The aim of this study is to compare the dosimetric performance of two CT acquisition protocols for the petrous bone: a standard fixed mAs protocol and a protocol using tube current modulation (TCM). By analyzing the scan length, dose-length product (DLP) and effective dose (ED) obtained with each protocol, we investigate whether TCM offers an advantage in terms of dose reduction while maintaining comparable image quality. To this end, 249 patients (women: 52%; men: 48%) were included in this study. The first center used TCM (120 kVp, 150 mA reference) for image acquisition, while the other centers opted for fixed mAs values. Acceptability of image quality was assessed using a standardized phantom (model 610 AAPM) by measuring noise uniformity and accuracy, contrast-to-noise ratio (CNR) and spatial resolution. The CTDIvol was not significantly different between center A and the other centers (p > 0.05), while DLP and ED were significantly different (p < 0.001), being reduced by a factor of 2 and 2.23 for scan length. We concluded that a scan with a 14.28% decrease in tube voltage from 140 kVp (136–170–210) mAs fixed to 120 kVp with TCM to 150 mA reference in helical scan mode can be recommended as an optimized protocol during CT examination of petrous bone while reducing DLP and ED to 50% without loss of diagnostic accuracy.

中文翻译：

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岩骨 CT 剂量评估：管电流调制和扫描长度的影响


本研究的目的是比较两种岩骨 CT 采集协议的剂量测定性能：标准固定 mAs 协议和使用管电流调制 (TCM) 的协议。通过分析每个方案获得的扫描长度、剂量长度乘积 (DLP) 和有效剂量 (ED)，我们研究了 TCM 是否在减少剂量方面具有优势，同时保持了可比较的图像质量。为此，本研究纳入了 249 名患者（女性：52%；男性：48%）。第一个中心使用 TCM（120 kVp，150 mA 参考）进行图像采集，而其他中心则选择固定 mAs 值。使用标准化模型（型号 610 AAPM）通过测量噪声均匀性和准确性、对比度噪声比 (CNR) 和空间分辨率来评估图像质量的可接受性。 A 中心和其他中心之间的 CTDIvol 没有显着差异 (p > 0.05)，而 DLP 和 ED 显着不同 (p < 0.001)，扫描长度减少了 2 倍和 2.23 倍。我们得出的结论是，在螺旋扫描模式下，管电压从 140 kVp (136–170–210) mAs 固定至 120 kVp（TCM 参考至 150 mA）下降 14.28% 的扫描可推荐作为岩骨 CT 检查期间的优化方案。骨，同时将 DLP 和 ED 降低至 50%，且不损失诊断准确性。