N148 X Yan et al In Xiajuxu Out of Xiajuxt 0100200300400500600700800 Figure 6. SXRF spectra from the Xiajuxu acupoint(solid line)and the surrounding tissues out of at Xiajuxu, respectively. The concentrations of Zn were different at Jianshi, Tiaokou and Xiajuxu acupuncture points but the ratios of the concentrations of Cu and Fe at all three points were approximately the same. The ratio between the concentrations of Cu and Fe may be an important characteristic of acupuncture points, since no fixed ratio for these elements was found in the surrounding tissues. The fluorescent emission depended on the position alon the meridian, as shown in figure 7. The emission from the Ximen acupuncture point was very weak. It may be due to the lower element concentrations in Ximen points, but the reason for the low concentration is still not known. Except for Ximen, their contents are obviously higher than in the surrounding tissues and there are closely similar ratios of Cu to Fe at Jianshi Tiaokou and Xiajuxu From the mapping spectra of samples 2 and 3 along the lines parallel to the meridian, it was found that the meridian line itself had significantly higher contents of the four metals, which gradually increased to a maximum coinciding with the acupuncture point. The full width half-maximum(FWHM) was found to be approximately 8 mm for sample 2 and 6 mm for sample 3, which coincides with the effective size of the acupuncture points. Taking the maximum as the center of the acupuncture point, the fluorescent intensities in directions parallel with and perpendicular to the meridian were mapped. It was found that away from the acupuncture point there was no fixed ratio among the contents of the four metals, in contrast to the fixed ratios found at the points themselves. Also, there were different trends in the elemental content reduction ratio(Ncenter-M)/Center)x 100%o in the meridian and perpendicular to it (where Ncenter is the integrated intensity in the center of the acupuncture point and N is the intensity from any neighboring point). The ratios are shown as percentages in table 1. The uncertainties of integrated fluorescent intensities calculated using AXIL are also given. The uncertainty for Cu is large due to its very low content. The points shown are displaced from upuncture point by 2 mm along the meridian and 1.4 mm in the perpendicular dire In the meridian direction, the ratio decreased less than in the perpendicular direction. These data suggest that acupuncture points are elliptical with the major axis being parallel to the meridianN148 X Yan et al Figure 6. SXRF spectra from the Xiajuxu acupoint (solid line) and the surrounding tissues out of Xiajuxu (dotted line). at Xiajuxu, respectively. The concentrations of Zn were different at Jianshi, Tiaokou and Xiajuxu acupuncture points but the ratios of the concentrations of Cu and Fe at all three points were approximately the same. The ratio between the concentrations of Cu and Fe may be an important characteristic of acupuncture points, since no fixed ratio for these elements was found in the surrounding tissues. The fluorescent emission depended on the position along the meridian, as shown in figure 7. The emission from the Ximen acupuncture point was very weak. It may be due to the lower element concentrations in Ximen points, but the reason for the low concentration is still not known. Except for Ximen, their contents are obviously higher than in the surrounding tissues and there are closely similar ratios of Cu to Fe at Jianshi, Tiaokou and Xiajuxu. From the mapping spectra of samples 2 and 3 along the lines parallel to the meridian, it was found that the meridian line itself had significantly higher contents of the four metals, which gradually increased to a maximum coinciding with the acupuncture point. The full width half-maximum (FWHM) was found to be approximately 8 mm for sample 2 and 6 mm for sample 3, which coincides with the effective size of the acupuncture points. Taking the maximum as the center of the acupuncture point, the fluorescent intensities in directions parallel with and perpendicular to the meridian were mapped. It was found that away from the acupuncture point there was no fixed ratio among the contents of the four metals, in contrast to the fixed ratios found at the points themselves. Also, there were different trends in the elemental content reduction ratio ((Ncenter − N)/Ncenter) × 100% in the meridian and perpendicular to it (where Ncenter is the integrated intensity in the center of the acupuncture point and N is the intensity from any neighboring point). The ratios are shown as percentages in table 1. The uncertainties of integrated fluorescent intensities calculated using AXIL are also given. The uncertainty for Cu is large due to its very low content. The points shown are displaced from the acupuncture point by 2 mm along the meridian and 1.4 mm in the perpendicular direction. In the meridian direction, the ratio decreased less than in the perpendicular direction. These data suggest that acupuncture points are elliptical with the major axis being parallel to the meridian