Dual-Input Dynamic Convolution for Positron Range Correction in PET Image Reconstruction

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Hauptverfasser: Mellak, Youness, Bousse, Alexandre, Merlin, Thibaut, Émond, Élise, Hakulinen, Mikko, Visvikis, Dimitris
Format: Preprint
Veröffentlicht: 2025
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author Mellak, Youness
Bousse, Alexandre
Merlin, Thibaut
Émond, Élise
Hakulinen, Mikko
Visvikis, Dimitris
author_facet Mellak, Youness
Bousse, Alexandre
Merlin, Thibaut
Émond, Élise
Hakulinen, Mikko
Visvikis, Dimitris
contents Positron range (PR) blurring degrades positron emission tomography (PET) image resolution, particularly for high-energy emitters like gallium-68 (68 Ga). We introduce Dual-Input Dynamic Convolution (DDConv), a novel computationally efficient approach trained with voxel-specific PR point spread functions (PSFs) from Monte Carlo (MC) simulations and designed to be utilized within an iterative reconstruction algorithm to perform PR correction (PRC). By dynamically inferring local blurring kernels through a trained convolutional neural network (CNN), DDConv captures complex tissue interfaces more accurately than prior methods. Additionally, it also computes the transpose operator, ensuring consistency within iterative PET reconstruction. Comparisons with a state-of-the-art, tissue-dependent correction confirm the advantages of DDConv in recovering higher-resolution details in heterogeneous regions, including bone-soft tissue and lung-soft tissue boundaries. Experiments across digital phantoms and MC-simulated data show that DDConv offers near-MC accuracy and outperforms the state-of-the-art technique, namely spatially-variant and tissue-dependent (SVTD), especially in areas with complex material interfaces. Results from real phantom experiments further confirm DD-Conv's robustness and practical applicability: while both DD-Conv and SVTD performed similarly in homogeneous soft-tissue regions, DDConv provided more accurate activity recovery and sharper delineation at heterogeneous lung-soft tissue interfaces. Our code available at https://github.com/mellak/ddconv-prc.
format Preprint
id arxiv_https___arxiv_org_abs_2503_00587
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dual-Input Dynamic Convolution for Positron Range Correction in PET Image Reconstruction
Mellak, Youness
Bousse, Alexandre
Merlin, Thibaut
Émond, Élise
Hakulinen, Mikko
Visvikis, Dimitris
Medical Physics
Positron range (PR) blurring degrades positron emission tomography (PET) image resolution, particularly for high-energy emitters like gallium-68 (68 Ga). We introduce Dual-Input Dynamic Convolution (DDConv), a novel computationally efficient approach trained with voxel-specific PR point spread functions (PSFs) from Monte Carlo (MC) simulations and designed to be utilized within an iterative reconstruction algorithm to perform PR correction (PRC). By dynamically inferring local blurring kernels through a trained convolutional neural network (CNN), DDConv captures complex tissue interfaces more accurately than prior methods. Additionally, it also computes the transpose operator, ensuring consistency within iterative PET reconstruction. Comparisons with a state-of-the-art, tissue-dependent correction confirm the advantages of DDConv in recovering higher-resolution details in heterogeneous regions, including bone-soft tissue and lung-soft tissue boundaries. Experiments across digital phantoms and MC-simulated data show that DDConv offers near-MC accuracy and outperforms the state-of-the-art technique, namely spatially-variant and tissue-dependent (SVTD), especially in areas with complex material interfaces. Results from real phantom experiments further confirm DD-Conv's robustness and practical applicability: while both DD-Conv and SVTD performed similarly in homogeneous soft-tissue regions, DDConv provided more accurate activity recovery and sharper delineation at heterogeneous lung-soft tissue interfaces. Our code available at https://github.com/mellak/ddconv-prc.
title Dual-Input Dynamic Convolution for Positron Range Correction in PET Image Reconstruction
topic Medical Physics
url https://arxiv.org/abs/2503.00587