为探讨SPECT双核素图像VOI阈值、体积和靶本比间关系,利用圆柱形体模内置10个空心球,按照1:7、1:6和1:5的靶本比,同时和分别注入99mTcO4-和18F-FDG,采集DISA和SIDA图像.采用阈值法勾画每个球体的感兴趣体积,拟合最佳阈值计算公式.最佳阈值计算公式为Tm=d+c×Bm/(e+f×Vm)+b/Vm.利用公式由球体真实体积计算的绝大多数阈值均在真实阈值所在的1%区间内,不在区间内者也处于该区间的上限或下限.无论DISA还是SIDA图像,利用VOI阈值、体积和靶本比间关系,以及球体真实体积均能较好地计算体积3.3～30.8 ml空心球体的最佳阈值,其误差小于1%.%Objective: To explore the relationshif of VOI threshold,Volume and B/S on DISA phantom images.Methods :Ten hollow spheres were placed in cylinder phantom. According to the B/S of 1:7, 1: 5 and 1:4,99mTcO4- and 18F- FDG was filled into the container and spheres simultaneously and separately. Images were acquired by DISA and SIDA protocol. Volume of interest (VOI) for each sphere was analyzed by threshold method and to fit expression individually for validating of the relationship. Results :The equation for the estimation of optimal threshold was as following Tm = d + c × Bm/(e + f × Vm) + b/Vm. In majority of data, the calculated threshold was in the 1％ interval that optimal thresholds were really in. Those who were not in were at the lower or upper intervals. Conclusions: Both DISA and SIDA images, based o the relationship of VOl threshold, Volume and B/S and real volume, this method could accurately caculate optimal threshold with an error less than 1％ for spheres whose volumes ranged from 3.3 to 30.8 ml.
展开▼
