scholarly journals SPECT- and PET-Based Approaches for Noninvasive Diagnosis of Acute Renal Allograft Rejection

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Helga Pawelski ◽  
Uta Schnöckel ◽  
Dominik Kentrup ◽  
Alexander Grabner ◽  
Michael Schäfers ◽  
...  
Keyword(s):  
Molecular Imaging ◽  
Allograft Rejection ◽  
Single Photon ◽  
Imaging Techniques ◽  
Transplant Rejection ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Noninvasive Diagnosis ◽  
Acute Allograft Rejection ◽  
Acute Renal Allograft Rejection

Molecular imaging techniques such as single photon emission computed tomography (SPECT) or positron emission tomography are promising tools for noninvasive diagnosis of acute allograft rejection (AR). Given the importance of renal transplantation and the limitation of available donors, detailed analysis of factors that affect transplant survival is important. Episodes of acute allograft rejection are a negative prognostic factor for long-term graft survival. Invasive core needle biopsies are still the “goldstandard” in rejection diagnostics. Nevertheless, they are cumbersome to the patient and carry the risk of significant graft injury. Notably, they cannot be performed on patients taking anticoagulant drugs. Therefore, a noninvasive tool assessing the whole organ for specific and fast detection of acute allograft rejection is desirable. We herein review SPECT- and PET-based approaches for noninvasive molecular imaging-based diagnostics of acute transplant rejection.

scholarly journals Radionuclide-Based Imaging of Breast Cancer: State of the Art

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5459
Author(s):  
Huiling Li ◽  
Zhen Liu ◽  
Lujie Yuan ◽  
Kevin Fan ◽  
Yongxue Zhang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Molecular Imaging ◽  
Single Photon ◽  
Morphological Changes ◽  
Imaging Techniques ◽  
Rapid Development ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Biological Processes ◽  
Functional Perspective

Breast cancer is a malignant tumor that can affect women worldwide and endanger their health and wellbeing. Early detection of breast cancer can significantly improve the prognosis and survival rate of patients, but with traditional anatomical imagine methods, it is difficult to detect lesions before morphological changes occur. Radionuclide-based molecular imaging based on positron emission tomography (PET) and single-photon emission computed tomography (SPECT) displays its advantages for detecting breast cancer from a functional perspective. Radionuclide labeling of small metabolic compounds can be used for imaging biological processes, while radionuclide labeling of ligands/antibodies can be used for imaging receptors. Noninvasive visualization of biological processes helps elucidate the metabolic state of breast cancer, while receptor-targeted radionuclide molecular imaging is sensitive and specific for visualization of the overexpressed molecular markers in breast cancer, contributing to early diagnosis and better management of cancer patients. The rapid development of radionuclide probes aids the diagnosis of breast cancer in various aspects. These probes target metabolism, amino acid transporters, cell proliferation, hypoxia, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), gastrin-releasing peptide receptor (GRPR) and so on. This article provides an overview of the development of radionuclide molecular imaging techniques present in preclinical or clinical studies, which are used as tools for early breast cancer diagnosis.

scholarly journals Ocular Biodistribution Studies Using Molecular Imaging

Pharmaceutics ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 237 ◽  
Author(s):  
Ana Castro-Balado ◽  
Cristina Mondelo-García ◽  
Miguel González-Barcia ◽  
Irene Zarra-Ferro ◽  
Francisco J Otero-Espinar ◽  
...  
Keyword(s):  
Molecular Imaging ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
High Sensitivity ◽  
New Drugs ◽  
Emission Computed Tomography ◽  
Pharmacokinetic Data ◽  
Biodistribution Studies

Classical methodologies used in ocular pharmacokinetics studies have difficulties to obtain information about topical and intraocular distribution and clearance of drugs and formulations. This is associated with multiple factors related to ophthalmic physiology, as well as the complexity and invasiveness intrinsic to the sampling. Molecular imaging is a new diagnostic discipline for in vivo imaging, which is emerging and spreading rapidly. Recent developments in molecular imaging techniques, such as positron emission tomography (PET), single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI), allow obtaining reliable pharmacokinetic data, which can be translated into improving the permanence of the ophthalmic drugs in its action site, leading to dosage optimisation. They can be used to study either topical or intraocular administration. With these techniques it is possible to obtain real-time visualisation, localisation, characterisation and quantification of the compounds after their administration, all in a reliable, safe and non-invasive way. None of these novel techniques presents simultaneously high sensitivity and specificity, but it is possible to study biological procedures with the information provided when the techniques are combined. With the results obtained, it is possible to assume that molecular imaging techniques are postulated as a resource with great potential for the research and development of new drugs and ophthalmic delivery systems.

Molecular Imaging: Implications for Oral Cancer

2010 ◽  
Vol 1 (1) ◽  
pp. 31-34
Author(s):  
Shubhasini A Raghavan
Keyword(s):  
Computed Tomography ◽  
Molecular Imaging ◽  
Oral Cancer ◽  
Single Photon ◽  
Indian Subcontinent ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Active Role ◽  
Emission Computed Tomography ◽  
World Population

ABSTRACT Cancer is a scourge that affects millions of the world population. The incidence of oral cancer is alarmingly high in the Indian subcontinent. What is more appalling is the low survival rate of these patients. Various efforts are being made to bring about early diagnosis, accurate staging and aggressive treatment. Molecular imaging is one step in this direction. Today, imaging plays a role not just in detecting what is radiopaque and what is radiolucent, but also plays a very active role in detecting disease down to the level of a single cell. The field of molecular imaging has been defined as ‘the visualization, characterization, and measurement of biologic processes at molecular and cellular levels in humans and other living systems’. The amalgamation of advanced imaging techniques such as Positron Emission Tomography and Single Photon Emission Computed Tomography with Computed Tomography, the use of newer contrast agents, incorporation of nanoparticles all have brought about these revolutionary changes in imaging. The purpose of this article is to describe the various techniques used in molecular imaging specifically highlighting their application in head and neck cancer.

scholarly journals Radiolabeling of Nucleic Acid Aptamers for Highly Sensitive Disease-Specific Molecular Imaging

2018 ◽  
Vol 11 (4) ◽  
pp. 106 ◽  
Author(s):  
Leila Hassanzadeh ◽  
Suxiang Chen ◽  
Rakesh Veedu
Keyword(s):  
Molecular Imaging ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Three Dimensional ◽  
Nuclear Imaging ◽  
Spect Imaging ◽  
Emission Computed Tomography ◽  
Nuclear Medicine Imaging ◽  
Highly Sensitive

Aptamers are short single-stranded DNA or RNA oligonucleotide ligand molecules with a unique three-dimensional shape, capable of binding to a defined molecular target with high affinity and specificity. Since their discovery, aptamers have been developed for various applications, including molecular imaging, particularly nuclear imaging that holds the highest potential for the clinical translation of aptamer-based molecular imaging probes. Their easy laboratory production without any batch-to-batch variations, their high stability, their small size with no immunogenicity and toxicity, and their flexibility to incorporate various functionalities without compromising the target binding affinity and specificity make aptamers an attractive class of targeted-imaging agents. Aptamer technology has been utilized in nuclear medicine imaging techniques, such as single photon emission computed tomography (SPECT) and positron emission tomography (PET), as highly sensitive and accurate biomedical imaging modalities towards clinical diagnostic applications. However, for aptamer-targeted PET and SPECT imaging, conjugation of appropriate radionuclides to aptamers is crucial. This review summarizes various strategies to link the radionuclides to chemically modified aptamers to accomplish aptamer-targeted PET and SPECT imaging.

scholarly journals Molecular Imaging of Experimental Abdominal Aortic Aneurysms

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Aneesh K. Ramaswamy ◽  
Mark Hamilton ◽  
Rucha V. Joshi ◽  
Benjamin P. Kline ◽  
Rui Li ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Molecular Imaging ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Aortic Aneurysms ◽  
Laboratory Research ◽  
Emission Computed Tomography ◽  
Chemical Application ◽  
Abdominal Aortic

Current laboratory research in the field of abdominal aortic aneurysm (AAA) disease often utilizes small animal experimental models induced by genetic manipulation or chemical application. This has led to the use and development of multiple high-resolution molecular imaging modalities capable of tracking disease progression, quantifying the role of inflammation, and evaluating the effects of potential therapeutics.In vivoimaging reduces the number of research animals used, provides molecular and cellular information, and allows for longitudinal studies, a necessity when tracking vessel expansion in a single animal. This review outlines developments of both established and emerging molecular imaging techniques used to study AAA disease. Beyond the typical modalities used for anatomical imaging, which include ultrasound (US) and computed tomography (CT), previous molecular imaging efforts have used magnetic resonance (MR), near-infrared fluorescence (NIRF), bioluminescence, single-photon emission computed tomography (SPECT), and positron emission tomography (PET). Mouse and rat AAA models will hopefully provide insight into potential disease mechanisms, and the development of advanced molecular imaging techniques, if clinically useful, may have translational potential. These efforts could help improve the management of aneurysms and better evaluate the therapeutic potential of new treatments for human AAA disease.

Recent Advances in Targeting Nuclear Molecular Imaging Driven by Tetrazine Bioorthogonal Chemistry

2020 ◽  
Vol 27 (23) ◽  
pp. 3924-3943 ◽  
Author(s):  
Ping Dong ◽  
Xueyi Wang ◽  
Junwei Zheng ◽  
Xiaoyang Zhang ◽  
Yiwen Li ◽  
...  
Keyword(s):  
Molecular Imaging ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Bioorthogonal Chemistry ◽  
Cellular Processes ◽  
Positron Emission ◽  
Diagnosis Of Cancer

Molecular imaging techniques apply sophisticated technologies to monitor, directly or indirectly, the spatiotemporal distribution of molecular or cellular processes for biomedical, diagnostic, or therapeutic purposes. For example, Single-Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) imaging, the most representative modalities of molecular imaging, enable earlier and more accurate diagnosis of cancer and cardiovascular diseases. New possibilities for noninvasive molecular imaging in vivo have emerged with advances in bioorthogonal chemistry. For example, tetrazine-related Inverse Electron Demand Diels-Alder (IEDDA) reactions can rapidly generate short-lived radioisotope probes in vivo that provide strong contrast for SPECT and PET. Here, we review pretargeting strategies for molecular imaging and novel radiotracers synthesized via tetrazine bioorthogonal chemistry. We systematically describe advances in direct radiolabeling and pretargeting approaches in SPECT and PET using metal and nonmetal radioisotopes based on tetrazine bioorthogonal reactions, and we discuss prospects for the future of such contrast agents.

scholarly journals Toward Molecular Imaging of Intestinal Pathology

2020 ◽  
Vol 26 (10) ◽  
pp. 1470-1484 ◽  
Author(s):  
Mariane Le Fur ◽  
Iris Y Zhou ◽  
Onofrio Catalano ◽  
Peter Caravan
Keyword(s):  
Computed Tomography ◽  
Molecular Imaging ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Major Complication ◽  
Emission Computed Tomography ◽  
Cross Sectional ◽  
Intestinal Fibrosis ◽  
Positron Emission

Abstract Inflammatory bowel disease (IBD) is defined by a chronic relapsing and remitting inflammation of the gastrointestinal tract, with intestinal fibrosis being a major complication. The etiology of IBD remains unknown, but it is thought to arise from a dysregulated and excessive immune response to gut luminal microbes triggered by genetic and environmental factors. To date, IBD has no cure, and treatments are currently directed at relieving symptoms and treating inflammation. The current diagnostic of IBD relies on endoscopy, which is invasive and does not provide information on the presence of extraluminal complications and molecular aspect of the disease. Cross-sectional imaging modalities such as computed tomography enterography (CTE), magnetic resonance enterography (MRE), positron emission tomography (PET), single photon emission computed tomography (SPECT), and hybrid modalities have demonstrated high accuracy for the diagnosis of IBD and can provide both functional and morphological information when combined with the use of molecular imaging probes. This review presents the state-of-the-art imaging techniques and molecular imaging approaches in the field of IBD and points out future directions that could help improve our understanding of IBD pathological processes, along with the development of efficient treatments.

scholarly journals Standardization of the [68Ga]Ga-PSMA-11 Radiolabeling Protocol in an Automatic Synthesis Module: Assessments for PET Imaging of Prostate Cancer

2021 ◽  
Vol 14 (5) ◽  
pp. 385
Author(s):  
Leonardo L. Fuscaldi ◽  
Danielle V. Sobral ◽  
Ana Claudia R. Durante ◽  
Fernanda F. Mendonça ◽  
Ana Cláudia C. Miranda ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Pet Imaging ◽  
Saline Solution ◽  
Serum Proteins ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Lncap Cells ◽  
Automatic Synthesis

Prostate-specific membrane antigen (PSMA) is a glycoprotein present in the prostate, that is overexpressed in prostate cancer (PCa). Recently, PSMA-directed radiopharmaceuticals have been developed, allowing the pinpointing of tumors with the Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) imaging techniques. The aim of the present work was to standardize and validate an automatic synthesis module-based radiolabeling protocol for [68Ga]Ga-PSMA-11, as well as to produce a radiopharmaceutical for PET imaging of PCa malignancies. [68Ga]Ga-PSMA-11 was evaluated to determine the radiochemical purity (RCP), stability in saline solution and serum, lipophilicity, affinity to serum proteins, binding and internalization to lymph node carcinoma of the prostate (LNCaP) cells, and ex vivo biodistribution in mice. The radiopharmaceutical was produced with an RCP of 99.06 ± 0.10%, which was assessed with reversed-phase high-performance liquid chromatography (RP-HPLC). The product was stable in saline solution for up to 4 h (RCP > 98%) and in serum for up to 1 h (RCP > 95%). The lipophilicity was determined as −3.80 ± 0.15, while the serum protein binding (SPB) was <17%. The percentages of binding to LNCaP cells were 4.07 ± 0.51% (30 min) and 4.56 ± 0.46% (60 min), while 19.22 ± 2.73% (30 min) and 16.85 ± 1.34% (60 min) of bound material was internalized. High accumulation of [68Ga]Ga-PSMA-11 was observed in the kidneys, spleen, and tumor, with a tumor-to-contralateral-muscle ratio of >8.5 and a tumor-to-blood ratio of >3.5. In conclusion, an automatic synthesis module-based radiolabeling protocol for [68Ga]Ga-PSMA-11 was standardized and the product was evaluated, thus verifying its characteristics for PET imaging of PCa tumors in a clinical environment.

Nuclear cardiology: state of the art

Heart ◽  
2021 ◽  
pp. heartjnl-2019-315628
Author(s):  
Rebecca Schofield ◽  
Leon Menezes ◽  
Stephen Richard Underwood
Keyword(s):  
Heart Failure ◽  
Myocardial Perfusion ◽  
Radionuclide Imaging ◽  
Single Photon ◽  
Imaging Techniques ◽  
Sympathetic Innervation ◽  
Photon Emission ◽  
Myocardial Inflammation ◽  
Emission Computed Tomography ◽  
Device Infection

Radionuclide imaging remains an essential component of modern cardiology. There is overlap with the information from other imaging techniques, but no technique is static and new developments have expanded its role. This review focuses on ischaemic heart disease, heart failure, infection and inflammation. Radiopharmaceutical development includes the wider availability of positron emission tomography (PET) tracers such as rubidium-82, which allows myocardial perfusion to be quantified in absolute terms. Compared with alternative techniques, myocardial perfusion scintigraphy PET and single photon emission computed tomography (SPECT) have the advantages of being widely applicable using exercise or pharmacological stress, full coverage of the myocardium and a measure of ischaemic burden, which helps to triage patients between medical therapy and revascularisation. Disadvantages include the availability of expertise in some cardiac centres and the lack of simple SPECT quantification, meaning that global abnormalities can be underestimated. In patients with heart failure, despite the findings of the STICH (Surgical Treatment for Ischemic Heart Failure) trial, there are still data to support the assessment of myocardial hibernation in predicting when abolition of ischaemia might lead to improvement in ventricular function. Imaging of sympathetic innervation is well validated, but simpler markers of prognosis mean that it has not been widely adopted. There are insufficient data to support its use in predicting the need for implanted devices, but non-randomised studies are promising. Other areas where radionuclide imaging is uniquely valuable are detection and monitoring of endocarditis, device infection, myocardial inflammation in sarcoidosis, myocarditis and so on, and reliable detection of deposition in suspected transthyretin-related amyloidosis.

scholarly journals Introduction to Infrared and Raman-Based Biomedical Molecular Imaging and Comparison with Other Modalities

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5547
Author(s):  
Carlos F. G. C. Geraldes
Keyword(s):  
Computed Tomography ◽  
Molecular Imaging ◽  
Single Photon ◽  
Ex Vivo ◽  
Photon Emission ◽  
Raman Imaging ◽  
Emission Computed Tomography ◽  
Label Free ◽  
Advantages And Disadvantages

Molecular imaging has rapidly developed to answer the need of image contrast in medical diagnostic imaging to go beyond morphological information to include functional differences in imaged tissues at the cellular and molecular levels. Vibrational (infrared (IR) and Raman) imaging has rapidly emerged among the molecular imaging modalities available, due to its label-free combination of high spatial resolution with chemical specificity. This article presents the physical basis of vibrational spectroscopy and imaging, followed by illustration of their preclinical in vitro applications in body fluids and cells, ex vivo tissues and in vivo small animals and ending with a brief discussion of their clinical translation. After comparing the advantages and disadvantages of IR/Raman imaging with the other main modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography/single-photon emission-computed tomography (PET/SPECT), ultrasound (US) and photoacoustic imaging (PAI), the design of multimodal probes combining vibrational imaging with other modalities is discussed, illustrated by some preclinical proof-of-concept examples.

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