Molecular Imaging最新文献

{"title":"Evaluation of Intraperitoneal [¹⁸F]-FDOPA Administration for Micro-PET Imaging in Mice and Assessment of the Effect of Subchronic Ketamine Dosing on Dopamine Synthesis Capacity.","authors":"Els F Halff, Sridhar Natesan, David R Bonsall, Mattia Veronese, Anna Garcia-Hidalgo, Michelle Kokkinou, Sac-Pham Tang, Laura J Riggall, Roger N Gunn, Elaine E Irvine, Dominic J Withers, Lisa A Wells, Oliver D Howes","doi":"10.1155/2022/4419221","DOIUrl":"10.1155/2022/4419221","url":null,"abstract":"<p><p>Positron emission tomography (PET) using the radiotracer [¹⁸F]-FDOPA provides a tool for studying brain dopamine synthesis capacity in animals and humans. We have previously standardised a micro-PET methodology in mice by intravenously administering [¹⁸F]-FDOPA via jugular vein cannulation and assessment of striatal dopamine synthesis capacity, indexed as the influx rate constant <i>K</i> _<i>i</i> ^Mod of [¹⁸F]-FDOPA, using an extended graphical Patlak analysis with the cerebellum as a reference region. This enables a direct comparison between preclinical and clinical output values. However, chronic intravenous catheters are technically difficult to maintain for longitudinal studies. Hence, in this study, intraperitoneal administration of [¹⁸F]-FDOPA was evaluated as a less-invasive alternative that facilitates longitudinal imaging. Our experiments comprised the following assessments: (i) comparison of [¹⁸F]-FDOPA uptake between intravenous and intraperitoneal radiotracer administration and optimisation of the time window used for extended Patlak analysis, (ii) comparison of <i>Ki</i> ^Mod in a within-subject design of both administration routes, (iii) test-retest evaluation of <i>Ki</i> ^Mod in a within-subject design of intraperitoneal radiotracer administration, and (iv) validation of <i>Ki</i> ^Mod estimates by comparing the two administration routes in a mouse model of hyperdopaminergia induced by subchronic ketamine. Our results demonstrate that intraperitoneal [¹⁸F]-FDOPA administration resulted in good brain uptake, with no significant effect of administration route on <i>Ki</i> ^Mod estimates (intraperitoneal: 0.024 ± 0.0047 min^-1, intravenous: 0.022 ± 0.0041 min^-1, <i>p</i> = 0.42) and similar coefficient of variation (intraperitoneal: 19.6%; intravenous: 18.4%). The technique had a moderate test-retest validity (intraclass correlation coefficient (ICC) = 0.52, <i>N</i> = 6) and thus supports longitudinal studies. Following subchronic ketamine administration, elevated <i>K</i> _<i>i</i> ^Mod as compared to control condition was measured with a large effect size for both methods (intraperitoneal: Cohen's <i>d</i> = 1.3; intravenous: Cohen's <i>d</i> = 0.9), providing further evidence that ketamine has lasting effects on the dopamine system, which could contribute to its therapeutic actions and/or abuse liability.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"2022 ","pages":"4419221"},"PeriodicalIF":2.2,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9881672/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9165489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compressed Sensing Photoacoustic Imaging Reconstruction Using Elastic Net Approach.","authors":"Xueyan Liu,&nbsp;Shuo Dai,&nbsp;Mengyu Wang,&nbsp;Yining Zhang","doi":"10.1155/2022/7877049","DOIUrl":"https://doi.org/10.1155/2022/7877049","url":null,"abstract":"<p><p>Photoacoustic imaging involves reconstructing an estimation of the absorbed energy density distribution from measured ultrasound data. The reconstruction task based on incomplete and noisy experimental data is usually an ill-posed problem that requires regularization to obtain meaningful solutions. The purpose of the work is to propose an elastic network (EN) model to improve the quality of reconstructed photoacoustic images. To evaluate the performance of the proposed method, a series of numerical simulations and tissue-mimicking phantom experiments are performed. The experiment results indicate that, compared with the <i>L</i> ₁-norm and <i>L</i> ₂-normbased regularization methods with different numerical phantoms, Gaussian noise of 10-50 dB, and different regularization parameters, the EN method with <i>α</i> = 0.5 has better image quality, calculation speed, and antinoise ability.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"2022 ","pages":"7877049"},"PeriodicalIF":2.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9881674/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10650670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preclinical Evaluation of an Activity-Based Probe for Intraoperative Imaging of Esophageal Cancer.","authors":"Gregory T Kennedy,&nbsp;Feredun S Azari,&nbsp;Bilal Nadeem,&nbsp;Ashley Chang,&nbsp;Alix Segil,&nbsp;Elizabeth Bernstein,&nbsp;Charuhas Desphande,&nbsp;John C Kucharczuk,&nbsp;Edward J Delikatny,&nbsp;Sunil Singhal","doi":"10.1155/2022/5447290","DOIUrl":"https://doi.org/10.1155/2022/5447290","url":null,"abstract":"<p><strong>Background: </strong>Early detection and complete resection are important prognostic factors for esophageal cancer (EC). Intraoperative molecular imaging (IMI) using tumor-targeted tracers is effective in many cancer types. However, there are no EC-specific IMI tracers. We sought to test a cathepsin activity-based tracer (VGT-309) for EC resection.</p><p><strong>Methods: </strong>Murine (AKR, HNM007) and human (OE19) EC cell lines were screened for cathepsin expression by western blotting. <i>In vitro</i> binding affinity of VGT-309 was evaluated by fluorescence microscopy. Flank tumor models were developed by injecting EC cells into the flanks of BALB/c or athymic nude mice. Mice pretreated with a cathepsin inhibitor (JPM-OEt) were used to confirm on target binding. Animals were injected with 2 mg/kg VGT-309, underwent IMI, and were sacrificed 24 hours after injection.</p><p><strong>Results: </strong>Cathepsins B, L, S, and X were expressed by EC cell lines, and all cell lines were labeled <i>in vitro</i> with VGT-309. Fluorescent signal was eliminated when cells were pretreated with JPM-OEt. On biodistribution analysis, VGT-309 accumulated in the liver, kidneys, and spleen without other organ involvement. VGT-309 selectively accumulated in flank allografts and xenografts, with mean signal-to-background ratio of 5.21 (IQR: 4.18-6.73) for flank allografts and 4.34 (IQR: 3.75-5.02) for flank xenografts. Fluorescence microscopy and histopathological analysis confirmed the selective accumulation of the tracer in tumors compared to background normal tissues.</p><p><strong>Conclusions: </strong>VGT-309 is an effective tracer for IMI of esophageal cancer. There is potential for clinical translation both as an adjunct to endoscopic detection and for complete removal of disease during esophagectomy.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"2022 ","pages":"5447290"},"PeriodicalIF":2.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9328188/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9451249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biodistribution of a Mitochondrial Metabolic Tracer, [¹⁸F]F-AraG, in Healthy Volunteers.","authors":"Jelena Levi,&nbsp;Heying Duan,&nbsp;Shahriar Yaghoubi,&nbsp;Juliet Packiasamy,&nbsp;Lyna Huynh,&nbsp;Tina Lam,&nbsp;Faiq Shaikh,&nbsp;Deepak Behera,&nbsp;Hong Song,&nbsp;Joseph Blecha,&nbsp;Salma Jivan,&nbsp;Youngho Seo,&nbsp;Henry F VanBrocklin","doi":"10.1155/2022/3667417","DOIUrl":"https://doi.org/10.1155/2022/3667417","url":null,"abstract":"<p><strong>Purpose: </strong>[¹⁸F]F-AraG is a radiolabeled nucleoside analog that shows relative specificity for activated T cells. The aim of this study was to investigate the biodistribution of [¹⁸F]F-AraG in healthy volunteers and assess the preliminary safety and radiation dosimetry.</p><p><strong>Methods: </strong>Six healthy subjects (three female and three male) between the ages of 24 and 60 participated in the study. Each subject received a bolus venous injection of [¹⁸F]F-AraG (dose range: 244.2-329.3 MBq) prior to four consecutive PET/MR whole-body scans. Blood samples were collected at regular intervals and vital signs monitored before and after tracer administration. Regions of interest were delineated for multiple organs, and the area under the time-activity curves was calculated for each organ and used to derive time-integrated activity coefficient (TIAC). TIACs were input for absorbed dose and effective dose calculations using OLINDA.</p><p><strong>Results: </strong>PET/MR examination was well tolerated, and no adverse effects to the administration of [¹⁸F]F-AraG were noted by the study participants. The biodistribution was generally reflective of the expression and activity profiles of the enzymes involved in [¹⁸F]F-AraG's cellular accumulation, mitochondrial kinase dGK, and SAMHD1. The highest uptake was observed in the kidneys and liver, while the brain, lung, bone marrow, and muscle showed low tracer uptake. The estimated effective dose for [¹⁸F]F-AraG was 0.0162 mSv/MBq (0.0167 mSv/MBq for females and 0.0157 mSv/MBq for males).</p><p><strong>Conclusion: </strong>Biodistribution of [¹⁸F]F-AraG in healthy volunteers was consistent with its association with mitochondrial metabolism. PET/MR [¹⁸F]F-AraG imaging was well tolerated, with a radiation dosimetry profile similar to other commonly used [¹⁸F]-labeled tracers. [¹⁸F]F-AraG's connection with mitochondrial biogenesis and favorable biodistribution characteristics make it an attractive tracer with a variety of potential applications.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"2022 ","pages":"3667417"},"PeriodicalIF":2.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9400547/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10397147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PET Study of Sphingosine-1-phosphate Receptor 1 Expression in Response to <i>S. aureus</i> Infection.","authors":"Hao Jiang, Jiwei Gu, Haiyang Zhao, Sumit Joshi, Joel S Perlmutter, Robert J Gropler, Robyn S Klein, Tammie L S Benzinger, Zhude Tu","doi":"10.1155/2021/9982020","DOIUrl":"10.1155/2021/9982020","url":null,"abstract":"<p><p>Sphingosine-1-phosphate receptor 1 (S1PR1) plays a crucial role in infectious diseases. Targeting S1PR1 provides protection against pathogens, such as influenza viruses. This study is aimed at investigating S1PR1 in response to bacterial infection by assessing S1PR1 expression in <i>S. aureus</i>-infected mice. A rodent local muscle bacterial infection model was developed by injecting <i>S. aureus</i> to the lower hind limb of Balb/c mice. The changes of S1PR1 expression in response to bacterial infection and blocking treatment were assessed using ex vivo biodistribution and <i>in vivo</i> positron emission tomography (PET) after intravenous injection of an S1PR1-specific radiotracer [¹⁸F]TZ4877. The specificity of [¹⁸F]TZ4877 was assessed using S1PR1-specific antagonist, NIBR-0213, and S1PR1-specific DsiRNA pretreated the animals. Immunohistochemical studies were performed to confirm the increase of S1PR1 expression in response to infection. <i>Ex vivo</i> biodistribution data showed that the uptake of [¹⁸F]TZ4877 was increased 30.6%, 54.3%, 74.3%, and 115.3% in the liver, kidney, pancreas, and thymus of the infected mice, respectively, compared to that in normal control mice, indicating that S1PR1 is involved in the early immune response to bacterial infection. NIBR-0213 or S1PR1-specific DsiRNA pretreatment reduced the tissue uptake of [¹⁸F]TZ4877, suggesting that uptake of [¹⁸F]TZ4877 is specific. Our PET/CT study data also confirmed that infected mice have increased [¹⁸F]TZ4877 uptake in several organs comparing to that in normal control mice. Particularly, compared to control mice, a 39% increase of [¹⁸F]TZ4877 uptake was observed in the infected muscle of <i>S. aureus</i> mice, indicating that S1PR1 expression was directly involved in the inflammatory response to infection. Overall, our study suggested that S1PR1 plays an important role in the early immune response to bacterial infection. The uptake of [¹⁸F]TZ4877 is tightly correlated with the S1R1 expression in response to <i>S. aureus</i> infection. PET with S1PR1-specific radiotracer [¹⁸F]TZ4877 could provide a noninvasive tool for detecting the early S1PR1 immune response to infectious diseases.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"2021 ","pages":"9982020"},"PeriodicalIF":2.8,"publicationDate":"2021-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8654346/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9235557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular MR-Imaging for Noninvasive Quantification of the Anti-Inflammatory Effect of Targeting Interleukin-1β in a Mouse Model of Aortic Aneurysm.","authors":"Julia Brangsch,&nbsp;Carolin Reimann,&nbsp;Jan Ole Kaufmann,&nbsp;Lisa Christine Adams,&nbsp;David Onthank,&nbsp;Christa Thöne-Reineke,&nbsp;Simon Robinson,&nbsp;Marco Wilke,&nbsp;Michael Weller,&nbsp;Rebecca Buchholz,&nbsp;Uwe Karst,&nbsp;Rene Botnar,&nbsp;Bernd Hamm,&nbsp;Marcus Richard Makowski","doi":"10.1177/1536012120961875","DOIUrl":"https://doi.org/10.1177/1536012120961875","url":null,"abstract":"<p><strong>Background: </strong>Molecular-MRI is a promising imaging modality for the assessment of abdominal aortic aneurysms (AAAs). Interleukin-1β (IL-1β) represents a new therapeutic tool for AAA-treatment, since pro-inflammatory cytokines are key-mediators of inflammation. This study investigates the potential of molecular-MRI to evaluate therapeutic effects of an anti-IL-1β-therapy on AAA-formation in a mouse-model.</p><p><strong>Methods: </strong>Osmotic-minipumps were implanted in apolipoprotein-deficient-mice (N = 27). One group (Ang-II+01BSUR group, n = 9) was infused with angiotensin-II (Ang-II) for 4 weeks and received an anti-murine IL-1β-antibody (01BSUR) 3 times. One group (Ang-II-group, n = 9) was infused with Ang-II for 4 weeks but received no treatment. Control-group (n = 9) was infused with saline and received no treatment. MR-imaging was performed using an elastin-specific gadolinium-based-probe (0.2 mmol/kg).</p><p><strong>Results: </strong>Mice of the Ang-II+01BSUR-group showed a lower aortic-diameter compared to mice of the Ang-II-group and control mice (p < 0.05). Using the elastin-specific-probe, a significant decrease in elastin-destruction was observed in mice of the Ang-II+01BSUR-group. In vivo MR-measurements correlated well with histopathology (y = 0.34x-13.81, R² = 0.84, p < 0.05), ICP-MS (y = 0.02x+2.39; R² = 0.81, p < 0.05) and LA-ICP-MS. Immunofluorescence and western-blotting confirmed a reduced IL-1β-expression.</p><p><strong>Conclusions: </strong>Molecular-MRI enables the early visualization and quantification of the anti-inflammatory-effects of an IL-1β-inhibitor in a mouse-model of AAAs. Responders and non-responders could be identified early after the initiation of the therapy using molecular-MRI.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"19 ","pages":"1536012120961875"},"PeriodicalIF":2.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1536012120961875","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38624854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[¹¹C]Methionine and [¹¹C]PBR28 as PET Imaging Tracers to Differentiate Metastatic Tumor Recurrence or Radiation Necrosis.","authors":"Thuy T Tran,&nbsp;Jean-Dominique Gallezot,&nbsp;Lucia B Jilaveanu,&nbsp;Christopher Zito,&nbsp;Gabriela Turcu,&nbsp;Keunpoong Lim,&nbsp;Nabeel Nabulsi,&nbsp;Henry Huang,&nbsp;Anita Huttner,&nbsp;Harriet M Kluger,&nbsp;Veronica L Chiang,&nbsp;Richard Carson","doi":"10.1177/1536012120968669","DOIUrl":"https://doi.org/10.1177/1536012120968669","url":null,"abstract":"<p><strong>Purpose: </strong>As stereotactic radiosurgery (SRS) and immunotherapy are increasingly used to treat brain metastases, incidence of radiation necrosis (RN) is consequently rising. Differentiating tumor regrowth (TR) from RN is vital in management but difficult to assess using MRI. We hypothesized that tumor methionine levels would be elevated given increased metabolism and high amino acid uptake, whereas RN would increase inflammation marked by upregulated translocator protein (PBR-TSPO), which can be quantified with specific PET tracers.</p><p><strong>Procedures: </strong>We performed a feasibility study to prospectively evaluate [¹¹C]methionine and [¹¹C]PBR28 using PET in 5 patients with 7 previously SRS-treated brain metastases demonstrating regrowth to differentiate TR from RN.</p><p><strong>Results: </strong>Sequential imaging with dual tracers was well-tolerated. [¹¹C]methionine was accurate for detecting pathologically confirmed TR in 7/7 lesions, whereas [¹¹C]PBR28 was only accurate in 3/7 lesions. Tumor PBR-TSPO expression was elevated in both melanoma and lung cancer cells, contributing to lack of specificity of [¹¹C]PBR28-PET.</p><p><strong>Conclusion: </strong>Sequential use of PET tracers is safe and effective. [¹¹C]Methionine was a reliable TR marker, but [¹¹C]PBR28 was not a reliable marker of RN. Studies are needed to determine the causes of post-radiation inflammation and identify specific markers of RN to improve diagnostic imaging.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"19 ","pages":"1536012120968669"},"PeriodicalIF":2.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1536012120968669","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38660675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Decade's Progress in the Development of Molecular Imaging Agents Targeting the Growth Hormone Secretagogue Receptor.","authors":"Marina D Childs,&nbsp;Leonard G Luyt","doi":"10.1177/1536012120952623","DOIUrl":"https://doi.org/10.1177/1536012120952623","url":null,"abstract":"<p><p>The growth hormone secretagogue receptor 1a (GHSR), also called the ghrelin receptor, is a G protein-coupled receptor known to play an important metabolic role in the regulation of various physiological processes, including energy expenditure, growth hormone secretion, and cell proliferation. This receptor has been implicated in numerous health issues including obesity, gastrointestinal disorders, type II diabetes, and regulation of body weight in patients with Prader-Willi syndrome, and there has been growing interest in studying its mechanism of behavior to unlock further applications of GHSR-targeted therapeutics. In addition, the GHSR is expressed in various types of cancer including prostate, breast, and testicular cancers, while aberrant expression has been reported in cardiac disease. Targeted molecular imaging of the GHSR could provide insights into its role in biological processes related to these disease states. Over the past decade, imaging probes targeting this receptor have been discovered for the imaging modalities PET, SPECT, and optical imaging. High-affinity analogues of ghrelin, the endogenous ligand for the GHSR, as well as small molecule inhibitors have been developed and evaluated both <i>in vitro</i> and in pre-clinical models. This review provides a comprehensive overview of the molecular imaging agents targeting the GHSR reported to the end of 2019.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"19 ","pages":"1536012120952623"},"PeriodicalIF":2.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1536012120952623","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38528878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From the Outside in: An Overview of Positron Imaging of Plant and Soil Processes.","authors":"Michael P Schmidt,&nbsp;Steven D Mamet,&nbsp;Richard A Ferrieri,&nbsp;Derek Peak,&nbsp;Steven D Siciliano","doi":"10.1177/1536012120966405","DOIUrl":"https://doi.org/10.1177/1536012120966405","url":null,"abstract":"<p><p>Positron-emitting nuclides have long been used as imaging agents in medical science to spatially trace processes non-invasively, allowing for real-time molecular imaging using low tracer concentrations. This ability to non-destructively visualize processes in real time also makes positron imaging uniquely suitable for probing various processes in plants and porous environmental media, such as soils and sediments. Here, we provide an overview of historical and current applications of positron imaging in environmental research. We highlight plant physiological research, where positron imaging has been used extensively to image dynamics of macronutrients, signalling molecules, trace elements, and contaminant metals under various conditions and perturbations. We describe how positron imaging is used in porous soils and sediments to visualize transport, flow, and microbial metabolic processes. We also address the interface between positron imaging and other imaging approaches, and present accompanying chemical analysis of labelled compounds for reviewed topics, highlighting the bridge between positron imaging and complementary techniques across scales. Finally, we discuss possible future applications of positron imaging and its potential as a nexus of interdisciplinary biogeochemical research.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"19 ","pages":"1536012120966405"},"PeriodicalIF":2.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1536012120966405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38548086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Imaging Windows for Tau PET Imaging Using ¹⁸F-PI2620 in Cognitively Normal Individuals, Mild Cognitive Impairment, and Alzheimer's Disease Patients.","authors":"Chanisa Chotipanich,&nbsp;Monchaya Nivorn,&nbsp;Anchisa Kunawudhi,&nbsp;Chetsadaporn Promteangtrong,&nbsp;Natphimol Boonkawin,&nbsp;Attapon Jantarato","doi":"10.1177/1536012120947582","DOIUrl":"10.1177/1536012120947582","url":null,"abstract":"<p><strong>Background: </strong>The study aimed to evaluate the appropriate uptake-timing in cognitively normal individuals, mild cognitive impairment (MCI), and Alzheimer's disease (AD) patients, using ¹⁸F-PI 2620 dynamic PET acquisition.</p><p><strong>Methods: </strong>Thirty-four MCI patients, 6 AD patients, and 24 cognitively normal individuals were enrolled in this study. A dynamic ¹⁸F-PI 2620 PET study was conducted at 30-75 minutes post-injection in these groups. Co-registration was applied between the dynamic acquisition PET and T1-weighted MRI to delineate various cortical regions. The standardized uptake value ratio (SUVR) was used for quantitative analysis. P-mod software with the Automated Anatomical Labeling (AAL)-merged atlas was employed to generate automatic volumes of interest for 11 brain regions.</p><p><strong>Results: </strong>The curves in most brain regions presented an average SUVR stability at 30-40 minutes post-injection in each group. The appropriate uptake-timing interval of ¹⁸F-PI 2620 was 30-75 minutes post injection for AD group and 30-40 minutes post injection for both cognitively normal individuals and MCI groups.</p><p><strong>Conclusion: </strong>Short uptake time around 30-40 minutes post-injection would be more comfortable and convenient for all patients, especially in those with dementia who were unable to stay motionless for long periods of scanning time in the scanner.</p>","PeriodicalId":18855,"journal":{"name":"Molecular Imaging","volume":"19 ","pages":"1536012120947582"},"PeriodicalIF":2.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1536012120947582","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38325157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}