Department of Radiology, University of Erlangen-Nürnberg, Maximiliansplatz 1, D-91054 Erlangen, Germany.
Eur J Radiol. 2012 Mar;81(3):e357-62. doi: 10.1016/j.ejrad.2011.11.027. Epub 2011 Dec 16.
Aim of this study was to compare DNA double-strand breaks (DSBs) in blood lymphocytes of patients undergoing high-pitch helical, low-pitch helical and sequential coronary CT angiography.
66 patients were examined with various scan protocols and modes (low-pitch helical scan: 100-120 kV, 320-438 mAs/rot, pitch 0.18-0.39, with or without ECG-pulsing, n=35; prospectively ECG-triggered high-pitch helical scan: 100-120 kV, 320-456 mAs/rotation, pitch 3.2-3.4, n=19; prospectively ECG-triggered sequential scan: 100-120 kV, 150-300 mAs or 320-370 mAs/rotation, n=12) either using a 64-slice or 128-slice dual-source CT or a 128-slice single source CT scanner. Blood samples were obtained before and 30 min after CT and DSBs were analyzed in isolated lymphocytes using γ-H2AX immunofluorescence microscopy. A significant increase of DSBs was measurable 30 min after CTA (range 0.01-0.71/cell). CT induced DSBs showed a significant correlation with the estimated effective dose (ρ=0.90, p<0.00001). Both prospectively ECG-triggered sequential (0.10 DSBs/cell, 176 mGy cm, p<0.00001) and high-pitch helical scan protocols (0.03 DSBs/cell, 109 mGy cm, p<0.00001) led to a significant reduction of median DLP and DSB levels compared to low-pitch helical scans (0.34 DSBs/cell, 828 mGy cm). A reduction of the tube voltage resulted in significantly lower whereas additional calcium scoring resulted in elevated DLP and DNA damages (p<0.05 each).
In coronary CTA, data acquisition protocols have a significant influence on the X-ray induced DSB levels. Using γ-H2AX immunofluorescence microscopy different scan modes in different CT generations can be compared concerning their biological impact.
本研究旨在比较行高螺旋、低螺旋和序贯冠状动脉 CT 血管造影的患者血液淋巴细胞中的 DNA 双链断裂（DSB）。
66 例患者分别采用不同的扫描方案和模式（低螺旋扫描：100-120kV，320-438mAs/转，螺距 0.18-0.39，带或不带心电图脉冲，n=35；前瞻性心电图触发高螺旋扫描：100-120kV，320-456mAs/转，螺距 3.2-3.4，n=19；前瞻性心电图触发序贯扫描：100-120kV，150-300mAs 或 320-370mAs/转，n=12），使用 64 层或 128 层双源 CT 或 128 层单源 CT 扫描仪。在 CT 前和 30 分钟后采集血液样本，并使用γ-H2AX 免疫荧光显微镜分析分离的淋巴细胞中的 DSB。CTA 后 30 分钟可测量到 DSB 的显著增加（范围 0.01-0.71/细胞）。CT 诱导的 DSB 与估计的有效剂量呈显著相关（ρ=0.90，p<0.00001）。前瞻性心电图触发序贯（0.10 DSBs/细胞，176mGycm，p<0.00001）和高螺旋扫描方案（0.03 DSBs/细胞，109mGycm，p<0.00001）与低螺旋扫描相比，中位 DLP 和 DSB 水平显著降低（0.34 DSBs/细胞，828mGycm）。降低管电压会导致 DLP 和 DNA 损伤显著降低（p<0.05），而额外的钙评分会导致 DLP 和 DNA 损伤升高（p<0.05）。
在冠状动脉 CTA 中，数据采集方案对 X 射线诱导的 DSB 水平有显著影响。使用γ-H2AX 免疫荧光显微镜，可以比较不同 CT 代次中不同扫描模式的生物学影响。
