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Background: Radio-guided surgery is a reliable approach used for localizing ground-glass opacities, lung nodules, and metastatic lymph nodes. Lung nodules, lymph node metastatic involvement, and ground-glass opacities often represent a challenge for surgical management and clinical work-up., Methods: PubMed research was conducted from January 1997 to June 2023 using the keywords "radioguided surgery and lung cancer"., Results: Different studies were conducted with different tracers: technetium-99m-albumin macroaggregates, cyanoacrylate combined to technetium-99m-sulfur colloid, indium-111-pentetreotide, and fluorine-18-deoxyglucose. A study proposed naphthalocyanine radio-labeled with copper-64. Radio-guided surgery has been demonstrated to be a reliable approach in localizing a lesion, and has a low radiological burden for personnel exposure and low morbidity. The lack of necessity to conduct radio-guided surgery under fluoroscopy or echography makes this radio-guided surgery an easy way of performing precise surgical procedures., Conclusions: Radio-guided surgery is a feasible approach useful for the intraoperative localization of ground-glass opacities, lung nodules, and metastatic lymph nodes. It is a valid alternative to the existing approaches due to its low cost, associated low morbidity, the possibility to perform the procedure after several hours, the low radiation dose applied, and the small amount of time that is required to perform it.

The aim of this systematic review is to provide a comprehensive overview of the existing literature, comparing 18 F-fluorodeoxyglucose (FDG) and 11 C-methionine (MET) for the imaging of multiple myeloma (MM) with positron emission computed tomography (PET/CT). Relevant studies published from 2013 up to March 2023 were selected by searching Scopus, PubMed, and Web of Science. Selected imaging studies were analyzed using a modified version of the critical Appraisal Skills Programme (CASP). Ten studies encompassing 335 patients were selected. On a patient-based analysis, MET sensitivity ranged between 75.6% and 100%, resulting higher than that measured for FDG (0-100%). MET outperformed FDG for the detection of focal lesions, diffuse bone marrow involvement and mixed patterns. PET-derived parameters resulted higher for MET than for FDG, with a strong correlation with clinical variables (e.g., monoclonal component and beta-2-microglobulin levels, bone marrow infiltration, etc.), although FDG maintained a prognostic impact on outcome prediction. When compared to other tracers or imaging modalities, MET showed stronger correlation and inter-observer agreement than FDG. Although biased by the small cohorts and requiring confirmation through multicenter studies, preliminary findings suggest that MET-PET should be preferred to FDG for PET imaging of MM, or alternatively used as a complementary imaging modality. Some issues, such as tracer availability and the role of MET with respect to other emerging tracers (i.e., 68 Ga-pentixafor, 18 F-FACBC and 18 F-FET), should be the topic of further investigations.

Our aim was to provide a comprehensive overview of the existing literature concerning the clinical applications of positron emission computed tomography (PET) with radiopharmaceuticals targeting the translocator protein (TSPO) in gliomas. A literature search for studies about TSPO PET in the last 10 years (from 2013 to February 2023) was carried out on PubMed, Scopus, and Web of Science using the following keywords: "PET" AND "Gliomas" AND "TSPO". The Critical Appraisal Skills Program checklist for diagnostic test studies was used for testing the quality of selected papers. Ten articles were selected, encompassing 314 glioma patients submitted to PET/CT (9/10) or PET/MRI (1/10) with TSPO ligands. Among the various available TSPO tracers, the most frequently used was the third-generation ligand, [ 18 F]-GE-180. TSPO PET results were useful to identify anaplastic transformation in gliomas and for the prognostic stratification of patients bearing homogeneous genetic alterations. When compared to amino-acid PET, TSPO PET with [ 18 F]-GE-180 presented superior image quality and provided larger and only partially overlapping PET-based volumes. Although biased by some issues (i.e., small sample size, most of the studies coming from the same country), preliminary applications of TSPO PET were encouraging. Further studies are needed to define implications in clinical practice and shape the role of TSPO PET for patients' selection for potential TSPO-targeted molecular therapies.

(1) Background: Tauopathies are a group of diseases characterized by the deposition of abnormal tau protein. They are distinguished into 3R, 4R, and 3R/4R tauopathies and also include Alzheimer's disease (AD) and chronic traumatic encephalopathy (CTE). Positron emission tomography (PET) imaging represents a pivotal instrument to guide clinicians. This systematic review aims to summarize the current and novel PET tracers. (2) Methods: Literature research was conducted on Pubmed, Scopus, Medline, Central, and the Web of Science using the query "pet ligands" and "tauopathies". Articles published from January 2018 to 9 February, 2023, were searched. Only studies on the development of novel PET radiotracers for imaging in tauopathies or comparative studies between existing PET tracers were included. (3) Results: A total of 126 articles were found, as follows: 96 were identified from PubMed, 27 from Scopus, one on Central, two on Medline, and zero on the Web of Science. Twenty-four duplicated works were excluded, and 63 articles did not satisfy the inclusion criteria. The remaining 40 articles were included for quality assessment. (4) Conclusions: PET imaging represents a valid instrument capable of helping clinicians in diagnosis, but it is not always perfect in differential diagnosis, even if further investigations on humans for novel promising ligands are needed.

Parkinson's disease is the second most common neurodegenerative disorder, affecting 2-3% of the population of patients >65 years. Although the standard diagnosis of PD is clinical, neuroimaging plays a key role in the evaluation of patients who present symptoms related to neurodegenerative disorders. MRI, DAT-SPECT, and PET with [ 18 F]-FDG are routinely used in the diagnosis and focus on the investigation of morphological changes, nigrostriatal degeneration or shifts in glucose metabolism in patients with parkinsonian syndromes. The aim of this study is to review the current PET radiotracers targeting TSPO, a transmembrane protein that is overexpressed by microglia in another pathophysiological process associated with neurodegenerative disorders known as neuroinflammation. To the best of our knowledge, neuroinflammation is present not only in PD but in many other neurodegenerative disorders, including AD, DLB, and MSA, as well as atypical parkinsonian syndromes. Therefore, in this study, specific patterns of microglial activation in PD and the differences in distribution volumes of these radiotracers in patients with PD as compared to other neurodegenerative disorders are reviewed.

The most frequent thyroid cancer is Differentiated Thyroid Cancer (DTC) representing more than 95% of cases. A suitable choice for the treatment of DTC is the systemic administration of 131-sodium or potassium iodide. It is an effective tool used for the irradiation of thyroid remnants, microscopic DTC, other nonresectable or incompletely resectable DTC, or all the cited purposes. Dosimetry represents a valid tool that permits a tailored therapy to be obtained, sparing healthy tissue and so minimizing potential damages to at-risk organs. Absorbed dose represents a reliable indicator of biological response due to its correlation to tissue irradiation effects. The present paper aims to focus attention on iodine therapy for DTC treatment and has developed due to the urgent need for standardization in procedures, since no unique approaches are available. This review aims to summarize new proposals for a dosimetry-based therapy and so explore new alternatives that could provide the possibility to achieve more tailored therapies, minimizing the possible side effects of radioiodine therapy for Differentiated Thyroid Cancer.

Background: our aim was to assess the diagnostic performance and clinical impact of 18 F-FDG PET/CT in patients with differentiated thyroid carcinoma (DTC), previously treated with surgery and radioiodine therapy (RAI)., Methods: patients subjected to 18 F-FDG PET/CT for suspected DTC recurrence in three Italian nuclear medicine units were evaluated. Two different clinical settings were identified: clinical setting 1 included patients (n = 40) that were enrolled according to the American Thyroid Association guidelines (i.e., negative 131 1-WBS and Tg level > 10 ng/mL); and clinical setting 2, that encompassed subjects (n = 26) with serum Tg ≤ 10 ng/mL but morphological findings suspected of relapse. PET/CT's impact was scored as significant if it provided an indication for surgery, or led to a novel therapeutic decision., Results: In total, 51/66 patients (77.3%) were 18 F-FDG positive, while 15 (22.7%) were negative. PET/CT showed an overall sensitivity and specificity of 84.4% and 75%, respectively. Sensitivity was higher in clinical setting 1 (89.1%) as compared to clinical setting 2 (76.1%), although this difference was not statistically significant ( p = 0.83). PET/CT influenced clinical management in 28 cases (42.4%), without a significant difference between the 2 groups of patients ( p = 0.6)., Conclusions: our preliminary data, although limited by the retrospective nature of the study and possible selection bias, suggest that 18 F-FDG PET/CT may be utilized for the detection of DTC recurrence in different clinical settings, with a meaningful impact on clinical management.

We investigated the diagnostic performance of Somatostatin Receptor Positron Emission Tomography/Computed Tomography (SSR-PET/CT) for the detection of primary lesion and initial staging of pancreatic neuroendocrine tumors (pNETs). A comprehensive literature search up to January 2020 was performed selecting studies in presence of: sample size ≥10 patients; index test (i.e., 68Ga-DOTATOC or 68Ga-DOTANOC or 68Ga-DOTATATE PET/CT); and outcomes (i.e., detection rate (DR), true positive, true negative, false positive, and false-negative). The methodological quality was evaluated with QUADAS-2. Pooled DR and pooled sensitivity and specificity for the identification of the primary tumor were assessed by a patient-based and a lesion-based analysis. Thirty-eight studies were selected for the qualitative analysis, while 18 papers were included in the meta-analysis. The number of pNET patients ranged from 10 to 142, for a total of 1143 subjects. At patient-based analysis, the pooled sensitivity and specificity for the assessment of primary pNET were 79.6% (95% confidence interval (95%CI): 71-87%) and 95% (95%CI: 75-100%) with a heterogeneity of 59.6% and 51.5%, respectively. Pooled DR for the primary lesion was 81% (95%CI: 65-90%) and 92% (95%CI: 80-97%), respectively, at patient-based and lesion-based analysis. In conclusion, SSR-PET/CT has high DR and diagnostic performances for primary lesion and initial staging of pNETs.