Department of Otolaryngology, Head and Neck Surgery, UKGM, University of Marburg, Baldingerstrasse, 35043 Marburg, Germany.
Eur Arch Otorhinolaryngol. 2013 Mar;270(4):1307-15. doi: 10.1007/s00405-012-2177-2. Epub 2012 Sep 18.
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, 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.
10 多年前，锥形束 CT（CBCT）在耳鼻喉放射学中得到应用。直到现在，研究的重点一直是评估该技术的临床限制。这项工作的目的是评估特定剂量，并确定鼻窦 CBCT 性能的潜在优化。基于不同的管参数（管电流、管电压和旋转角度），使用 Accu-I-tomo F17（Morita，京都，日本）在头模上拍摄鼻和鼻窦的图像。使用 OSL 剂量测量仪测量透镜和腮腺的剂量。独立观察者评估成像质量。根据手术重要解剖结构的检查表对所有数据集进行审查。即使在最低辐射暴露（4mA、76kV、180°，CTDI=1.8mGy）下，成像质量也足够。当然，成像质量会明显下降，因此为 4mA、84kV 和 180°旋转角度（CTDI=2.4mGy）设定了可靠的平均值。在此组合中，与最大可能调整（8mA、90kV、360°，CTDI=10.9mGy）相比，透镜剂量降低了 92%，腮腺剂量降低了 77%。CBCT 有优化的潜力。改变旋转角度（180°而不是 360°）可使剂量减少 50%。此外，从慢性鼻-鼻窦炎的临床角度来看，剂量可以显著减少。因此，有必要加强关于所需成像质量的疾病特异性的跨学科讨论。
