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1.
Metastatic Seeding Attacks Bone Marrow, Not Bone: Rectifying Ongoing Misconceptions.
Raynor, WY, Al-Zaghal, A, Zadeh, MZ, Seraj, SM, Alavi, A
PET clinics. 2019;(1):135-144
Abstract
Conventional modalities, such as bone scintigraphy, are commonly used to assess osseous abnormalities in skeletal metastasis. Fluorine-18 (18F)-sodium fluoride (NaF) PET similarly portrays osteoblastic activity but with improved spatial and contrast resolution and more accurate anatomic localization. However, these modalities rely on indirect evidence for tumor activity. PET imaging with 18F-fluorodeoxyglucose (FDG) and tumor-specific tracers may have an increased role by directly portraying the metabolic activity of cancer cells, which are often seeded in bone marrow and cause osseous disease after initial latency. This article describes the utility and limitations of these modalities in assessing skeletal metastases.
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2.
124I Positron Emission Tomography/Computed Tomography Versus Conventional Radioiodine Imaging in Differentiated Thyroid Cancer: A Review.
Wu, D, Ylli, D, Heimlich, SL, Burman, KD, Wartofsky, L, Van Nostrand, D
Thyroid : official journal of the American Thyroid Association. 2019;(11):1523-1535
Abstract
Background: Studies report a wide spectrum of 124I positron emission tomography (PET)/computed tomography (CT) sensitivity and specificity in the detection of differentiated thyroid cancer (DTC) lesions. This study reviews the lesion detection rate of pretherapy 124I PET/CT in different patient populations and further analyzes the factors necessary for a better detection on 124I PET/CT. Methods: A literature search was performed using multiple different databases (MEDLINE, EMBASE, Northern Lights, and handsearching) covering 1996 to April 2018. Two reviewers reviewed and extracted study data for 124I, 123I, and 131I scans in DTC. Results: This review includes 4 retrospective and 10 prospective studies in which 495 DTC patients underwent 124I and 131I imaging; no studies made comparisons with 123I. In the reports that compared 124I PET/CT with diagnostic 131I scans, there were a total of 72 patients in whom 120 lesions were detected on 124I imaging, whereas only 52 were detected on diagnostic 131I scans. In publications that compared 124I with post-therapy 131I scans in 266 patients, 410 lesions were detected with 124I PET, whereas 390 were detected on post-therapy 131I scans. Based on 124I PET/CT in six studies, TNM staging was revised in 15-21% of patients, and disease management was altered in 5-29% of patients. Conclusions:124I PET/CT is able to identify a greater number of foci compared with diagnostic 131I scans. 124I PET may have better detection compared with post-therapy 131I scans in patients who are 131I therapy naive, have less aggressive pathology, or do not have disseminated lung metastases. Additional metastatic lesion detection by 124I PET may have a significant clinical impact in the management of patients before 131I therapy in some patients.
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3.
The clinical significance of incidental soft tissue uptake on whole body 18F-sodium fluoride bone PET-CT.
Usmani, S, Gnanasegaran, G, Marafi, F, Esmail, A, Ahmed, N, Van den Wyngaert, T
Clinical radiology. 2019;(2):95-110
Abstract
18F-sodium fluoride (NaF) is a PET bone imaging agent and is commonly used in imaging patients with cancer; however, similar to technetium-99m medronic acid (99mTc-MDP), it can be useful in the evaluation of benign bone and joint conditions. NaF is an excellent bone-seeking agent with high bone uptake due to rapid single-pass extraction. It has negligible plasma protein binding, rapid blood, renal clearance, high bone uptake and almost all NaF delivered is retained by bone after a single pass of blood; however, uptake of NaF can be observed in non-osseous structures such as the arterial vasculature, gastrointestinal tract, genitourinary tract, and viscera. In this article, we present a spectrum of clinical cases with non-osseous NaF uptake in patients referred for cancer staging.
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4.
Positron emission tomography with computed tomography imaging (PET/CT) for the radiotherapy planning definition of the biological target volume: PART 1.
Alongi, P, Laudicella, R, Desideri, I, Chiaravalloti, A, Borghetti, P, Quartuccio, N, Fiore, M, Evangelista, L, Marino, L, Caobelli, F, et al
Critical reviews in oncology/hematology. 2019;:74-79
Abstract
AIM: Functional and molecular imaging, including positron emission tomography with computed tomography imaging (PET/CT) is increasing for radiotherapy (RT) definition of the target volume. This expert review summarizes existing data of functional imaging modalities and RT management, in terms of target volume delineation, for the following anatomical districts: brain (for primary and secondary tumors), head/neck and lung. MATERIALS AND METHODS A collection of available published data was made, by PubMed a search. Only original articles were carefully and critically revised. RESULTS For primary and secondary brain tumors, amino acid PET radiotracers could be useful to identify microscopic residual areas and to differ between recurrence and treatment-related alterations in case of re-irradiation. As for head and neck neoplasms may benefit from precise PET/CT-based target delineation, due to the major capability to identify high-risk RT areas. In primary and secondary lung cancer, PET/CT could be useful both to delimit a tumor and collapsed lungs and as a predictive parameter of treatment response. CONCLUSION Taken together, molecular and functional imaging approaches offer a major step to individualize radiotherapeutic care going forward. Nevertheless, several uncertainties remain on the standard method to properly assess the target volume definition including PET information for primary and secondary brain tumors.
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5.
The role of 124I PET/CT lesion dosimetry in differentiated thyroid cancer.
Weber, M, Binse, I, Nagarajah, J, Bockisch, A, Herrmann, K, Jentzen, W
The quarterly journal of nuclear medicine and molecular imaging : official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of.... 2019;(3):235-252
Abstract
Radioiodine therapy of thyroid cancer was the first successful radionuclide therapy in the treatments of cancer, although its clinical use is empirical and not based on precise dosimetry. 124I is a positron-emitting radionuclide and positron emission tomography/computed tomography (PET/CT) with 124I currently provides the most accurate estimation of the absorbed (radiation) dose to thyroid cancer lesions. In the application, serial 124I PET/CT scans are performed to determine the time uptake curves and to delineate the volumes of the lesions. The 124I data are then used to project the absorbed dose per unit administered 131I activity. The results are part of the decision-making process to individually guide treatment plans, in particular by tailoring the therapeutic 131I activity in radioiodine therapy. The aim of this review is to provide an overview of 124I PET/CT lesion dosimetry of differentiated thyroid cancer including: 1) an historical overview; 2) the general properties of 124I and its activity measurement; 3) the main factors impairing PET image quantification; 4) an optimized lesion dosimetry protocol used in our group to make this manuscript self-contained; as well as 5) a summary of important clinical studies.
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6.
Pediatric Musculoskeletal Imaging: The Indications for and Applications of PET/Computed Tomography.
Khalatbari, H, Parisi, MT, Kwatra, N, Harrison, DJ, Shulkin, BL
PET clinics. 2019;(1):145-174
Abstract
The use of PET/computed tomography (CT) for the evaluation and management of children, adolescents, and young adults continues to expand. The principal tracer used is 18F-fluorodeoxyglucose and the principal indication is oncology, particularly musculoskeletal neoplasms. The purpose of this article is to review the common applications of PET/CT for imaging of musculoskeletal issues in pediatrics and to introduce the use of PET/CT for nononcologic issues, such as infectious/inflammatory disorders, and review the use of 18F-sodium fluoride in trauma and sports-related injuries.
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7.
Evolving Roles of Fluorodeoxyglucose and Sodium Fluoride in Assessment of Multiple Myeloma Patients: Introducing a Novel Method of PET Quantification to Overcome Shortcomings of the Existing Approaches.
Zadeh, MZ, Raynor, WY, Seraj, SM, Ayubcha, C, Kothekar, E, Werner, T, Alavi, A
PET clinics. 2019;(3):341-352
Abstract
PET with fluorodeoxyglucose and sodium fluoride (NaF) radiotracers has shown a great promise in assessing patients with multiple myeloma (MM). However, the standardization of PET/computed tomography scans interpretation in patients with myeloma in clinical practice is still debatable. This article reviews available data regarding the use of fluorodeoxyglucose and NaF PET in patients with MM. Introduced is a novel method of PET quantification as applied to patients with MM. A new concept for PET-based evaluation of patients with MM is also discussed: dual time point imaging. Finally, the role of NaF in assessment of cardiovascular complications of MM is described.
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8.
Imaging of Merkel Cell Carcinoma: What Imaging Experts Should Know.
Akaike, G, Akaike, T, Fadl, SA, Lachance, K, Nghiem, P, Behnia, F
Radiographics : a review publication of the Radiological Society of North America, Inc. 2019;(7):2069-2084
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Abstract
Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine tumor with a higher mortality rate than melanoma. Approximately 40% of MCC patients have nodal or distant metastasis at initial presentation, and one-third of patients will develop distant metastatic disease over their clinical course. Although MCC is rare, its incidence has been steadily increasing. Furthermore, the immunogenicity of MCC and its diagnostic and therapeutic application have made MCC one of the most rapidly developing topics in dermatology and oncology. Owing to the aggressive and complex nature of MCC, a multidisciplinary approach is necessary for management of this tumor, including dermatologists, surgeons, radiation oncologists, medical oncologists, pathologists, radiologists, and nuclear medicine physicians. Imaging plays a crucial role in diagnosis, planning for surgery or radiation therapy, and assessment of treatment response and surveillance. However, MCC is still not well recognized among radiologists and nuclear medicine physicians, likely owing to its rarity. The purpose of this review is to raise awareness of MCC among imaging experts by describing the epidemiology, pathophysiology, and clinical features of MCC and current clinical management with a focus on the role of imaging. The authors highlight imaging findings characteristic of MCC, as well as the clinical significance of CT, MRI, sentinel lymph node mapping, fluorine 18 fluorodeoxyglucose PET/CT, and other nuclear medicine studies such as bone scintigraphy and somatostatin receptor scintigraphy. ©RSNA, 2019.
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Accuracy of 18F-FDOPA Positron Emission Tomography and 18F-FET Positron Emission Tomography for Differentiating Radiation Necrosis from Brain Tumor Recurrence.
Yu, J, Zheng, J, Xu, W, Weng, J, Gao, L, Tao, L, Liang, F, Zhang, J
World neurosurgery. 2018;:e1211-e1224
Abstract
BACKGROUND Distinguishing radiation necrosis from brain tumor recurrence remains challenging. We performed a meta-analysis to assess the diagnostic accuracy of 2 different amino acid tracers used in positron emission tomography/computed tomography scans: 18F-FDOPA (6-[18F]-fluoro-L-3,4-dihydroxyphenylalanine) and 18F-FET (O-(2-18F-fluoroethyl)-L-tyrosine). METHODS We searched for studies in 3 databases: PubMed, Embase, and Chinese Biomedical databases. The data were extracted from eligible studies and then processed with heterogeneity test, threshold effect test, and calculations of sensitivity, specificity, and area under the summary receiver operating characteristic curve. Meta-regression and subgroup analyses were performed to explore the source of heterogeneity. RESULTS A total of 48 studies (18F-FDOPA, n = 21; 18F-FET, n = 27) were included. Quantitative synthesis determined pooled weight values in the 18F-FDOPA and 18F-FET groups: sensitivity, 0.85 versus 0.82; specificity, 0.77 versus 0.80; diagnostic odds ratio, 21.7 versus 23.03; area under the curve (AUC) values, 0.8771 versus 0.8976 (P = 0.46). Moreover, the type of tumor was identified as the possible source of the significant heterogeneity (I2 = 52%; P = 0.003) found in the 18F-FDOPA group. In meta-regression and subgroup analyses, 18F-FDOPA showed better diagnostic accuracy in patients with glioma compared with patients with brain metastases (AUC values, 0.9691 vs. 0.837; P < 0.01). 18F-FDOPA also showed a significant advantage in the diagnosis of glioma recurrence compared with 18F-FET (AUC values, 0.9691 vs. 0.9124; P = 0.015). CONCLUSIONS Both 18F-FDOPA and 18F-FET exhibit moderate overall accuracy in diagnosing brain tumor recurrence from radiation necrosis. However, 18F-FDOPA is more adept at diagnosing glioma recurrence compared with brain metastases, and it is more effective than 18F-FET in diagnosing glioma recurrence.
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10.
PET/CT in the Diagnosis and Workup of Sarcoidosis: Focus on Atypical Manifestations.
Akaike, G, Itani, M, Shah, H, Ahuja, J, Yilmaz Gunes, B, Assaker, R, Behnia, F
Radiographics : a review publication of the Radiological Society of North America, Inc. 2018;(5):1536-1549
Abstract
Sarcoidosis is a multisystem disease characterized by the formation of noncaseating granulomas. Lung and intrathoracic lymph nodes are classic sites of involvement; however, sarcoidosis can affect any site in the body. The clinical course is extremely variable, and the imaging features are diverse and dependent on the affected site, degree of inflammation, and treatment the patient receives. Atypical manifestations and imaging findings can make diagnosis and/or management challenging. In addition, assessment of treatment response can be difficult in the setting of chronic disease. Fluorine 18 fluorodeoxyglucose (FDG) PET/CT is sensitive for assessment of the inflammatory activity of sarcoidosis in any organ. Although FDG PET/CT is not included in the standard workup for sarcoidosis, there has been growing evidence that supports the value of this examination in guiding diagnosis and management. FDG PET/CT may be especially useful for assessing reversible granuloma, treatment response, disease extent, occult disease, and cardiac or osseous sarcoidosis, and determining the most suitable biopsy site. Capability to image the entire body during a single examination is advantageous in cases of systemic disease such as sarcoidosis. The authors review the use of FDG PET/CT, providing up-to-date evidence and describing various cases of sarcoidosis in which FDG PET/CT has an important role in diagnosis and/or management. They also discuss the usefulness of FDG PET/CT in cases of selective manifestations of sarcoidosis. ©RSNA, 2018.