CR技术与胶片照相技术的特性对比试验

The Characteristics Comparison Experiments of Computed Radiography and Film Radiography Techniques

计算机射线成像(CR)技术在成像机理、获得图像的途径上与胶片照相有着本质的区别。为了更好地应用CR技术,对比试验了其在Pb增感屏影响、空间分辨力和散射线影响方面与胶片照相技术的差异。试验得出,Pb增感屏在CR技术照相时起不到增感作用,其主要作用是过滤散射线,提高检测灵敏度。CR技术的分辨力可达50μm甚至25μm,已经达到了与胶片技术相同的实际效果,因此不必要求CR的成像板像素达到胶片颗粒度水平。同时,CR技术对散射线的敏感程度要超过胶片技术,因此要得到较好的图像质量,在CR技术应用中必须注意防护散射线。试验结果使检测人员能更好地了解CR技术与胶片技术的差异,更有效地推广CR技术在工业领域的应用。

The imaging principle and ways of obtaining image in computed radiography （CR） technique is totally different to the film radiography technique in. In order to apply CR technique into industry field well, comparison experiments between CR and film radiography techniques were carried out on three mainly factors as Pb intensity screen effect, resolution and scattering radiographic effect. Comparison experiment results showed that there was no intensity effect while using Pb intensity screen on CR technique, whose main effect was to filter the scattering ray and improve the testing sensitivity. The resolution of CR technique was as high as 50 ~m and even better than 25 ptm, which already reached the practical identity of film radiography technique. So it is not so necessary to require the CR imaging plate to get such a high image pixel as the granule level of radiographic film. At the same time, CR technique is much more sensitive on the scattering ray than the film radiography technique, so it is necessary to take notice of the scattering ray prevention in order to get a good image quality. The above-mentioned testing results can help the inspection personnel welI master the difference between CR technique and film radiography technique, and could effectively promote the application of CR technique in industry.