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Molecular Imaging and Biology Feb 2022In oncology, biomarker research aimed to provide insights on cancer biology via positron emission tomography (PET) and single photon emission tomography (SPECT) imaging... (Review)
Review
In oncology, biomarker research aimed to provide insights on cancer biology via positron emission tomography (PET) and single photon emission tomography (SPECT) imaging has seen an incredible growth in the past two decades. Despite the increased number of publications on PET/SPECT radiopharmaceuticals, the field lacked standardization of in vitro and in vivo parameters necessary for the characterization of any radiotracer. Through the efforts of the World Molecular Imaging Society Education Committee, this white paper lays down validation studies that are essential to chemically and biologically characterize new radiopharmaceuticals derived from small molecules, peptides or proteins. Finally, a brief overview of the steps toward translation is also presented.Herein, we discuss the following: Chemistry and radiochemistry metrics to establish the identity of the imaging agent. In vitro and in vivo studies to examine the radiotracer's mechanism of action, which includes target specificity, pharmacokinetics and in vivo metabolism.
Topics: Medical Oncology; Positron-Emission Tomography; Radiochemistry; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon
PubMed: 34542804
DOI: 10.1007/s11307-021-01645-6 -
Molecules (Basel, Switzerland) Oct 2022Molecular imaging is the visual representation of biological processes that take place at the cellular or molecular level in living organisms. To date, molecular imaging... (Review)
Review
Molecular imaging is the visual representation of biological processes that take place at the cellular or molecular level in living organisms. To date, molecular imaging plays an important role in the transition from conventional medical practice to precision medicine. Among all imaging modalities, positron emission tomography (PET) has great advantages in sensitivity and the ability to obtain absolute imaging quantification after corrections for photon attenuation and scattering. Due to the ability to label a host of unique molecules of biological interest, including endogenous, naturally occurring substrates and drug-like compounds, the role of PET has been well established in the field of molecular imaging. In this article, we provide an overview of the recent advances in the development of PET radiopharmaceuticals and their clinical applications in oncology.
Topics: Radiopharmaceuticals; Positron-Emission Tomography; Molecular Imaging
PubMed: 36296381
DOI: 10.3390/molecules27206790 -
The British Journal of Radiology Sep 2020Atherosclerosis is a systemic inflammatory disease typified by the development of lipid-rich atheroma (plaques), the rupture of which are a major cause of myocardial... (Review)
Review
Atherosclerosis is a systemic inflammatory disease typified by the development of lipid-rich atheroma (plaques), the rupture of which are a major cause of myocardial infarction and stroke. Anatomical evaluation of the plaque considering only the degree of luminal stenosis overlooks features associated with vulnerable plaques, such as high-risk morphological features or pathophysiology, and hence risks missing vulnerable or ruptured non-stenotic plaques. Consequently, there has been interest in identifying these markers of vulnerability using either MRI for morphology, or positron emission tomography (PET) for physiological processes involved in atherogenesis. The advent of hybrid PET/MRI scanners offers the potential to combine the strengths of PET and MRI to allow comprehensive assessment of the atherosclerotic plaque. This review will discuss the principles and technical aspects of hybrid PET/MRI assessment of atherosclerosis, and consider how combining the complementary modalities of PET and MRI has already furthered our understanding of atherogenesis, advanced drug development, and how it may hold potential for clinical application.
Topics: Atherosclerosis; Carotid Stenosis; Forecasting; Humans; Magnetic Resonance Imaging; Multimodal Imaging; Plaque, Atherosclerotic; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Vascular Calcification
PubMed: 32238077
DOI: 10.1259/bjr.20190921 -
Journal of Nuclear Cardiology :... Jun 2022
Topics: Heart; Heart Transplantation; Humans; Positron-Emission Tomography; Tomography, X-Ray Computed
PubMed: 33527331
DOI: 10.1007/s12350-020-02514-5 -
Clinical Gastroenterology and... Nov 2021Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease characterized by lobular inflammation and hepatocyte injury and is a key...
Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease characterized by lobular inflammation and hepatocyte injury and is a key determinant of clinical outcome. Liver biopsy remains the gold standard for diagnosis but is limited by risks of the procedure and interobserver variability. Although magnetic resonance imaging (MRI)-based technology may provide novel means to identify NASH, there remains a significant need for other modalities to diagnose NASH noninvasively. Glucose transport, an integral tissue process altered in NASH, is measurable with F-fluorodeoxyglucose positron emission tomography (FDG PET). Because unenhanced computed tomography (CT) scan can detect hepatic steatosis quite reliably, and PET combines unenhanced CT for attenuation correction, we hypothesized that measurement of the combination of glucose transport by PET and steatosis by CT could yield a reliable radiologic correlate of NASH.
Topics: Humans; Liver; Magnetic Resonance Imaging; Non-alcoholic Fatty Liver Disease; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Tomography, X-Ray Computed
PubMed: 33075553
DOI: 10.1016/j.cgh.2020.10.029 -
Seminars in Nuclear Medicine Nov 2021The role of hybrid imaging with 2-[18F] flourodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) is continuously evolving and now... (Review)
Review
The role of hybrid imaging with 2-[18F] flourodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) is continuously evolving and now considered standard practice in evaluation of disease stage, treatment response, recurrent disease and follow-up for numerous primary malignancies. In gynecological malignancies FDG PET/CT plays an important role, not only in the assessment of disease in the pre-and post-therapy setting, but also in radiation therapy (RT) planning by defining the metabolically active gross tumor volume (GTV. The glucose analogue radiotracer, FDG, is by far the most utilized radiotracer in PET/CT and is typically seen with high uptake in malignant cells. The radiotracer FDG has a high sensitivity but low specificity for malignancy, as benign processes with an inflammatory response for example infection, are also FDG-avid. In the evaluation of the female pelvic region an awareness of potential confounding factors in the interpretation of FDG is essential as variations of FDG uptake occur in accordance with the menstrual cycle and the menopausal state. Incidental imaging findings in the female genital can pose differential diagnostic challenges as false-positive and false-negative findings in benign and malignant processes are not uncommon. Gynecological malignancies continue to pose major public health problems with cervical cancer as the fourth most common cancer in women ranking after breast cancer, colorectal cancer and lung cancer. Familiarity with frequently encountered benign and malignant variants and pitfalls in FDG PET/CT in the female pelvic region can aid the reader in differential diagnostic considerations.
Topics: Female; Fluorodeoxyglucose F18; Humans; Lung Neoplasms; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography
PubMed: 34253332
DOI: 10.1053/j.semnuclmed.2021.06.006 -
Seminars in Nuclear Medicine Jul 2022Diuretic scintigraphy includes single-photon emitting radiotracers for planar and single photon emission computed tomography (SPECT) imaging as well as agents for... (Review)
Review
Diuretic scintigraphy includes single-photon emitting radiotracers for planar and single photon emission computed tomography (SPECT) imaging as well as agents for positron emission tomography (PET). These radiotracers provide split-renal functional parameters, including glomerular filtration rate, effective renal plasma flow, tubular function, and/or renal blood flow. Beyond measuring kidney function, the tracer principle also allows for the assessment of various pathophysiological processes in the renal parenchyma, for example ongoing inflammation, activation of angiotensin II type 1 receptor in patients with renovascular hypertension, deterioration of mitochondrial complex I following acute or chronic kidney injury, or characterization of indeterminate renal masses. Providing a whole-body read-out, PET also enables the assessment of kidney-organ interactions, for example cardiorenal crosstalk after primary cardiac injury. This manuscript provides an overview of established clinical applications for single-photon-emitting and PET radiotracers for renal radionuclide imaging. Future perspectives in the field will also be highlighted, such as introduction of PET-guided strategies for drug dose optimization and the recent introduction of radiotracers targeting fibroblast activation protein inhibition, which may allow differentiation between acute inflammatory vs chronic fibrosis in the kidneys.
Topics: Humans; Kidney; Positron-Emission Tomography; Radionuclide Imaging; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon
PubMed: 35058040
DOI: 10.1053/j.semnuclmed.2021.12.003 -
Chinese Clinical Oncology Apr 2024Positron emission tomography (PET) imaging has been useful in delineating tumor volumes and allowing for improved radiation treatment. The field of PET-guided... (Review)
Review
BACKGROUND AND OBJECTIVE
Positron emission tomography (PET) imaging has been useful in delineating tumor volumes and allowing for improved radiation treatment. The field of PET-guided radiotherapy is rapidly growing and will have significant impact on radiotherapy delivery in the future. This narrative review provides an overview of the current state of PET-guided radiotherapy as well as the future directions of the field.
METHODS
For this narrative review, PubMed was searched for articles from 2010-2023. A total of 18 keywords or phrases were searched to provide an overview of PET-guided radiotherapy, radiotracers, the role of PET-guided radiotherapy in oligometastatic disease, and biology-guided radiotherapy (BgRT). The first 300 results for each keyword were searched and relevant articles were extracted. The references of these articles were also reviewed for relevant articles.
KEY CONTENT AND FINDINGS
In radiotherapy, 18F-2-fluoro-2-deoxy-D-glucose (F-FDG or FDG) is the major radiotracer for PET and when combined with computed tomography (CT) scan allows for anatomic visualization of metabolically active malignancy. Novel radiotracers are being explored to delineate certain cell types and numerous tumor metrics including metabolism, hypoxia, vascularity, and cellular proliferation. This molecular and functional imaging will provide improved tumor characterization. Through these radiotracers, radiation plans can employ dose painting by creating different dose levels based upon specific risk factors of the target volume. Additionally, biologic imaging during radiotherapy can allow for adaptation of the radiation plan based on response to treatment. Dose painting and adaptive radiotherapy should improve the therapeutic ratio through more selective dose delivery. The novel PET-linear accelerator hopes to combine these techniques and more by using radiotracers to deliver BgRT. The areas of radiotracer uptake will serve as fiducials to guide radiotherapy to themselves. This technique may prove promising in the growing area of oligometastatic radiation treatment.
CONCLUSIONS
Significant challenges exist for the future of PET-guided radiotherapy. However, with the advancements being made, PET imaging is set to change the delivery of radiotherapy.
Topics: Humans; Positron-Emission Tomography; Radiotherapy, Image-Guided; Neoplasms
PubMed: 38711177
DOI: 10.21037/cco-23-143 -
International Journal of Molecular... Jun 2023Various papers have introduced the use of positron emission tomography (PET) with [Ga]Ga-radiolabeled fibroblast-activation protein inhibitor (FAPi) radiopharmaceuticals... (Meta-Analysis)
Meta-Analysis Review
Various papers have introduced the use of positron emission tomography (PET) with [Ga]Ga-radiolabeled fibroblast-activation protein inhibitor (FAPi) radiopharmaceuticals in different subtypes of gastric cancer (GC). Our aim was to assess the diagnostic performance of this novel molecular imaging technique in GC with a systematic review and meta-analysis. A straightforward literature search of papers concerning the diagnostic performance of FAP-targeted PET imaging was performed. Original articles evaluating this novel molecular imaging examination in both newly diagnosed GC patients and GC patients with disease relapse were included. The systematic review included nine original studies, and eight of them were also eligible for meta-analysis. The quantitative synthesis provided pooled detection rates of 95% and 97% for the assessment of primary tumor and distant metastases, respectively, and a pooled sensitivity and specificity of 74% and 89%, respectively, for regional lymph node metastases. Significant statistical heterogeneity among the included studies was found only in the analysis of the primary tumor detection rate (I = 64%). Conclusions: Beyond the limitations of this systematic review and meta-analysis (i.e., all the included studies were conducted in Asia, and using [F]FDG PET/CT as a comparator of the index test), the quantitative data provided demonstrate the promising diagnostic performance of FAP-targeted PET imaging in GC. Nevertheless, more prospective multicentric studies are needed to confirm the excellent performances of FAP-targeted PET in this cluster of patients.
Topics: Humans; Positron Emission Tomography Computed Tomography; Stomach Neoplasms; Prospective Studies; Neoplasm Recurrence, Local; Positron-Emission Tomography; Radiopharmaceuticals; Fluorodeoxyglucose F18; Gallium Radioisotopes
PubMed: 37373285
DOI: 10.3390/ijms241210136 -
American Journal of Rhinology & Allergy Sep 2023Positron emission tomography (PET) scan is a valuable imaging modality widely used in the management of cancers. Its usage is well defined for most head and neck... (Review)
Review
BACKGROUND
Positron emission tomography (PET) scan is a valuable imaging modality widely used in the management of cancers. Its usage is well defined for most head and neck malignancies. However, there is a lack of consensus regarding the utility of PET scan for sinonasal malignancies. This is highlighted by the latest international consensus statement on endoscopic skull base surgery.
OBJECTIVE
This systematic review aims to clarify the role of PET scan in the management of sinonasal malignancies.
METHODS
We conducted a comprehensive literature search using PubMed, MEDLINE, EMBASE, Web of Science, CINAHL, and Cochrane databases for research studies of interest. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) updated statement was used to guide the review.
RESULTS
In total, 1807 articles were assessed for eligibility. Thirty-nine original papers, published between 2004 and 2021, met inclusion criteria. Seven articles focused on the role of PET scan for inverted papilloma, 23 for sinonasal carcinoma, 4 for melanoma, and 3 for lymphoma, and finally, 3 articles focused on the use of specific PET scan tracers for sinonasal malignancies. Qualitative summaries for each potential role of PET scans were provided. In general, included studies were retrospective in nature with low level of evidence.
CONCLUSIONS
In general, and across all types of sinonasal malignancies, PET scan yielded positive results regarding detection and initial staging. It was also considered as the modality of choice for detection of distant metastases, except in the case of sinonasal lymphoma. PET scan's main limit resides in its inability to detect lesions in or close to the metabolic activity of the brain.
Topics: Humans; Positron Emission Tomography Computed Tomography; Retrospective Studies; Positron-Emission Tomography; Paranasal Sinus Neoplasms; Lymphoma
PubMed: 37229633
DOI: 10.1177/19458924231177854