Trapezoidal back projection for positron emission tomography reconstruction

Abstract Background In the back projection step of the 3D PET reconstruction, all Lines of Responses (LORs) that go through a given voxel need to be identified and included in an integral. The standard Monte Carlo solution to this task samples stochastically the surfaces of the detector crystals and...

Full description

Saved in:
Bibliographic Details
Main Authors: Dóra Varnyú, Krisztián Paczári, László Szirmay-Kalos
Format: Article
Language:English
Published: SpringerOpen 2024-12-01
Series:EJNMMI Physics
Subjects:
Online Access:https://doi.org/10.1186/s40658-024-00710-7
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850086558934237184
author Dóra Varnyú
Krisztián Paczári
László Szirmay-Kalos
author_facet Dóra Varnyú
Krisztián Paczári
László Szirmay-Kalos
author_sort Dóra Varnyú
collection DOAJ
description Abstract Background In the back projection step of the 3D PET reconstruction, all Lines of Responses (LORs) that go through a given voxel need to be identified and included in an integral. The standard Monte Carlo solution to this task samples stochastically the surfaces of the detector crystals and the volume of the voxel to search for valid LORs. To get a low noise Monte Carlo estimate, the number of samples needs to be very high, making the computational cost of the projection significant. In this paper, a novel deterministic projection algorithm called trapezoidal back projection (TBP) is proposed that replaces the extensive Monte Carlo sampling. Its goal is to determine all LORs that contribute to a given voxel together with their exact contribution weights. This is achieved by trapezoidal rasterization and a pre-computed look-up table. Results The precision and speed of the proposed TBP algorithm were compared to that of the Monte Carlo back projection of 1000, 10,000 and 100,000 samples. Measurements were run on a National Electrical Manufacturers Association (NEMA) NU 4-2008 image quality phantom as well as on a mouse acquisition. Results show that the TBP algorithm achieves the same low noise level (2.5 Uniformity %STD) as the Monte Carlo method with the highest sample number, but 13 times faster—the highest-precision Monte Carlo back projection takes 31.3 s, while TBP takes only 2.3 s on the NEMA NU 4-2008 image quality phantom of $$200 \times 200 \times 333$$ 200 × 200 × 333 voxels. Conclusion The proposed deterministic TBP algorithm achieves a low noise level in a short runtime, thus it can be a promising solution for the back projection of the 3D PET reconstruction. Its performance advantage could be used to reduce either the reconstruction time, the data acquisition time, or the noise level of the image.
format Article
id doaj-art-5d3e7bc080a1462d853eceeb2bc6a190
institution DOAJ
issn 2197-7364
language English
publishDate 2024-12-01
publisher SpringerOpen
record_format Article
series EJNMMI Physics
spelling doaj-art-5d3e7bc080a1462d853eceeb2bc6a1902025-08-20T02:43:27ZengSpringerOpenEJNMMI Physics2197-73642024-12-0111112310.1186/s40658-024-00710-7Trapezoidal back projection for positron emission tomography reconstructionDóra Varnyú0Krisztián Paczári1László Szirmay-Kalos2Mediso Medical Imaging SystemsMediso Medical Imaging SystemsDepartment of Control Engineering and Information Technology, Budapest University of Technology and EconomicsAbstract Background In the back projection step of the 3D PET reconstruction, all Lines of Responses (LORs) that go through a given voxel need to be identified and included in an integral. The standard Monte Carlo solution to this task samples stochastically the surfaces of the detector crystals and the volume of the voxel to search for valid LORs. To get a low noise Monte Carlo estimate, the number of samples needs to be very high, making the computational cost of the projection significant. In this paper, a novel deterministic projection algorithm called trapezoidal back projection (TBP) is proposed that replaces the extensive Monte Carlo sampling. Its goal is to determine all LORs that contribute to a given voxel together with their exact contribution weights. This is achieved by trapezoidal rasterization and a pre-computed look-up table. Results The precision and speed of the proposed TBP algorithm were compared to that of the Monte Carlo back projection of 1000, 10,000 and 100,000 samples. Measurements were run on a National Electrical Manufacturers Association (NEMA) NU 4-2008 image quality phantom as well as on a mouse acquisition. Results show that the TBP algorithm achieves the same low noise level (2.5 Uniformity %STD) as the Monte Carlo method with the highest sample number, but 13 times faster—the highest-precision Monte Carlo back projection takes 31.3 s, while TBP takes only 2.3 s on the NEMA NU 4-2008 image quality phantom of $$200 \times 200 \times 333$$ 200 × 200 × 333 voxels. Conclusion The proposed deterministic TBP algorithm achieves a low noise level in a short runtime, thus it can be a promising solution for the back projection of the 3D PET reconstruction. Its performance advantage could be used to reduce either the reconstruction time, the data acquisition time, or the noise level of the image.https://doi.org/10.1186/s40658-024-00710-7Back projectionGraphics processing unit (GPU)Maximum-likelihood expectation-maximization (ML-EM)Monte Carlo integrationPositron emission tomography (PET)
spellingShingle Dóra Varnyú
Krisztián Paczári
László Szirmay-Kalos
Trapezoidal back projection for positron emission tomography reconstruction
EJNMMI Physics
Back projection
Graphics processing unit (GPU)
Maximum-likelihood expectation-maximization (ML-EM)
Monte Carlo integration
Positron emission tomography (PET)
title Trapezoidal back projection for positron emission tomography reconstruction
title_full Trapezoidal back projection for positron emission tomography reconstruction
title_fullStr Trapezoidal back projection for positron emission tomography reconstruction
title_full_unstemmed Trapezoidal back projection for positron emission tomography reconstruction
title_short Trapezoidal back projection for positron emission tomography reconstruction
title_sort trapezoidal back projection for positron emission tomography reconstruction
topic Back projection
Graphics processing unit (GPU)
Maximum-likelihood expectation-maximization (ML-EM)
Monte Carlo integration
Positron emission tomography (PET)
url https://doi.org/10.1186/s40658-024-00710-7
work_keys_str_mv AT doravarnyu trapezoidalbackprojectionforpositronemissiontomographyreconstruction
AT krisztianpaczari trapezoidalbackprojectionforpositronemissiontomographyreconstruction
AT laszloszirmaykalos trapezoidalbackprojectionforpositronemissiontomographyreconstruction