Nuclear Medicine Communications最新文献

Objective: Fluorodeoxyglucose PET/computed tomography (FDG PET/CT) is effective in detecting large vessel vasculitis. Digital PET cameras have improved spatial resolution compared with analog PET, resulting in more prominent physiological uptake in arterial walls. This study's goal was to define qualitative normal variants of arterial activity on digital PET/CT.

Methods: We retrospectively reviewed 126 oncological PET/CT studies. Exclusion criteria included history of vasculitis, immunosuppressant therapy, hyperglycemia, or altered FDG biodistribution. Qualitative vessel wall activity (common carotid, brachiocephalic, subclavian, aorta, and femoral) was visually graded by two nuclear physicians with guideline-proposed criteria: 0: ≤mediastinum, 1: liver, where grade 3 is compatible, 2 is possible, and <2 is negative for vasculitis. Cranial artery uptake was visually graded as follows: grade 0: ≤surrounding tissues, grade 1: just above surrounding tissues, and grade 2: significantly above surrounding tissues, with grades 1 and 2 considered positive for cranial artery vasculitis.

Results: Large vessel uptake was grade 3 in 0 subjects, grade 2 in four subjects (3%), grade 1 in 87 subjects (69%), and grade 0 in 35 subjects (28%). In studies acquired ≥75 min post-injection, 1/15 subjects had grade 2 uptake. Four subjects (3%) had grade 1 vertebral artery uptake. No subjects had temporal, maxillary, or occipital artery uptake.

Conclusion: A minority of our subjects presented with grade 2 large vessel uptake, which was associated with longer uptake times, or grade 1 cranial artery uptake, which was associated with higher age and glycemia. These findings should be interpreted with caution in patients referred for suspected vasculitis, as they may represent normal variants on digital PET.

Radiation treatments [radiotherapy and radionuclide treatments (RNTs)] are one of the main and effective treatment modalities of cancer. Globally, the number of cancer patients treated with radionuclides are much less as compared to number of radiotherapy cases but with the development of new radiotracers, most notably 177 Lu and 225 Ac-labeled prostate-specific membrane antigen ligands, and 223 Ra-dichloride for prostate cancer and 177 Lu-somatostatin analogs for neuroendocrine tumors, there is a significant rise in RNTs in the last decade. As therapeutic applications of nuclear medicine is on the rise, the aim of this review is to summarize biological responses to radiation treatments and molecular mechanisms of radiation-induced cell death (e.g. ionization, DNA damages such as double-strand breaks, DNA repair mechanisms, types of cell deaths such as apoptosis, necrosis, and immunogenic cell death), histopathological changes with radiation treatments, and role of PET imaging in RNTs as part of radionuclide theranostics for selecting and planning patients for RNTs, dosimetry, predicting and assessing response to RNTs, predicting toxicities, and other possible PET findings which may be seen after RNTs such as activation of immune system.

Objective: Limited safety data have been published on fluorine-18 ( 18 F) meta-fluorobenzylguanidine ( m FBG), a new PET radiopharmaceutical for imaging neural crest and neuroendocrine tumors. As part of a prospective clinical trial, safety data in patients with neuroblastoma were collected and analyzed.

Methods: Between April 2015 and January 2022, 27 patients with neuroblastoma underwent 18 F- m FBG PET imaging as part of an ongoing single-center phase 1/2 trial (NCT02348749). Pre- and postinjection safety assessments were performed, including vital sign measurement and observation for occurrence of adverse events (AEs).

Results: m FBG administration resulted in no significant changes in measured vital signs. Two subjects had transient, grade 1 facial flushing shortly after the administration, which resolved within a few minutes. Neither subject had a clinically significant change in pulse or blood pressure on postadministration measurements.

Conclusion: In this investigation of the potential clinical utility of m FBG PET imaging, no significant adverse safety signals were noted. Two mild, self-limited AEs were observed, without associated changes in vital signs. No grade 2 or higher AEs were noted. The findings are consistent with a favorable safety profile for m FBG in the target population of patients with neuroblastoma.

Objective: Patients with chronic kidney disease (CKD) have an increased risk of adverse cardio-cerebrovascular events. The purpose of this study is to evaluate the prognostic predictors over 5 years in patients with CKD including haemodialysis.

Methods: In this multicenter, prospective cohort study performed with the Gunma-CKD SPECT Study protocol, 311 patients with CKD [estimated glomerular filtration rate (eGFR) < 60 min/ml/1.73 m 2 ], including 50 patients on haemodialysis, undergoing stress Tc-99m-tetrofosmin SPECT for suspected ischaemic heart disease were followed for 5 years. MACCRE was evaluated, and summed stress score, summed rest score, summed difference score (SDS), left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV) and ejection fraction (LVEF) were evaluated by electrocardiogram-gated SPECT.

Results: Of the 311 patients, 268 were followed for 5 years, and of those patients, 126 experienced MACCRE: cardiac death, n  = 15; sudden death, n  = 5, nonfatal myocardial infarction, n  = 5; hospitalization for heart failure, n  = 16; cerebrovascular accident, n  = 9; revascularization, n  = 49; renal events (haemodialysis initiation/kidney transplantation), n  = 20 and other cardiovascular events, n  = 7. In univariate Cox analysis, eGFR ( P  < 0.0001), haemoglobin ( P  = 0.001), SDS ( P  = 0.0001), LVEDV ( P  = 0.002), LVESV ( P  = 0.0003) and LVEF ( P  < 0.0001) were associated with MACCRE, and in multivariate Cox analysis, eGFR ( P  = 0.014) and SDS ( P  = 0.002) were strongly associated with MACCRE. In Kaplan-Meier analysis, the event-free survival rate for MACCRE was better in patients with SDS below 3 than in those with SDS of 3 or higher ( P  < 0.0001, log-rank test) and in patients with eGFR of 18 or higher than in those with eGFR below 18 ( P <  0.0001, log-rank test).

Conclusion: In patients with CKD, SDS and eGFR are reliable prognostic markers for the occurrence of MACCRE over 5 years.

Objective: Hyperthyroidism, a prevalent endocrine disorder, disrupts metabolic balance and cardiovascular health, affecting millions globally. Radioactive iodine (RAI), a treatment for hyperthyroidism, employs high-energy beta particles to reduce thyroid tissue, lowering volume and hormone levels. This study utilizes bibliometric analysis to outline RAI's evolution and identify hotspots in hyperthyroidism treatment.

Methods: A total of 2904 articles and reviews published between 1981 and 2023 were retrieved from the Web of Science Core Collection using the research strategy. Bibliometric analyses, employing VOSviewer and CiteSpace, were performed to visualize the cooperation network, evolution, and hot topics.

Results: Annual publications rose in waves, 2904 papers from 2564 institutions, and 84 countries. The USA led, contributing the largest share, with the journal Thyroid dominating publication. The University of Pisa contributed the most articles. Co-occurrence analysis classified keywords into five clusters: treatment mechanism, safety, effectiveness assessment, individualized radioactive dosage, and management. The development of RAI therapy for hyperthyroidism can be divided into three stages: safety and efficacy assessment, personalized treatment plans, and treatment of drug-resistant and surgery-resistant hyperthyroidism.

Conclusion: Attention to RAI in hyperthyroidism should be significantly increased. It is necessary to establish collaborations between authors, countries, and institutions to promote the development of this field. Recent research has focused on personalized radioactive dosage formulation and follow-up. Future studies are likely to concentrate on drug-resistant and surgery-resistant hyperthyroidism, which is also worthy of investigation. These findings provide a new perspective on the study of RAI in hyperthyroidism, potentially contributing to the improvement of the quality of life for patients with hyperthyroidism.

Objectives: The objective of this study is to evaluate the diagnostic performance of neck fluorodeoxyglucose (FDG) PET/MRI in addition to whole-body PET/computed tomography (CT) and to compare it with MRI in the detection of suspicion of disease relapse in patients with differentiated thyroid cancer (DTC) who underwent total thyroidectomy and radioactive iodine therapy.

Methods: Twenty-nine patients with DTC who underwent whole-body 18 F-FDG PET/CT followed by neck PET/MRI because of increased serum thyroglobulin (Tg) or anti-Tg antibody levels and negative 131 I whole-body scan were included. At least 6 months of clinical and radiological (neck ultrasound) follow-up or histopathological examination results were accepted as the gold standard. Lesion and compartment-based analyses were performed to evaluate the diagnostic performances of PET/CT, MRI, and PET/MRI. In addition, changes of clinical management were evaluated.

Results: On lesion-based analysis, for PET/CT, MRI, and PET/MRI: sensitivity: 33.3, 33.3, and 37%; specificity: 90.1, 87.9, and 95.9%; accuracy: 87.5, 85.4, and 93.2 were calculated, respectively. Specificity of PET/MRI was significantly superior to PET/CT and MRI ( P  of0.001); however, sensitivity of PET/MRI was not significant to PET/CT and MRI ( P  of0.05). On compartment-based analysis, specificity of PET/MRI and MRI were comparable but significantly superior to PET/CT at levels 1 and 2; however, specificity of PET/CT and PET/MRI were comparable but significantly superior than MRI, especially at levels 3, 4, and 5.

Conclusion: PET/MRI especially helps in the accurate exclusion of findings that are suspicious on PET/CT and MRI, and has the potential to change the clinical management by identifying uncertain neck findings.

Background: The objective of this study is to explore and compare the potential utility of fibroblast activation protein inhibitor (FAPI) and fluorodeoxyglucose PET/computed tomography (CT) in assessing sarcopenia among patients with malignant tumors.

Methods: A retrospective analysis was conducted on 127 patients with histologically confirmed malignant tumors who underwent both 18 F/ 68 Ga-FAPI and fluorine-18-fluorodeoxyglucose ( 18 F-FDG) PET/CT scans. Clinical characteristics and PET/CT parameters of maximum and mean standard uptake value (SUV max and SUV mean ) of muscle at the 3 rd lumbar (L3) level were reviewed. Skeletal muscle area at the L3 level was measured, and skeletal muscle index was calculated to determine sarcopenia. The association between sarcopenia and PET/CT parameters was analyzed.

Results: The incidence of sarcopenia was 41.7% among these 127 patients. Higher age, male, lower BMI, lower SUV max and SUV mean of muscle from 18 F/ 68 Ga-FAPI PET/CT, and lower SUV max of muscle from 18 F-FDG PET/CT were correlated with a higher prevalence of sarcopenia ( P  < 0.05). Besides, no significant differences in SUV max and SUV mean of muscle were noted between 18 F-FAPI and 68 Ga-FAPI groups. The best cutoff value of SUV max of muscle from 18 F/ 68 Ga-FAPI PET/CT was 1.17, yielding the area under the curve (AUC) of 0.764 and sensitivity and specificity of 74.3% and 71.7%, while the optimal cutoff value of SUV max of muscle from 18 F-FDG PET/CT was 0.76, with an AUC of 0.642 and sensitivity and specificity of 36.5% and 86.8%, respectively.

Conclusion: Patients with sarcopenia exhibit decreased muscle uptake of FAPI and fluorodeoxyglucose. FAPI PET/CT emerges as a more valuable tool for sarcopenia assessment in patients with malignant tumors compared to fluorodeoxyglucose PET/CT.

Objective: Diagnosis of early onset dementia is critical for initiating management. Although structural MRI is an established procedure for dementia evaluation, early cases may be missed. Neurodegenerative diseases lead to reductions in glucose consumption and grey matter volume loss. Our primary aim was to establish whether metabolic changes precede perfusion abnormalities in early cases of dementia especially, frontotemporal dementia (FTD). Secondly to study if cerebral atrophy using Pasquier visual rating scales can be used reliably to correlate with hypometabolism in this group of patients.

Materials and methods: A total of 56 patients (M:F = 39:17) with memory loss as per the DSM-5 diagnostic criteria were clinically and neurologically examined and referred for 18 F-Fluorodeoxyglucose (FDG) PET brain imaging. A few patients who had a prior (recent, <1 week) MR brain underwent brain 18 F-FDG PET-CT, and all others were considered for simultaneous 18 F-FDG PETMR imaging of brain. T2-weighted images were used to report Pasquier rating scales in all our patients as per recommendation.

Results: Cognitive assessments were analysed along with neuroimaging findings. Highest diagnostic performance was obtained with 18 F-FDG PET for identifying early FTD in our series of patients. Sensitivity, specificity and accuracy of FDG and arterial spin labeling (ASL) using simultaneous PETMR were found to be 96.34%/90.1%/89 : 53.57%/62.12%/78, respectively. Cerebral atrophy rated using Pasquier visual scales showed the lowest diagnostic performance. Our study showed that the earliest phase of cognitive decline was found to be associated with specific patterns of hypometabolism, even in the absence of atrophy, which are currently considered diagnostic biomarkers.

Conclusion: Metabolic derangements indeed precede perfusion changes and cerebral atrophy in the setting of early dementia. Simultaneous FDG PETMR is being recommended as the investigation of choice for the evaluation of early FTD. This pilot study shows that FDG PET outperforms cognitive assessments and anatomical imaging modalities in early dementia evaluation. Although ASL can detect perfusion deficits in dementia, compared with FDG PET, its sensitivity and specificity for discerning early onset dementia from controls remain inferior to FDG PET. Pasquier scales, although easy to implement, cannot replace FDG PET metabolic findings, which start very early in the neuronal disease process.

With the advancement of radiotherapy technology in the medical field, the amount of radioactive waste has rapidly increased, and the International Atomic Energy Agency (IAEA) has proposed waste deregulation standards based on individual dose, collective dose, and nuclide concentration. The purpose of this study is to define the standard period (1 day) required to measure collected radioactive waste using direct and indirect methods with a radioactivity meter, ensure that the radiation dose remains below the allowable level, and transport the waste safely. In this study, 131 I low-dose (30 mCi) radioactive waste discarded after radioiodine treatment at a medical institution was collected, and a measuring container was prepared to measure radioactivity concentration according to IAEA standards. The experiments showed that the minimum number of days required for the contamination levels of the inner and outer parts of containers and therapeutic plastics to fall below the tolerance limit were 6, 1, and 5 days, respectively. Conversely, the contamination levels measured immediately after 131 I treatments in the cases of Styrofoam and paper boxes were below the tolerance limit. The study emphasizes the need for a safe disposal process and active radioactive waste management operations by radioactive waste transporters by specifying the scope for safe transportation beyond the permissible limit.

Objective: This study aims to assess the role of 18 F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) in suspected recurrent ovarian carcinoma. Several clinical and PET parameters were assessed to evaluate disease burden and prognosis.

Methods: We did a single-center, retrospective study in patients with suspected recurrent ovarian carcinoma who underwent 18 F-FDG PET/CT. The disease burden on the scan was evaluated. We calculated several semiquantitative markers, including standard uptake values (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Survival analysis was done with clinical parameters, CA-125 levels, disease distribution, and metabolic markers.

Results: Fifty-two patients were included in the study. Half of the patients had suspected recurrence within 12 months of primary diagnosis. PET/CT scan suggested disease in 35 (67.3%) patients. Multiple metastatic sites were noted in 21 (40.4%) patients. Extra-abdominal metastases were seen in 15 (28.8%) patients. Eight patients had 18 F-FDG avid disease despite a low CA-125 level (<35 IU). Young patients (<50 years), extra-abdominal disease, multiple metastases, and higher restaging were associated with poor outcomes. Meanwhile, treatment history, CA-125 level, and post-PET/CT treatment had no significant effect on survival. MTV@40% SUV (>17.21) and TLG@40% SUV (>68.7) had the sensitivity of 87.5% and 75% for predicting disease outcome.

Conclusion: Recurrent ovarian carcinoma commonly presents with multiple metastasis and extra-abdominal metastases. 18 F-FDG PET/CT-guided patterns of disease distribution were significant markers for poor prognosis. Disease burden on PET/CT-derived semiquantitative parameters was associated with poor outcomes.