PET/CT 4D门控扫描技术的试验验证与分析

Experimental verification and analysis of PET/CT 4D gated scanning technique

目的:分析研究正电子发射计算机断层显像/计算机断层显像(PET/CT)4D门控扫描技术的实际应用意义及其具体实现方法和成像结果。方法:选取场内测试时的模体数据以及在医院就诊且进行PET/CT扫描的1例患者4D门控扫描数据,采用东软医疗PET/CT系统及AnzaiAZ-733V呼吸系统对其进行呼吸门控检查,按照一个呼吸周期时间等分划分的方法,划分6个期相获得多期重建图像,将美国国家电气制造商协会(NEMA)图像质量(IQ)标准模体与患者扫描结果进行对比分析,比较常规非门控扫描和4D门控扫描结果的差异。结果:从划分好的患者多期相重建图像中的肝尖位置变化及划定的感兴趣区域(ROI)内的均值对比度计算结果进行分析,比较不同呼吸期相下重建图像,可以明显看出肝尖部位按周期性规律的沿轴向方向的位置周期性变化以及肝尖与肝中和肺底的对比度差异,验证了4D呼吸门控扫描的有效性。结论:PET/CT 4D门控扫描技术可以有效减轻胸腔位置由于呼吸运动导致的肺部和肝部边界变模糊现象及恢复器官组织对比度以降低定量准确性等误差影响,提高胸腔位置重建图像质量,为后续定量检测及其他临床应用提供保障。

Objective:To analyze and study the practical application significance of positron emission tomography/computed tomography(PET/CT)4D gated scanning technique,the specific implementation method and the imaging results.Methods:The intra-field phantom data that were tested and the 4-dementational(4D)gated scanning data of 1 patient who underwent PET/CT were selected,and the Neusoft Medical PET/CT system and Anzai AZ-733V respiratory system were used to perform examination of respiratory gating.Multi-phase reconstruction images were obtained by dividing a respiratory cycle into six phases by time equality.The standard phantom of images quality(IQ)of American national electrical manufactures association(NEMA)was used to compare and analyze with the scanning result of patient,and the difference of the reconstruction results between the conventional non-gated scan and 4D gated scanning results were compared.Results:The reconstruction images under different respiratory phases were analyzed and compared from the position change of the liver tip in the segmented multi-phase reconstruction images and the calculated results of contrast ratio of mean value within the designated region of interest(ROI).It can be clearly found that the periodical change of the position of the liver tip along the axial direction according to the periodical regulation,and the difference of the contrast ratio among the liver tip,liver medium and the base of lung,which verified the effectiveness of the 4D respiratory gated scanning.Conclusion:PET/CT 4D gated scanning technique can effectively relieve the blurring phenomenon of lung boundary and liver boundary of thoracic cavity position caused by respiratory movement,and can recover contrast of organ and tissue to reduce error influence of quantitative accuracy and others,and can improve the quality of reconstructed image of the position of thoracic cavity,and can provide guarantee for subsequent quantitative detection and other clinical applications.