Heinz-Peer G, Weninger F, Nowotny R, Herold C J
Universitätsklinik für Radiodiagnostik, Wien.
Radiologe. 1996 Jun;36(6):470-4. doi: 10.1007/s001170050099.
Introduction of the computed tomography index CTDI and the multiple scan average dose (MSAD) has led to standardization of the dose description in CT examinations. Despite the use of these dose parameters, many different dosages are reported in the literature for different CT methods. In addition, there is still a wide range of radiation dosimetry results reported for conventional CT, helical CT, and HRCT used in chest examinations. The variations in dosage are mainly due to differences in factors affecting the dose, i.e. beam geometry, beam quality, scanner geometry ("generation"), and operating parameters. In addition, CT dosimetry instrumentation and methodology make a contribution to dosages. Recent studies calculating differences in factors affecting dosage and CT dosimetry and using similar operating parameters, show similar results in CT dosimetry for conventional and helical CT. On the other hand, dosages for HRCT were greatly reduced. This was mainly caused by narrow beam collimation and increasing section spacing.
计算机断层扫描指数CTDI和多扫描平均剂量（MSAD）的引入，使得CT检查中的剂量描述得以标准化。尽管使用了这些剂量参数，但文献中针对不同CT方法报道了许多不同的剂量。此外，胸部检查中使用的传统CT、螺旋CT和高分辨率CT（HRCT）的辐射剂量学结果仍有很大差异。剂量的变化主要是由于影响剂量的因素不同，即线束几何形状、线束质量、扫描器几何形状（“代”）和操作参数。此外，CT剂量测定仪器和方法也会对剂量产生影响。最近的研究计算了影响剂量的因素与CT剂量测定之间的差异，并使用了相似的操作参数，结果表明传统CT和螺旋CT的CT剂量测定结果相似。另一方面，HRCT的剂量大幅降低。这主要是由于窄束准直和增加层间距所致。
