In this paper we present OMEGA, an open-source software, for efficient and fast image reconstruction in positron emission tomography (PET). OMEGA uses the scripting language of MATLAB and GNU Octave allowing reconstruction of PET data with a MATLAB or GNU Octave interface. The goal of OMEGA is to allow easy and fast reconstruction of any PET data, and to provide a computationally efficient, easy-access platform for development of new PET algorithms with built-in forward and backward projection operations available to the user as a MATLAB/Octave class. OMEGA also includes direct support for GATE simulated data, facilitating easy evaluation of the new algorithms using Monte Carlo simulated PET data. OMEGA supports parallel computing by utilizing OpenMP for CPU implementations and OpenCL for GPU allowing any hardware to be used. OMEGA includes built-in function for the computation of normalization correction and allows several other corrections to be applied such as attenuation, randoms or scatter. OMEGA includes several different maximum-likelihood and maximum a posteriori (MAP) algorithms with several different priors. The user can also input their own priors to the built-in MAP functions. The image reconstruction in OMEGA can be computed either by using an explicitly computed system matrix or with a matrix-free formalism, where the latter can be accelerated with OpenCL. We provide an overview on the software and present some examples utilizing the different features of the software.

在本文中，我们介绍了 OMEGA，一种开源软件，用于在正电子发射断层扫描 (PET) 中进行高效和快速的图像重建。OMEGA 使用 MATLAB 和 GNU Octave 的脚本语言，允许使用 MATLAB 或 GNU Octave 接口重建 PET 数据。OMEGA 的目标是允许轻松快速地重建任何 PET 数据，并提供一个计算效率高、易于访问的平台，用于开发新的 PET 算法，其中内置前向和后向投影操作，用户可以使用 MATLAB/八度班。OMEGA 还包括对 GATE 模拟数据的直接支持，便于使用 Monte Carlo 模拟 PET 数据轻松评估新算法。OMEGA 通过将 OpenMP 用于 CPU 实现，将 OpenCL 用于 GPU 来支持并行计算，从而允许使用任何硬件。OMEGA 包含用于计算归一化校正的内置函数，并允许应用其他几种校正，例如衰减、随机或散射。OMEGA 包括几个不同的最大似然和最大值具有几种不同先验的后验（MAP）算法。用户还可以将自己的先验输入到内置的 MAP 功能中。OMEGA 中的图像重建可以通过使用显式计算的系统矩阵或无矩阵形式来计算，后者可以使用 OpenCL 加速。我们提供该软件的概述，并提供一些利用该软件不同功能的示例。