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Applied Radiation and Isotopes :... Aug 2014Until recently, iodine-124 was not considered to be an attractive isotope for medical applications owing to its complex radioactive decay scheme, which includes several... (Review)
Review
Until recently, iodine-124 was not considered to be an attractive isotope for medical applications owing to its complex radioactive decay scheme, which includes several high-energy gamma rays. However, its unique chemical properties, and convenient half-life of 4.2 days indicated it would be only a matter of time for its frequent application to become a reality. The development of new medical imaging techniques, especially improvements in the technology of positron emission tomography (PET), such as the development of new detectors and signal processing electronics, has opened up new prospects for its application. With the increasing use of PET in medical oncology, pharmacokinetics, and drug metabolism, (124)I-labeled radiopharmaceuticals are now becoming one of the most useful tools for PET imaging, and owing to the convenient half-life of I-124, they can be used in PET scanners far away from the radionuclide production site. Thus far, the limited availability of this radionuclide has been an impediment to its wider application in clinical use. For example, sodium [(124)I]-iodide is potentially useful for diagnosis and dosimetry in thyroid disease and [(124)I]-M-iodobenzylguanidine ([(124)I]-MIBG) has enormous potential for use in cardiovascular imaging, diagnosis, and dosimetry of malignant diseases such as neuroblastoma, paraganglioma, pheochromocytoma, and carcinoids. However, despite that potential, both are still not widely used. This is a typical scenario of a rising new star among the new PET tracers.
Topics: Animals; Humans; Image Enhancement; Iodine Radioisotopes; Isotope Labeling; Positron-Emission Tomography; Radiopharmaceuticals
PubMed: 24747530
DOI: 10.1016/j.apradiso.2014.03.026 -
Journal of the American College of... Feb 2020
Topics: Amyloid; Amyloidosis; Biomarkers; Humans; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography
PubMed: 32000950
DOI: 10.1016/j.jacc.2019.11.038 -
Current Cardiology Reports Dec 2022The purpose of this review is to provide an overview of the role of PET MPI in the detection of CAD, focussing on the added value of MBF for diagnosis and... (Review)
Review
PURPOSE OF REVIEW
The purpose of this review is to provide an overview of the role of PET MPI in the detection of CAD, focussing on the added value of MBF for diagnosis and prognostication.
RECENT FINDINGS
Positron emission tomography (PET) myocardial perfusion imaging (MPI) is increasingly used for the risk stratification of patients with suspected or established coronary artery disease (CAD). PET MPI provides accurate and reproducible non-invasive quantification of myocardial blood flow (MBF) at rest and during hyperemia, providing incremental information over conventional myocardial perfusion alone. Inclusion of MBF in PET MPI interpretation improves both its sensitivity and specificity. Moreover, quantitative MBF measurements have repeatedly been shown to offer incremental and independent prognostic information over conventional clinical markers in a broad range of conditions, including in CAD. Quantitative MBF measurement is now an established and powerful tool enabling accurate risk stratification and guiding patients' management. The role of PET MPI and flow quantification in cardiac allograft vasculopathy (CAV), which represents a particular form of CAD, will also be reviewed.
Topics: Humans; Coronary Artery Disease; Myocardial Perfusion Imaging; Positron Emission Tomography Computed Tomography; Coronary Angiography; Positron-Emission Tomography; Fractional Flow Reserve, Myocardial; Coronary Circulation; Prognosis
PubMed: 36348147
DOI: 10.1007/s11886-022-01805-2 -
Journal of Clinical Pharmacology Jul 2016Several membrane transporters belonging to the adenosine triphosphate-binding cassette (ABC) and solute carrier (SLC) families can transport drugs and drug metabolites... (Review)
Review
Several membrane transporters belonging to the adenosine triphosphate-binding cassette (ABC) and solute carrier (SLC) families can transport drugs and drug metabolites and thereby exert an effect on drug absorption, distribution, and excretion, which may potentially lead to transporter-mediated drug-drug interactions (DDIs). Some transporter-mediated DDIs may lead to changes in organ distribution of drugs (eg, brain, liver, kidneys) without affecting plasma concentrations. Positron emission tomography (PET) is a noninvasive imaging method that allows studying of the distribution of radiolabeled drugs to different organs and tissues and is therefore the method of choice to quantitatively assess transporter-mediated DDIs on a tissue level. There are 2 approaches to how PET can be used in transporter-mediated DDI studies. When the drug of interest is a potential perpetrator of DDIs, it may be administered in unlabeled form to assess its influence on tissue distribution of a generic transporter-specific PET tracer (probe substrate). When the drug of interest is a potential victim of DDIs, it may be radiolabeled with carbon-11 or fluorine-18 and used in combination with a prototypical transporter inhibitor (eg, rifampicin). PET has already been used both in preclinical species and in humans to assess the effects of transporter-mediated DDIs on drug disposition in different organ systems, such as brain, liver, and kidneys, for which examples are given in the present review article. Given the growing importance of membrane transporters with respect to drug safety and efficacy, PET is expected to play an increasingly important role in future drug development.
Topics: Animals; Brain; Drug Discovery; Drug Evaluation, Preclinical; Drug Interactions; Humans; Membrane Transport Proteins; Pharmaceutical Preparations; Positron-Emission Tomography
PubMed: 27385172
DOI: 10.1002/jcph.722 -
Methods in Molecular Biology (Clifton,... 2019Positron emission tomography (PET) enables the noninvasive spatiotemporal analysis of cancer metabolism in vivo. Both natural and nonnatural PET tracers have been...
Positron emission tomography (PET) enables the noninvasive spatiotemporal analysis of cancer metabolism in vivo. Both natural and nonnatural PET tracers have been developed to assess metabolic pathways during tumorigenesis, cancer progression, and metastasis. Here we describe the dynamic in vivo PET/CT imaging of the glucose analogue [F]fluoro-2-deoxy-D-glucose (FDG), taking into consideration the methodology for alternative metabolic PET substrates.
Topics: Animals; Biomarkers; Carbon Radioisotopes; Disease Models, Animal; Energy Metabolism; Fluorodeoxyglucose F18; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Metabolic Networks and Pathways; Mice; Neoplasms; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Radiopharmaceuticals
PubMed: 30725448
DOI: 10.1007/978-1-4939-9027-6_2 -
Methods in Molecular Biology (Clifton,... 2022A Zr-oxine ex vivo cell labeling method for tracking various cells by positron emission tomography (PET) imaging has recently been developed. Zr-oxine is synthesized...
A Zr-oxine ex vivo cell labeling method for tracking various cells by positron emission tomography (PET) imaging has recently been developed. Zr-oxine is synthesized from oxine and Zr-chloride, which was converted from Zr-oxalate, with neutralization. To track migration of natural killer (NK) cells in vivo in real time by PET imaging, NK cells are labeled with Zr-oxine ex vivo and infused to a recipient. The labeling is performed by mixing Zr-oxine solution to NK cell suspension at room temperature, followed by washing. Care should be taken to label the cells at optimal radioactivity doses that maintain their viability and functionality. Zr-oxine labeled NK cells can be tracked for their migration and distribution by PET/computed tomography imaging for at least 7 days. Of note, this protocol is applicable to other types of cells.
Topics: Killer Cells, Natural; Oxyquinoline; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Zirconium
PubMed: 35344173
DOI: 10.1007/978-1-0716-2160-8_11 -
Seminars in Nuclear Medicine May 2015Whole-body PET/MR hybrid imaging combines excellent soft tissue contrast and various functional imaging parameters provided by MR with high sensitivity and... (Review)
Review
Whole-body PET/MR hybrid imaging combines excellent soft tissue contrast and various functional imaging parameters provided by MR with high sensitivity and quantification of radiotracer uptake provided by PET. Although clinical evaluation now is under way, PET/MR demands for new technologies and innovative solutions, currently subject to interdisciplinary research. Attenuation correction (AC) of human soft tissues and of hardware components has to be MR based to maintain quantification of PET imaging as CT attenuation information is missing. MR-based AC is inherently associated with the following challenges: patient tissues are segmented into only few tissue classes, providing discrete attenuation coefficients; bone is substituted as soft tissue in MR-based AC; the limited field of view in MRI leads to truncations in body imaging and, consequently, in MR-based AC; and correct segmentation of lung tissue may be hampered by breathing artifacts. Use of time of flight during PET image acquisition and reconstruction, however, may improve the accuracy of AC. This article provides a status of current image acquisition options in PET/MR hybrid imaging.
Topics: Artifacts; Equipment Design; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Positron-Emission Tomography
PubMed: 25841274
DOI: 10.1053/j.semnuclmed.2014.12.001 -
The Quarterly Journal of Nuclear... Mar 2022Compared to positron emission tomography/computed tomography (PET/CT), the uptake of PET- magnetic resonance imaging (MRI) has been slow, even more so in clinical...
Compared to positron emission tomography/computed tomography (PET/CT), the uptake of PET- magnetic resonance imaging (MRI) has been slow, even more so in clinical practice compared to the (pre-)clinical research setting. However, for applications in musculoskeletal (MSK) research, the combination of PET and MRI into a single modality offers attractive advantages over other imaging modalities. Most importantly, MRI has exquisite soft-tissue detail without the use of contrast agents or ionizing radiation, superior bone marrow visualization, and an extensive spectrum of distinct multiparametric assessment methods. In the preclinical setting, the introduction of PET inserts for small-animal MRI machines has proven to be a successful concept in bringing this technology to the lab. Initial hurdles in quantification have been mainly overcome in this setting. In parallel, a promising range of radiochemistry techniques has been developed to create multimodality probes that offer the possibility of simultaneously querying different metabolic pathways. Not only will these applications help in elucidating disease mechanisms, but they can also facilitate drug development. The clinical applications of PET/MRI in MSK are still limited, but encouraging initial results with novel radiotracers suggest a high potential for use in various MSK conditions, including osteoarthritis, rheumatoid arthritis, ankylosing spondylitis and inflammation and infection. Further innovations will be required to bring down the cost of PET/MRI to justify a broader clinical implementation, and remaining issues with quality control and standardization also need to be addressed. Nevertheless, PET/MRI is a powerful platform for MSK research with distinct qualities that are not offered by other techniques.
Topics: Animals; Humans; Magnetic Resonance Imaging; Multimodal Imaging; Musculoskeletal Diseases; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography
PubMed: 35005878
DOI: 10.23736/S1824-4785.22.03434-3 -
Investigative Radiology Oct 2016Attenuation correction (AC) is an essential step in the positron emission tomography (PET) data reconstruction process to provide accurate and quantitative PET images.... (Review)
Review
Attenuation correction (AC) is an essential step in the positron emission tomography (PET) data reconstruction process to provide accurate and quantitative PET images. The introduction of PET/magnetic resonance (MR) hybrid systems has raised new challenges but also possibilities regarding PET AC. While in PET/computed tomography (CT) imaging, CT images can be converted to attenuation maps, MR images in PET/MR do not provide a direct relation to attenuation. For the AC of patient tissues, new methods have been suggested, for example, based on image segmentation, atlas registration, or ultrashort echo time MR sequences. Another challenge in PET/MR hybrid imaging is AC of hardware components that are placed in the PET/MR field of view, such as the patient table or various radiofrequency (RF) coils covering the body of the patient for MR signal detection. Hardware components can be categorized into 4 different groups: (1) patient table, (2) RF receiver coils, (3) radiation therapy equipment, and (4) PET and MR imaging phantoms. For rigid and stationary objects, such as the patient table and some RF coils like the head/neck coil, predefined CT-based attenuation maps stored on the system can be used for automatic AC. Flexible RF coils are not included into the AC process till now because they can vary in position as well as in shape and are not accurately detectable with the PET/MR system.This work summarizes challenges, established methods, new concepts, and the state of art in hardware component AC in the context of PET/MR hybrid imaging. The work also gives an overview of PET/MR hardware devices, their attenuation properties, and their effect on PET quantification.
Topics: Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Multimodal Imaging; Phantoms, Imaging; Positron-Emission Tomography
PubMed: 27175550
DOI: 10.1097/RLI.0000000000000289 -
Magnetic Resonance Imaging Clinics of... May 2017Combined PET/MR imaging scanners capable of acquiring simultaneously the complementary information provided by the 2 imaging modalities are now available for human use.... (Review)
Review
Combined PET/MR imaging scanners capable of acquiring simultaneously the complementary information provided by the 2 imaging modalities are now available for human use. After addressing the hardware challenges for integrating the 2 imaging modalities, most of the efforts in the field have focused on developing MR-based attenuation correction methods for neurologic and whole-body applications, implementing approaches for improving one modality by using the data provided by the other and exploring research and clinical applications that could benefit from the synergistic use of the multimodal data.
Topics: Humans; Magnetic Resonance Imaging; Multimodal Imaging; Positron-Emission Tomography
PubMed: 28390525
DOI: 10.1016/j.mric.2017.01.002