scholarly journals Fifty Shades of Scandium: Comparative Study of PET Capabilities Using Sc-43 and Sc-44 with Respect to Conventional Clinical Radionuclides

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1826
Author(s):  
Thiago V. M. Lima ◽  
Silvano Gnesin ◽  
Klaus Strobel ◽  
Maria del Sol Pérez ◽  
Justus E. Roos ◽  
...  
Keyword(s):  
Production Method ◽  
High Energy ◽  
Signal Recovery ◽  
Recovery Coefficient ◽  
Γ Radiation ◽  
Quantitative Pet ◽  
Positron Emission ◽  
Quantitative Accuracy ◽  
Pet Ct ◽  
Gallium 68

Scandium-44 has been proposed as a valuable radionuclide for Positron Emission Tomography (PET). Recently, scandium-43 was introduced as a more favorable option, as it does not emit high-energy γ-radiation; however, its currently employed production method results in a mixture of scandium-43 and scandium-44. The interest in new radionuclides for diagnostic nuclear medicine critically depends on the option for image-based quantification. We aimed to evaluate and compare the quantitative capabilities of scandium-43/scandium-44 in a commercial PET/CT device with respect to more conventional clinical radionuclides (fluorine-18 and gallium-68). With this purpose, we characterized and compared quantitative PET data from a mixture of scandium-43/scandium-44 (~68% scandium-43), scandium-44, fluorine-18 and gallium-68, respectively. A NEMA image-quality phantom was filled with the different radionuclides using clinical-relevant lesion-to-background activity concentration ratios; images were acquired in a Siemens Biograph Vision PET/CT. Quantitative accuracy with scandium-43/scandium-44 in the phantom’s background was within 9%, which is in agreement with fluorine-18-based PET standards. Coefficient of variance (COV) was 6.32% and signal recovery in the lesions provided RCmax (recovery coefficient) values of 0.66, 0.90, 1.03, 1.04, 1.12 and 1.11 for lesions of 10-, 13-, 17-, 22-, 28- and 37-mm diameter, respectively. These results are in agreement with EARL reference values for fluorine-18 PET. The results in this work showed that accurate quantitative scandium-43/44 PET/CT is achievable in commercial devices. This may promote the future introduction of scandium-43/44-labelled radiopharmaceuticals into clinical use.

scholarly journals Influence of patient motion on quantitative accuracy in cardiac 15O-water positron emission tomography

2021 ◽  
Author(s):  
Jonny Nordström ◽  
Hendrik J. Harms ◽  
Tanja Kero ◽  
Jens Sörensen ◽  
Mark Lubberink
Keyword(s):  
Motion Detection ◽  
Detection Algorithm ◽  
Clinical Effects ◽  
Average Deviation ◽  
Patient Motion ◽  
Motion Data ◽  
Positron Emission ◽  
Quantitative Accuracy ◽  
Pet Ct ◽  
Using Data

Abstract Background Patient motion is a common problem during cardiac PET. The purpose of the present study was to investigate to what extent motions influence the quantitative accuracy of cardiac 15O-water PET/CT and to develop a method for automated motion detection. Method Frequency and magnitude of motion was assessed visually using data from 50 clinical 15O-water PET/CT scans. Simulations of 4 types of motions with amplitude of 5 to 20 mm were performed based on data from 10 scans. An automated motion detection algorithm was evaluated on clinical and simulated motion data. MBF and PTF of all simulated scans were compared to the original scan used as reference. Results Patient motion was detected in 68% of clinical cases by visual inspection. All observed motions were small with amplitudes less than half the LV wall thickness. A clear pattern of motion influence was seen in the simulations with a decrease of myocardial blood flow (MBF) in the region of myocardium to where the motion was directed. The perfusable tissue fraction (PTF) trended in the opposite direction. Global absolute average deviation of MBF was 3.1% ± 1.8% and 7.3% ± 6.3% for motions with maximum amplitudes of 5 and 20 mm, respectively. Automated motion detection showed a sensitivity of 90% for simulated motions ≥ 10 mm but struggled with the smaller (≤ 5 mm) simulated (sensitivity 45%) and clinical motions (accuracy 48%). Conclusion Patient motion can impair the quantitative accuracy of MBF. However, at typically occurring levels of patient motion, effects are similar to or only slightly larger than inter-observer variability, and downstream clinical effects are likely negligible.

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.

Transconvolution and the virtual positron emission tomograph-A new method for cross calibration in quantitative PET/CT imaging

2013 ◽  
Vol 40 (6Part1) ◽  
pp. 062503 ◽  
Author(s):  
George A. Prenosil ◽  
Thilo Weitzel ◽  
Michael Hentschel ◽  
Bernd Klaeser ◽  
Thomas Krause
Keyword(s):  
Ct Imaging ◽  
New Method ◽  
Positron Emission Tomograph ◽  
Quantitative Pet ◽  
Positron Emission ◽  
Pet Ct ◽  
Cross Calibration

scholarly journals Recurrent Medullary Carcinoma detected by Gallium-68 Positron Emission Tomography

2013 ◽  
Vol 5 (2) ◽  
pp. 59-60
Author(s):  
Cigdem Soydal ◽  
Mine Araz ◽  
Ozlem N Kucuk ◽  
Elgin Ozkan ◽  
Taner Demirer
Keyword(s):  
Positron Emission Tomography ◽  
Thyroid Cancer ◽  
Medullary Thyroid Cancer ◽  
Medullary Carcinoma ◽  
Emission Tomography ◽  
Thyroid Cancer Patient ◽  
Medullary Thyroid ◽  
Positron Emission ◽  
Pet Ct ◽  
Gallium 68

ABSTRACT In this case, we would like to share our experience of a recurrent medullary thyroid cancer patient whose recurrence was detected by Ga-68 DOTATATE PET/CT. How to cite this article Soydal C, Ozkan E, Araz M, Kucuk ON, Demirer T. Recurrent Medullary Carcinoma detected by Gallium-68 Positron Emission Tomography. World J Endoc Surg 2013;5(2):59-60.

scholarly journals Estimating the Shielding Requirements for a Newly Planned PET-CT Facility

2019 ◽  
Vol 21 (2) ◽  
pp. 102-107
Author(s):  
Md Nahid Hossain ◽  
Md Shohag Mia ◽  
Tanvir Ahmed Biman ◽  
Raihan Hussain ◽  
Mohammed Fazlul Kabir
Keyword(s):  
Positron Emission Tomography ◽  
Cost Effective ◽  
High Energy ◽  
Radiation Shielding ◽  
Emission Tomography ◽  
Scanning System ◽  
Annihilation Radiation ◽  
Safety Standards ◽  
Positron Emission ◽  
Pet Ct

Positron Emission Tomography (PET) combined with Computed Tomography (CT) is a powerful and very sensitive diagnostic tool that integrates functional and anatomical imaging into one combined scanning system. Positron emission tomography is based on the characteristic way in which positrons annihilate by combining with an electron. This process usually results in the emission of two 511 KeV photons which travel in opposite directions. These 511 KeV annihilation photons are much higher energy than other diagnostic radiations. Because of this high energy of the annihilation radiation, shielding requirements for a PET facility are different from most of the other diagnostic imaging facilities and it’s a very important consideration in the design of a PET or PET-CT imaging facility. As a result, significant shielding may be required in floors and ceilings as well as adjacent walls in a PET-CT facility. In this work we present the estimation of the shielding requirements for a newly planned PET-CT facility. Shielding calculations of adjacent walls were presented for both controlled and uncontrolled areas. Formulas were used to calculate the shielding materials following the basic AAPM (American Association of Physicists in Medicine) guidelines. This mathematical analysis of the shielding estimation is very important for a newly planned PET-CT facility. Adequate safe planning with vendor, facility architect and a qualified medical physicist are essential to make a cost effective and safe design while maintaining radiation safety standards with regulatory limits. Bangladesh J. Nuclear Med. 21(2): 102-107, July 2018  

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

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Louise M. Fanchon ◽  
Bradley J. Beattie ◽  
Keith Pentlow ◽  
Steven M. Larson ◽  
John L. Humm
Keyword(s):  
Expectation Maximization ◽  
Convergence Rates ◽  
Expectation Maximization Algorithm ◽  
Activity Level ◽  
Ct Scanner ◽  
Quantitative Pet ◽  
Quantitative Accuracy ◽  
Pet Ct ◽  
Pile Up ◽  
Therapeutic Doses

Abstract Background The goal of this work was to determine the quantitative accuracy and optimal reconstruction parameters for 124I-PET imaging in the presence of therapeutic levels of 131I. In this effort, images were acquired on a GE D710 PET/CT scanner using a NEMA IEC phantom with spheres containing 124I and increasing amounts of 131I activity in the background. At each activity level, two scans were acquired, one with the phantom centered in the field of view (FOV) and one 11.2 cm off-center. Reconstructions used an ordered subset expectation maximization algorithm with up to 100 iterations of 16 subsets, with and without time-of-flight (TOF) information. Results were evaluated visually and by comparing the 124I activity relative to the scan performed in the absence of 131I. Results 131I within the FOV added to the randoms rate, to dead time, and to pile-up within the detectors. Using our standard clinical reconstruction parameters, the image quality and quantitative accuracy suffered at 131I activities above 1.4 GBq. Convergence rates slowed progressively in the presence of increasing amounts of 131I for both TOF and nonTOF reconstructions. TOF reconstructions converged more quickly than nonTOF but often towards erroneous concentrations. Iterating nonTOF reconstructions to convergence produced quantitatively accurate images except for the off-center phantom at the very highest level of background 131I tested. Conclusions This study shows that quantitative PET is feasible in the presence of large amounts of 131I. The high randoms fractions resulted in slow reconstruction convergence and negatively impacted TOF corrections and/or the accuracy of TOF information. Therefore, increased iterations and nonTOF reconstructions are recommended.

Quantitative Musculoskeletal Tumor Imaging

2020 ◽  
Vol 24 (04) ◽  
pp. 428-440
Author(s):  
B Matthew Howe ◽  
Stephen M. Broski ◽  
Laurel A. Littrell ◽  
Kay M. Pepin ◽  
Doris E. Wenger
Keyword(s):  
Tumor Imaging ◽  
Three Dimensional ◽  
Musculoskeletal Tumor ◽  
Dynamic Contrast Enhancement ◽  
Three Dimensional Printing ◽  
Musculoskeletal Tumors ◽  
Quantitative Pet ◽  
Positron Emission ◽  
Pet Ct ◽  
Magnetic Resonance Imaging Mri

AbstractThe role of quantitative magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) techniques continues to grow and evolve in the evaluation of musculoskeletal tumors. In this review we discuss the MRI quantitative techniques of volumetric measurement, chemical shift imaging, diffusion-weighted imaging, elastography, spectroscopy, and dynamic contrast enhancement. We also review quantitative PET techniques in the evaluation of musculoskeletal tumors, as well as virtual surgical planning and three-dimensional printing.

scholarly journals Evaluation of a Method Combining Physical Experiment and Data Insertion For the Assessment of PET-CT Systems

2021 ◽  
Author(s):  
Quentin Maronnier ◽  
Frédéric Courbon ◽  
Olivier Caselles
Keyword(s):  
Original Data ◽  
Quality Standard ◽  
Physical Experiment ◽  
P Value ◽  
Recovery Coefficient ◽  
Standard Sphere ◽  
Positron Emission ◽  
Pet Ct ◽  
Simulated Series ◽  
Pet Scanners

Abstract Background: To evaluate and compare Positron Emission Tomography (PET) devices among them, tests are performed on phantoms that generally consist in simple geometrical objects, fillable with radiotracers. On one hand, those tests bring a control over the experiment through the operator preparation but on the other hand, they are limited in terms of reproducibility, repeatability and are time-consuming, in particular, if several replications are required. To overcome these restrictions, we designed a method combining physical experiment and data insertion that aims to avoid experimental repetitions while testing multiple configurations for the performance evaluation of PET scanners.Methods: Based on the National Electrical Manufacturers Association Image Quality standard, four experiments, with different spheres-to-background ratios: 2:1, 4:1, 6:1 and 8:1, were performed. An additional acquisition was done with a radioactive background and no activity within the spheres. It was created as a baseline to artificially simulate the radioactive spheres and reproduce initial experiments. Standard sphere set was replaced by smaller target sizes (4, 5, 6, 8, 10 and 13 mm) to match current detectability performance of PET scanners. Images were reconstructed following standard guidelines, i.e. using OSEM algorithm, and an additional BPL reconstruction was performed. We visually compared experimental and simulated images. We measured the activity concentration values into the spheres to calculate the mean and maximum recovery coefficient (RCmean and RCmax ) which we used in a quantitative analysis.Results: No significant visual discrepancies were identified between experimental and simulated series. Mann-Whitney U tests comparing simulated and experimental distributions showed no statistical differences for both RCmean (P value = 0.611) and RCmax (P value = 0.720). Spearman tests revealed high correlation for RCmean (ρ = 0.974, P value < 0.001) and RCmax (ρ = 0.974, P value < 0.001) between both datasets. According to Bland-Altman plots, we highlighted slight shifts in RCmean and RCmax of respectively 2.1 ± 16.9 % and 3.3 ± 22.3 %.Conclusions: The method produced realistic results compared to experimental data. Known synthesized information fused with original data allows full exploration of the system's capabilities while avoiding the limitations associated with repeated experiments.

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