多层面CT机剂量的测量与分析

The Measurement and Analysis for MSCT Dose

目的:分析多层面CT(MSCT)中影响剂量的因素,探讨降低多层面CT中病人辐射剂量的方法。方法:采用标准CT剂量测试体模测量4层面CT的剂量,计算出加权CT剂量指数。结果:(1)所有影响单层面CT剂量的因素仍然影响M SCT,此外在MSCT中还有一些特殊因素影响CT剂量。(2)在MSCT中,高速度模式要比高质量模式节省50%的剂量。(3)在剂量剖面线宽度(RPW)保持不变时,改变层厚和层数不会影响剂量值。在所有扫描模式中,当RPW增加时,CTDI100w降低。结论:必须认识在M SCT中影响剂量的各种因素,在保证图像质量的前提下尽可能地降低辐射剂量。

Objective： Factors affecting multi-slice CT （MSCT） dose were analyzed, to provide rules of thumb that assist in minimizing the radiation dose in MSCT. Methods： The dose phantom was used to measure dose for a MSCT, and the weighted CT dose index were calculated. Results： （1）All the factors affecting single slice CT also have the same effect on MSCT, besides, there are other special factors affecting radiation dose in MSCT.（2）High speed mode values are 50% lower than high-quality values.（3）A change in the section thickness does not change the absorbed radiation dose. in all scanning modes CTDI100w decreased when RPW increased. Conclusion： CT doses must be controlled to get good image quality to the greatest extent with least dose on the basis of understanding the factors affecting MSCT radiation dose.