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Lars Poulsen Tolbod

Point-spread function reconstructed PET images of sub-centimeter lesions are not quantitative

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Point-spread function reconstructed PET images of sub-centimeter lesions are not quantitative. / Munk, O L; Tolbod, L P; Hansen, S B; Bogsrud, T V.

In: EJNMMI physics, Vol. 4, No. 1, 5, 12.2017.

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@article{1100d074809948a9a48a052ef83dc61d,
title = "Point-spread function reconstructed PET images of sub-centimeter lesions are not quantitative",
abstract = "BACKGROUND: PET image reconstruction methods include modeling of resolution degrading phenomena, often referred to as point-spread function (PSF) reconstruction. The aim of this study was to develop a clinically relevant phantom and characterize the reproducibility and accuracy of high-resolution PSF reconstructed images of small lesions, which is a prerequisite for using PET in the prediction and evaluation of responses to treatment. Sets of small homogeneous (18)F-spheres (range 3-12 mm diameter, relevant for small lesions and lymph nodes) were suspended and covered by a (11)C-silicone, which provided a scattering medium and a varying sphere-to-background ratio. Repeated measurements were made on PET/CT scanners from two vendors using a wide range of reconstruction parameters. Recovery coefficients (RCs) were measured for clinically used volume-of-interest definitions.RESULTS: For non-PSF images, RCs were reproducible and fell monotonically as the sphere diameter decreased, which is the expected behavior. PSF images converged slower and had artifacts: RCs did not fall monotonically as sphere diameters decreased but had a maximum RC for sphere sizes around 8 mm, RCs could be greater than 1, and RCs were less reproducible. To some degree, post-reconstruction filters could suppress PSF artifacts.CONCLUSIONS: High-resolution PSF images of small lesions showed artifacts that could lead to serious misinterpretations when used for monitoring treatment response. Thus, it could be safer to use non-PSF reconstruction for quantitative purposes unless PSF reconstruction parameters are optimized for the specific task.",
keywords = "Journal Article",
author = "Munk, {O L} and Tolbod, {L P} and Hansen, {S B} and Bogsrud, {T V}",
year = "2017",
month = dec,
doi = "10.1186/s40658-016-0169-9",
language = "English",
volume = "4",
journal = "EJNMMI physics",
issn = "2197-7364",
publisher = "Springer International Publishing AG",
number = "1",

}

RIS

TY - JOUR

T1 - Point-spread function reconstructed PET images of sub-centimeter lesions are not quantitative

AU - Munk, O L

AU - Tolbod, L P

AU - Hansen, S B

AU - Bogsrud, T V

PY - 2017/12

Y1 - 2017/12

N2 - BACKGROUND: PET image reconstruction methods include modeling of resolution degrading phenomena, often referred to as point-spread function (PSF) reconstruction. The aim of this study was to develop a clinically relevant phantom and characterize the reproducibility and accuracy of high-resolution PSF reconstructed images of small lesions, which is a prerequisite for using PET in the prediction and evaluation of responses to treatment. Sets of small homogeneous (18)F-spheres (range 3-12 mm diameter, relevant for small lesions and lymph nodes) were suspended and covered by a (11)C-silicone, which provided a scattering medium and a varying sphere-to-background ratio. Repeated measurements were made on PET/CT scanners from two vendors using a wide range of reconstruction parameters. Recovery coefficients (RCs) were measured for clinically used volume-of-interest definitions.RESULTS: For non-PSF images, RCs were reproducible and fell monotonically as the sphere diameter decreased, which is the expected behavior. PSF images converged slower and had artifacts: RCs did not fall monotonically as sphere diameters decreased but had a maximum RC for sphere sizes around 8 mm, RCs could be greater than 1, and RCs were less reproducible. To some degree, post-reconstruction filters could suppress PSF artifacts.CONCLUSIONS: High-resolution PSF images of small lesions showed artifacts that could lead to serious misinterpretations when used for monitoring treatment response. Thus, it could be safer to use non-PSF reconstruction for quantitative purposes unless PSF reconstruction parameters are optimized for the specific task.

AB - BACKGROUND: PET image reconstruction methods include modeling of resolution degrading phenomena, often referred to as point-spread function (PSF) reconstruction. The aim of this study was to develop a clinically relevant phantom and characterize the reproducibility and accuracy of high-resolution PSF reconstructed images of small lesions, which is a prerequisite for using PET in the prediction and evaluation of responses to treatment. Sets of small homogeneous (18)F-spheres (range 3-12 mm diameter, relevant for small lesions and lymph nodes) were suspended and covered by a (11)C-silicone, which provided a scattering medium and a varying sphere-to-background ratio. Repeated measurements were made on PET/CT scanners from two vendors using a wide range of reconstruction parameters. Recovery coefficients (RCs) were measured for clinically used volume-of-interest definitions.RESULTS: For non-PSF images, RCs were reproducible and fell monotonically as the sphere diameter decreased, which is the expected behavior. PSF images converged slower and had artifacts: RCs did not fall monotonically as sphere diameters decreased but had a maximum RC for sphere sizes around 8 mm, RCs could be greater than 1, and RCs were less reproducible. To some degree, post-reconstruction filters could suppress PSF artifacts.CONCLUSIONS: High-resolution PSF images of small lesions showed artifacts that could lead to serious misinterpretations when used for monitoring treatment response. Thus, it could be safer to use non-PSF reconstruction for quantitative purposes unless PSF reconstruction parameters are optimized for the specific task.

KW - Journal Article

U2 - 10.1186/s40658-016-0169-9

DO - 10.1186/s40658-016-0169-9

M3 - Journal article

C2 - 28091957

VL - 4

JO - EJNMMI physics

JF - EJNMMI physics

SN - 2197-7364

IS - 1

M1 - 5

ER -