Overbeck Nanna, Ahangari Sahar, Conti Maurizio, Panin Vladimir, Azam Aleena, Kurbegovic Sorel, Kjær Andreas, Højgaard Liselotte, Korsholm Kirsten, Fischer Barbara Malene, Andersen Flemming Littrup, Andersen Thomas Lund
Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital-Rigshospitalet, 2100 Copenhagen, Denmark.
Siemens Medical Solutions Inc., Knoxville, TN 37932, USA.
Diagnostics (Basel). 2024 May 22;14(11):1075. doi: 10.3390/diagnostics14111075.
Incorrect scatter scaling of positron emission tomography (PET) images can lead to halo artifacts, quantitative bias, or reconstruction failure. Tail-fitted scatter scaling (TFSS) possesses performance limitations in multiple cases. This study aims to investigate a novel method for scatter scaling: maximum-likelihood scatter scaling (MLSS) in scenarios where TFSS tends to induce artifacts or are observed to cause reconstruction abortion. [Ga]Ga-RGD PET scans of nine patients were included in cohort 1 in the scope of investigating the reduction of halo artifacts relative to the scatter estimation method. PET scans of 30 patients administrated with [Ga]Ga-uPAR were included in cohort 2, used for an evaluation of the robustness of MLSS in cases where TFSS-integrated reconstructions are observed to fail. A visual inspection of MLSS-corrected images scored higher than TFSS-corrected reconstructions of cohort 1. The quantitative investigation near the bladder showed a relative difference in tracer uptake of up to 94.7%. A reconstruction of scans included in cohort 2 resulted in failure in 23 cases when TFSS was used. The lesion uptake values of cohort 2 showed no significant difference. MLSS is suggested as an alternative scatter-scaling method relative to TFSS with the aim of reducing halo artifacts and a robust reconstruction process.
正电子发射断层扫描（PET）图像中不正确的散射缩放会导致晕轮伪影、定量偏差或重建失败。尾部拟合散射缩放（TFSS）在多种情况下存在性能限制。本研究旨在探讨一种新的散射缩放方法：最大似然散射缩放（MLSS），用于TFSS容易引发伪影或导致重建失败的情况。在研究相对于散射估计方法减少晕轮伪影的范围内，队列1纳入了9例患者的[Ga]Ga-RGD PET扫描。队列2纳入了30例接受[Ga]Ga-uPAR治疗患者的PET扫描，用于评估在观察到TFSS整合重建失败的情况下MLSS的稳健性。对MLSS校正图像的视觉检查得分高于队列1的TFSS校正重建。膀胱附近的定量研究显示示踪剂摄取的相对差异高达94.7%。当使用TFSS时，队列2中纳入的扫描重建在23例中失败。队列2的病变摄取值无显著差异。建议将MLSS作为相对于TFSS的另一种散射缩放方法，以减少晕轮伪影并实现稳健的重建过程。
