优化钇-90轫致辐射SPECT显像能窗:体外实验研究

Optimization of energy window of yttrium-90 bremsstrahlung SPECT imaging:In vitro experimental study

目的观察中能通用(MEGP)准直器不同能窗对钇90(^(90)Y)轫致辐射SPECT图像质量的影响,遴选最佳显像能窗。方法获取^(90)Y轫致辐射能谱,比较MEGP准直器不同能窗下图像灵敏度、源感兴趣区计数/视野内总计数百分比(S/FOV%)及信号/背景比(S/B)。结果所获^(90)Y轫致辐射能谱呈连续曲线,MEGP准直器下能峰为76.2 keV。MEGP准直器显像清晰。以10%、20%窗宽显示图像的S/FOV%与S/B差异均无统计学意义(P均>0.05),而后者灵敏度更高(P<0.05)。70~90 keV图像灵敏度较高而S/FOV%及S/B有所下降;40~60 keV图像S/FOV%、S/B均较高而灵敏度较低;100 keV±20%能窗图像灵敏度、S/FOV%及S/B均较高,分别为69.73%、0.62和1.64。结论以MEGP准直器行^(90)Y轫致辐射显像时,20%窗宽图像质量优于10%窗宽;100 keV±20%图像灵敏度较高且S/FOV%及S/B无明显降低。

Objective To observe the influence of different energy windows of the medium-energy general-purpose(MEGP)collimator on image quality,so as to optimize the energy window of yttrium-90(^(90)Y)bremsstrahlung SPECT imaging.Methods^(90)Y bremsstrahlung spectrum was acquired,and the sensitivity,percentage of the source counts in useful field of view(S/FOV%)and signal-to-background ratio(S/B)of^(90)Y bremsstrahlung SPECT imaging at MEGP under different energy windows were compared.Results The energy spectrum of^(90)Y bremsstrahlung was a continuous curve,with the peak of 76.2 keV with MEGP collimator.The images obtained with MEGP collimator were clear,and no significant differences of S/FOV%nor S/B was found between 10%and 20%window width groups(both P>0.05),but the sensitivities of the latter was higher than the former(P<0.05).The sensitivity of 70—90 keV images was relatively high,while the S/FOV%and S/B had decreased.The S/FOV%and S/B of images ranging from 40—60 keV were high,but the sensitivity was low.Images acquired with 100 keV±20%showed fairly high sensitivity,S/FOV%and S/B,which was 69.73%,0.62 and 1.64,respectively.Conclusion When performing^(90)Y bremsstrahlung SPECT with MEGP collimator,the image quality at 20%window width was better than at 10%window width,and 100 keV±20%showed fairly high sensitivity and not significantly decreased S/FOV%and S/B.