...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physics in medicine and biology. >Comparison of basis functions for 3D PET reconstruction using a Monte Carlo system matrix
【24h】

Comparison of basis functions for 3D PET reconstruction using a Monte Carlo system matrix

机译：使用蒙特卡洛系统矩阵进行3D PET重建的基本函数比较

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In emission tomography, iterative statistical methods are accepted as the reconstruction algorithms that achieve the best image quality. The accuracy of these methods relies partly on the quality of the system response matrix (SRM) that characterizes the scanner. The more physical phenomena included in the SRM, the higher the SRM quality, and therefore higher image quality is obtained from the reconstruction process. High-resolution small animal scanners contain as many as 10 310 4 small crystal pairs, while the field of view (FOV) is divided into hundreds of thousands of small voxels. These two characteristics have a significant impact on the number of elements to be calculated in the SRM. Monte Carlo (MC) methods have gained popularity as a way of calculating the SRM, due to the increased accuracy achievable, at the cost of introducing some statistical noise and long simulation times. In the work presented here the SRM is calculated using MC methods exploiting the cylindrical symmetries of the scanner, significantly reducing the simulation time necessary to calculate a high statistical quality SRM and the storage space necessary. The use of cylindrical symmetries makes polar voxels a convenient basis function. Alternatively, spherically symmetric basis functions result in improved noise properties compared to cubic and polar basis functions. The quality of reconstructed images using polar voxels, spherically symmetric basis functions on a polar grid, cubic voxels and post-reconstruction filtered polar and cubic voxels is compared from a noise and spatial resolution perspective. This study demonstrates that polar voxels perform as well as cubic voxels, reducing the simulation time necessary to calculate the SRM and the disk space necessary to store it. Results showed that spherically symmetric functions outperform polar and cubic basis functions in terms of noise properties, at the cost of slightly degraded spatial resolution, larger SRM file size and longer reconstruction times. However, we demonstrate that post-reconstruction smoothing, usually applied in emission imaging to reduce the level of noise, can produce a spatial resolution degradation of 50%, while spherically symmetric basis functions produce a degradation of only 6%, compared to polar and cubic voxels, at the same noise level. Therefore, the image quality trade-off obtained with blobs is higher than that obtained with cubic or polar voxels.
机译：在放射断层扫描中，迭代统计方法被接受为获得最佳图像质量的重建算法。这些方法的准确性部分取决于表征扫描仪的系统响应矩阵（SRM）的质量。 SRM中包含的物理现象越多，SRM质量越高，因此从重建过程中可以获得更高的图像质量。高分辨率小型动物扫描仪包含多达10 310 4个小晶体对，而视场（FOV）则分为数十万个小体素。这两个特征对SRM中要计算的元素数量有很大影响。蒙特卡洛（MC）方法由于可达到的精度提高而作为计算SRM的一种方法而受到欢迎，但以引入一些统计噪声和较长的仿真时间为代价。在此处介绍的工作中，使用MC方法利用扫描仪的圆柱对称性来计算SRM，从而显着减少了计算高统计质量SRM和所需存储空间所需的仿真时间。圆柱对称的使用使极性体素成为方便的基础函数。可替代地，与立方和极基函数相比，球对称基函数导致改善的噪声特性。从噪声和空间分辨率的角度比较了使用极性体素，极坐标网格上的球对称基函数，立方体素以及重建后过滤的极性和立方体素的重建图像的质量。这项研究表明，极性体素的性能与立方体素相同，从而减少了计算SRM所需的仿真时间以及存储SRM所需的磁盘空间。结果表明，在噪声特性方面，球对称函数优于极性和立方函数，但代价是空间分辨率略微降低，SRM文件大小更大且重建时间更长。但是，我们证明，通常用于发射成像以降低噪声水平的重建后平滑可以产生50％的空间分辨率下降，而与极性和立方相比，球对称基函数只能产生6％的下降在相同的噪声水平下的体素。因此，使用斑点获得的图像质量折衷要高于使用立方体或极性体素获得的图像质量。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号