X线照片均方根值粒状度的测试探讨

Investigation of Testing of RMS Graininess of Radiography

作者介绍了Ｘ线照片均方根值（ｒｏｏｔｍｅａｎｓｑｕａｒｅ，ＲＭＳ）粒状度的测试原理及方法。对Ｃａ－ＷＯ＿４／Ｆｕｊｉ和ＢａＦＣＩ：Ｅｕ／Ｆｕｊｉ两种屏胶系统在不同条件下的ＲＭＳ值进行了测试。结果：在同一条件下，稀土增感屏ＢａＦＣｌ：Ｅｕ／Ｆｕｊｉ胶片系统的ＲＭＳ值大；随着管电压的升高，两种屏胶系统的ＲＭＳ值都增大。作者对产生Ｘ线照片ＲＭＳ粒状度的原因进行了讨论。本研究结果并结合有关文献表明：控制Ｘ线照片斑点的主要措施是管电压不要过高，所用稀土增感因数不宜过大，即所用ｍＡｓ值不宜过小。

In this paper the principle and method of testing of RMS(Root Mean Square )graininess of radiograph were described.Two kinds of filrnscreen systetms:CaWO/Fuji and BaFCl:Eu / Fuji,were tested.The results indicated the RMS value of BaFCl Eu /Fuji system was greater than that of CaWO/Fuji system under the same condition,In addition,the RMS values of both systems increased with increase of X-ray tube voltage. The authors discussed the causes of graininess on a radiograph.This study together with related reports indicated that an effective way of controlling film mottle was to refrain from usmg too high tube voItage and too big intensifying screen factor which translated into too small mAs value.