The phasel-contrast CT imaging and X-ray fluorescence analysis of Zusanli acupuncture point (ST 36) based on synchrotron radiation

In this paper, the micro-structure of Zusanli acupuncture point was studied using synchrotron radiation-based phase contrast CT imaging (PCI-CT) method and X-ray fluorescence (XRF) analysis method. The micro-structures of the point were displayed through the topography and trace elements distributions. In this experiment, there are good results for PCI-CT method based on synchrotron radiation; the special resolution reached the dimension of micrometer. Compared to the images of the PCI-CT, which were taken at acupuncture points and non-acupuncture point areas, we find the micro vessels gather in the acupuncture points. In addition, the structures of acupuncture points are different from the surrounding tissues through XRF mapping method. The acupuncture points´ structure is different from that of the non-acupuncture points. In the acupuncture point area there is some micro-vascular aggregation, which reveals the differences of the acupoints and non-acupoints. The content of trace elements at the acupuncture points are more than those in the surrounding tissues, which can be inferred that there were the accumulation of trace elements at the acupuncture points´ area. The XRF mapping shows that the distributions of Ca, Fe, Cu and Zn elements were similar to their morphology. These differences demonstrate the existence of the acupuncture points. We hope that these results can provide a new basis for our scientific understanding of acupuncture points.