World Journal of Nuclear Medicine最新文献

In terms of cancer-related deaths, lung cancer is the most common type. To prevent this malignant and dangerous disease from progressing, early and differential diagnoses are very critical. A combination of dimercaptosuccinic acid and pentavalent ^99m Tc under alkaline conditions, ^99m Tc (V)-DMSA, can be used for malignant tumors' early diagnosis and prognosis. The ^99m Tc (V)-DMSA radiotracer is most commonly used for follow-up of medullary thyroid cancer metastases, but it is also successful in lung cancer and other malignancies. In this case, a 65-year-old woman with a recent history of nonproductive cough and mild dyspnea and suspicious small masses of lungs in computed tomography was selected for imaging with ^99m Tc (V)-DMSA to evaluate the condition of radiotracer uptake in the lung masses. The whole-body and single-photon emission computed tomography imaging with semiquantitative analysis showed abnormal uptakes in the lesions and the patient underwent to transbronchial biopsy and bronchial washing cytology that confirmed non-small cell lung cancer.

Inspired by international frameworks, New Zealand established a nationally coordinated peptide receptor radionuclide therapy service. This article reflects on the key steps involved in building the service, including the formation of a national neuroendocrine tumor (NET) multidisciplinary meeting, the role of patient advocacy, and the integration of local research. The successful creation of the service, despite significant challenges, demonstrates the value of collaboration between clinicians, government, universities, and patient groups in achieving equitable, high-quality care.

Orbital metastases from malignant tumors are uncommon. In 25% of cases, they are the first sign of an undiagnosed cancer, and they account for approximately 7 to 12% of lung cancer cases. A lack of awareness about this condition can lead to misdiagnosis, distinguishing malignant from benign lesions. We present the case of a 65-year-old patient with orbital metastasis from lung cancer. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) was crucial in diagnosing this, revealing hypermetabolism in the left lung mass as well as intense uptake in the right retro-orbital region, which was confirmed as orbital metastasis through cerebro-orbital magnetic resonance imaging. For 2 months, our patient had right eye pain and decreased visual acuity and no attention was paid to these symptoms. Through this clinical case, the authors highlight the utility of 18F-FDG PET/CT in the diagnosis of primary malignancy in lung cancer patients, who presented with orbital metastasis as the first sign.

The global expansion of theranostics, a field combining molecular imaging and targeted therapy, has accelerated with the Food and Drug Administration approvals of Lutathera and Pluvicto. However, significant challenges hinder equitable access, particularly in low- and middle-income countries (LMICs). These include infrastructure limitations, such as the high cost of gamma cameras, positron emission tomography/computed tomography scanners, cyclotrons, and maintenance, as well as disparities in the availability of radiopharmaceuticals. In LMICs, one single-photon emission computerized tomography scanner may serve 33 million people, compared with 57,000 in high-income countries. Furthermore, shortages of key isotopes like 99Mo and 177Lu highlight vulnerabilities in global supply chains. Staffing and training are critical issues, as delivering theranostic services requires specialized teams that are often scarce in LMICs. The International Atomic Energy Agency (IAEA) addresses these challenges by offering training programs, developing databases like IMAGINE and NUMDAB, and fostering technical cooperation among member states. To improve access to theranostic services, strategies such as using alternative imaging methods and enhancing local radiopharmaceutical production are recommended. The IAEA's Rays of Hope initiative aims to strengthen regional capacities, improve infrastructure, and address the critical shortage of trained professionals. A coordinated global effort is essential to overcome these barriers, reduce costs, and ensure equitable access to theranostics, particularly in resource-limited settings.

Objective: This article aims to assess the presence of skeletal and soft tissue infections before or after treatment and to assess treatment response in Ga-68 citrate positron emission tomography/computed tomography (PET/CT) scan positive patients.

Materials and methods: A prospective study was conducted for 43 patients. The eligibility criteria included those patients clinically suspected of infections who underwent a Ga-68 citrate PET/CT. Exclusion criteria were pregnancy and lactation. Patients with suspicion of infection or treatment failure underwent a Ga-68 citrate PET/CT between January 2020 and November 2021. Among these, eight patients underwent a follow-up scan posttreatment to assess their treatment response. The Institutional Review Board (IRB No.12511) approved the study.

Results: Forty-three patients underwent a diagnostic Ga-68 citrate PET/CT scan. The scan interpretation was based on visual comparison of uptake of Ga-68 citrate in the region of interest, which was compared with the normal side/adjacent soft tissue/blood pool. The semiquantitative parameter maximum standardized uptake value was retrospectively analyzed as well. PET/CT findings were correlated with tissue diagnosis, clinical symptoms, biochemical parameters like C-reactive protein (CRP), erythrocyte sedimentation rate, and total leukocyte count, and other imaging modalities with a statistically significant association with CRP ( p  = 0.001). Tissue diagnosis was considered the gold standard and out of the 43 patients included in the study, 27 had a tissue diagnosis. Sensitivity, specificity, negative predictive value, positive predictive value, and accuracy were calculated at 100, 87.5, 100, 95, and 96.3%, respectively.

Conclusion: Ga-68 citrate is a promising tool to assess the presence of bone and soft tissue infections before or after treatment.

Objective: The aim of this study was to evaluate the clinicopathological factors and stimulated thyroglobulin (Tg) course related to the occurrence of locoregional recurrence (LRR) in differentiated thyroid cancer (DTC) patients with biochemical incomplete response (BIR) as well as the value of fluorine-18 fluorodeoxyglucose ( ¹⁸ F-FDG) positron emission tomography (PET)/computed tomography (CT) in these patients.

Methods: A total of 253 DTC adult patients initially treated with total thyroidectomy and iodine-131 (RAI-131) ablation and showed BIR on follow-up were enrolled in the study. All clinical, laboratory, pathological, radiological, and follow-up data were retrieved from their records.

Results: Seventy-three out of the 253 BIR patients developed LRR during follow-up with the median time to recurrence of 27 months. In all, 61.6% of those who developed LRR were females, 78.1% were papillary thyroid carcinomas, 35.6% had initial regional nodal deposits, and the primary tumors were T2 and T3 in 78.2% of these patients ( p  < 0.05). The median Tg level for those who developed LRR compared with those who remained free was 18 versus 17 ng/mL, respectively, at 6 months of follow-up. Meanwhile, on further 1-year follow-up, the median value spontaneously increased for the positive group to 37.6 ng/mL and decreased for those who remained free to 3 ng/mL. Eighty percent of the patients with a rising course of Tg level developed structural LRR ( p  < 0.001). ¹⁸ F-FDG PET/CT showed the highest sensitivity and negative predictive value (NPV) of 100% in the detection of LRR compared with sensitivity values of 92.86 and 85.71% and NPV of 99.58 and 99.17%, respectively, with ultrasound (US) and RAI-131 scan. Meanwhile the highest specificity and positive predictive value (PPV) of 100% were observed noted with RAI-131 compared to specificity values of 99.16 and 99.58% and PPV of 87.50 and 92.86% with PET/CT and US, respectively. A cutoff point (SUVmax of 3.65) was successfully marked to discriminate those positive versus negative LRR with sensitivity and specificity of 100% and p -value of less than 0.001.

Conclusion: Structural LRR after BIR appears to be more commonly associated with worse clinicopathological parameters and the incremental Tg levels serve as an indicator of its higher incidence. ¹⁸ F-FDG PET/CT has been shown to be a valuable diagnostic tool rather than a prognostic one in these patients.

Patients of head and neck squamous cell carcinoma (HNSCC) experience increased risk of developing second primary cancer (SPC) necessitating active surveillance during their disease course. SPCs are associated with poor prognosis and are the leading cause of long-term morbidity and mortality impacting survival of patients with HNSCC. Small cell neuroendocrine carcinoma (SmNEC) is a rare but aggressive neoplasm with poor prognosis and high risk of local recurrence and distant metastasis. We report an exceedingly rare case of nasopharyngeal carcinoma (NPC) presenting as a recurrence in the form of metachronous second primary to primary SmNEC 9 years after chemotherapy. The dual tracer positron emission tomography and computed tomography (PET/CT) imaging approach ([ ⁶⁸ Ga]Ga-DOTATATE-PET/CT with ¹⁸ F-FDG-PET/CT) was explored in such metachronous NPCs, and the findings are illustrated with its potential for theranostic applications. NPC is a rare malignancy with significant geographical variations in incidence rates. Somatostatin receptor 2 (SSTR2) expression in NPC is well documented and can serve as a potential theragnostic marker in advanced NPC where the successful outcome is minimal with currently available treatment modalities.

Purpose  The aim of our study was to evaluate the compatibility of lacrimal syringe test with dacryoscintigraphy (DSG) in the postoperative evaluation of external dacryocystorhinostomy (Ext-DCR) surgery. Material and Methods  Thirty eyes of 30 patients suffering from unilateral epiphora with discharge and showing complete obstruction on lacrimal irrigation test were included in the study. Patients with dysfunctional lacrimal pump function, revision surgery, partial obstruction, and ocular surface diseases were not included in the study. Verification of the nasolacrimal duct obstruction (NLDO) was achieved with dye disappearance test, Jones test 1 (JT 1), and JT 2. According to the type of obstruction seen on DSG, patients were classified into two groups: presac and postsac obstruction. Patients with complete obstruction detected in the lacrimal syringing and dynamic scintigraphy underwent Ext-DCR, and the results were evaluated. Results  Thirty patients, mean age 58.93 ± 12.11 years, all with unilateral NLDO were included in the study. All had grade 5 Munk score epiphora and discharge. The mean duration of obstruction was 24.57 ± 10.65 months. In the lacrimal irrigation test, all patients had complete obstruction in one eye, while the other eye was normal. According to preoperative DSG results, there were 20 (66.7%) patients with presac delay and 10 (33.3%) patients with postsac delay. All patients underwent Ext-DCR with silicone tube intubation and were followed for 1 year. Although there was symptomatic improvement in all patients and the lacrimal syringing test was patent, no change was seen in scintigraphy. Conclusion  Although DSG is a sensitive nuclear medicine method, it is not useful for predicting the functional success of the Ext-DSR.

Ewing's sarcoma (ES) is a mesenchymal origin malignant neoplasm that affects children and adolescents. It is the second most common type of bone sarcoma and accounts for approximately 1.5% of all childhood cancers with an annual incidence of 1 to 3 cases per million children under 16 years of age. In this article, we present the case of a 16-year-old adolescent girl. Lung metastasis at the initial diagnosis of ES is relatively uncommon but carries significant prognostic implications. Lung metastases in ES can vary significantly in size, ranging from small nodules (just a few millimeters in size) to the largest reported case being 15 cm. The size of the metastases impacts the choice of therapeutic strategies and the prognosis. Approximately 30% of patients with ES experience a relapse, with the lungs being a common site for metastatic disease. Relapsed lung metastasis on follow-up is a critical concern in the long-term management of ES. We describe a relapsed case of ES in a 16-year-old adolescent girl who presented with a solitary large metastatic right lung mass, with the longest dimension of 16 cm on craniocaudal measurement. The primary site of the tumor was the left distal femur, for which the patient received six cycles of neoadjuvant chemotherapy, followed by en bloc tumor excision and rotationplasty of the left distal femur, after which the patient received seven cycles of adjuvant chemotherapy. Subsequent 5 years of regular follow-up was asymptomatic. Later, the patient presented with back pain and cough, and was diagnosed with a solitary large right lung mass. Computed tomography (CT) guided biopsy of the right lung mass revealed a metastatic ES, for which she underwent chemoradiotherapy. This case highlights the large size of solitary lung metastases in relapsed ES.