This paper presents a novel image reconstruction pipeline for three-gamma (3-γ) positron emission tomography (PET) aimed at improving spatial resolution and reducing noise in nuclear medicine; the proposed Direct3γ pipeline addresses the inherent challenges in 3-γ PET systems, such as detector imperfections and uncertainty in photon interaction points, with a key feature being its ability to determine the order of interactions through a model trained on Monte Carlo (MC) simulations using the Geant4 Application for Tomography Emission (GATE) toolkit, thus providing the necessary information to construct Compton cones which intersect with the line of response (LOR) to estimate the emission point; the pipeline processes 3-γ PET raw data, reconstructs histoimages by propagating energy and spatial uncertainties along the LOR, and applies a 3-D convolutional neural network (CNN) to refine these intermediate images into high-quality reconstructions, further enhancing image quality through supervised learning and adversarial losses that preserve fine structural details; experimental results show that Direct3γ consistently outperforms conventional 200-ps time-of-flight (TOF) PET in terms of structural similarity index measure (SSIM) and peak signal-to-noise ratio (PSNR).
Analysis methods for in-beam PET images in proton therapy treatment verification: a comparison based on Monte Carlo simulations
背景和目的：束内正电子发射断层成像（PET）是质子治疗中可用于体内非侵入性治疗监测的模式之一。可以比较在各种治疗会话期间获得的PET分布，以便识别具有解剖学变化的区域。本工作的目的是在质子治疗验证的分次间PET图像比较的背景下测试和比较不同的分析方法。研究方法：在我们的研究中，我们使用FLUKA Monte Carlo代码和人工生成的CT扫描来模拟质子治疗过程中不同阶段的束内PET分布。我们比较了Beam-Eye-View方法、Most-Likely-Shift方法、基于体素的形态学方法和伽马评估方法，以比较治疗开始时和治疗几周后的PET图像。将结果与CT扫描进行比较。结果和结论：如果有很多统计数据可用，则三维方法（如VBM和伽马）优于二维方法（如MLS和BEV），因为这些方法允许识别具有异常活动的区域。VBM方法的缺点是需要大量的MC模拟。伽马分析的缺点是，在公差标准上不存在临床适应症。在计算时间方面，BEV和MLS方法是优选的。我们建议同时使用这四种方法，以便最好地确定活动变化的位置和原因。
Simulations of gamma quanta scattering in a single module of the J-PET detector
本文描述了湮没γ量子在塑料闪烁体中散射的模拟。这样的条带构成了新提出的正电子发射断层成像中的基本检测模块，该正电子发射断层成像利用塑料发光体代替无机晶体。详细阐述了康普顿散射链的模拟算法，并对截面为5 mm x 19 mm的闪烁体条带进行了一系列模拟。所得结果表明，仅在约8%的事件中发生次级相互作用，其中只有25个$\%$发生在距离初级相互作用大于0.5 cm的地方。还确定了在初级和次级相互作用中产生的光信号与延迟重叠，延迟分布的特征在于约40 ps的FWHM。
Towards AI Lesion Tracking in PET/CT Imaging: A Siamese-based CNN Pipeline applied on PSMA PET/CT Scans
Technical University of Munich（慕尼黑工业大学）；TUM School of Natural Sciences（慕尼黑工业大学自然科学学院）；Johns Hopkins University School of Medicine（约翰霍普金斯大学医学院）；Munich Institute of Biomedical Engineering（慕尼黑生物医学工程研究所）
Can $^{225}$Ac be imaged on a long axial field-of-view PET/CT with standard clinical settings?
Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern（伯尔尼大学医院因塞尔斯皮塔尔核医学科）；Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern（伯尔尼大学爱因斯坦基础物理中心高能物理实验室）
University of California, San Francisco（加州大学旧金山分校）；University of New Mexico（新墨西哥大学）；Washington University（华盛顿大学）；University of Iowa（爱荷华大学）；University of Washington（华盛顿大学）
