Potential of dosage reduction in cone-beam-computed tomography (CBCT) for radiological diagnostics of the paranasal sinu
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RHINOLOGY
Potential of dosage reduction in cone-beam-computed tomography (CBCT) for radiological diagnostics of the paranasal sinuses C. Gu¨ldner • A. Ningo • J. Voigt • I. Diogo J. Heinrichs • R. Weber • T. Wilhelm • M. Fiebich
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Received: 13 June 2012 / Accepted: 3 September 2012 / Published online: 18 September 2012 Ó Springer-Verlag 2012
Abstract More than 10 years ago, cone-beam-computed tomography (CBCT) was introduced in ENT radiology. Until now, the focus of research was to evaluate clinical limits of this technique. The aim of this work is the evaluation of specific dosages and the identification of potential optimization in the performance of CBCT of the paranasal sinuses. Based on different tube parameters (tube current, tube voltage, and rotation angles), images of the nose and the paranasal sinuses were taken on a phantom head with the Accu-I-tomo F17 (Morita, Kyoto, Japan). The dosages applied to the lens and parotid gland were measured with OSL dosimetry. The imaging quality was evaluated by independent observers. All datasets were reviewed according to a checklist of surgically important anatomic structures. Even for lowest radiation exposure (4 mA, 76 kV, 180°, computed tomography dosage index (CTDI) = 1.8 mGy), the imaging quality was sufficient. Of course a significant reduction of the imaging quality could be seen, so a reliable mean was set for 4 mA, 84 kV,
C. Gu¨ldner (&) I. Diogo R. Weber Department of Otolaryngology, Head and Neck Surgery, UKGM, University of Marburg, Baldingerstrasse, 35043 Marburg, Germany e-mail: [email protected] A. Ningo J. Voigt M. Fiebich Institute for Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany J. Heinrichs Department of Neuroradiology, UKGM, University of Marburg, Marburg, Germany T. Wilhelm Department of Otolaryngology, Head and Neck Surgery, Helios Klinikum Borna, Borna, Germany
and 180° rotation angle (CTDI = 2.4 mGy). In this combination, a reduction of 92 % in lens-dose and of 77 % of dosage at the parotid gland was observed in comparison to the maximal possible adjustments (8 mA, 90 kV, 360°, CTDI = 10.9 mGy). There is potential for optimization in CBCT. Changing the rotation angle (180° instead of 360°) leads to a dose reduction of 50 %. Furthermore from clinical point of view in case of chronic rhinosinusitis a relevant reduction of dosage is possible. Therefore, it is necessary to intensify the interdisciplinary discussion about the disease specifics required quality of imaging. Keywords Digital volume tomography (DVT) Cone-beam-computed tomography (CBCT) OSL dosimetry Dosage of lens Chronic rhinosinusitis Imaging ENT
Introduction The knowledge about the individual anatomic situation plays a central role for surgeons to plan interventions and to prevent complications. The current German guidelines for chronic rhinosinusitis recommend radiological imaging before surgery of the paranasal sinuses as a standard procedure [1]. The formerly used conventional radiography has been rep
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