Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Med Phys. 2010 Oct;37(10):5306-12. doi: 10.1118/1.3491806.
Carbon nanotube (CNT) based field emission x-ray source technology has recently been investigated for diagnostic imaging applications because of its attractive characteristics including electronic programmability, fast switching, distributed source, and multiplexing. The purpose of this article is to demonstrate the potential of this technology for high-resolution prospective-gated cardiac micro-CT imaging.
A dynamic cone-beam micro-CT scanner was constructed using a rotating gantry, a stationary mouse bed, a flat-panel detector, and a sealed CNT based microfocus x-ray source. The compact single-beam CNT x-ray source was operated at 50 KVp and 2 mA anode current with 100 microm x 100 microm effective focal spot size. Using an intravenously administered iodinated blood-pool contrast agent, prospective cardiac and respiratory-gated micro-CT images of beating mouse hearts were obtained from ten anesthetized free-breathing mice in their natural position. Four-dimensional cardiac images were also obtained by gating the image acquisition to different phases in the cardiac cycle.
High-resolution CT images of beating mouse hearts were obtained at 15 ms temporal resolution and 6.2 lp/mm spatial resolution at 10% of system MTF. The images were reconstructed at 76 microm isotropic voxel size. The data acquisition time for two cardiac phases was 44 +/- 9 min. The CT values observed within the ventricles and the ventricle wall were 455 +/- 49 and 120 +/- 48 HU, respectively. The entrance dose for the acquisition of a single phase of the cardiac cycle was 0.10 Gy.
A high-resolution dynamic micro-CT scanner was developed from a compact CNT microfocus x-ray source and its feasibility for prospective-gated cardiac micro-CT imaging of free-breathing mice under their natural position was demonstrated.
碳纳米管（CNT）基场发射 X 射线源技术最近因其具有吸引力的特性，包括电子可编程性、快速切换、分布式源和复用性，已被研究用于诊断成像应用。本文的目的是展示该技术在高分辨率前瞻性门控心脏微 CT 成像中的潜力。
使用旋转机架、固定鼠床、平板探测器和密封的 CNT 基微焦点 X 射线源构建了动态锥束微 CT 扫描仪。紧凑型单束 CNT X 射线源在 50 KVp 和 2 mA 阳极电流下运行，有效焦点尺寸为 100 微米 x 100 微米。使用静脉内给予的碘基血池造影剂，从处于其自然位置的十只麻醉自由呼吸的小鼠中获得了跳动小鼠心脏的前瞻性心脏和呼吸门控微 CT 图像。通过将门控图像采集到心脏周期的不同相位，还获得了四维心脏图像。
以 15 毫秒的时间分辨率和 6.2 lp/mm 的空间分辨率获得了跳动小鼠心脏的高分辨率 CT 图像，在系统 MTF 的 10%处。图像以 76 微米各向同性体素大小重建。两个心动周期的采集时间为 44 +/- 9 分钟。在心室和心室壁内观察到的 CT 值分别为 455 +/- 49 和 120 +/- 48 HU。单次心动周期采集的入口剂量为 0.10 Gy。
从紧凑型 CNT 微焦点 X 射线源开发了一种高分辨率动态微 CT 扫描仪，并证明了其在其自然位置下对自由呼吸小鼠进行前瞻性门控心脏微 CT 成像的可行性。
