前瞻性心电门控触发应用高螺距螺旋数据采集技术减少冠状动脉 CT 血管造影中血淋巴细胞的 X 射线所致 DNA 双链断裂。

Reduction of X-ray induced DNA double-strand breaks in blood lymphocytes during coronary CT angiography using high-pitch spiral data acquisition with prospective ECG-triggering.

机构信息

Department of Radiology, University of Erlangen-Nürnberg, Erlangen, Germany.

出版信息

Invest Radiol. 2010 Apr;45(4):182-7. doi: 10.1097/RLI.0b013e3181d3eddf.

DOI:10.1097/RLI.0b013e3181d3eddf

PMID:20177387

Abstract

OBJECTIVES

Purpose of this study was to compare the effect of high-pitch spiral data acquisition with prospective electrocardiography (ECG)-triggering on the x-ray induced DNA damages to blood lymphocytes with commonly used low-pitch spiral scans.

MATERIALS AND METHODS

Thirty four patients underwent coronary computed tomography angiography either using high-pitch spiral data acquisition (n = 15; dual-source computed tomography (CT) scanner, 38.4 mm collimation, 100-120 kV, 320-456 mAs/rotation, pitch value 3.2-3.4) or using a low-pitch protocol (n = 19; dual-source CT scanner, 19.2 mm collimation, 120 kV, 330-438 mAs/rotation, pitch 0.2-0.39, ECG-based tube current modulation). Blood samples were obtained before and 30 minutes after CT. Lymphocytes were isolated, stained against the phosphorylated histone variant gammaH2AX, and DNA double-strand breaks (DSBs) were visualized using fluorescence microscopy. Radiation dose to the blood was estimated by relating in vivo DSB levels to values of in vitro irradiated blood samples (50 mGy). Dose length product was registered as provided by the patient protocol.

RESULTS

Total dose length product ranged from 101 to 237 (median 112) mGy cm in high-pitch and from 524 to 1283 (median 1025) mGy cm in low-pitch scans (P < 0.0001). The median CT induced DSB level 30 minutes after exposure was significantly lower after high-pitch (0.04 DSBs/cell, range 0.02-0.10 DSBs/cell) compared with low-pitch scans (0.39 DSBs/cell, 0.22-0.71 DSBs/cell, P < 0.0001). Both DSB levels and radiation dose to the blood showed a significant correlation to the dose length product (r = 0.82, P < 0.0001). The radiation dose to the blood was significantly reduced in the high-pitch (median 3.1, range 2.0-8.1 mGy) compared with the low-pitch group (median 26.9; range 14.2-44.9 mGy, P < 0.0001).

CONCLUSIONS

Prospectively ECG-triggered high-pitch spiral data acquisition can considerably reduce the radiation dose to the blood in coronary CT angiography as compared with low pitch protocols.

摘要

目的

本研究旨在比较高螺距螺旋数据采集与常规低螺距螺旋扫描在冠状动脉 CT 血管造影中前瞻性心电图（ECG）触发对血淋巴细胞中 X 射线诱导的 DNA 损伤的影响。

材料和方法

34 名患者接受冠状动脉 CT 血管造影，其中 15 名患者采用高螺距螺旋数据采集（双源 CT 扫描仪，38.4mm 准直器，100-120kV，320-456mAs/转，螺距值 3.2-3.4），19 名患者采用低螺距方案（双源 CT 扫描仪，19.2mm 准直器，120kV，330-438mAs/转，螺距值 0.2-0.39，基于 ECG 的管电流调制）。在 CT 前和 30 分钟后采集血样。分离淋巴细胞，用磷酸化组蛋白变体 γH2AX 染色，用荧光显微镜观察 DNA 双链断裂（DSB）。通过将体内 DSB 水平与体外照射血样的水平相关联，估计血液中的辐射剂量（50mGy）。剂量长度乘积按患者方案记录。

结果

高螺距的总剂量长度乘积范围为 101 至 237（中位数 112）mGycm，低螺距的总剂量长度乘积范围为 524 至 1283（中位数 1025）mGycm（P<0.0001）。与低螺距扫描相比，高螺距扫描后 30 分钟暴露后 CT 诱导的 DSB 水平明显较低（0.04 DSBs/细胞，范围 0.02-0.10 DSBs/细胞）（P<0.0001）。DSB 水平和血液辐射剂量均与剂量长度乘积呈显著相关（r=0.82，P<0.0001）。与低螺距组（中位数 26.9；范围 14.2-44.9mGy，P<0.0001）相比，高螺距组（中位数 3.1；范围 2.0-8.1mGy）的血液辐射剂量显著降低。