Nuclear Medicine Communications最新文献

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 18F/68Ga-FAPI and fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT scans. Clinical characteristics and PET/CT parameters of maximum and mean standard uptake value (SUVmax and SUVmean) of muscle at the 3rd 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 SUVmax and SUVmean of muscle from 18F/68Ga-FAPI PET/CT, and lower SUVmax of muscle from 18F-FDG PET/CT were correlated with a higher prevalence of sarcopenia (P < 0.05). Besides, no significant differences in SUVmax and SUVmean of muscle were noted between 18F-FAPI and 68Ga-FAPI groups. The best cutoff value of SUVmax of muscle from 18F/68Ga-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 SUVmax of muscle from 18F-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.

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, 131I 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 131I 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: Limited safety data have been published on fluorine-18 (18F) meta-fluorobenzylguanidine (mFBG), 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 18F-mFBG 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: mFBG 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 mFBG 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 mFBG in the target population of patients with neuroblastoma.

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.

Background: Microvascular infiltration (MVI) before liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) is associated with postoperative tumor recurrence and survival. MVI is mainly assessed by pathological analysis of tissue samples, which is invasive and heterogeneous. PET/computed tomography (PET/CT) with 18 F-labeled fluorodeoxyglucose ( 18 F-FDG) as a tracer has been widely used in the examination of malignant tumors. This study investigated the association between 18 F-FDG PET/CT metabolic parameters and MVI before LT in HCC patients.

Methods: About 124 HCC patients who had 18 F-FDG PET/CT examination before LT were included. The patients' clinicopathological features and 18 F-FDG PET/CT metabolic parameters were recorded. Correlations between clinicopathological features, 18 F-FDG PET/CT metabolic parameters, and MVI were analyzed. ROC curve was used to determine the optimal diagnostic cutoff value, area under the curve (AUC), sensitivity, and specificity for predictors of MVI.

Result: In total 72 (58.06%) patients were detected with MVI among the 124 HCC patients. Univariate analysis showed that tumor size ( P  = 0.001), T stage ( P  < 0.001), maximum standardized uptake value (SUV max ) ( P  < 0.001), minimum standardized uptake value (SUV min ) ( P  = 0.031), mean standardized uptake value (SUV mean ) ( P  = 0.001), peak standardized uptake value (SUV peak ) ( P  = 0.001), tumor-to-liver ratio (SUV ratio ) ( P  = 0.010), total lesion glycolysis (TLG) ( P  = 0.006), metabolic tumor volume (MTV) ( P  = 0.011) and MVI were significantly different. Multivariate logistic regression showed that tumor size ( P  = 0.018), T stage ( P  = 0.017), TLG ( P  = 0.023), and MTV ( P  = 0.015) were independent predictors of MVI. In the receiver operating characteristic curve, TLG predicted MVI with an AUC value of 0.645. MTV predicted MVI with an AUC value of 0.635. Patients with tumor size ≥5 cm, T3-4, TLG > 400.67, and MTV > 80.58 had a higher incidence of MVI.

Conclusion: 18 F-FDG PET/CT metabolic parameters correlate with MVI and may be used as a noninvasive technique to predict MVI before LT in HCC patients.

Salivary gland scintigraphy (SGS) is an imaging technique to evaluate functional aspects of the salivary glands. First described in 1965, visual analyses of summed images and of time-activity curves generated through regions of interest (ROI) are still the main evaluation tools used in clinical practice. An alternative to ROI-based analysis is the use of parametric images, which are images generated through pixel-by-pixel calculation of parameters from the original frames. In this article, we would like to present some parametric images for SGS studies and how to create and use them. Two images, vascular flow and uptake velocity, were created using the intercept and slope of a linear model of the frames from after the first to fifth minute of acquisition. And two others, excretion fraction and absolute excretion, by subtraction and division methods of the frames before and after sialogogue stimulation. These images allow the visualization of the spatial distribution and heterogeneity of these quantitative parameters, favoring different forms of analysis and helping with image segmentation. After more than a year of using these images in daily routine, our general impression is that they have been very helpful. This article, however, still represents only our early experiences with this technique, and clinical studies are yet needed to better evaluate this method.

[ 75 Se]tauroselcholic acid (SeHCAT) retention measurement provides a noninvasive test for bile acid diarrhea (BAD); however, it is sensitive to the presence of other radionuclides. Two SeHCAT patients at the Royal Free Hospital (RFH) had significant discrepancies between the lower photopeak (111-159 keV) and central photopeak (242-296 keV) windows, indicating contamination with a radionuclide other than 75 Selenium. These patients had received lutetium-177 oxodotreotide ( 177 Lu-DOTATATE) therapy 98 and 151 days before their SeHCAT tests. Traces of 177 Lu may be retained longer than typically modeled, along with the contaminant 177m Lu. This work includes a retrospective audit to examine the prevalence of SeHCAT tests being affected by 177 Lu and phantom measurements to investigate the potential impact. Of 579 patients who received 177 Lu-DOTATATE therapy at our center, 11 subsequently attended for a SeHCAT test. The two previously identified patients may have had compromised SeHCAT results; however, the other patients had longer intervals between their therapy and test, and their tests are believed to be valid. Spectra were acquired from a phantom containing either a SeHCAT capsule or a mixture of 177 Lu/ 177m Lu representative of a patient >90 days after their treatment. The SeHCAT spectrum was scaled to produce simulated day-7 spectra, and the SeHCAT retention that would have been calculated if 177 Lu/ 177m Lu were present was determined. All SeHCAT measurement windows are affected by the 177 Lu/ 177m Lu, producing clinically significant errors. Patients requiring SeHCAT testing should be asked whether they have ever received 177 Lu-DOTATATE. Patient-specific background measurements may be useful for checking for significant levels of other radionuclides.

Objective: Visual assessments of amyloid-β PET, used for Alzheimer's disease (AD) diagnosis and treatment evaluation, require a careful approach when different PET ligands are utilized. Because the gray matter (GM) and white matter (WM) ligand bindings vary with age, the objective was to investigate the agreement between visual reads of 11 C- and 18 F-PET scans.

Methods: Cognitively unimpaired (CU) younger adults ( N  =   30; 39.5   ±   6.0   years), CU older adults ( N  =   30; 68.6   ±   5.9   years), and adults with AD ( N  =   22; 67.0   ±   8.5   years) underwent brain MRI, 11 C-Pittsburgh compound-B (PiB)-PET, and 18 F-flutemetamol-PET. Amyloid-β deposition was assessed visually by two nuclear medicine specialists on 11 C-PiB-PET and 18 F-flutemetamol-PET, and quantitatively by PET centiloids.

Results: Seventy-two 11 C-PiB-PET and 18 F-flutemetamol-PET visual reads were concordant. However, 1 18 F-flutemetamol-PET and 9 11 C-PiB-PET were discordant with quantitative values. In four additional cases, while 11 C-PiB-PET and 18 F-flutemetamol-PET visual reads were concordant, they were discordant with quantitative values. Disagreements in CU younger adults were only with 11 C-PiB-PET visual reads. The remaining disagreements were with CU older adults.

Conclusion: Age, GM/WM binding, amyloid-β load, and disease severity may affect visual assessments of PET ligands. Increase in WM binding with age causes a loss of contrast between GM and WM on 11 C-PiB-PET, particularly in CU younger adults, leading to false positivity. In CU older adults, increased WM signal may bleed more into cortical regions, hiding subtle cortical uptake, especially with 18 F-flutemetamol, whereas 11 C-PiB can detect true regional positivity. Understanding these differences will improve patient care and treatment evaluation in clinic and clinical trials.

Objective: This study was conducted to explore the differential diagnostic value of PET/computed tomography (PET/CT) combined with high-resolution computed tomography (HRCT) in predicting the invasiveness of ground-glass nodules (GGNs).

Materials and methods: This retrospective analysis included 67 patients (mean age 62.5 ± 8.4, including 45 females and 22 males) with GGNs who underwent preoperative 18 F-fluorodeoxyglucose ( 18 F-FDG) PET/CT and HRCT examinations between January 2018 and October 2022. Based on the postoperative pathological results of lung adenocarcinoma, the patients were classified into two groups: invasive adenocarcinoma (IAC) and non-IAC. Besides, the clinical and imaging information of these patients was collected. HRCT signs include the existence of air bronchial signals, vascular convergence, pleural indentation, lobulation, and spiculation. Moreover, the diameter of solid components (D Solid ), diameter of ground-glass nodules (D GGN ), and computed tomography values of ground-glass nodules (CT GGN ) were measured concurrently. Furthermore, the mean standardized uptake value, maximal standardized uptake value (SUVmax), metabolic tumor volume, and total lesion glycolysis were assessed during PET/CT. Associations between invasiveness and these factors were evaluated using univariate and multivariate analyses.

Results: The results of logistic regression analysis demonstrated that D GGN , D Solid , consolidation tumor ratio (CTR), CT GGN , and SUVmax were independent predictors in the IAC group. The combined diagnosis based on these five predictors revealed that area under the curve was 0.825.

Conclusion: The D GGN , D Solid , CTR, CT GGN , and SUVmax in GGNs were independent predictors of IAC, and combining 18 F-FDG PET/CT metabolic parameters with HRCT may improve the predictive value of pathological classification in lung adenocarcinoma.