Detection of respiratory tumour motion using intrinsic list mode-driven gating in positron emission tomography
Detection of respiratory tumour motion using intrinsic list mode-driven gating in positron emission tomography
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DOI：
10.1007/s00259-010-1533-y
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发表时间：
2010-12-01
影响因子：
9.1
通讯作者：
Schaefers, Klaus P.
中科院分区：
文献类型：
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作者：
Buether, Florian;Ernst, Iris;Schaefers, Klaus P.
众所周知，PET 扫描期间器官的呼吸运动会降低 PET 图像质量，可能导致图像模糊、衰减伪影和错误的示踪剂定量。基于列表模式的门控已被证明可以减少心脏 PET 中的这些缺陷。本研究评估了肿瘤 PET 扫描的这些内在门控方法。总共 34 名患有肝脏或肺部肿瘤的患者（总共 14 名肝脏肿瘤和 27 名肺部肿瘤）接受了肿瘤区域的 15 分钟单床列表模式 PET 扫描。其中，15 名患者（总共 8 名肝脏肿瘤和 11 名肺部肿瘤）通过在患者腹部记录标记的摄像机进行监测，从而捕获 PET 门控的呼吸运动（视频方法）。通过将列表模式流划分为 200 毫秒帧、确定重合数量（灵敏度方法）并计算相同帧中测量的计数率的轴向质心（质心方法），推导出进一步的选通信息。此外，通过在正弦图空间中分割肿瘤（分段灵敏度/质心方法），仅使用源自肿瘤区域的重合来评估这些基于列表模式的方法。测量的呼气末和吸气末之间的肿瘤位移以及门控图像中表观摄取的增加作为门控准确性的衡量标准。为了估计准确性，还进行了模拟小肿瘤的移动活动源的胸部模型研究。所有方法都以不同的成功程度解决了呼吸运动。分段质心法的结果最好，平均比其他方法产生更大的位移和吸收值。由于呼吸周期期间活动进入视野，简单质心方法在位移方面表现较差。基于灵敏度和基于视频的方法都会产生类似的结果。列表模式驱动的 PET 门控，尤其是分段质心方法，在肝脏和肺部肿瘤的 PET 扫描中是可行且准确的。
Respiratory motion of organs during PET scans is known to degrade PET image quality, potentially resulting in blurred images, attenuation artefacts and erroneous tracer quantification. List mode-based gating has been shown to reduce these pitfalls in cardiac PET. This study evaluates these intrinsic gating methods for tumour PET scans.A total of 34 patients with liver or lung tumours (14 liver tumours and 27 lung tumours in all) underwent a 15-min single-bed list mode PET scan of the tumour region. Of these, 15 patients (8 liver and 11 lung tumours in total) were monitored by a video camera registering a marker on the patient's abdomen, thus capturing the respiratory motion for PET gating (video method). Further gating information was deduced by dividing the list mode stream into 200-ms frames, determining the number of coincidences (sensitivity method) and computing the axial centre of mass of the measured count rates in the same frames (centre of mass method). Additionally, these list mode-based methods were evaluated using only coincidences originating from the tumour region by segmenting the tumour in sinogram space (segmented sensitivity/centre of mass method). Measured displacement of the tumours between end-expiration and end-inspiration and the increase in apparent uptake in the gated images served as a measure for the exactness of gating. To estimate the accuracy, a thorax phantom study with moved activity sources simulating small tumours was also performed.All methods resolved the respiratory motion with varying success. The best results were seen in the segmented centre of mass method, on average leading to larger displacements and uptake values than the other methods. The simple centre of mass method performed worse in terms of displacements due to activities moving into the field of view during the respiratory cycle. Both sensitivity- and video-based methods lead to similar results.List mode-driven PET gating, especially the segmented centre of mass method, is feasible and accurate in PET scans of liver and lung tumours.