Moore S C, Judy P F, Garnic J D, Kambic G X, Bonk F, Cochran G, Margosian P, McCroskey W, Foote F
Med Phys. 1983 Nov-Dec;10(6):846-55. doi: 10.1118/1.595420.
A fourth-generation scanner has been modified to perform prospectively gated cardiac computed tomography (CT). A computer program monitors the electrocardiogram (ECG) and predicts when to initiate the next scan in a gated series in order to acquire all projection data for a desired phase of the heart cycle. The system has been tested with dogs and has produced cross-sectional images of all phases of the cardiac cycle. Eight to ten scans per series were sufficient to obtain reproducible images of each transverse section in the end-diastolic and end-systolic phases. The radiation dose to the skin was approximately 1.4 cGy per scan. The prospectively gated system is more than twice as efficient as a retrospectively gated system in obtaining complete angular projection data for a 10% heart cycle window. A temporal smoothing technique to suppress reconstruction artifacts due to sorting inconsistent projection data was developed and evaluated. Image noise was reduced by averaging together any overlapping projection data. Prospectively gated cardiac CT has also been used to demonstrate that the error in attenuation measured with a single nongated CT scan through the heart can be as large as 50-60 CT numbers outside the heart in the lung field.
一台第四代扫描仪已被改装用于进行前瞻性门控心脏计算机断层扫描（CT）。一个计算机程序监测心电图（ECG），并预测何时启动门控系列中的下一次扫描，以便获取心动周期所需阶段的所有投影数据。该系统已在狗身上进行了测试，并生成了心动周期所有阶段的横截面图像。每个系列进行八到十次扫描足以获得舒张末期和收缩末期各横断层面的可重复图像。每次扫描对皮肤的辐射剂量约为1.4 cGy。在获取10%心动周期窗口的完整角度投影数据方面，前瞻性门控系统的效率是回顾性门控系统的两倍多。开发并评估了一种用于抑制因分类不一致的投影数据而产生的重建伪影的时间平滑技术。通过对任何重叠的投影数据进行平均来降低图像噪声。前瞻性门控心脏CT还被用于证明，通过心脏进行单次非门控CT扫描测量的衰减误差在肺野中心脏外可能高达50 - 60个CT值。
