Bonney Lara M, Walker Matthew D, McGowan Daniel R
Department of Medical Physics and Clinical Engineering, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
EJNMMI Phys. 2025 Feb 3;12(1):10. doi: 10.1186/s40658-025-00722-x.
Zirconium-89 (Zr-89) PET tracers have become increasingly significant in the field of nuclear medicine due to their 3-day physical half-life, allowing for the study of dynamic biological processes over relatively long timeframes. To date there has been limited publication of studies focused on optimisation of acquisition parameters for Zr-89 PET. This paper outlines a short phantom study investigating the optimal beta regularization parameter for quantitation and noise in block sequential regularised expectation maximisation (BSREM) also known as Bayesian penalized likelihood (BPL) reconstruction, for varying image noise characteristics (acquisition duration).
The choice of the beta regularisation parameter substantially impacts image quality and quantitation. For larger volumes, BSREM reconstruction enhanced image quality (lower noise) and maintained quantitation, whereas for smaller volumes quantitation worsened as compared to OSEM for high regularisation parameters.
Where BSREM reconstruction is used for Zr-89 images, careful attention must be paid to the choice of weighting factor, especially for quantitative clinical studies. The effect of varying beta on several measures of image quality was characterised for the case of a phantom, with the results indicating that the value of beta for optimal Zr-89 quantitation is lower than what is generally used for optimal visualisation. This work demonstrates the need for careful attention to the reconstruction methods used for quantitative imaging studies, such as those required for theragnostic imaging.
锆 - 89（Zr - 89）正电子发射断层显像（PET）示踪剂因其3天的物理半衰期在核医学领域变得越来越重要，这使得在相对较长的时间范围内研究动态生物过程成为可能。迄今为止，专注于优化Zr - 89 PET采集参数的研究发表有限。本文概述了一项简短的体模研究，该研究针对不同的图像噪声特征（采集持续时间），研究了在块序贯正则化期望最大化（BSREM，也称为贝叶斯惩罚似然法（BPL））重建中用于定量和噪声的最佳β正则化参数。
β正则化参数的选择对图像质量和定量有重大影响。对于较大体积，BSREM重建提高了图像质量（降低了噪声）并保持了定量，而对于较小体积，与高正则化参数下的有序子集期望最大化（OSEM）相比，定量变差。
在将BSREM重建用于Zr - 89图像时，必须特别注意加权因子的选择，尤其是对于定量临床研究。针对体模情况，表征了β变化对几种图像质量测量的影响，结果表明，用于Zr - 89最佳定量的β值低于通常用于最佳可视化的β值。这项工作表明，对于定量成像研究，如治疗诊断成像所需的研究，需要仔细关注所使用的重建方法。
