TG DAC: MONTE CARLO CALCULATION OF SYSTEM MATRIX FOR PET INSERT DEVICE FOR BREA

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们正在开发一种新型的正电子发射断层扫描(PET)设备，用于乳房成像应用，它使用传统PET/CT扫描仪中的高分辨率半圆形探测器环来放大乳房周围的区域，以获得高分辨率图像。为了帮助开发我们的系统，我们必须执行真实的蒙特卡罗模拟，以了解我们系统的性能并生成系统矩阵。系统矩阵表示在成像视场中检测到源自体素的一对伽马射线的概率。可以使用统计迭代重建框架中的系统矩阵来估计患者体内的放射性分布。我们评估了现有的蒙特卡罗模拟程序包，如基于Geant4的模拟程序GATE，来执行此模拟研究，但发现现有的软件都不能有效地处理我们独特的系统几何形状。我们正在开发自己的模拟程序，以高效的方式对我们的几何图形进行具体建模。我们希望评估我们的模拟程序的准确性，一旦完成，将生成完整的系统矩阵，并使用TeraGrid计算资源执行图像重建。为了实现这些目标，我们预计我们将需要全额30,000个SU开发拨款。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are developing a new type of PET (positron emission tomography) device for breast imaging applications that uses a high-resolution semi-circular ring of detectors within a conventional PET/CT scanner to zoom-in on the region around a breast to obtain high-resolution images. To aid the development of our system, we must perform realistic Monte Carlo simulations to understand the performance of our system and to generate a system matrix. A system matrix represents the probability of detecting a pair of gamma rays originated from a voxel in the imaging field of view. One can use the system matrix in a statistical iterative reconstruction framework to estimate the distribution of radioactivity in the patient. We have evaluated existing Monte Carlo simulation packages such as GATE, a Geant4-based simulation program, to perform this simulation study, but found that none of the existing software will handle our unique system geometry efficiently. We are developing our own simulation program that specifically models our geometry in an efficient fashion. We would like to evaluate the accuracy of our simulation program, and once done, generate the full system matrix, and perform image reconstruction using the Teragrid computing resources. To achieve these goals, we anticipate that we will need a full 30,000 SU development allocation.