Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.
Center for Radiology and Nuclear Medicine, Diakovere Henriettenstift, Hannover, Germany.
PLoS One. 2021 Apr 23;16(4):e0250490. doi: 10.1371/journal.pone.0250490. eCollection 2021.
The objective of this study is to identify essential aspects influencing radiation dose in computed tomography [CT] of the chest, abdomen and pelvis by intraindividual comparison of imaging parameters and patient related factors. All patients receiving at least two consecutive CT examinations for tumor staging or follow-up within a period of 22 months were included in this retrospective study. Different CT dose estimates (computed tomography dose index [CTDIvol], dose length product [DLP], size-specific dose estimate [SSDE]) were correlated with patient's body mass index [BMI], scan length and technical parameters (tube current, tube voltage, pitch, noise level, level of iterative reconstruction). Repeated-measures-analysis was initiated with focus on response variables (CTDIvol, DLP, SSDE) and possible factors (age, BMI, noise, scan length, peak kilovoltage [kVp], tube current, pitch, adaptive statistical iterative reconstruction [ASIR]). A univariate-linear-mixed-model with repeated-measures-analysis followed by Bonferroni adjustments was used to find associations between CT imaging parameters, BMI and dose estimates followed by a subsequent multivariate-mixed-model with repeated-measures-analysis with Bonferroni adjustments for significant parameters. A p-value <0.05 was considered statistically significant. We found all dose estimates in all imaging regions were substantially affected by tube current. The iterative reconstruction significantly influenced all dose estimates in the thoracoabdominopelvic scans as well as DLP and SSDE in chest-CT. Pitch factor affected all dose parameters in the thoracoabdominopelvic CT group. These results provide further evidence that tube current has a pivotal role and potential in radiation dose management. The use of iterative reconstruction algorithms can substantially decrease radiation dose especially in thoracoabdominopelvic and chest-CT-scans. Pitch factor should be kept at a level of ≥1.0 in order to reduce radiation dose.
本研究旨在通过个体内比较成像参数和患者相关因素，确定影响胸部、腹部和盆腔 CT[计算机断层扫描]辐射剂量的基本方面。本回顾性研究纳入了 22 个月内至少连续两次因肿瘤分期或随访而接受 CT 检查的所有患者。将不同的 CT 剂量估计值（CT 剂量指数[CTDIvol]、剂量长度乘积[DLP]、体积特异性剂量估计值[SSDE]）与患者的体重指数[BMI]、扫描长度和技术参数（管电流、管电压、螺距、噪声水平、迭代重建水平）相关联。采用重复测量分析，重点关注反应变量（CTDIvol、DLP、SSDE）和可能的因素（年龄、BMI、噪声、扫描长度、峰值千伏[kVp]、管电流、螺距、自适应统计迭代重建[ASIR]）。采用具有重复测量分析的单变量线性混合模型，然后进行 Bonferroni 调整，以发现 CT 成像参数、BMI 和剂量估计值之间的关联，然后进行具有重复测量分析的多变量混合模型，对有意义的参数进行 Bonferroni 调整。p 值<0.05 被认为具有统计学意义。我们发现所有成像区域的所有剂量估计值都受到管电流的显著影响。迭代重建显著影响了胸腹部 CT 中的所有剂量估计值以及胸部 CT 中的 DLP 和 SSDE。螺距因子影响了胸腹部 CT 组中的所有剂量参数。这些结果进一步证明了管电流在辐射剂量管理中具有关键作用和潜力。迭代重建算法的使用可以显著降低辐射剂量，特别是在胸腹部和胸部 CT 扫描中。为了降低辐射剂量，应将螺距因子保持在≥1.0 的水平。
