The spatially-variant back-projection point kernel function of an energy-subtraction Compton scatter camera for medical imaging
The spatially-variant back-projection point kernel function of an energy-subtraction Compton scatter camera for medical imaging
复制标题
医学成像减能康普顿散射相机的空间变化反投影点核函数
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
C. Bonnerave
中科院分区：
文献类型：
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作者：
R. Rohe;M. Sharfi;K.A. Kecevar;J. Valentine;C. Bonnerave
减能康普顿散射相机 (ESCSC) 此前曾被提议用于核医学中用作生物示踪剂的放射性药物的体内 3D 成像。为了进一步评估这种 ESCSC 设计的实用性，探索并提出了与图像重建相关的研究。一般来说，康普顿散射相机的工作原理是发射的伽马射线在主探测器系统中经历康普顿散射相互作用，然后被辅助探测器系统吸收。使用测量到的相互作用能量和位置，可以对锥体表面进行反投影，该锥体表面截取伽马射线发射点附近的发射空间（接近度取决于分辨率）。当将多个锥体反向投影并线性叠加到源空间中时，计算应包括标准化每个锥体贡献的总权重，以及当您远离锥体顶点时差分截取面积如何增加（即，距顶点越远的截取体素赋予的权重越小）。基于模拟数据的反投影“绘画内核轮廓”与位于 ESCSC 相机几何结构内多个位置（揭示空间变化程度）的点源相对应。根据这些结果，可以推导出空间变异点核函数（例如，通过 3-D 插值）以供将来在图像重建中使用。此外，还比较了两种不同的反投影算法。
An energy-subtraction Compton scatter camera (ESCSC) was previously proposed for in-vivo 3-D imaging of radiopharmaceuticals used as bio-tracers in nuclear medicine. To further evaluate the usefulness of this ESCSC design, studies pertaining to image reconstruction are explored and presented. Generally speaking, a Compton scatter camera works on the principle that an emitted gamma ray undergoes a Compton scatter interaction in a primary detector system and then is subsequently absorbed by a secondary detector system. Using the measured interaction energies and positions, a cone surface can be backprojected which intercepts the emission space near the point of the gamma-ray emission (proximity depends on resolution). When backprojecting and linearly superposing multiple cones into a source space, calculations should include normalizing the total weight contributed by each cone as well as how the differentially intercepted area increases as you move farther away from the vertex of the cone (i.e., intercepted voxels farther away from the vertex are given less weight). Backprojected "paint-kernel profiles", based upon simulated data, are presented corresponding to point sources located at several positions (revealing the degree of spatial variance) within the ESCSC camera geometry. From these results the spatially variant point kernel function may be deduced (e.g., via 3-D interpolation) for future use in image reconstruction. Additionally, two different algorithms for backprojection are compared.