故障现象在扫描过程中，半野（ｈａｌｆｆｉｅｌｄ）图像出现随机伪影；继之全野（ｆｕｌｆｉｅｌｄ）半野扫描不能转换，只能做全野扫描。故障分析与排除半野图像出现随机伪影，首先考虑校正数据失真。重新做半野水模校正，校正后的半野水模图像仍有随机伪影；于是怀疑计... Symptoms In the scanning process, random artifacts appear in the halffield image; following the fulfield scan, the whole field scan can only be performed. Failure analysis and elimination of random artifacts appear in half-images. First, the correction of data distortion is considered. Re-doing the half-time water model correction, the corrected half-water model image still has random artifacts;