An 18-year-old man presented with hypercalcemia and suspected primary hyperparathyroidism. Initial complete thyroid ultrasound revealed no significant abnormalities. However, ectopic parathyroid hyperfunction could not be excluded. Subsequent 18 F-fluoromethylcholine ( 18 F-FCH) PET/CT demonstrated a focus of increased tracer uptake in the anterior superior mediastinum, suggestive of an ectopic parathyroid adenoma. Guided by imaging localization, the patient underwent minimally invasive excision. Postoperative pathologic biopsy confirmed the lesion as an ectopic parathyroid adenoma. This case demonstrates that 18 F-FCH PET/CT can accurately locate ectopic parathyroid adenomas, creating an efficient and safe diagnostic and treatment pathway for patients.

Sarcomas represent a heterogeneous group of malignant neoplasms arising from mesenchymal tissue and remain challenging to diagnose and treat. Fibroblast activation protein (FAP), highly expressed in the tumor microenvironment, has emerged as a attractive target for molecular imaging. This review aims to evaluate the role of fibroblast activation protein inhibitors (FAPI) in sarcoma diagnosis and therapy. Following PRISMA guidelines, we searched PubMed, Embase, and Web of Science for studies published between 2018 and 2025 investigating FAPI in sarcoma imaging or treatment. Diagnostic study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Twelve studies comprising 398 patients met inclusion criteria. Six diagnostic studies (361 patients, 2,477 lesions) reported a pooled detection rate of 89.7

PURPOSE:This study aimed to evaluate the prognostic significance of fluorine-18 ( 18 F) fluorodeoxyglucose PET/computed tomography (CT) metabolic parameters in patients with primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL). METHODS:We retrospectively analyzed 24 PGI-DLBCL patients treated with R-CHOP chemotherapy. Continuous variables were dichotomized at the median and compared using the t-test, whereas categorical variables [e.g. gender, cell origin (germinal center B-cell/non-germinal center B-cell)] were compared using the Chi-square test. Spearman correlation analysis was performed to examine relationships between metabolic parameters and potential prognostic factors. Univariate Kaplan-Meier survival analysis and multivariate Cox regression were used to identify independent prognostic factors for progression-free survival and overall survival. Prognostic differences among risk groups were also assessed. RESULTS:Total lesion glycolysis (TLG), lactate dehydrogenase, International Prognostic Index (IPI), National Comprehensive Cancer Network-IPI, metabolic tumor volume (△MTV, representing changes in MTV between baseline and interim PET/CT), and clinical staging differed significantly between high and low-MTV groups (all P  < 0.05).TLG, △MTV, lactate dehydrogenase, IPI score, National Comprehensive Cancer Network-IPI score, and clinical stage were significantly correlated with MTV (all P  < 0.05). Receiver operating characteristic analysis indicated that MTV, standardized uptake value (△SUV max , changes in SUV max between baseline and interim PET/CT), TLG, and ΔMTV effectively predicted mid-term remission. Multivariate analysis identified MTV and ΔSUV max as independent predictors of progression-free survival ( P  < 0.05), whereas ΔSUV max was independently associated with overall survival ( P  < 0.05). Cox regression analysis revealed significant prognostic differences among subgroups ( P  < 0.0001). CONCLUSION:MTV, △SUV max , TLG, and △MTV are effective for evaluating for mid-term remission in PGI-DLBCL patients. Among them, MTV and △SUV max serve as independent prognostic factors.

Tumor heterogeneity severely limits the efficacy of single-targeted radiopharmaceuticals. FAP and CAIX are important biomarkers overexpressed in tumors and the tumor microenvironment. We designed a PEG4-modified heterodimeric radioligand, FC, for dual targeting of FAP and CAIX. FC showed high binding affinity toward FAP (IC50 = 18.2 ± 0.23 nM). [68Ga]Ga-FC exhibited significantly higher tumor uptake than monomeric tracers in FAP- or CAIX-positive tumor models at 120 min postinjection. PEG4 modification markedly enhanced hydrophilicity, tumor retention, and in vivo stability. Mirco-SPECT imaging showed strong tumor accumulation of [177Lu]Lu-FC up to 168 h. A single dose of [177Lu]Lu-FC (29.6 MBq) achieved complete tumor suppression in HEK293-FAP tumor-bearing mice with no obvious organ toxicity. [68Ga]Ga/[177Lu]Lu-FC represents a promising theranostic agent for FAP-positive malignancies.

Primary extraskeletal Ewing sarcoma in the soft tissue of the neck is rare. A 29-year-old woman underwent 18F-FDG PET/CT and 68Ga-DOTATATE PET/CT for a mass in her neck. The patient complained of pain in the right side of the neck for 6 months. Both scans showed increased imaging agent uptake in the neck mass, which was subsequently diagnosed as extraskeletal Ewing sarcoma.

The heterogeneous expression of tumor biomarkers limits the diagnostic performance of single-target imaging agents. Carbonic anhydrase IX (CAIX) is highly expressed in hypoxic regions of clear cell renal cell carcinoma (ccRCC) and multiple solid tumors, whereas prostate-specific membrane antigen (PSMA) is specifically upregulated in tumor-associated neovasculature. Both targets have been implicated in tumor metastasis and poor clinical outcomes. This study aimed to design and evaluate a novel bispecific PET tracer, [68Ga]Ga-PCA, targeting both CAIX and PSMA, with the goal of achieving improved tumor-specific uptake. Subcutaneous xenograft models were established in nude mice by inoculation with OS-RC-2, PC3-PIP, and HEK-293 cells. PET/CT imaging and biodistribution studies were performed following intravenous administration of [68Ga]Ga-PCA. Target specificity was evaluated via competitive blocking assays employing excess unlabeled ligand. Immunohistochemical staining was performed to validate the expression profiles of the targets within the tumors. After being labeled with gallium-68, [68Ga]Ga-PCA showed favorable physicochemical properties, such as a high radiolabeling yield (>80%), radiochemical purity over 95%, good stability in vitro, and an albumin-binding rate of 93.44 ± 0.81%. PET/CT imaging revealed pronounced and specific tracer accumulation in both OS-RC-2 and PC3-PIP tumor models. In OS-RC-2 tumors (PSMA+/CAIX+), the SUVmax (13.10 ± 0.84) was higher than those of the single-target tracers [68Ga]Ga-DOTA-NY104 (5.31 ± 0.77) and [68Ga]Ga-PSMA (2.31 ± 0.49) at 60 min postinjection. An excess of unlabeled DOTA-NY104, a PSMA-targeted ligand, or a mix of the two ligands can block the uptake of [68Ga]Ga-PCA. These results demonstrate that the tracer can bind to both targets at once. In conclusion, [68Ga]Ga-PCA is a bispecific PET tracer that targets both hypoxic tumor cells and tumor neovasculature by binding to both CAIX and PSMA. The probe exhibited significant specificity, advantageous imaging contrast, and robust blocking validation, indicating its potential for molecular imaging of malignancies, including clear cell renal cell carcinoma (ccRCC).

18 F-Flortaucipir, as a classical Tau protein visualizer, has been widely used in the diagnosis of neurodegenerative diseases, especially Alzheimer disease. This report describes a case of intense uptake of 18 F-Flortaucipir at 2 sites of reduced bone mineral density in the skull, but no radioactivity uptake was seen on 18 F-FDG and 18 F-Florbetapir PET/CT imaging at the same lesion sites. The mechanism behind 18 F-Flortaucipir uptake in focal osteopenia remains unclear. This study provides evidence for the mechanism of the above phenomenon.

Diffusion-based generative models are a novel class of generative models recently shown to outperform supervised learning-based methods and other generative models in various applications. Several pioneer studies have demonstrated the potential of applying diffusion models to the restoration of medical images. A major practical limitation of diffusion models is time consumption. In this study, we propose a novel acceleration technique targeting denoising diffusion probabilistic models (DDPM) processing of volumetric scans of multi-phasic CT. The proposed method utilizes a tiered sampling step sharing mechanism to utilize the anatomical similarity at multiple scales across different phases and different spatial slices. The proposed method enables 40x speed up compared to the conventional workflow while maintaining high fidelity restoration of the images.

A 20-year-old man was admitted to our hospital with neck pain. A contrast-enhanced CT revealed a heterogeneously enhancing mass in the posterior elements of the C5 vertebra. On 18 F-FDG PET/CT, this solitary lesion had significant FDG uptake with an SUVmax of 7.61. The patient underwent a posterior surgical approach to excise the bony lesion located at C5. The postoperative pathologic examination showed an aneurysmal bone cyst. Our case demonstrates that aneurysmal bone cyst can exhibit intense 18 F-FDG uptake. Therefore, for solitary vertebral lesions with significant FDG avidity, aneurysmal bone cyst should be included in the differential diagnosis.

A 29-year-old woman with papillary thyroid cancer underwent thyroidectomy and parathyroid auto-transplantation. One month after surgery, the patient received radioiodine therapy. Two days after 131 I administration, localized 131 I uptake in the right sternocleidomastoid muscle was detected by post-therapy 131 I whole-body scintigraphy. We found that the 131 I uptake area was colocalized at the site of parathyroid transplantation.

An 86-year-old man presented with slurred speech and right lower limb shaking for 1 month. Initial brain MRI revealed an abnormal signal lesion in the left parietal lobe with peripheral parenchymal edema, and brain metastases were suspected. Subsequent PET/CT showed increased focal FDG uptake in the left parietal lobe, accompanied by bands of surrounding brain parenchyma edema. No other abnormal lesions were observed on 18 F-FDG PET/CT except for increased inflammatory lymph node activity in the left hilar region. Finally, the cerebrospinal fluid puncture culture showed a Micrococcus luteus infection. Therefore, the clinical diagnosis was infectious lesions.

A 29-year-old woman presented with asthma, fever, generalized rash, and numbness in the ring and pinky fingers of her right hand. Laboratory studies showed significant increases in blood eosinophils, C-reactive protein, and IgE, but ANCA (antineutrophil cytoplasmic antibodies) were negative. The 18 F-FDG PET/CT suggests scattered, segmented FDG uptake around small and medium vessels throughout the body. After comprehensive analysis, the patient's final clinical diagnosis was eosinophilic granulomatous vasculitis.

ABSTRACT:An 81-year-old woman experienced compression symptoms due to diffuse enlargement of the thyroid gland. The cytopathological results of thyroid fine-needle suggested malignancy. Therefore, she underwent bilateral thyroidectomy. Postoperative pathology indicated mucosa-associated lymphoid tissue (MALT) lymphoma. Three months later, she found a progressively enlarged mass in her neck. The biopsy showed MALT lymphoma with highly aggressive B-cell lymphoma transformation. 18F-FDG PET/CT showed increased metabolism in multiple lymph nodes. However, some of these lymph nodes were negative in 68Ga-pentxafor PET/CT. Our case demonstrated that 68Ga-pentixafor may have limited value in evaluating MALT lymphoma transformation.

Ovarian cancer with cutaneous metastases is quite rare. We report the findings of cutaneous metastases from ovarian cancer on Ga-68-FAPI PET/CT imaging. A 53-year-old woman with cutaneous metastases from ovarian cancer was enrolled in Ga-68-FAPI PET/CT clinical trial. The images showed intense FAPI activity in the known cutaneous metastases.

Recent studies have shown the potential of fibroblast activating protein inhibitor (FAPI) PET imaging for pancreatic cancer assessment. This article is dedicated to comparing the diagnostic efficacy of FAPI PET and [18F]fluorodeoxyglucose (FDG) PET in the evaluation of primary tumors, lymph nodes, and distant metastases in pancreatic cancer. In this review, we conducted a systematic search of studies published in PubMed and Web of Science databases up to September 18, 2023. All included studies used radionuclide labeled FAPI and FDG as PET diagnostic tracers to evaluate their applicability in patients with pancreatic cancer. The FAPI PET imaging group showed significantly higher sensitivity in the detection of primary lesions (1.000, [95

ABSTRACT:A 67-year-old man underwent 18 F-FDG PET/CT for lung cancer staging. Interestingly, the PET scan revealed strip-shaped FDG uptake in the right inguinal contoured area, which was later confirmed as a right varicocele through ultrasound imaging.

Abstract Two children with neuroblastoma underwent tumor resection and postoperative chemotherapy. After treatment, they participated in a clinical trial and received 18F-MFBG and 18F-FDG PET/CT examinations. Although similar lesions were found in the 2 examinations, the uptake pattern was different. The lymph nodes and bone lesions had intense 18F-MFBG activity, whereas 18F-FDG uptake was not very impressive. The uptake of bone marrow by 18F-MFBG was significantly stronger than that by 18F-FDG. This case emphasizes that 18F-MFBG PET/CT is superior to 18F-FDG PET/CT in detecting the metastases of neuroblastoma.

ABSTRACT:A 67-year-old woman presented with dysphagia for 2 months. Enhanced chest CT suggested thickening of the esophageal wall, which was suspected to be a malignancy. The patient then underwent 18 F-FDG and 68 Ga-FAPI PET/CT. Increased uptake was observed in both tracers in the thickened esophageal wall. However, biopsy demonstrated candida infection of esophagus. After treatment, the symptoms of the patient were relieved.