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Management of patient dose and image noise in routine pediatric CT abdominal examinations

Verdun, Francis ; Lepori, D. ; Monnin, Pascal ; Valley, Jean-François ; Schnyder, Pierre ; Gudinchet, F.

In: European Radiology, 2004, vol. 14, no. 5, p. 835-841

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    Titre
    • Management of patient dose and image noise in routine pediatric CT abdominal examinations
    Auteur
    • Verdun, Francis. University Institute for Applied Radiophysics, Grand-Pré 1, 1007, Lausanne, Switzerland
    • Lepori, D.. Department of Diagnostic and Interventional Radiology, University Hospital Center (CHUV), 1011, Lausanne, Switzerland
    • Monnin, Pascal. University Institute for Applied Radiophysics, Grand-Pré 1, 1007, Lausanne, Switzerland
    • Valley, Jean-François. University Institute for Applied Radiophysics, Grand-Pré 1, 1007, Lausanne, Switzerland
    • Schnyder, Pierre. Department of Diagnostic and Interventional Radiology, University Hospital Center (CHUV), 1011, Lausanne, Switzerland
    • Gudinchet, F.. Department of Diagnostic and Interventional Radiology, University Hospital Center (CHUV), 1011, Lausanne, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • European Radiology, 2004, vol. 14, no. 5, p. 835-841. Springer-Verlag; http://www.springer.de
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:312247
    Summary
    The aim was to propose a strategy for finding reasonable compromises between image noise and dose as a function of patient weight. Weighted CT dose index (CTDIw) was measured on a multidetector-row CT unit using CTDI test objects of 16, 24 and 32cm in diameter at 80, 100, 120 and 140kV. These test objects were then scanned in helical mode using a wide range of tube currents and voltages with a reconstructed slice thickness of 5mm. For each set of acquisition parameter image noise was measured and the Rose model observer was used to test two strategies for proposing a reasonable compromise between dose and low-contrast detection performance: (1) the use of a unique noise level for all test object diameters, and (2) the use of a unique dose efficacy level defined as the noise reduction per unit dose. Published data were used to define four weight classes and an acquisition protocol was proposed for each class. The protocols have been applied in clinical routine for more than one year. CTDIvol values of 6.7, 9.4, 15.9 and 24.5mGy were proposed for the following weight classes: 2.5-5, 5-15, 15-30 and 30-50kg with image noise levels in the range of 10-15HU. The proposed method allows patient dose and image noise to be controlled in such a way that dose reduction does not impair the detection of low-contrast lesions. The proposed values correspond to high- quality images and can be reduced if only high-contrast organs are assessed