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Journal of Nuclear Medicine Technology Sep 2022This study measured the typical emitted radiation rate from the urinary bladder of PET patients after their scan and investigated simple methods for reducing the emitted...
This study measured the typical emitted radiation rate from the urinary bladder of PET patients after their scan and investigated simple methods for reducing the emitted radiation before discharge. The study included 83 patients (63 F-FDG and 20 F-NaF patients). Emitted radiation from the patients' urinary bladder was measured with an ionization survey meter at a 1-m distance, presuming the urinary bladder to be the primary source of radiation. The measurements were taken at different time points after PET image acquisition: immediate (prevoid 1), voided (postvoid 1), after waiting 30 min in the uptake room while drinking 500 mL of water (prevoid 2), and voided again (postvoid 2). For F-FDG patients, the reduction of emitted radiation due to drinking water and voiding alone from prevoid 1 to decay-corrected postvoid 2 was an average of 22.49% ± 7.48% (13.65 ± 3.42 μSv/h to 10.48 ± 2.37 μSv/h, < 0.001). For F-NaF patients, the reduction was an average of 25.80% ± 10.03% (9.83 ± 2.01 μSv/h to 7.23 ± 1.49 μSv/h, < 0.001). In addition to the physical decay of the radiotracers, using the biologic clearance properties resulted in a significant decrease of the emitted radiation in this study. Implementing additional water consumption to facilitate voiding with 30 min of wait time before discharging certain F-FDG and F-NaF patients who need to be in close contact with others, such as elderly, caregivers, and inpatients, might facilitate lowering their emitted radiation by an average of 22%-25% due to voiding, not counting in the physical decay that should add an additional 17% reduction.
Topics: Aged; Biological Products; Drinking Water; Fluorodeoxyglucose F18; Humans; Positron-Emission Tomography; Radiation Exposure
PubMed: 35440475
DOI: 10.2967/jnmt.121.263223 -
Proceedings of the National Academy of... Aug 2021The amino acid and oligopeptide transporter Solute carrier family 15 member A4 (SLC15A4), which resides in lysosomes and is preferentially expressed in immune cells,...
The amino acid and oligopeptide transporter Solute carrier family 15 member A4 (SLC15A4), which resides in lysosomes and is preferentially expressed in immune cells, plays critical roles in the pathogenesis of lupus and colitis in murine models. Toll-like receptor (TLR)7/9- and nucleotide-binding oligomerization domain-containing protein 1 (NOD1)-mediated inflammatory responses require SLC15A4 function for regulating the mechanistic target of rapamycin complex 1 (mTORC1) or transporting L-Ala-γ-D-Glu-meso-diaminopimelic acid, IL-12: interleukin-12 (Tri-DAP), respectively. Here, we further investigated the mechanism of how SLC15A4 directs inflammatory responses. Proximity-dependent biotin identification revealed glycolysis as highly enriched gene ontology terms. Fluxome analyses in macrophages indicated that SLC15A4 loss causes insufficient biotransformation of pyruvate to the tricarboxylic acid cycle, while increasing glutaminolysis to the cycle. Furthermore, SLC15A4 was required for M1-prone metabolic change and inflammatory IL-12 cytokine productions after TLR9 stimulation. SLC15A4 could be in close proximity to AMP-activated protein kinase (AMPK) and mTOR, and SLC15A4 deficiency impaired TLR-mediated AMPK activation. Interestingly, SLC15A4-intact but not SLC15A4-deficient macrophages became resistant to fluctuations in environmental nutrient levels by limiting the use of the glutamine source; thus, SLC15A4 was critical for macrophage's respiratory homeostasis. Our findings reveal a mechanism of metabolic regulation in which an amino acid transporter acts as a gatekeeper that protects immune cells' ability to acquire an M1-prone metabolic phenotype in inflammatory tissues by mitigating metabolic stress.
Topics: 4-Chloro-7-nitrobenzofurazan; Animals; Cell Differentiation; Cell Line; Dendritic Cells; Deoxyglucose; Energy Metabolism; Gene Expression Regulation; Gene Silencing; Humans; Macrophages; Membrane Transport Proteins; Mice; Mice, Knockout; Nerve Tissue Proteins; Oligodeoxyribonucleotides
PubMed: 34385317
DOI: 10.1073/pnas.2100295118 -
Biomedicine & Pharmacotherapy =... Dec 2022Chronic exposure to high glucose inside the human body helps in the progression of cancer by activating various signaling pathways including PI3K, Akt, mTOR, Ras, Raf,... (Review)
Review
Chronic exposure to high glucose inside the human body helps in the progression of cancer by activating various signaling pathways including PI3K, Akt, mTOR, Ras, Raf, MAPK, and PKC. Hyperglycemia induces ROS and AGE production and decreases the functional activities of the cellular antioxidant system. By downregulating the prolyl hydroxylase, it stabilizes HIF-α leading to EMT-induced cancer progression and inhibition of apoptosis. High glucose level increases inflammation by creating a pro-inflammatory environment through the production of certain pro-inflammatory mediators (cytokines, chemokines, leukotrienes), and by influencing the recruitment of immune cells, leukocytes in the inflamed region. High glucose impairs the immune response and dysregulates ROS formation through the alteration in ETC and glutaminolysis which makes hyperglycemic patients more susceptible to viral infection. 2-DG is a modified form of D-glucose, that shows anticancer, anti-inflammatory, and anti-viral effects. It enters the cells through GLUT transporters and is converted into 2-deoxy-D-glucose-6-phosphate with the help of hexokinase. It inhibits the glycolysis, the TCA cycle, and the pentose phosphate pathway leading to ATP depletion. By downregulating glucose uptake and energy (ATP) production it halts various pathways responsible for cancer progression. It promotes the formation of anti-inflammatory mediators, and macrophage polarization, and also modulates immune function, which decreases inflammation. 2-DG inhibits PI3K/Akt/mTOR and upregulates the AMPK pathway, causing activation of the SIRT-4 gene that reduces lipogenesis, glucose uptake, nucleotide formation, and alters viral replication thus reducing the chances of infection.
Topics: Humans; Glucose; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; TOR Serine-Threonine Kinases; Cell Proliferation; Glycolysis; Neoplasms; Deoxyglucose; Inflammation; Adenosine Triphosphate; Virus Diseases
PubMed: 36228369
DOI: 10.1016/j.biopha.2022.113801 -
Epilepsy & Behavior : E&B Mar 20232-deoxy-D-glucose (2DG) is a glucose analog differing from glucose only by removal of an oxygen atom at the 2 position, which prevents the isomerization of... (Review)
Review
2-deoxy-D-glucose (2DG) is a glucose analog differing from glucose only by removal of an oxygen atom at the 2 position, which prevents the isomerization of glucose-6-phosphate to fructose-6-phosphate, and thereby reversibly inhibits glycolysis. PET studies of regional brain glucose utilization positron-emitting 18F-2DG demonstrate that brain regions generating seizures have diminished glucose utilization during interictal conditions, but rapidly transition to markedly increased glucose delivery and utilization during seizures, particularly in status epilepticus (SE). 2-deoxy-D-glucose has acute antiseizure actions in multiple in vivo and in vitro seizure models, including models of SE induced by the chemo convulsants pilocarpine and kainic acid, suggesting that focal enhanced delivery of 2DG to ictal brain circuits is a potential novel anticonvulsant intervention for the treatment of SE.
Topics: Humans; Deoxyglucose; Status Epilepticus; Seizures; Glucose; Glycolysis; Pilocarpine
PubMed: 36804714
DOI: 10.1016/j.yebeh.2023.109108 -
European Radiology Nov 2023
Topics: Humans; Gallium Radioisotopes; Positron Emission Tomography Computed Tomography; Fluorodeoxyglucose F18
PubMed: 37171487
DOI: 10.1007/s00330-023-09715-9 -
In Vivo (Athens, Greece) 20231,5-Anhydro-d-fructose (1,5-AF, saccharide) and 1,5-anhydro-d-glucitol (1,5-AG) converted from 1,5-AF via the glycemic pathway have health benefits. However, this...
BACKGROUND/AIM
1,5-Anhydro-d-fructose (1,5-AF, saccharide) and 1,5-anhydro-d-glucitol (1,5-AG) converted from 1,5-AF via the glycemic pathway have health benefits. However, this metabolism has not been sufficiently elucidated. To clarify the in vivo metabolism of 1,5-AF to 1,5-AG, porcine (blood kinetics) and human (urinary excretion) studies were conducted.
MATERIALS AND METHODS
Microminipigs were administrated 1,5-AF orally or intravenously. Blood samples were obtained to analyse the kinetics of 1,5-AF and 1,5-AG. Urine samples were collected from human subjects who had orally ingested 1,5-AF, and the amounts of 1,5-AF and 1,5-AG excreted in the urine were analysed.
RESULTS
In blood kinetics analysis, the time to the maximum concentration of 1,5-AF after intravenous administration was 0.5 h, whereas 1,5-AF was not observed after oral administration. The times to the maximum concentration of 1,5-AG after intravenous and oral administration were 1.5 h and 2 h, respectively. In urinary excretion, the concentration of 1,5-AG in urine rapidly increased after the administration of 1,5-AF, peaked at 2 h, whereas 1,5-AF was not detected.
CONCLUSION
1,5-AF was rapidly metabolized to 1.5-AG in vivo in swine and human.
Topics: Humans; Animals; Swine; Sorbitol; Deoxyglucose; Fructose
PubMed: 37103066
DOI: 10.21873/invivo.13176 -
Neuroradiology Aug 2023Anti-leucine glioma-inactivated protein 1 (anti-LGI1) autoimmune encephalitis (AE) presents as subacute memory loss, behavioral changes, and seizures. Diagnosis and...
OBJECTIVES
Anti-leucine glioma-inactivated protein 1 (anti-LGI1) autoimmune encephalitis (AE) presents as subacute memory loss, behavioral changes, and seizures. Diagnosis and treatment delays can result in long term sequelae, including cognitive impairment. F-FDG PET/CT may be more sensitive than MRI in patients with AE. Our objective was to determine if anti-LGI1 is associated with a distinct pattern of FDG uptake and whether this pattern persists following treatment.
METHODS
NineteenF-FDG PET/CT brain scans (13 pre-treatment, 6 convalescent phase) for 13 patients with anti-LGI1 were studied using NeuroQ™ and CortexID™. The sensitivity of the PET images was compared to MRI. The Z scores of 47 brain regions between the pre-treatment and next available follow-up images during convalescence were compared.
RESULTS
All F-FDG PET/CT scans demonstrated abnormal FDG uptake, while only 6 (42.9%) pre-treatment brain MRIs were abnormal. The pre-treatment scans demonstrated hypermetabolism in the bilateral medial temporal cortices, basal ganglia, brain stem, and cerebellum and hypometabolism in bilateral medial and mid frontal, cingulate, and parietotemporal cortices. Overall, the brain uptake during convalescence showed improvement of the Z scores towards 0 or normalization of previous hypometabolic activity in medial frontal cortex, inferior frontal cortex, Broca's region, parietotemporal cortex, and posterior cingulate cortex and previous hypermetabolic activity in medial temporal cortices, caudate, midbrain, pons and cerebellum.
CONCLUSIONS
Brain FDG uptake was more commonly abnormal than MRI in the pre-treatment phase of anti-LGI1, and patterns of dysmetabolism differed in the pre-treatment and convalescent phases. These findings may expedite the diagnosis, treatment, and monitoring of anti-LGI1 patients.
Topics: Humans; Fluorodeoxyglucose F18; Positron Emission Tomography Computed Tomography; Leucine; Convalescence; Magnetic Resonance Imaging; Glioma; Autoimmune Diseases of the Nervous System
PubMed: 37264220
DOI: 10.1007/s00234-023-03165-2 -
PloS One 2022One major challenge in PET radiomics is its sensitivity to noise. Low signal-to-noise ratio (SNR) affects not only the precision but also the accuracy of quantitative...
INTRODUCTION
One major challenge in PET radiomics is its sensitivity to noise. Low signal-to-noise ratio (SNR) affects not only the precision but also the accuracy of quantitative metrics extracted from the images resulting in noise-induced bias. This phantom study aims to identify the radiomic features that are robust to noise in terms of precision and accuracy and to explore some methods that might help to correct noise-induced bias.
METHODS
A phantom containing three 18F-FDG filled 3D printed inserts, reflecting heterogeneous tracer uptake and realistic tumor shapes, was used in the study. The three different phantom inserts were filled and scanned with three different tumor-to-background ratios, simulating a total of nine different tumors. From the 40-minute list-mode data, ten frames each for 5 s, 10 s, 30 s, and 120 s frame duration were reconstructed to generate images with different noise levels. Under these noise conditions, the precision and accuracy of the radiomic features were analyzed using intraclass correlation coefficient (ICC) and similarity distance metric (SDM) respectively. Based on the ICC and SDM values, the radiomic features were categorized into four groups: poor, moderate, good, and excellent precision and accuracy. A "difference image" created by subtracting two statistically equivalent replicate images was used to develop a model to correct the noise-induced bias. Several regression methods (e.g., linear, exponential, sigmoid, and power-law) were tested. The best fitting model was chosen based on Akaike information criteria.
RESULTS
Several radiomic features derived from low SNR images have high repeatability, with 68% of radiomic features having ICC ≥ 0.9 for images with a frame duration of 5 s. However, most features show a systematic bias that correlates with the increase in noise level. Out of 143 features with noise-induced bias, the SDM values were improved based on a regression model (53 features to excellent and 67 to good) indicating that the noise-induced bias of these features can be, at least partially, corrected.
CONCLUSION
To have a predictive value, radiomic features should reflect tumor characteristics and be minimally affected by noise. The present study has shown that it is possible to correct for noise-induced bias, at least in a subset of the features, using a regression model based on the local image noise estimates.
Topics: Bias; Fluorodeoxyglucose F18; Image Processing, Computer-Assisted; Phantoms, Imaging; Positron-Emission Tomography
PubMed: 36006959
DOI: 10.1371/journal.pone.0272643 -
Japanese Journal of Radiology May 2023[F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a well-established modality with high sensitivity for the diagnosis and staging of oncologic patients.... (Review)
Review
[F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a well-established modality with high sensitivity for the diagnosis and staging of oncologic patients. FDG is taken up by the glucose transporter of the cell membrane and becomes trapped within the cell. In addition to malignant neoplasms, active inflammatory lesions and some kinds of benign tumors also accumulate FDG. Moreover, the degree of uptake into normal organs and tissues depends on various physiological conditions, which is affected by various medical procedures, treatments, and drugs. To avoid misleading interpretations, it is important to recognize possible situations of unexpected abnormal accumulation that mimic tumor lesions. In this review, we present various FDG findings associated with surgical or medical procedures and treatments. Some findings reflect the expected physiological reaction to treatment, and some show inflammation due to prior procedures. Occasionally, FDG-PET visualizes other disorders that are unrelated to the malignancy, which may be associated with the adverse effects of certain drugs that the patient is taking. Careful review of medical records and detailed interviews of patients are thus necessary.
Topics: Humans; Fluorodeoxyglucose F18; Radiopharmaceuticals; Positron-Emission Tomography; Inflammation
PubMed: 36575286
DOI: 10.1007/s11604-022-01376-w -
Current Oncology Reports Jul 2020Molecular imaging with positron emission tomography (PET) is a powerful tool to visualize breast cancer characteristics. Nonetheless, implementation of PET imaging into... (Review)
Review
PURPOSE OF REVIEW
Molecular imaging with positron emission tomography (PET) is a powerful tool to visualize breast cancer characteristics. Nonetheless, implementation of PET imaging into cancer care is challenging, and essential steps have been outlined in the international "imaging biomarker roadmap." In this review, we identify hurdles and provide recommendations for implementation of PET biomarkers in breast cancer care, focusing on the PET tracers 2-[F]-fluoro-2-deoxyglucose ([F]-FDG), sodium [F]-fluoride ([F]-NaF), 16α-[F]-fluoroestradiol ([F]-FES), and [Zr]-trastuzumab.
RECENT FINDINGS
Technical validity of [F]-FDG, [F]-NaF, and [F]-FES is established and supported by international guidelines. However, support for clinical validity and utility is still pending for these PET tracers in breast cancer, due to variable endpoints and procedures in clinical studies. Assessment of clinical validity and utility is essential towards implementation; however, these steps are still lacking for PET biomarkers in breast cancer. This could be solved by adding PET biomarkers to randomized trials, development of imaging data warehouses, and harmonization of endpoints and procedures.
Topics: Biomarkers; Breast Neoplasms; Female; Fluorodeoxyglucose F18; Humans; Molecular Imaging; Positron Emission Tomography Computed Tomography
PubMed: 32627087
DOI: 10.1007/s11912-020-00940-9