SU-FF-I-104: Performance of a PET-CT Scanner for Hot Lesion at High Activity Concentration

Abstract BackgroundTime-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality in low counts acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on 18F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment. MethodsThe NEMA-IQ phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR), and body mass index (BMI). The phantom was filled with an average concentration of 5.3 kBq/mL of FDG solution and the spheres with TBR of 21.2, 8.8, and 5.0 in 3 different sessions. Images were acquired at varying background activity concentration from 5.1 to 1.3 kBq/mL and images were reconstructed for ESD of 30-151 seconds per bed position with and without Point Spread Function (PSF) correction. The parameters were all considered in a single analysis using multiple linear regression methods. ResultsAs expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and BMI of the phantom, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the weight of the patient and TBR of the lesion. ConclusionsAC and ESD proved to be effective tools in modulating CNR. ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.

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The role of activity, scan duration and patient's weight in the optimization of 18FDG imaging protocols on a TOF-PET/CT scanner

10.21203/rs.3.rs-17743/v1 ◽

2020 ◽

Author(s):

Roberta Matheoud ◽

Naema Al-Maymani ◽

Alessia Oldani ◽

Gian Mauro Sacchetti ◽

Marco Brambilla ◽

...

Keyword(s):

Image Quality ◽

Activity Concentration ◽

Whole Body ◽

Internal Diameter ◽

Ct Scanner ◽

Recovery Coefficient ◽

Pet Ct ◽

Bed Position ◽

Tof Pet

Abstract Background : Time-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality , in low counts acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on 18 F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment.Methods : The NEMA-IEC body phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR), and weight. The phantom was filled with 5.3 kBq/mL of FDG solution and the spheres with TBR of 21, 9, and 5 in 3 different sessions. Images were acquired at varying activity concentration from 5.1 to 1.3 kBq/mL and images were reconstructed for ESD of 30-151 seconds per bed position with and without Point Spread Function (PSF) correction. The parameters were all considered in simultaneous experiments and in a single analysis using multiple linear regression methods.Results : As expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and weight of the patient, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the weight of the patient and TBR of the lesion.Conclusions : Due to the interchangeable role of AC and ESD in modulating CRC, ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.

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The role of activity, scan duration and patient’s body mass index in the optimization of FDG imaging protocols on a TOF-PET/CT scanner

EJNMMI Physics ◽

10.1186/s40658-021-00380-9 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Roberta Matheoud ◽

Naema Al-Maymani ◽

Alessia Oldani ◽

Gian Mauro Sacchetti ◽

Marco Brambilla ◽

...

Keyword(s):

Body Mass Index ◽

Image Quality ◽

Body Mass ◽

Activity Concentration ◽

Background Activity ◽

Whole Body ◽

Internal Diameter ◽

Ct Scanner ◽

Pet Ct ◽

Tof Pet

Abstract Background Time-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality in low count acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on the 18F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF-PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment. Methods The NEMA-IQ phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR) and body mass index (BMI). The phantom was filled with an average concentration of 5.3 kBq/ml of FDG solution and the spheres with TBR of 21.2, 8.8 and 5.0 in 3 different sessions. Images were acquired at varying background activity concentration from 5.1 to 1.3 kBq/ml, and images were reconstructed for ESD of 30–151 s per bed position with and without point spread function (PSF) correction. The parameters were all considered in a single analysis using multiple linear regression methods. Results As expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and BMI of the phantom, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the BMI of the patient and TBR of the lesion. Conclusions AC and ESD proved to be effective tools in modulating CNR. ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.

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Longitudinal monitoring of reconstructed activity concentration on a clinical time-of-flight PET/CT scanner

Journal of Medical Imaging ◽

10.1117/1.jmi.4.1.011004 ◽

2016 ◽

Vol 4 (1) ◽

pp. 011004

Author(s):

Lawrence R. MacDonald ◽

Amy E. Perkins ◽

Chi-Hua Tung

Keyword(s):

Activity Concentration ◽

Time Of Flight ◽

Ct Scanner ◽

Pet Ct

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Quantitative investigation of inter-crystal scatter and penetration in the GE Discovery RX PET/CT scanner using Monte Carlo simulations

IEEE Nuclear Science Symposuim & Medical Imaging Conference ◽

10.1109/nssmic.2010.5874218 ◽

2010 ◽

Cited By ~ 2

Author(s):

N Zeraatkar ◽

M R Ay ◽

S Sarkar ◽

P Geramifar ◽

A Rahmim

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Ct Scanner ◽

Quantitative Investigation ◽

Pet Ct

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A combined PET/CT scanner: the path to true image fusion

British Journal of Radiology ◽

10.1259/bjr.75.suppl_9.750024 ◽

2002 ◽

Vol 75 (suppl_9) ◽

pp. S24-S30 ◽

Cited By ~ 146

Author(s):

D W Townsend ◽

T Beyer

Keyword(s):

Image Fusion ◽

Ct Scanner ◽

Pet Ct

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Investigation of a Dedicated, High Resolution PET/CT Scanner for Staging and Treatment Planning of Head and Neck Cancer

IEEE Transactions on Nuclear Science ◽

10.1109/tns.2015.2463727 ◽

2015 ◽

Vol 62 (5) ◽

pp. 2057-2066

Author(s):

Raymond R. Raylman ◽

Alexander V. Stolin ◽

Prashanth Sompalli ◽

Nicole Bunda Randall ◽

Peter F. Martone ◽

...

Keyword(s):

Head And Neck Cancer ◽

High Resolution ◽

Head And Neck ◽

Treatment Planning ◽

Neck Cancer ◽

Ct Scanner ◽

Pet Ct

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Optimizing reconstruction parameters for quantitative 124I-PET in the presence of therapeutic doses of 131I

10.21203/rs.3.rs-289963/v1 ◽

2021 ◽

Author(s):

Louise Fanchon ◽

Brad Beattie ◽

Keith Pentlow ◽

Steven Larson ◽

John Laurence Humm

Keyword(s):

Image Quality ◽

Dead Time ◽

Activity Level ◽

Ct Scanner ◽

Random Coincidence ◽

Quantitative Pet ◽

Quantitative Accuracy ◽

Pet Ct ◽

Therapeutic Doses ◽

Pet Detectors

Abstract Purpose To determine the accuracy of quantitative 124I PET imaging in the presence of therapeutic levels of 131I.Material and Methods Multiple PET images were acquired using a NEMA IEC phantom with spheres containing 0.4 MBq/cc of 124I and increasing amount of 131I activity in the phantom background (0 to 3.76 GBq). Acquisitions were performed on a GE Discovery 710 PET/CT scanner. At each 131I activity level two scans were acquired, one with the phantom at the center of the field of view (FOV) and one 11 cm off-center. Images were reconstructed with an ordered subset expectation maximization (OSEM) algorithm using between 1 and 25 iterations of 16 subsets. Results were evaluated visually and by comparing the 124I activity relative to the baseline PET performed in the absence of 131I.Results The presence of 131I within the PET FOV added to the random coincidence rate, to dead-time and to pile-up within the PET detectors. Using our standard clinical reconstruction parameters, the image quality and quantitative accuracy suffered at 131I background activities above 1.4 GBq. However, increasing the number of iterations resulted in dramatic improvements in image quality and quantitative accuracy. Projection space measurements suggest that the dead time corrections implemented on the scanner perform well even at the highest singles count rate tested (52 Mcps).Conclusion This study shows that 124I quantitative PET is feasible in the presence of large amounts of 131I on a GE D710. The high random coincidence fraction slows the reconstruction convergence rate, therefore iterations equivalent to at least 8x16 are recommended.

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3D Printing 18F Radioactive Phantoms for PET Imaging

10.21203/rs.3.rs-136006/v1 ◽

2020 ◽

Author(s):

Daniel Gillett ◽

Daniel Marsden ◽

Safia Ballout ◽

Bala Attili ◽

Nick Bird ◽

...

Keyword(s):

Double Helix ◽

Human Anatomy ◽

Radioactive Material ◽

Ct Scanner ◽

Pet Ct ◽

Radioactive Concentration ◽

3D Printed ◽

Single Use ◽

The Mean ◽

Cylinders And Spheres

Abstract Purpose: Phantoms are routinely used in molecular imaging to assess scanner performance. However, traditional phantoms with fillable shapes do not replicate human anatomy. 3D printed phantoms have overcome this by creating phantoms which replicate human anatomy which can be filled with radioactive material. The problem with these is that small objects suffer from boundary effects and therefore boundary-free objects are desirable. The purpose of this study was to explore the feasibility of creating resin-based 3D printed phantoms using 18 F-FDG. Methods: Radioactive resin was created using an emulsion of printer resin and 18 F-FDG. A series of test objects were printed including twenty identical cylinders, ten spheres with increasing diameters (2 mm to 20 mm) and a double helix. Radioactive concentration uniformity, printing accuracy and the amount of leaching were assessed. Results: Creating radioactive resin was simple and effective. The radioactivity remained bound to the resin for the duration that it was radioactive. The radioactive concentration was uniform among identical objects; the CoV of the mean, max and total signal were 3.6%, 3.8% and 2.6%, respectively. The printed cylinders and spheres were found to be within 4% of the model dimensions. A double helix was successfully printed as a test for the printer and appeared as expected on the PET scanner. The amount of radioactivity leached into the water was measurable (0.72%) but not visible above background on the imaging. Conclusions: Creating an 18F-FDG radioactive resin emulsion is a simple and effective way to create boundary-free, accurate, complex 3D phantoms that can be imaged using a PET/CT scanner. This technique could be used to print clinically realistic phantoms, however, they are single use, and cannot be made hollow without an exit hole. Also, there is a small amount of leaching of the radioactivity to take into consideration.

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