Search Results (1,203)

Background/Objectives: Precise staging and tumor delineation are essential for optimizing treatment and enhancing outcomes of radiotherapy (RT). While computed tomography (CT)-based RT remains standard, fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) offers improved detection of primary and nodal disease. This study investigates the role of PET/CT in RT planning of HNSCC. Methods: Fifty-one HNSCC patients underwent radical volumetric modulated arc RT with concurrent cisplatin chemotherapy in a prospective study. Two RT plans per patient were sequentially created by a single oncologist using CT-only and PET/CT data, respectively. Planning target volumes (PTVs) for primary and nodal regions were independently defined, and dose–volume histograms were analyzed and compared. Results: PET/CT significantly affected TNM staging, increasing the T-stage in 11.8% of patients and the N-stage in 33.3%. Distant metastases were found in 9.8% of patients, leading to a redefinition of the overall treatment policy. PET/CT-based planning improved primary tumor PTV coverage (PTV4) in 37.2% (19/51) of cases. The tumor areas excluded from the CT-based planning received an average of 85.6% of the prescribed PTV4 dose (range 18–93%), while in PET/CT planning, they received 95.4% (range 93–99%) (p < 0.0001). Nodal PTV areas requiring a booster dose (PTV2) were adjusted in 33.3% (17/51) of patients during PET-CT planning. These nodal areas received an average of 85.6% of the prescribed dose for PTV2 (range 18–93%) during CT planning, compared to 95.4% (range 93–99%) during PET/CT planning. There was no statistically significant difference in the dose received by organs at risk between CT- and PET/CT-RT planning. Conclusions: PET/CT improves target delineation for primary tumors and lymph nodes, also allowing for dose escalation in metabolically highly active lesions in patients with HNSCC. The method also reveals occult distant metastases in a subset of patients, enabling personalized treatment strategies. Full article

Background/Objectives: Epidemiological and clinical studies have linked both hypothyroidism and hyperthyroidism to adverse cardiac outcomes, including heart failure and myocardial fibrosis. Triiodothyronine (T3), a biologically active thyroid hormone, is important for cardiovascular homeostasis. While the effects of physiological and non-physiological T3 levels on cardiomyocytes have been extensively investigated, the impact of hypothyroidism and hyperthyroidism on cardiac stromal cells (CSCs), which constitute the majority of the cells in the heart, remains understudied. Given CSCs’ essential role in extracellular matrix (ECM) remodeling and paracrine signaling, understanding their response to altered T3 states is necessary to fully elucidate the thyroid hormone-induced cardiac responses. Methods: Cardiac stromal cells were isolated from human atrial appendages and cultured under hypothyroid (0 nM T3), euthyroid (2.5 nM T3), and hyperthyroid (25 nM T3) conditions for 24 (short term) and 120 h (long term). The cells were harvested after 24 h of treatment using trypsin and automatically counted, and their ECM-related gene and growth factor expression levels were assessed using quantitative RT-PCR. Cardiac glucose uptake in hypothyroid, euthyroid, and hyperthyroid mice was monitored using [18F]-FDG PET/CT at acute (7 days) and chronic (42 days) time points. Results: Both hypo- and hyperthyroidism significantly increased the number of CSCs harvested after 24 h. There were acute alterations in the expression of the ECM-related genes COL1A1, COL3A1, TIMP3 (p < 0.05), and TIMP1 (p < 0.01). Similarly, growth factors such as PDGF-A (p < 0.001), TGF-b, and IGF1 (p < 0.05) were transiently upregulated under non-physiological T3 conditions, especially hypothyroidism. Most of these alterations were attenuated or reversed at the 120 h time point. In vivo PET imaging revealed significant increases in cardiac glucose uptake under acute hypothyroidism (p < 0.05) and decreases under acute hyperthyroidism (p < 0.05). However, these metabolic shifts normalized with chronic exposure, paralleling the transient nature of the gene expression changes observed in vitro. Conclusions: Non-physiological T3 concentrations induce proliferation and changes in ECM-related and growth factor gene expression in CSCs. Most of these changes are acute and return to normal levels after chronic exposure. These transient cellular responses correlate closely with the cardiac metabolic response patterns to acute and chronic hypothyroidism and hyperthyroidism. Full article

Background/Objectives: Accurate risk stratification at diagnosis is crucial for the optimal management of diffuse large B-cell lymphoma (DLBCL). While Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) is the standard imaging modality for staging, the prognostic value of non-tumoral uptake patterns remains under investigation. Here, we aimed to investigate the prognostic significance of qualitative splenic [¹⁸F]FDG uptake on baseline PET/CT in patients with newly diagnosed DLBCL, focusing on relapse-free survival (RFS) and overall survival (OS). Methods: This retrospective study included consecutive patients with newly diagnosed DLBCL in a Korean cohort who underwent baseline [¹⁸F]FDG PET/CT between December 2016 and August 2023. Qualitative splenic uptake was visually assessed on maximum intensity projection images. Associations between splenic uptake, prognostic indices, and clinicopathologic characteristics were evaluated. Survival outcomes and independent prognostic factors were analyzed using Kaplan–Meier methods and Cox proportional hazards regression models. Results: A total of 142 patients were analyzed (43 relapsed, 58 died). Positive splenic [¹⁸F]FDG uptake was observed in 72 patients and was significantly more frequent in patients who relapsed (p < 0.001). Positive splenic uptake was significantly associated with inferior RFS (p < 0.001) and OS (p = 0.010). For RFS, advanced Ann Arbor stage, ECOG performance status, and extranodal involvement were also significant factors. In multivariable analysis, positive splenic uptake remained an independent predictor of poorer RFS (hazard ratio 2.175, p = 0.043), along with advanced stage (hazard ratio 2.872, p = 0.004). Conclusions: Qualitative splenic [¹⁸F]FDG uptake on baseline PET/CT is associated with adverse clinical outcomes in patients with DLBCL and serves as an independent prognostic factor for RFS. Full article

Objective: We present the first clinical experience with the BIOGRAPH One next-generation PET/MRI system scanner, evaluating its performance for body and brain imaging in patients across multiple tracers. Methods: A total of 59 patients were scanned on the BIOGRAPH One PET/MRI following standard clinical PET/CT (n = 52) or first-generation PET/MRI (Biograph mMR, n = 7). Scans comprised 30 total body (TB), whole body (WB), or regional scans with [¹⁸F]FDG, and 29 brain scans with either [¹⁸F]FDG (n = 5), [¹⁸F]FE-PE2I (n = 10), [¹⁸F]FET (n = 4), or [⁶⁸Ga]Ga-DOTATOC (n = 10). The PET image quality was visually assessed using a 5-point Likert scale (1 = very good to 5 = very bad) and compared with clinical scans acquired on either a current-generation digital PET/CT or a first-generation PET/MRI system, including evaluation of diagnostic concordance. PET quantification and image noise was compared in brain and WB/TB [¹⁸F]FDG PET scans. Results: PET image quality was rated as good or very good in 93% of scans with a median [inter-quartile range] score of 1.5 [1.5;2]. In 99% of cases, image quality was judged equal to or better than the clinical reference scan (median score 3 [2.5;3]). Diagnostic concordance was observed in 99% of readings. Imaging metrics revealed the anticipated regional bias in brain imaging, while no significant bias was observed in body imaging. Image noise was comparable to that observed with digital PET/CT and demonstrated superiority over first-generation PET/MRI despite potential degradation related to isotope decay in BIOGRAPH One PET/MRI acquisitions scans performed at the end of the imaging workflow. Conclusions: Within the study limitations related to sequential imaging, the BIOGRAPH One PET/MRI scanner demonstrated improved PET sensitivity and workflow potential over its first-generation predecessor, which may allow for broader clinical and research applications. Full article

Introduction: [¹⁸F]-DCFPyL (Piflufolastat [¹⁸F]) is a prostate-specific membrane antigen (PSMA)-targeted position emission tomography (PET) radiotracer for detecting the biochemical recurrence (BCR) of prostate cancer (PCa). This study evaluates its economic impact compared with [⁶⁸Ga]-PSMA-11, [¹⁸F]-FCH, and [¹⁸F]-PSMA-1007 from the Spanish National Healthcare System’s perspective. Methods: A cost–consequence model, over a 5-year time horizon, simulated the diagnostic and treatment pathway based on radiotracer-specific accuracy and disease localization. Treatment options included a radical prostatectomy, radiation therapy, androgen deprivation therapy (ADT), and radiation therapy + ADT. Costs were calculated for true/false positives and negatives. Due to limited data availability, key inputs were informed by expert opinions, supported by published meta-analyses, public sources, and literature. Officially published Spanish prices were applied: EUR 2000 for [¹⁸F]-DCFPyL, [⁶⁸Ga]-PSMA-11, and [¹⁸F]-PSMA-1007, and EUR 1144 for [¹⁸F]-FCH. Results: The use of [¹⁸F]-DCFPyL led to fewer unnecessary therapies; specifically, it led to 11,229 (74%) fewer than [⁶⁸Ga]-PSMA-11, and 5180 (56%) and 7771 (66%) fewer than [¹⁸F]-FCH and [¹⁸F]-PSMA-1007, respectively. It achieved significant cost savings for repeated testing: EUR 15M (43%) versus [⁶⁸Ga]-PSMA-11, EUR 37M (65%) versus [¹⁸F]-FCH, and EUR 27M (58%) versus [¹⁸F]-PSMA-1007. Cost savings for false positives were EUR 15M (50%) against [⁶⁸Ga]-PSMA-11, EUR 22M (60%) versus [¹⁸F]-FCH, and EUR 29M (66%) compared with [¹⁸F]-PSMA-1007. The cost per correct diagnosis was reduced by EUR 198 (8%) compared with [⁶⁸Ga]-PSMA-11 and EUR 377 (15%) relative to [¹⁸F]-PSMA-1007, while showing a EUR 635 (40%) increase compared with [¹⁸F]-FCH. Conclusions: [¹⁸F]-DCFPyL offers a cost-saving option for BCR detection within the Spanish National Healthcare System by reducing the number of unnecessary therapies, the cost of false positives, and repeat testing compared with alternative radiotracers. These improvements support the potential for better diagnostic outcomes and more informed downstream clinical decision-making. Full article

Objectives: Respiratory motion degrades the quantitative accuracy and test–retest (TRT) reliability of fluorine-18 fluorodeoxyglucose ([¹⁸F] FDG) positron emission tomography (PET)/computed tomography (CT) in lung cancer. This study investigated whether a deep-learning-based respiratory motion correction (RMC) method improves the TRT reliability and image quality of [¹⁸F] FDG PET tumor quantification compared with non-motion-corrected (NMC) reconstructions. Methods: Thirty-one patients with primary lung cancer underwent three PET acquisitions: whole body free breathing (Scan1), thoracic free breathing (Scan2), and thoracic controlled breathing (ScanCB). Each dataset was reconstructed with and without RMC. Visual assessments of liver motion artifacts, lesion clarity, and PET-CT co-registration were scored. Lung tumors were segmented to derive standardized uptake value max (SUVmax), SUVmean, metabolic tumor volume (MTV), PET-derived lesion length (PLL), and total lesion glycolysis (TLG). Visual image scores and TRT reliability of tumor quantification were compared using Kruskal–Wallis one-way analysis of variance and intraclass correlation coefficients (ICCs). Results: RMC reconstructions achieved higher visual scores of lesion clarity and PET-CT co-registration across all lung lobes and significantly reduced liver motion artifacts compared with NMC reconstructions. Differences in SUVmax, SUVmean, PLL, MTV, and TLG between Scan2 and ScanCB were significantly smaller with RMC than with NMC. ICCs for SUVmax, SUVmean, MTV, and TLG were higher between scans with RMC than NMC reconstructions, indicating improved TRT reliability. Conclusions: The deep-learning-based RMC method improved the image quality and TRT reproducibility of [¹⁸F] FDG PET/CT quantification in lung cancer, supporting its potential for routine adoption in therapy-response assessments. Full article

This study establishes a murine model of corticosteroid-associated osteonecrosis of the femoral head (ONFH) using a sustained-release prednisolone pellet and evaluates mitochondrial stress using ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and changes in key histologic markers of bone over a 6-week period. Sixteen 12-week-old Balb/C mice were divided into two groups: a prednisolone group (PRED) and a control group (SHAM). The PRED group received a subcutaneous 60-day sustained-release pellet containing 2.5 mg of prednisolone, while the SHAM group received placebo pellets. PET/CT imaging was performed at 1, 3, and 6 weeks. Bone mineral density (BMD) measurements, and histomorphological analyses for the number of empty lacunae, osteoblasts, osteoclasts, and NADPH oxidase (NOX) 2, a marker for oxidative stress, were conducted at 4 or 6 weeks. PET/CT imaging demonstrated increased uptake in the femoral head at 3 weeks in the PRED group. This was accompanied by increased numbers of empty lacunae and osteoclasts, increased oxidative stress, and decreased alkaline phosphatase staining at 4 weeks in the PRED group. We have successfully established and validated a small murine model of ONFH. The findings of this preclinical study suggest a critical timeline for potential interventions to mitigate the early adverse effects of continuous corticosteroid exposure on bone. Full article

Background/Objectives: This study aimed to evaluate the prognostic value of ¹⁸F-FDG PET/CT-based secondary lymphoid organ metabolic ratios—spleen/liver (SLR), bone marrow/liver (BLR), and ileocecal region/liver (ILR)—and hematological inflammation markers (neutrophil/lymphocyte ratio [NLR] and systemic immune-inflammation index [SII]) obtained before nivolumab treatment in relation to survival in patients with advanced non-small cell lung cancer (NSCLC). Methods: This retrospective single-center study included 79 advanced NSCLC patients who were treated with nivolumab monotherapy at Marmara University Faculty of Medicine Hospital between 2022 and 2024. Pretreatment SLR, BLR, and ILR ratios were calculated from ¹⁸F-FDG PET/CT examinations; NLR and SII values were obtained from hematological data. Survival outcomes were analyzed using the Kaplan–Meier method, and prognostic factors were assessed using Cox proportional hazards regression analysis. In a subset of patients, an exploratory longitudinal analysis was performed using early follow-up PET/CT to assess follow-up-to-baseline changes in immune-organ metabolic ratios in relation to overall survival. Results: High NLR and SII levels were significantly associated with shorter progression-free survival and overall survival. In contrast, no significant associations were observed between PET/CT-derived metabolic ratios (SLR, BLR, and ILR) and survival. Multivariate analysis identified the presence of liver metastases and a high NLR as independent adverse prognostic factors for overall survival. Conclusions: In this homogeneous real-world cohort treated exclusively with single-agent nivolumab, PET/CT-derived secondary lymphoid organ metabolic ratios showed limited prognostic value at baseline and during early on-treatment assessment. In contrast, hematological inflammation markers, especially high NLR levels, are strong prognostic indicators of survival and may complement established clinical factors in risk stratification. Full article

Background: Sarcoidosis is a multisystem inflammatory disorder characterized by non-caseating granulomas, most commonly affecting the lungs and intrathoracic lymph nodes. Angiotensin-converting enzyme (ACE) levels and calcium abnormalities are recognized biomarkers, while ^18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is increasingly used to assess disease activity. However, neither provides sufficient diagnostic accuracy alone. Therefore, this study aimed to investigate the relationship between FDG-PET/CT metabolic findings and serum ACE and calcium (Ca²⁺) levels as surrogate indicators of inflammatory metabolic intensity in sarcoidosis. Methods: In this retrospective single-center study, 127 patients with pulmonary sarcoidosis who underwent PET/CT at diagnosis were evaluated. Demographic and clinical data, ACE, and Ca²⁺ levels were recorded. FDG uptake in mediastinal, pulmonary, and extrapulmonary sites was analyzed, and correlations with biomarkers were assessed. Results: The cohort included 89 females (70.1%) and 38 males (29.9%), mean age 51.3 ± 11.9 years. FDG uptake was most frequent in mediastinal lymph nodes (84.3%) and lung parenchyma (40.9%). ACE levels correlated weakly with total SUVmax (r = 0.214, p = 0.019). Calcium levels correlated with extrapulmonary SUVmax (r = 0.327, p = 0.001) and were higher in patients with extrapulmonary involvement (p = 0.045). No associations were found between symptom presence and biomarkers or SUVmax values. Conclusions: FDG-PET/CT metabolic parameters, particularly total and extrapulmonary SUVmax, demonstrated modest yet statistically significant associations with ACE and calcium levels. These findings suggest that a combined biomarker-imaging approach may provide complementary information regarding inflammatory metabolic intensity and systemic involvement; however, the results should be interpreted as exploratory and require validation in prospective studies. Full article

Background/Objectives: Cardiac sarcoidosis (CS) is a challenging diagnosis due to its subclinical progression and the limitations of existing screening tools. Cardiac magnetic resonance (CMR) and PET/CT imaging have improved diagnosis and detection. Aldosterone, a hormone with known profibrotic effects, may offer additional diagnostic value. We therefore aimed to determine whether plasma aldosterone level is associated with myocardial fibrosis, independent of active inflammation, in CS. Methods: This observational study included 541 patients with biopsy-proven sarcoidosis and preserved left ventricular ejection fraction (LVEF ≥ 50%). All underwent CMR with extracellular volume (ECV) mapping and 18F-FDG PET/CT to assess myocardial fibrosis and inflammation, respectively. Plasma aldosterone levels were also measured. Results: Plasma aldosterone levels were significantly higher in patients with cardiac sarcoidosis (172 [IQR 106–235] pg/mL) compared to those without cardiac involvement (143 [100–205] pg/mL, p = 0.02). Aldosterone was independently associated with the presence of late gadolinium enhancement (LGE) on CMR (OR 1.002 per 1 pg/mL increase; 95% CI 1.001–1.004, p = 0.04) and with higher ECV values (β = 0.008 per 1 pg/mL, p = 0.001). Regression analysis showed that aldosterone is associated with ECV (b-0.009, CI: 0.002–0.016, p = 0.009) and there was no interaction according to LGE status indicating a relationship with diffuse myocardial fibrosis even in the absence of visible scarring. No association was observed with T1-, T2-, or PET/CT-defined inflammation. Conclusions: Plasma aldosterone is a robust marker of myocardial fibrosis in sarcoidosis, particularly in early or subclinical stages. Its correlation with ECV—but not with inflammatory imaging markers—suggests its link with myocardial diffuse fibrotic remodeling before, and independently of, overt scarring or inflammation. Full article

Background/Objectives: Hepatocellular carcinoma remains a major cause of death from cancer globally. While ¹⁸F-FDG PET/CT is commonly used for tumor imaging, its sensitivity is limited, especially due to high liver background uptake. Recently, ⁶⁸Ga-FAPI PET/CT, which targets fibroblast activation protein in tumor stroma, has emerged as a promising diagnostic tool. In this study, we aimed to assess the diagnostic performance of ⁶⁸Ga-FAPI-04 PET/CT in HCC patients with and without liver cirrhosis and to explore the relationship between PET metrics, tumor size, and PIVKA-II serum marker. Methods: In this prospective single-center study, 59 patients with confirmed HCC (37 with cirrhosis, 22 without) underwent ⁶⁸Ga-FAPI-04 PET/CT. The standard dose (1.5–2.0 MBq/kg) was administered intravenously, and imaging was carried out 60 min post-injection. Semi-quantitative parameters including SUVmax, SUVmean, and tumor-to-background ratio were calculated. Diagnostic performance was assessed using histopathology and multimodal imaging. Statistical analyses included the Mann–Whitney U test and Spearman correlation. Results: The overall sensitivity for HCC detection was 89.8%, with a specificity of 60% and accuracy of 87%. Sensitivity and specificity showed a tendency to be lower in cirrhotic compared with non-cirrhotic patients, with a notably higher background liver uptake in cirrhosis (SUVmax 3.60 vs. 1.3, p < 0.001), resulting in lower TBR values (3.7 vs. 7.0, p < 0.001). A strong correlation between SUVmax and tumor size was seen in non-cirrhotic HCC, while a moderate association between SUVmax and PIVKA-II levels was observed in cirrhotic patients. Conclusions:⁶⁸Ga-FAPI-04 PET/CT demonstrates high sensitivity for HCC detection and may serve as a complementary imaging modality, particularly when interpreted through conventional cross-sectional imaging. Image interpretation in cirrhotic livers may be challenging due to increased background uptake and reduced TBR. Associations between PET-derived parameters, tumor size, and serum PIVKA-II levels should be considered hypothesis-generating and require validation in larger, multicenter studies with clinical outcome data. Full article

Prostate cancer remains one of the most common malignancies in men worldwide, with incidence and mortality steadily increasing across diverse populations. While early detection and radical prostatectomy can achieve durable control in a subset of patients, approximately 40% of men will ultimately experience biochemical recurrence often in the absence of clinically detectable disease. Conventional imaging approaches—CT, MRI, and bone scintigraphy—have limited sensitivity for early relapses, frequently leading to delayed diagnosis and suboptimal treatment planning. The discovery of prostate-specific membrane antigen (PSMA) in 1987 and its subsequent clinical translation into positron emission tomography (PET) imaging with [⁶⁸Ga]Ga-PSMA-11 in 2012, followed by U.S. FDA approval in 2020, has transformed the landscape of prostate cancer imaging. PSMA PET has demonstrated superior accuracy over conventional imaging, as highlighted in the landmark proPSMA trial and now serves as the foundation for theranostic approaches that integrate diagnostic imaging with targeted radioligand therapy. The clinical approval of [¹⁷⁷Lu]Lu-PSMA-617 (Pluvicto^®: (lutetium Lu 177 vipivotide tetraxetan, Advanced Accelerator Applications USA, Inc., a Novartis company) has established targeted radioligand therapy as a viable option for men with metastatic castration-resistant prostate cancer, extending survival in patients with limited alternatives. Emerging strategies, including next-generation ligands with improved tumor uptake and altered clearance pathways, as well as the integration of artificial intelligence for imaging quantification, are poised to further refine patient selection, dosimetry, and treatment outcomes. This review highlights the evolution of PSMA-based imaging and therapy, discusses current clinical applications and limitations, and outlines future directions for optimizing theranostic strategies in prostate cancer care. Full article

Background: Positron emission tomography (PET) is a valuable tool in the diagnosis of cardiovascular infections. However, increased radiotracer uptake can also be observed in non-infectious inflammatory processes, leading to potential false positives. This study analyzed the uptake related to left atrial appendage closure devices (LAACD—AtriClip^®) to determine its association with infectious or inflammatory processes. Methods: We retrospectively analyzed 28 PET/CT scans from 20 patients with implanted LAACDs: 24 using ¹⁸F-fluorodeoxyglucose (FDG) and 4 using ¹⁸F-Choline (CHO). Clinical, laboratory, and imaging data were reviewed, and PET uptake was measured semi-quantitatively. All patients had at least 12 months of follow-up after PET imaging to assess for evidence of device-related infection. Results: Homogeneous PET uptake in the LAACD was observed in 93% (26/28) of the PET studies, regardless of the radiotracer used, clinical indication, or time since implantation. Clinical follow-up and laboratory findings revealed no signs of infection related to the LAACD in any case. SUV ratios did not differ significantly between the three PET indication groups (infection, neoplasia, or other; p = 0.46), nor between scans performed in patients with and without other confirmed infections unrelated to the LAACD (p = 0.37). Conclusions: FDG and CHO uptake in LAACDs appears to be a consistent and reproducible finding, most likely reflecting a sterile inflammatory response postoperative inflammatory uptake rather than true infection. Clear recognition of this uptake pattern is important to prevent misinterpretation and reduce the risk of false-positive PET/CT results in patients evaluated for suspected cardiovascular infections. Full article

Introduction: Radiotracer-based nuclear imaging, including positron emission tomography (PET) and single-photon emission computed tomography (SPECT), can complement conventional cross-sectional imaging in renal cell carcinoma (RCC) by providing biological characterisation of tumour metabolism, angiogenesis, hypoxia, and the tumour microenvironment. While computed tomography (CT) and magnetic resonance imaging (MRI) remain the diagnostic standard, accumulating evidence suggests that selected nuclear imaging techniques may offer incremental value in specific clinical scenarios. Methods: A narrative literature review was performed using PubMed, Embase, and Web of Science to identify preclinical, retrospective, and prospective studies evaluating PET and SPECT radiotracers in localised and metastatic RCC. Priority was given to meta-analyses, multicentre prospective trials, and studies with histopathological correlation. Results: [¹⁸F]fluorodeoxyglucose (FDG) PET/CT demonstrates limited sensitivity for primary renal tumours (pooled sensitivity of approximately 60%) but performs substantially better in metastatic and recurrent disease (pooled sensitivity and specificity of approximately 85–90%), where uptake correlates with tumour grade, progression-free survival, and overall survival. [^99mTc]sestamibi SPECT/CT differentiates oncocytoma and hybrid oncocytic/chromophobe tumours from malignant RCC with pooled sensitivity and specificity of around 85–90%, supporting its role in evaluating indeterminate renal masses rather than staging. Prostate-specific membrane antigen (PSMA) PET/CT shows high detection rates in clear-cell RCC, particularly in metastatic disease, with reported sensitivities of approximately 85–90% and management changes in up to 40–50% of selected cohorts. Carbonic anhydrase IX (CAIX)-targeted PET/CT enables the biologically specific visualisation of clear-cell RCC, achieving sensitivities and specificities in the range of 85–90% in prospective phase II and III trials for primary tumour characterisation. Fibroblast activation protein inhibitor (FAPI) PET/CT demonstrates high tumour-to-background uptake in early RCC studies, but evidence remains preliminary, with small cohorts and recognised non-specific uptake in benign inflammatory and fibrotic conditions. Conclusions: Radiotracer-based nuclear imaging provides complementary, biology-driven insights in RCC that extend beyond anatomical assessment. While most modalities remain adjunctive or investigational and are not recommended for routine use, selective application in carefully chosen clinical scenarios may enhance tumour characterisation, prognostication, and personalised treatment planning. Full article

A radioiodine-refractory differentiated thyroid cancer patient with rising serum thyroglobulin (Tg) levels underwent ¹⁸F-FDG PET/CT scan, which showed a hypermetabolic region in the proximal segment of esophagus, leading to ambiguity in diagnosis. MRI was immediately added, and PET/MRI fusion image localized an air-containing lesion interlinked with esophagus with enhanced T2 hyperintense mucosal signal, indicating an inflammatory esophageal diverticulum, which was subsequently verified by endoscopy. This case highlights the added value of PET/MRI image fusion in cases with inconclusive ¹⁸F-FDG PET/CT findings, requiring no additional tests and utilizing existing software, thereby minimizing the need for invasive procedures. Full article