Clinical Nuclear Medicine

Differentiated thyroid carcinoma constitutes over 90% of all thyroid cancers. The standard treatment approach involves total or near-total thyroidectomy with or without neck dissection followed by 131I whole-body scintigraphy (WBS) to detect local or distant metastases. Radioiodine offers high sensitivity and specificity for detection of metastatic disease in well differentiated thyroid carcinoma. However, despite its high accuracy, 131I WBS demonstrates false-positive results, mostly at inflammatory or infective site...

A 64-year-old woman presented with chest pain while eating and was referred to our hospital. Physical examination revealed abdominal distension, tenderness, and lower-extremity edema. Imaging revealed a large gallbladder tumor infiltrating the liver, with ascites and pleural effusion. A biopsy confirmed a poorly differentiated adenocarcinoma with SMARCA4 deficiency (cT3N2M1, cStage IV). Chemotherapy was ineffective and led to tumor progression. The patient died 9 months later. Recently, attention has been paid to SMARCA4 deficiency, which is a genetic mutation found in tumors...

The occurrence of cutaneous metastases in prostate cancer is exceedingly rare. Many benign lesions and nonprostatic cancers can express the prostate-specific membrane antigen (PSMA). They can potentially mimic metastasis of prostate cancer and lead to misinterpretation of PSMA PET/CT findings. Additionally, it has significant management and prognostic implications. We present a rare case of an 88-year-old man with metastatic castration-resistant prostate cancer who showed a PSMA-expressing subcutaneous nodule in the scalp on 18F-PSMA-1007 PET/CT, raising the suspicion of cutaneous metastasis...

Juxtaglomerular cell tumor or reninoma is an extremely rare, typically benign, renin-secreting tumor of the kidney that causes secondary hypertension. We describe 99mTc-MIBI SPECT/CT findings in a case of juxtaglomerular cell tumor. The renal tumor showed isodensity and photopenia on 99mTc-MIBI SPECT/CT. This case indicates that juxtaglomerular cell tumor can appear cold on 99mTc-MIBI SPECT/CT, mimicking renal cell carcinoma.

A 43-year-old woman diagnosed with refractory diffuse large B-cell lymphoma was referred to chimeric antigen receptor T-cell therapy at our institution. After 3 cycles of bridging therapy, preinfusion 18F-FDG PET/CT suggested a complete metabolic response. 18F-FDG PET/CT 1 month after chimeric antigen receptor T-cell infusion showed 2 foci of elevated activity in the spleen, which was finally confirmed as pseudoprogression.

Inflammatory variant of well-differentiated liposarcoma is a rare subtype of liposarcoma, and its imaging features have been rarely reported. We describe FDG PET/CT findings in a case of well-differentiated inflammatory liposarcoma. The tumor showed no detectable fat and intense FDG uptake and caused diffuse FDG uptake of the bone marrow due to paraneoplastic leukemoid reaction. Microscopically, there were extensive inflammatory infiltrates in the tumor, which may contribute to the intense FDG uptake. This case indicates that although well-differentiated liposarcoma usually shows low-grade FDG uptake, inflammatory variant of well-differentiated liposarcoma can show intense FDG uptake mimicking high-grade liposarcoma...

PURPOSE OF THE REPORT: Although early detection of individuals at risk of dementia conversion is important in patients with Parkinson's disease (PD), there is still no consensus on neuroimaging biomarkers for predicting future cognitive decline. We aimed to investigate whether cerebral perfusion patterns on early-phase 18F-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane (18F-FP-CIT) PET have the potential to serve as a neuroimaging predictor for early dementia conversion in patients with PD...

A 7-year-old girl with known brain metastasis from neuroblastoma developed new onset of severe headache. A brain MRI confirmed known metastasis in the right frontal lobe of the brain without new abnormalities. The patient was enrolled in a clinical trial using 18F-MFBG PET/CT to evaluate patients with neuroblastoma. The images confirmed abnormal activity in the known lesion in the right frontal lobe. In addition, the PET showed additional foci of abnormal activity in the left cerebellopontine region. A follow-up brain MRI study acquired 4 months later revealed abnormal signals in the same region...

Chordoid meningiomas, rare meningioma variants, are characterized by their histopathological features and clinical behavior resembling that of other chondroid/myxoid neoplasms. We present a case of pathology-proven chordoid meningioma imaged with both 68Ga-DOTATATE and 18F-FDG PET images during a complicated postoperative course with multiple episodes of local recurrence and, ultimately, extracranial metastasis. This case underscores the aggressive behavior of chordoid meningiomas while highlighting how molecular imaging plays an important role in clinical monitoring and guidance of management...

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...

225Ac-PSMA treatment demonstrated low hematologic toxicity for prostate cancer with diffuse red marrow infiltration. A 70-year-old man with diffuse bone metastases of castration-resistant prostate cancer received 225Ac-PSMA radiation therapy. After 1 treatment cycle, the patient's skeletal lesions demonstrated a significant response and a significant decrease in PSA. 225Ac-PSMA may be a promising therapeutic option for metastatic castration-resistant prostate cancer patients with high bone metastatic burden...

A 72-year-old man presented with a painless penile mass for 3 months. Contrast-enhanced CT revealed heterogeneous enhancement, whereas 18F-FDG PET/CT displayed inhomogeneous 18F-FDG accumulation in the lesion without other abnormal activity. The histopathological examination from biopsied specimen confirmed the diagnosis of a plasmacytoma. However, the subsequent tests, including serum/urine immunofixation electrophoresis, serum/urine free light chain assay, and bone marrow smear/biopsy, did not show any abnormalities...

An 85-year-old man with prostate cancer and de novo bone metastases was treated with hormonal therapy with resolution of bone lesions, improved primary disease, and improved serum tumor markers. Although on hormonal therapy, biochemical recurrence prompted performance of 18F-fluciclovine PET/CT. Fluciclovine PET/CT revealed primary prostate cancer progression with incidental note of avid foci in the colon for which colonoscopy was recommended. Colonoscopy with biopsy was performed with pathology revealing primary colon adenocarcinoma...

Aggressive fibromatosis is a relatively rare disease. We describe 68Ga-FAPI-04 PET/CT findings in a case of histologically proved mesenteric aggressive fibromatosis. 68Ga-FAPI-04 PET/CT revealed a mass in the mesentery with increased FAPI activity. This case indicates that FAPI PET may be useful for evaluation of aggressive fibromatosis.

A 72-year-old man revealed typical findings of cardiac sarcoidosis on cardiovascular MRI. However, 18F-FDG PET showed no hypermetabolism. Therefore, immunosuppression was not initiated. After 2 years, ventricular arrhythmias and heart failure worsened. 68Ga-fibroblast activation protein inhibitor PET was initiated to evaluate potential adverse remodeling due to progressive myocardial fibrosis. A second 18F-FDG PET still revealed no hypermetabolism, and the patient received an implanted cardioverter defibrillator after electrophysiological risk stratification...

We present a case series of 5 patients diagnosed with schwannoma and 1 patient diagnosed with astrocytoma who underwent PSMA PET imaging for tumor detection. We retrospectively analyzed the records of 4 male and 2 female patients (mean age, 53.2 ± 13.2) who underwent PSMA PET imaging between March and September 2023. PET interpretation showed increased Ga-PSMA-11 accumulation in all patients with a mean SUVmax of 3.11 ± 1.8. This series underscores PSMA PET's potential for CNS neoplasm detection.

PURPOSE: Chronic recurrent multifocal osteomyelitis (CRMO), or chronic nonbacterial osteomyelitis, is difficult to diagnose. The accurate diagnosis of CRMO relies on comprehensive imaging examinations because of its multifocal nature. In this regard, 18F-FDG PET/CT has demonstrated significant utility in inflammatory diseases. This study tries to determine the value of FDG PET/CT in the evaluation of CRMO. PATIENTS AND METHODS: We retrospectively collected imaging data from pediatric CRMO patients who underwent FDG PET/CT scans...

PURPOSE: A monoclonal antibody, trastuzumab, is used for immunotherapy for HER2-expressing breast cancers. Large-sized antibodies demonstrate hepatobiliary clearance and slower pharmacokinetics. A trastuzumab fragment (Fab; 45 kDa) has been generated for theranostic use. PATIENTS AND METHODS: Fab was generated by papain digestion. Trastuzumab and Fab have been radiolabelled with 177Lu after being conjugated with a bifunctional chelating. The affinity and target specificity were studied in vitro...

We report findings from 68Ga-DOTATATE and 68Ga-FAPI PET/CT in a 43-year-old woman with neuroendocrine neoplasms. DOTATATE and FAPI uptake differed in different lesions. These results suggest a potential value for dual-tracer imaging in the evaluation of neuroendocrine neoplasms that have different grades.

We present a case of sarcoidosis with a rare presentation of involvement of peripheral nerves of the lower limbs and subcutaneous nodules detected on 18F-FDG PET/CT. The patient also had involvement of the spinal nerves and dura, histologically proven to be sarcoidosis. There were other manifestations of systemic sarcoidosis like metabolically active cervical and mediastinal lymphadenopathy. This case highlights the role of 18F-FDG PET/CT in evaluating the uncommon sites of sarcoid involvement. Although many cases of sarcoid involvement of central nervous system have been reported, peripheral nerves involvement in the extremities was not found on a literature search...