Joint Reconstruction of the Activity and the Attenuation in PET by Diffusion Posterior Sampling: a Feasibility Study

TL;DR

This paper presents a new diffusion posterior sampling framework for joint PET activity and attenuation reconstruction, effectively addressing crosstalk issues and outperforming traditional methods in 2D phantom experiments.

Contribution

The study introduces a diffusion model-based approach for joint PET reconstruction, a novel application that improves upon existing MLAA methods by mitigating crosstalk without TOF data.

Findings

DPS outperforms MLAA in 2D phantom reconstructions.

The method produces consistent, high-quality images without TOF information.

Preliminary results suggest feasibility for extension to 3D data.

Abstract

This study introduces a novel framework for joint reconstruction of the activity and the attenuation (JRAA) in positron emission tomography (PET) using diffusion posterior sampling (DPS). By leveraging diffusion models (DMs), this approach directly addresses activity-attenuation dependencies, mitigating crosstalk issues prevalent in non-time-of-flight (TOF) settings. Experimental evaluations, conducted using 2-dimensional (2-D) XCAT phantom data, demonstrate that DPS significantly outperforms traditional maximum likelihood activity and attenuation (MLAA) methods, producing consistent and high-quality reconstructions even in the absence of TOF information. Ongoing work aims to extend our method to real 3-dimensional (3-D) data with encouraging preliminary findings.