Physiological gating of the MARS spectral micro CT scanner
Physiological gating of the MARS spectral micro CT scanner
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MARS 光谱微型 CT 扫描仪的生理门控
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Weddell
中科院分区：
文献类型：
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作者：
I. Glass;A. Butler;P. Butler;P. Bones;S. Weddell
为了减少心血管运动引起的图像模糊，研究了Medipix全分辨率系统(MARS)频谱CT扫描仪的两种生理性门控方法：前瞻性和回溯性。该扫描仪目前是为扫描小动物而设计的，但有计划在未来将其扩展到临床应用。已经实施了预期门控，以便根据心脏和肺的状态在特定时间收集投影数据。另一种回溯性门控方法允许扫描仪尽可能快地收集投影，但记录每次采集时的心和肺状态。为了验证门控的有效性，建立了一个利用气动系统操作的心肺模型。这个模型是通过将液体乳胶覆盖在3D打印模型上而创建的，事实证明，它成功地模拟了有节奏的运动。一个附着在“心脏”外表面的标记被用来评估如何获得始终如一的投影获取。使用体模进行预期浇注的初步结果显示取得了一定的成功。心率分别为60、200和320次/分时，标记物欧氏距离的标准差在45.0μm~116.0μm之间。研究表明，来自门控检测系统的触发信号与数据采集之间的时间有很大的差异。将需要进一步的发展来减少这种差异。
Two methods of physiological gating, prospective and retrospective, have been investigated for the Medipix All-Resolution Systems (MARS) spectral CT scanner in order to reduce image blurring due to cardiovascular motion. The scanner is currently designed for scanning small animals, however there are plans to extend it to clinical applications in future. Prospective gating has been implemented such that projection data is collected at specific times, dependent on the state of the heart and lungs. The alternative approach of retrospective gating allows the scanner to collect projections as fast as possible, but records the state of the heart and lungs at each acquisition. In order to validate the effectiveness of the gating, a heart and lungs phantom operated by means of a pneumatic system was built. The phantom was created by laying liquid latex over a 3D printed former and proved successful at simulating rhythmical motion. A marker attached to the “heart” outer surface was used to assess how consistently projection acquisitions could be obtained. Preliminary results for prospective gating with the phantom show some success. The standard deviation of marker Euclidean distance ranged between 45.0 μm and 116.0 μm for cardiac rates of 60, 200 and 320 bpm. Investigation indicated that there was significant variation in the time between the trigger signal from the gating detection system and the data acquisition. Further development will be required to reduce this variation.