TY - JOUR

T1 - Improved Positron Emission Tomography Quantification

T2 - Evaluation of a Maximum-Likelihood Scatter Scaling Algorithm

AU - Overbeck, Nanna

AU - Ahangari, Sahar

AU - Conti, Maurizio

AU - Panin, Vladimir

AU - Azam, Aleena

AU - Kurbegovic, Sorel

AU - Kjær, Andreas

AU - Højgaard, Liselotte

AU - Korsholm, Kirsten

AU - Fischer, Barbara Malene

AU - Andersen, Flemming Littrup

AU - Andersen, Thomas Lund

N1 - Publisher Copyright: © 2024 by the authors.

PY - 2024

Y1 - 2024

N2 - 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. [68Ga]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 [68Ga]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.

AB - 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. [68Ga]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 [68Ga]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.

KW - halo artifacts

KW - maximum likelihood

KW - PET/MRI

KW - scatter correction

KW - scatter scaling

U2 - 10.3390/diagnostics14111075

DO - 10.3390/diagnostics14111075

M3 - Journal article

C2 - 38893602

AN - SCOPUS:85195825502

VL - 14

JO - Diagnostics

JF - Diagnostics

SN - 2075-4418

IS - 11

M1 - 1075

ER -