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Molecules (Basel, Switzerland) May 2021Radiotracers are widely used in medical imaging, using techniques of gamma-camera imaging (scintigraphy and SPECT) or positron emission tomography (PET). In bone marrow... (Review)
Review
INTRODUCTION
Radiotracers are widely used in medical imaging, using techniques of gamma-camera imaging (scintigraphy and SPECT) or positron emission tomography (PET). In bone marrow infection, there is no single routine test available that can detect infection with sufficiently high diagnostic accuracy. Here, we review radiotracers used for imaging of bone marrow infection, also known as osteomyelitis, with a focus on why these molecules are relevant for the task, based on their physiological uptake mechanisms. The review comprises [Ga]Ga-citrate, radiolabelled leukocytes, radiolabelled nanocolloids (bone marrow) and radiolabelled phosphonates (bone structure), and [F]FDG as established radiotracers for bone marrow infection imaging. Tracers that are under development or testing for this purpose include [Ga]Ga-citrate, [F]FDG, [F]FDS and other non-glucose sugar analogues, [O]water, [C]methionine, [C]donepezil, [Tc]Tc-IL-8, [Ga]Ga-Siglec-9, phage-display selected peptides, and the antimicrobial peptide [Tc]Tc-UBI or [Ga]Ga-NOTA-UBI.
CONCLUSION
Molecular radiotracers allow studies of physiological processes such as infection. None of the reviewed molecules are ideal for the imaging of infections, whether bone marrow or otherwise, but each can give information about a separate aspect such as physiology or biochemistry. Knowledge of uptake mechanisms, pitfalls, and challenges is useful in both the use and development of medically relevant radioactive tracers.
Topics: Bone Marrow; Humans; Positron-Emission Tomography; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon
PubMed: 34070537
DOI: 10.3390/molecules26113159 -
Seminars in Nuclear Medicine May 2021Amyloid-β (Aβ) PET imaging has now been available for over 15 years. The ability to detect Aβ in vivo has greatly improved the clinical and research landscape of... (Review)
Review
Amyloid-β (Aβ) PET imaging has now been available for over 15 years. The ability to detect Aβ in vivo has greatly improved the clinical and research landscape of Alzheimer's disease (AD) and other neurodegenerative conditions. Aβ imaging provides very reliable, accurate, and reproducible measurements of regional and global Aβ burden in the brain. It has proved invaluable in anti-Aβ therapy trials, and is now recognized as a powerful diagnostic tool. The appropriate use of Aβ PET, when combined with comprehensive clinical evaluation by a dementia-trained specialist, can improve the accuracy of a clinical diagnosis of AD and substantially alter management. It can assist in differentiating AD from other neurodegenerative conditions, often by its ability to rule out the presence of Aβ. When combined with tau imaging, further increase in specificity for the diagnosis of AD can be achieved. The integration of Aβ PET, in conjunction with biomarkers of tau, neurodegeneration and neuroinflammation, into large, longitudinal, observational cohort studies continues to increase our understanding of the development of AD. Its incorporation into clinical trials has been pivotal in defining the most effective anti-Aβ biological therapies and optimal dosing so that effective disease modifying therapy now appears imminent. Aβ deposition is a gradual and protracted process, permitting a wide treatment window for anti-Aβ therapies and Aβ PET has made trials in this preclinical AD period feasible. Continuing improvement in Aβ tracer target to background ratio is allowing trials in earlier AD that tailor drug dosage to Aβ level. The quest to standardize quantification and define universally applicable thresholds for all Aβ tracers has produced the Centiloid method. Centiloid values that correlate well with neuropathologic findings and prognosis have been identified. Rapid cloud-based automated individual scan analysis is now possible and does not require MRI. Challenges remain, particularly around cross camera standardized uptake value ratio variation that need to be addressed. This review will compare available Aβ radiotracers, discuss approaches to quantification, as well as the clinical and research applications of Aβ PET.
Topics: Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Brain; Humans; Positron-Emission Tomography; tau Proteins
PubMed: 33482999
DOI: 10.1053/j.semnuclmed.2020.12.005 -
Nuclear Medicine and Molecular Imaging Oct 2021Since the foundation of the Korean Society of Nuclear Medicine in 1961, clinical nuclear oncology has been a major part of clinical nuclear medicine in Korea. There are... (Review)
Review
Since the foundation of the Korean Society of Nuclear Medicine in 1961, clinical nuclear oncology has been a major part of clinical nuclear medicine in Korea. There are several important events for the development of clinical nuclear oncology in Korea. First, a scintillating type gamma camera was adopted in 1969, which enabled to perform modern oncological gamma imaging. Second, Tc-99 m generator was imported to Korea since 1979, which promoted the wide clinical use of gamma camera imaging by using various kinds of Tc-99 m labeled radiopharmaceuticals. Third, a gamma camera with single photon emission tomography (SPECT) capability was first installed in 1980, which has been used for various kinds of tumor SPECT imaging. Fourth, in 1994, clinical positron emission tomography (PET) scanner and cyclotron with a production of F-18 fluorodeoxyglucose were first installed in Korea. Fifth, Korean Board of Nuclear Medicine was established in 1995, which contributed in the education and manpower training of dedicated nuclear medicine physicians in Korea. Finally, an integrated PET/CT scanner was first installed in 2002. Since that, PET/CT imaging has been a major imaging tool in clinical nuclear oncology in Korea. In this review, a brief history of clinical nuclear oncology in Korea is described.
PubMed: 34721714
DOI: 10.1007/s13139-021-00711-9 -
Seminars in Nuclear Medicine Jul 2018Cerenkov luminescence (CL) is blue glow light produced by charged subatomic particles travelling faster than the phase velocity of light in a dielectric medium such as... (Review)
Review
Cerenkov luminescence (CL) is blue glow light produced by charged subatomic particles travelling faster than the phase velocity of light in a dielectric medium such as water or tissue. CL was first discovered in 1934, but for biomedical research it was recognized only in 2009 after advances in optical camera sensors brought the required high sensitivity. Recently, applications of CL from clinical radionuclides have been rapidly expanding to include not only preclinical and clinical biomedical imaging but also an approach to therapy. Cerenkov Luminescence Imaging (CLI) utilizes CL generated from clinically relevant radionuclides alongside optical imaging instrumentation. CLI is advantageous over traditional nuclear imaging methods in terms of infrastructure cost, resolution, and imaging time. Furthermore, CLI is a truly multimodal imaging method where the same agent can be detected by two independent modalities, with optical (CL) imaging and with positron emission tomography (PET) imaging. CL has been combined with small molecules, biomolecules and nanoparticles to improve diagnosis and therapy in cancer research. Here, we cover the fundamental breakthroughs and recent advances in reagents and instrumentation methods for CLI as well as therapeutic application of CL.
Topics: Animals; Humans; Inventions; Nuclear Medicine; Optical Imaging
PubMed: 29852945
DOI: 10.1053/j.semnuclmed.2018.02.007 -
Saudi Pharmaceutical Journal : SPJ :... Feb 2023The paper begins by identifying the key historical elements in the development of nuclear medicine imaging, focusing on the Anger camera and single photon emission... (Review)
Review
The paper begins by identifying the key historical elements in the development of nuclear medicine imaging, focusing on the Anger camera and single photon emission computed tomography (SPECT) technologies. In this context, key reference is made to the physics of detection in Anger camera systems, especially key components such as the sodium iodide crystal, the function and performance of photomultiplier tubes, and the collimator design. It is discovered that within each component of technology, there are fundamental physical relationships that govern the performance of each component, and that overall image quality is the result of the complex interaction of all such elements. The increasing use of SPECT/CT imaging is described and illustrated with a range of typical clinical applications, which include brain, spinal, cardiac, and cancer studies. The use of CT imaging functionality allows for SPECT image correction based on compensation for absorption within tissue. Reference is also made to the basics of positron emission tomography (PET) imaging and, in particular, to the integration of PET/CT systems where the anatomy profile of the CT image is used to provide correction for photon absorption. A summary is provided of the radionuclides and radiopharmaceuticals commonly used in PET/CT imaging and a range of image studies referenced includes those of nasopharyngeal carcinoma, lung cancer investigation, brain investigation (cancer detection and dementia) and cardiac function. Reference is made to the development of "time of flight" (TOF) technology for improving of image resolution in PET/CT systems. Furthermore, SPECT/CT and PET/CT imaging systems are compared, where a key factor identified is the significantly higher number of photons detected with PET/CT technology and improved image resolution.
PubMed: 36942267
DOI: 10.1016/j.jsps.2022.12.013 -
Nuclear Instruments & Methods in... Oct 2019Wide-field time-correlated single photon counting detection techniques, where the position and the arrival time of the photons are recorded simultaneously using a... (Review)
Review
Wide-field time-correlated single photon counting detection techniques, where the position and the arrival time of the photons are recorded simultaneously using a camera, have made some advances recently. The technology and instrumentation used for this approach is employed in areas such as nuclear science, mass spectroscopy and positron emission tomography, but here, we discuss some of the wide-field TCSPC methods, for applications in fluorescence microscopy. We describe work by us and others as presented in the Ulitima fast imaging and tracking conference at the Argonne National Laboratory in September 2018, from phosphorescence lifetime imaging (PLIM) microscopy on the microsecond time scale to FLIM) on the nanosecond time scale, and highlight some applications of these techniques.
PubMed: 31645797
DOI: 10.1016/j.nima.2019.162365 -
Seminars in Nuclear Medicine Sep 2022Breast cancer survival is significantly improved over the past decades due to major improvements in anti-tumor therapies and the implementation of regular screening,... (Review)
Review
Breast cancer survival is significantly improved over the past decades due to major improvements in anti-tumor therapies and the implementation of regular screening, which leads to early detection of breast cancer. Therefore, it is of utmost importance to prevent patients from long-term side effects, including radiotherapy-induced cardiotoxicity. Radiotherapy may contribute to damage of myocardial structures on the cellular level, which eventually could result in various types of cardiovascular problems, including coronary artery disease and (non-)ischemic cardiomyopathy, leading to heart failure. These cardiac complications of radiotherapy are preceded by alterations in myocardial perfusion and blood flow. Therefore, early detection of these alterations is important to prevent the progression of these pathophysiological processes. Several radionuclide imaging techniques may contribute to the early detection of these changes. Single-Photon Emission Computed Tomography (SPECT) cameras can be used to create Multigated Acquisition scans in order to assess the left ventricular systolic and diastolic function. Furthermore, SPECT cameras are used for myocardial perfusion imaging with radiopharmaceuticals such as Tc-sestamibi and Tc-tetrofosmin. Accurate quantitative measurement of myocardial blood flow (MBF), can be performed by Positron Emission Tomography (PET), as the uptake of some of the tracers used for PET-based MBF measurement almost creates a linear relationship with MBF, resulting in very accurate blood flow quantification. Furthermore, there are PET and SPECT tracers that can assess inflammation and denervation of the cardiac sympathetic nervous system. Research over the past decades has mainly focused on the long-term development of left ventricular impairment and perfusion defects. Considering laterality of the breast cancer, some early studies have shown that women irradiated for left-sided breast cancer are more prone to cardiotoxic side effects than women irradiated for right-sided breast cancer. The left-sided radiation field in these trials, which predominantly used older radiotherapy techniques without heart-sparing techniques, included a larger volume of the heart and left ventricle, leading to increased unavoidable radiation exposure to the heart due to the close proximity of the radiation treatment volume. Although radiotherapy for breast cancer exposes the heart to incidental radiation, several improvements and technical developments over the last decades resulted in continuous reduction of radiation dose and volume exposure to the heart. In addition, radiotherapy reduces loco-regional tumor recurrences and death from breast cancer and improves survival. Therefore, in the majority of patients, the benefits of radiotherapy outweigh the potential very low risk of cardiovascular adverse events after radiotherapy. This review addresses existing nuclear imaging techniques, which can be used to evaluate (long-term) effects of radiotherapy-induced mechanical cardiac dysfunction and discusses the potential use of more novel nuclear imaging techniques, which are promising in the assessment of early signs of cardiac dysfunction in selected irradiated breast cancer patients.
Topics: Breast Neoplasms; Cardiotoxicity; Female; Heart Diseases; Humans; Neoplasm Recurrence, Local; Nuclear Medicine; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon
PubMed: 35246310
DOI: 10.1053/j.semnuclmed.2022.02.001 -
British Medical Bulletin Sep 2018Radionuclides for leucocyte kinetic studies have progressed from non-gamma emitting cell-labelling radionuclides through gamma emitting nuclides that allow imaging of... (Review)
Review
INTRODUCTION
Radionuclides for leucocyte kinetic studies have progressed from non-gamma emitting cell-labelling radionuclides through gamma emitting nuclides that allow imaging of leucocyte kinetics, to the next goal of positron emission tomography (PET).
SOURCES OF DATA
Mostly the authors' own studies, following on from studies of the early pioneers.
AREAS OF CONTROVERSY
From early imaging studies, it appeared that the majority of the marginated granulocyte pool was located in the lungs. However, later work disputed this by demonstrating the exquisite sensitivity of granulocytes to ex vivo isolation and labelling, and that excessive lung activity is artefactual.
AREAS OF AGREEMENT
Following refinement of labelling techniques, it was shown that the majority of marginated granulocytes are located in the spleen and bone marrow. The majority of leucocytes have a pulmonary vascular transit time only a few seconds longer than erythrocytes. The minority showing slow transit, ~5% in healthy persons, is increased in systemic inflammatory disorders that cause neutrophil priming and loss of deformability. Using a range of imaging techniques, including gamma camera imaging, whole-body counting and single photon-emission computerized tomography, labelled granulocytes were subsequently used to image pulmonary trafficking in lobar pneumonia, bronchiectasis, chronic obstructive pulmonary disease and adult respiratory distress syndrome.
GROWING POINTS
More recently, eosinophils have been separated in pure form using magnetic bead technology for the study of eosinophil trafficking in asthma.
AREAS TIMELY FOR DEVELOPING RESEARCH
These include advancement of eosinophil imaging, development of monocyte labelling, development of cell labelling with PET tracers and the tracking of lymphocytes.
Topics: Granulocytes; Humans; Isotope Labeling; Leukocytes; Lung Diseases; Positron-Emission Tomography; Radioisotopes
PubMed: 30052802
DOI: 10.1093/bmb/ldy022 -
Cancer Control : Journal of the Moffitt... Jul 2013Imaging of prostate carcinoma is an important adjunct to clinical evaluation and prostate specific antigen measurement for detecting metastases and tumor recurrence. In... (Review)
Review
BACKGROUND
Imaging of prostate carcinoma is an important adjunct to clinical evaluation and prostate specific antigen measurement for detecting metastases and tumor recurrence. In the past, the ability to assess intraprostatic tumor was limited.
METHODS
Pertinent literature was reviewed to describe the capabilities and limitations of the currently available imaging techniques for assessing prostate carcinoma. Evaluation of primary tumor and metastatic disease by ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine techniques is discussed.
RESULTS
Ultrasonography and MRI have limited usefulness for local staging of prostate cancer because of suboptimal sensitivity and specificity for identifying tumor extent and capsular penetration. Additional MRI techniques such as magnetic resonance-based perfusion imaging, diffusion imaging, and spectroscopy may provide incremental benefit. CT and bone scanning provide an assessment of metastatic disease but are also limited by the poor sensitivity of lymph node size as a criterion for detecting metastases. Novel imaging techniques such as hybrid imaging devices in the form of single-photon emission CT/CT gamma cameras, positron emission tomography/CT cameras, and, in the near future, positron emission tomography/MRI combined with tumor specific imaging radiotracers may have a significant impact on tumor staging and treatment response.
CONCLUSIONS
Cross-sectional imaging and scintigraphy have an important role in assessing prostate carcinoma metastases and treatment response. Increasingly, the incremental value of primary tumor imaging through MRI is being realized.
Topics: Animals; Diagnostic Imaging; Humans; Male; Prostatic Neoplasms
PubMed: 23811700
DOI: 10.1177/107327481302000304