The Test Study Of Hard X-Ray Phase Contrast Imaging

Backgrounds and objective Since the discovery of X-rays by Conrad Rontgen in 1895,almost all the practical uses of radiography for human imaging have been based on X-ray absorbtion contrast and optic geometric.This absorbtion contrast imaging utilized the high penetrability of X-ray, when it pass through an object alone different paths will be differentially absorbed and the intensity pattern of the emerging beam records the distribution of absorbing materials within the sample.this methed can give the materials inner information which others can not supply.even through ,as the soft tissue which based on light elements because the soft tissue only have little absorbtion or no absorbtion or have little diffrential in absorbtion so it only investigated few information within soft tissue .in 1965,doctor Bonse.U find,for light elements,e.g.carbon,hydrogen,oxygen,nitrogen.,the cross section of the phase shift is 1000 times larger than that of absorbtion,it means the sensitivity of this method is about a thousand times larger than the absorbtion contrast,indicating the possibility of obtaining equivalent information about an object,with a considerably reduced absorbed dose,as compared with absorbtion imaging.this techniques have advantages to image the internal structure of thick sample,at the same time it can improve the resolution greatly and reach several micron.with the advent of synchrotron radiation facility,this phase contrast imaging techniques go into reality and gained high attation.at present, this techniques about phase contrast imaging have improved greatly and phse contrast-CT is available.in our country it is initial .in this article we introduce our test that perfomed in Beijing synchrotron radiation facility (BSRF),several biological object were used in this test and obtained phase contrast imaging.the quality of this imaging were analysised and compared with that absorbtion imaging so that to find the difference between that two imaging.Methods we performed some experiments to obtain phase contrast imagings andabsorbtion contrast imagings of several different biological objects in Beijing synchrotron radiation facility(BSRF 4WIA).the object include small aquarium goldfish, phymateus, SD mouse trabcular bone and joint, these biological objects with the suit projecting condition (Beam Intensity and exposure time), statistics were perfomed between phase contrast imagings and absorbtion contrast imagings. Wilcoxon and Kruskal-Wallis methods were used to compared the two imaging qulity.then understand the theory of phase contrast imaging.Results there are manifest difference between that two imaging, phase contrast imagings have high quality than that of absorbtion imaging( Z= -6.68 P < 0.001 ),the soft tissue contrast and resolution were improved greatly in phase contrast imaging.high spatial coherence X- ray source and proper distance between objects and CCD is very important to phase contrast imaging.Conclusion 1. we can obtain satisfied phase contrast imaging in Beijing synchrotron radiation facility(BSRF 4WIA).the condition of imaging is determined by high spatial coherence X- ray source and proper distance between objects and CCD .2. high spatial coherence X- ray source and suit distance between objects and CCD is very important to phase contrast imaging, the soft tissue contrast and resolution were improved greatly in phase contrast imaging.3. the suit distance between objects and CCD is essantial to phase contrast imaging,it determined the contrast and resolution of phase contrast imaging.