Sabarudin Akmal, Sun Zhonghua, Ng Kwan-Hoong
Department of Imaging and Applied Physics, Curtin University, Perth, Western Australia, Australia.
J Med Imaging Radiat Oncol. 2012 Feb;56(1):5-17. doi: 10.1111/j.1754-9485.2011.02335.x.
The purpose of this paper is to perform a systematic review on radiation dose reduction in coronary computed tomography (CT) angiography that is done using different generations of multidetector CT (MDCT) scanners ranging from four-slice to 320-slice CTs, and have different dose-saving techniques. The method followed was to search for references on coronary CT angiography (CTA) that had been published in English between 1998 and February 2011. The effective radiation dose reported in each study based on different generations of MDCT scanners was analysed and compared between the types of scanners, gender, exposure factors and scanning protocols. Sixty-six studies were eligible for inclusion in this analysis. The mean effective dose (ED) for MDCT angiography with retrospective electrocardiogram (ECG) gating without use of any dose-saving protocol was 6.0 ± 2.8, 10.4 ± 4.90 and 11.8 ± 5.9 mSv for four-slice, 16-slice and 64-slice CTs, respectively. More dose-saving strategies were applied in recent CT generations including prospective ECG-gating protocols, application of lower tube voltage and tube current modulation to achieve a noteworthy dose reduction. Prospective ECG-gating protocol was increasingly used in 64, 125, 256 and 320 slices with corresponding ED of 4.1 ± 1.7, 3.6 ± 0.4, 3.0 ± 1.9 and 7.6 ± 1.6 mSv, respectively. Lower tube voltage and tube current modulation were widely applied in 64-slice CT and resulted in significant dose reduction (P < 0.05). This analysis has shown that dose-saving strategies can substantially reduce the radiation dose in CT coronary angiography. The fact that more and more clinicians are opting for dose-saving strategies in CT coronary angiography indicates an increased awareness of risks associated with high radiation doses among them.
本文的目的是对冠状动脉计算机断层扫描（CT）血管造影中的辐射剂量降低情况进行系统评价，该检查使用了不同代的多排CT（MDCT）扫描仪，从4排到320排CT，且具备不同的剂量节省技术。采用的方法是检索1998年至2011年2月间以英文发表的关于冠状动脉CT血管造影（CTA）的参考文献。分析并比较了基于不同代MDCT扫描仪的每项研究中报告的有效辐射剂量，比较内容包括扫描仪类型、性别、曝光因素和扫描方案。66项研究符合纳入本分析的条件。对于未使用任何剂量节省方案的回顾性心电图（ECG）门控MDCT血管造影，4排、16排和64排CT的平均有效剂量（ED）分别为6.0±2.8、10.4±4.90和11.8±5.9 mSv。在最近几代CT中应用了更多的剂量节省策略，包括前瞻性ECG门控方案、应用较低的管电压和管电流调制，以实现显著的剂量降低。前瞻性ECG门控方案在64、125、256和320排CT中使用得越来越多，相应的ED分别为4.1±1.7 mSv、3.6±0.4 mSv、3.0±1.9 mSv和7.6±1.6 mSv。较低的管电压和管电流调制在64排CT中广泛应用，并导致显著的剂量降低（P<0.05）。该分析表明，剂量节省策略可大幅降低CT冠状动脉造影中的辐射剂量。越来越多的临床医生在CT冠状动脉造影中选择剂量节省策略，这一事实表明他们对高辐射剂量相关风险的认识有所提高。
