顎顔面CT撮影における患者被曝線量の低減 : localizer image について  [in Japanese] Patient Dose Reduction in CT Examination in the Oral and Maxillofacial Region : Optimization of Localizer Image Acquisition  [in Japanese]

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Author(s)

    • 岡村 和俊 OKAMURA Kazutoshi
    • 九州大学歯学研究院口腔画像情報科学分野 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University
    • 吉田 豊 YOSHIDA Yutaka
    • 九州大学歯学研究院口腔画像情報科学分野 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University
    • 中山 英二 NAKAYAMA Eiji
    • 九州大学歯学研究院口腔画像情報科学分野 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University
    • 徳森 謙二 TOKUMORI Kenji
    • 九州大学歯学研究院口腔画像情報科学分野 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University
    • 吉浦 一紀 YOSHIURA Kazunori
    • 九州大学歯学研究院口腔画像情報科学分野 Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University

Abstract

Computed tomography (CT) is one of the main sources of medical radiation exposure. In addition, the recent trend towards higher image quality may lead to further increase of the patient dose. Though the exposure dose reduction of the patient is an important issue, dose reduction may lead to low image quality. Possible solution may be reduction of unnecessary images. Therefore, we evaluated the dosage of the localizer image that does not contribute to a diagnosis directly. The dose was measured using a human head & neck Rando Phantom (Alderson Research Laboratories, USA) in the localizer scan with CT scanner Aquilion (Toshiba Medical, Japan). Thermo-Luminescence-Dosimeters (TLD) were set on eyes, pituitary gland, parotid glands, submandibular glands, thyroid gland and skin surface. All scans were obtained at 120 kV and the tube current was decreased from 200 mA to 10 mA. The dose of a localizer image accounted for a large ratio in head & neck CT examination. The organ dose decreased in proportion to tube current and the head & neck localizer image obtained with 10mA was found to be acceptable. In evaluation by radiological technologists, all the landmarks could be confirmed even in the lowest setting. It was suggested that dose reduction of the localizer image can contribute to the total dose reduction.

Journal

  • Shika Hoshasen

    Shika Hoshasen 49(1), 7-12, 2009-12-31

    Japanese Society for Oral and Maxillofacial Radiology

References:  23

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