT is very high. In such a background, a diagnosis reference level of Japan is announced and contributes to revision of scan protocol and optimization of medical radiation exposure in each institution. In our paper, we describe the change of CT dose index, the latest measurement and radiation dose management.
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  • Hajime SAKAMOTO
    2018 Volume 36 Issue 1 Pages 9-14
    Published: 2018
    Released on J-STAGE: January 31, 2018
    JOURNAL FREE ACCESS
    Total skin dose of patient resulting from interventional radiological (IVR) procedures have the potential to exceed the threshold doses for deterministic effects such as erythema and epilation. It is desirable to measure entrance skin dose value non-invasively, easily and at real time. In this report, we explain the way of dose management for medical exposure in IVR. We also introduce the procedure of simply estimating entrance skin dose in clinical situation using machine indication dose and dose area product, and the method of measuring reference dose of machine according to DRLs2015.
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  • Yusuke KOBA
    2018 Volume 36 Issue 1 Pages 15-20
    Published: 2018
    Released on J-STAGE: January 31, 2018
    JOURNAL FREE ACCESS
    Although radiation diagnostics is widely prevalent, the individual patient exposure dose is not necessarily sufficiently evaluated at present. The exposure conditions and the dose index are managed as value of medical exposure, but the evaluation of the exposure dose of each patient is also important. However, it is a problem that general patient exposure dose evaluation tools are cause enormous time and effort to use for all the imaging of each facility. In order to solve these problems NIRS is developing system to automatically calculate patient exposure dose of CT imaging by using management information such as RDSR and in the future not only CT but also other modality it aims to develop the system.
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  • Yuji ODA
    2018 Volume 36 Issue 1 Pages 21-25
    Published: 2018
    Released on J-STAGE: January 31, 2018
    JOURNAL FREE ACCESS
    Manufacturers and trade groups support optimization activity that users lead by working on standardization of apparatuses and functions. Manufacturers and trade groups work on standardization of equipment, systems, and functions. It will support the optimization activity that the user leads. There is standardizations in not only the international standards such as the IEC standards but also the local standard such as the NEMA standards. Apparatuses are adapted to the international standards and the local standards. Safety level in apparatus operation improves in a point of dose management by these activity.
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  • Hiroaki YAMAUCHI
    2018 Volume 36 Issue 1 Pages 26-31
    Published: 2018
    Released on J-STAGE: January 31, 2018
    JOURNAL FREE ACCESS
    The necessity of medical exposure management is being advocated from various organizations in Japan and overseas. Electronic record of radiation dose information is mandatory in some states in the United States. And in Europe it is recommended to utilize diagnostic reference level and manage patient medical exposure. The importance of the dose management system is globally recognized, and it is gradually spreading even in Japan. But the specific operation method is not yet widely known. Radimetrics provided by Bayer Yakuhin, Ltd. is a system that can manage various dose indices in radiological examinations. Radimetrics support optimization utilizing the diagnostic reference level and automatically calculate the dose index such as effective dose in the CT examination and entrance skin dose in the angiographic procedure, which was difficult to compute in the past. We believe that Radimetrics contributes to quality control of radiological equipment, patient safety and development of radiology.
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Work-in-progress
  • Yongbum LEE, Yuki IIJIMA, Tomomi OHMURA, Akira HASEGAWA, Noriyuki TAKA ...
    2018 Volume 36 Issue 1 Pages 32-35
    Published: 2018
    Released on J-STAGE: January 31, 2018
    JOURNAL FREE ACCESS
    CT perfusion (CTP) by 4D-CT is commonly used in diagnosis of cerebral ischemia. However, CTP maps potentially vary depending on commercial CTP software. Therefore, this paper proposed a computerized detection method for cerebral ischemic region from 4D-CT. Cross-sectional images with basal ganglia were determined, and then adaptive partial median filter (APMF) which was an edge-preserving-smoothing filter was implemented. A mask image was subtracted from the APMF images to identify blood-vessel regions with contrast agent. Region of interests (ROIs) were placed on the subtracted images for symmetric comparison of blood vessel's area. If blood vessel's areas in the corresponding ROIs were significantly different, the ROI with smaller blood vessel's area was determined as ischemic region. In comparison with CTP maps, the proposed method was able to detect several ischemic regions and distinguish affected side and healthy side. Therefore, it would be useful for ischemic diagnosis in 4D-CT.
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