scholarly journals Evaluation of the Impact of Out-of-Axial FOV Scattering Medium on Random Coincidence Rates on Discovery 690 PET/CT Scanner: A Simulation Study

2020 ◽  
Author(s):  
Mahak Osouli Alamdari ◽  
Pardis Ghafarian ◽  
Parham Geramifar ◽  
Mohammad Reza Ay
Keyword(s):  
Imaging Technique ◽  
Field Of View ◽  
Ct Scanner ◽  
Scattering Medium ◽  
Nuclear Medicine Imaging ◽  
Axial Field ◽  
Random Coincidence ◽  
Positron Emission ◽  
Pet Ct ◽  
The Impact

Purpose: Positron Emission Tomography (PET) imaging is a nuclear medicine imaging technique based on the recording of two photons as coincidence created by positron annihilation. Materials and Methods: PET coincidence events include true and unwanted coincidences (random, scattered, multiple coincidences). We modeled the Discovery 690 (D-690) PET scanner using the GATE simulation tool and estimated the effect of the diameter of the scattering medium out of the Axial Field Of View (AFOV) on the random coincidence rates. Results: The validation results indicated that the average difference between simulated and measured data for sensitivity and scatter fraction tests are 5% and 3%, respectively. Moreover, the results revealed that the increasing diameter of the scattering medium out of the AFOV has a direct effect on the random coincidence rates within the Field Of View (FOV). Conclusion: The study concluded that the presence of a scattering medium near the FOV increases the rate of random coincidences.  

scholarly journals Feasibility of late acquisition [68Ga]Ga-PSMA-11 PET/CT using a long axial field-of-view PET/CT scanner for the diagnosis of recurrent prostate cancer—first clinical experiences

2021 ◽  
Author(s):  
Ian Alberts ◽  
George Prenosil ◽  
Clemens Mingels ◽  
Karl Peter Bohn ◽  
Marco Viscione ◽  
...  
Keyword(s):  
Image Quality ◽  
Case Series ◽  
Likert Scale ◽  
Target Lesion ◽  
Field Of View ◽  
Ct Scanner ◽  
Axial Field ◽  
Retrospective Case ◽  
Imaging Quality ◽  
Pet Ct

Abstract Purpose While acquisition of images in [68 Ga]Ga-PSMA-11 following longer uptake times can improve lesion uptake and contrast, resultant imaging quality and count statistics are limited by the isotope’s half-life (68 min). Here, we present a series of cases demonstrating that when performed using a long axial field-of-view (LAFOV) PET/CT system, late imaging is feasible and can even provide improved image quality compared to regular acquisitions. Methods In this retrospective case series, we report our initial experiences with 10 patients who underwent standard imaging at 1 h p.i. following administration of 192 ± 36 MBq [68 Ga]Ga-PSMA-11 with additional late imaging performed at 4 h p.i. Images were acquired in a single bed position for 6 min at 1 h p.i. and 16 min p.i. at 4 h p.i. using a LAFOV scanner (106 cm axial FOV). Two experienced nuclear medicine physicians reviewed all scans in consensus and evaluated overall image quality (5-point Likert scale), lesion uptake in terms of standardised uptake values (SUV), tumour to background ratio (TBR) and target-lesion signal to background noise (SNR). Results Subjective image quality as rated on a 5-point Likert scale was only modestly lower for late acquisitions (4.2/5 at 4 h p.i.; 5/5 1 h p.i.), TBR was significantly improved (4 h: 3.41 vs 1 h: 1.93, p < 0.001) and SNR was improved with borderline significance (4 h: 33.02 vs 1 h: 24.80, p = 0.062) at later imaging. Images were obtained with total acquisition times comparable to routine examinations on standard axial FOV scanners. Conclusion Late acquisition in tandem with a LAFOV PET/CT resulted in improvements in TBR and SNR and was associated with only modest impairment in subjective visual imaging quality. These data show that later acquisition times for [68 Ga]Ga-PSMA-11 may be preferable when performed on LAFOV systems.

scholarly journals Performance evaluation of the uEXPLORER Total-body PET/CT scanner based on NEMA NU 2-2018 with additional tests to characterize long axial field-of-view PET scanners

2020 ◽  
pp. jnumed.120.250597 ◽  
Author(s):  
Benjamin A. Spencer ◽  
Eric Berg ◽  
Jeffrey P. Schmall ◽  
Negar Omidvari ◽  
Edwin K. Leung ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Field Of View ◽  
Ct Scanner ◽  
Axial Field ◽  
Pet Ct ◽  
Total Body ◽  
Pet Scanners

Performance Characteristics of a New LSO PET/CT Scanner With Extended Axial Field-of-View and PSF Reconstruction

2009 ◽  
Vol 56 (3) ◽  
pp. 633-639 ◽  
Author(s):  
Bjoern W. Jakoby ◽  
Yanic Bercier ◽  
Charles C. Watson ◽  
Bernard Bendriem ◽  
David W. Townsend
Keyword(s):  
Performance Characteristics ◽  
Field Of View ◽  
Ct Scanner ◽  
Axial Field ◽  
Pet Ct

scholarly journals The impact of particulate electron paramagnetic resonance oxygen sensors on fluorodeoxyglucose imaging characteristics detected via positron emission tomography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip E. Schaner ◽  
Ly-Binh-An Tran ◽  
Bassem I. Zaki ◽  
Harold M. Swartz ◽  
Eugene Demidenko ◽  
...  
Keyword(s):  
Fdg Pet ◽  
Oxygen Sensor ◽  
Oxygen Sensors ◽  
Paramagnetic Resonance ◽  
Imaging Characteristics ◽  
Positron Emission ◽  
Pet Ct ◽  
Fdg Pet Ct ◽  
The Impact ◽  
Electron Paramagnetic

AbstractDuring a first-in-humans clinical trial investigating electron paramagnetic resonance tumor oximetry, a patient injected with the particulate oxygen sensor Printex ink was found to have unexpected fluorodeoxyglucose (FDG) uptake in a dermal nodule via positron emission tomography (PET). This nodule co-localized with the Printex ink injection; biopsy of the area, due to concern for malignancy, revealed findings consistent with ink and an associated inflammatory reaction. Investigations were subsequently performed to assess the impact of oxygen sensors on FDG-PET/CT imaging. A retrospective analysis of three clinical tumor oximetry trials involving two oxygen sensors (charcoal particulates and LiNc-BuO microcrystals) in 22 patients was performed to evaluate FDG imaging characteristics. The impact of clinically used oxygen sensors (carbon black, charcoal particulates, LiNc-BuO microcrystals) on FDG-PET/CT imaging after implantation in rat muscle (n = 12) was investigated. The retrospective review revealed no other patients with FDG avidity associated with particulate sensors. The preclinical investigation found no injected oxygen sensor whose mean standard uptake values differed significantly from sham injections. The risk of a false-positive FDG-PET/CT scan due to oxygen sensors appears low. However, in the right clinical context the potential exists that an associated inflammatory reaction may confound interpretation.

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

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.

PV Modeling of Medical Imaging Systems

Benford's Law ◽  
2015 ◽  
Author(s):  
John Chiverton ◽  
Kevin Wells
Keyword(s):  
Medical Imaging ◽  
Gold Standard ◽  
Ground Truth ◽  
Imaging Data ◽  
Nuclear Medicine Imaging ◽  
Phantom Imaging ◽  
Positron Emission ◽  
Pet Ct ◽  
Many Sources

This chapter applies a Bayesian formulation of the Partial Volume (PV) effect, based on the Benford distribution, to the statistical classification of nuclear medicine imaging data: specifically Positron Emission Tomography (PET) acquired as part of a PET-CT phantom imaging procedure. The Benford distribution is a discrete probability distribution of great interest for medical imaging, because it describes the probabilities of occurrence of single digits in many sources of data. The chapter thus describes the PET-CT imaging and post-processing process to derive a gold standard. Moreover, this chapter uses it as a ground truth for the assessment of a Benford classifier formulation. The use of this gold standard shows that the classification of both the simulated and real phantom imaging data is well described by the Benford distribution.

Empfehlungen zur Durchführung der Ganz körper-18F-FDG-PET und -PET/CT bei Kindern mit onkologischen Erkrankungen

2010 ◽  
Vol 49 (06) ◽  
pp. 225-233 ◽  
Author(s):  
J. Stauss ◽  
T. Pfluger ◽  
K. U. Juergens ◽  
R. Kluge ◽  
H. Amthauer ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
Fdg Pet ◽  
German Society ◽  
Emission Tomography ◽  
Ct Scanner ◽  
High Radiation ◽  
Additional Information ◽  
Paediatric Committee ◽  
Positron Emission ◽  
Pet Ct

SummaryThe purpose of these guidelines is to offer the nuclear medicine and the appropriate interdisciplinary team a framework for performing and reporting positron emission tomography (PET) and the combination with computed tomography (PET/CT) in children with malignant diseases mainly using the radiopharmaceutical 18F-fluorodeoxy-glucose (FDG). These guidelines are based on the recent guidelines of the Paediatric Committee of the European Association of Nuclear Medicine (EANM) (57) and have been translated and adapted to the current conditions in Germany. The adaptation of CT-parameters using PET/CT in children is covered in a more detailed way than in the EANM guideline taking into account that in Germany already a good portion of PET examinations is performed using an integrated PET/CT-scanner. Furthermore, a CT-scan without adaption of the CT acquisition parameters would result in a not tolerably high radiation exposition of the child. There are excellent guidelines for FDG PET and PET/CT in oncology published by the German Society of Nuclear Medicine (Deutsche Gesellschaft für Nuklearmedizin, DGN) (42) and EANM (4). These guidelines aim at providing additional information on issues particularly relevant to PET and PET/CT imaging in children. These guidelines should be taken in the context of local and national current standards of quality and rules.

Etiology of Solitary Extrapulmonary Positron Emission Tomography and Computed Tomography Findings in Patients With Lung Cancer

2005 ◽  
Vol 23 (28) ◽  
pp. 6846-6853 ◽  
Author(s):  
Didier Lardinois ◽  
Walter Weder ◽  
Marina Roudas ◽  
Gustav K. von Schulthess ◽  
Michaela Tutic ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Lung Cancer ◽  
Positron Emission Tomography ◽  
Ct Imaging ◽  
Emission Tomography ◽  
Whole Body ◽  
Benign Tumors ◽  
Positron Emission ◽  
Pet Ct ◽  
The Impact

Purpose The aim of this prospective study was to assess the incidence and the nature of solitary extrapulmonary [18F] fluorodeoxyglucose (FDG) accumulations in patients with non–small-cell lung cancer (NSCLC) staged with integrated positron emission tomography and computed tomography (PET/CT) and to evaluate the impact on management. Patients and Methods A total of 350 patients with NSCLC underwent whole-body PET/CT imaging. All solitary extrapulmonary FDG accumulations were evaluated by histopathology, further imaging, or clinical follow-up. Results PET/CT imaging revealed extrapulmonary lesions in 110 patients. In 72 patients (21%), solitary lesions were present. A diagnosis was obtained in 69 of these patients, including 37 (54%) with solitary metastases and 32 (46%) with lesions unrelated to the lung primary. Histopathologic examinations of these 32 lesions revealed a second clinically unsuspected malignancy or a recurrence of a previous diagnosed carcinoma in six patients (19%) and a benign tumor or inflammatory lesion in 26 patients (81%). The six malignancies consisted of carcinoma of the breast in two patients, and carcinoma of the orbit, esophagus, prostate, and non-Hodgkin's lymphoma in one patient each. Benign tumors and inflammatory lesions included eight colon adenomas, four Warthin's tumors, one granuloma of the lower jaw, one adenoma of the thyroid gland, one compensatory muscle activity due to vocal chord palsy, two occurrences of arthritis, three occurrences of reflux esophagitis, two occurrences of pancreatitis, two occurrences of diverticulitis, one hemorrhoidal inflammation, and one rib fracture. Conclusion Solitary extrapulmonary FDG accumulations in patients with newly diagnosed lung cancer should be analyzed critically for correct staging and optimal therapy, given that up to half of the lesions may represent unrelated malignancies or benign disease.

Positron Emission Tomography: Clinical Applications and Pharmaceutical Care

1994 ◽  
Vol 7 (3) ◽  
pp. 124-139 ◽  
Author(s):  
Richard J. Hammes ◽  
John W. Babich
Keyword(s):  
Positron Emission Tomography ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Building Blocks ◽  
Emission Tomography ◽  
Pharmacokinetic Parameters ◽  
Nuclear Medicine Imaging ◽  
Receptor Ligands ◽  
Positron Emission

Positron emission tomography {PET) is a nuclear medicine imaging technique which exploits the unique physical characteristics of radionuclides that decay by positron emission. These characteristics allow for in vivo quantitative measurement of three-dimensional distributions of radioactivity with a spatial resolution of 5 mm using current detector technology. In addition to these physical advantages, PET is the only imaging technique that can use the short-lived positron emitting radionuclides of the so-called “organic” elements: carbon (C-11), nitrogen (N-13), and oxygen (0–15). These elements are the building blocks of physiological compounds and can be used to study most enzymes, receptors, and other metabolically important compounds and their associated reactions. PET allows for the study of a variety of physiological and biochemical processes through the application of particular radiopharmaceuticals. PET has also been used to study the interaction of receptor-specific ligands in several receptor systems including dopaminergic, adrenergic, serotinergic, and opiod. C-11 and F-18 labeled receptor ligands have been used to study receptor selectivity and receptor concentrations in vivo. Recently, PET has been used to measure the pharmacokinetics of several novel antibiotics in humans allowing the direct measurement of tissue concentrations and correlation with classical pharmacokinetic parameters. This review discusses some of the current applications of PET in more detail.

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