Nuclear Medicine Communications最新文献

Objective: This study validated the optimal acquisition and reconstruction conditions for technetium-99m dimercaptosuccinic acid single-photon emission computed tomography examinations in neonates.

Methods: We developed renal phantoms representing neonatal and adult kidneys, derived from clinical data to achieve this. The radioactivity concentration to be encapsulated in the renal part was adjusted according to the Japanese consensus guidelines for the appropriate implementation of pediatric nuclear medicine examinations. The evaluation of optimal acquisition conditions considered factors such as acquisition time and magnification ratio, while the determination of optimal reconstruction conditions focused on the cutoff frequency of the Butterworth filter and the appropriate correction methods. The physical evaluation assessed defect contrast and background coefficient of variation, while the visual evaluation assessed the ability of the images to depict the defect.

Results: The defect contrast was almost constant after acquisition times of 10 min for neonates and 12 min for adults. For the magnification ratio, the effect was greater for neonates than for adults. In addition, in contrast to adults, the use of resolution recovery significantly decreased scores in visual evaluation in neonates.

Conclusion: Our study suggests better images can be obtained in neonates with shorter acquisition times than adults. In addition, the optimal reconstruction conditions are shown to differ between neonates and adults.

Objective: The objective of this study is to determine an optimal threshold for the maximum standardized uptake value (SUVmax) of 18 F-fluorodeoxyglucose PET/CT to predict the newly proposed high-grade tumor classification and assess its prognostic significance in invasive lung adenocarcinoma (LUAD).

Methods: Surgical specimens from 185 patients with pathological stage I invasive LUAD in the training group, along with 90 patients in the validation group, were analyzed using the novel IASLC grading system. The receiver operating characteristic curve was used to determine the optimal SUVmax threshold and assess its predictive accuracy. Disease-free survival (DFS) and overall survival (OS) were analyzed using Kaplan-Meier survival curves and Cox regression analysis.

Results: Linear correlation analysis demonstrated a significant positive association between SUVmax and the proportion of high-grade histological patterns ( R ² = 0.346, P  < 0.001). The optimal SUVmax cutoff for predicting grade 3 tumors was 3.8, with an area under the curve of 0.866 in the training dataset and 0.899 in the validation dataset. Multivariate logistic regression analysis identified an SUVmax >3.8 as an independent predictor of grade 3 tumors ( P  < 0.001). In Cox regression analysis, SUVmax >3.8 was independently associated with reduced DFS (HR = 4.009, 95% CI: 1.568-10.250, P  = 0.004) and OS (HR = 5.536, 95% CI: 1.175-26.075, P  = 0.030).

Conclusion: As a noninvasive preoperative parameter, SUVmax >3.8 is a significant indicator of high-grade tumors as classified by the IASLC grading system and is strongly associated with worse DFS and OS.

The objective is to assess whether the degree of metabolic uptake of the primary tumor and axillary lymph nodes (ALNs) on baseline [ 18 F] fluorodeoxyglucose ([ 18 F]FDG) PET/CT is associated with the probability to achieve axillary pathologic complete response (pCR) in clinically node-positive (cN+) breast cancer patients treated with neoadjuvant systemic therapy (NST), overall and per clinical subtype. Studies that assessed the maximum standardized uptake value (SUVmax) in the primary tumor and ALNs on baseline [ 18 F]FDG PET/CT and reported axillary pCR rates in patients diagnosed with cN+ invasive breast cancer treated with NST, followed by surgery, were searched. Area under the curve (AUC) values were obtained. A total of seven studies (561 patients) were included. The mean baseline SUVmax of the primary tumor ranged from 8.1 (±4.3) to 9.8 (±7.2). Mean baseline axillary SUVmax ranged from 6.0 (±5.6) to 7.3 (±6.2). The axillary pCR rate ranged from 38.0% to 48.1%. Considering the primary tumor, no study reported on the association between baseline SUVmax and the axillary pCR rate. Considering the ALNs, the AUC value for baseline axillary SUVmax to predict axillary pCR ranged from 0.52 [95% confidence interval (CI): 0.39-0.65; all subtypes included] to 0.74 (95% CI: 0.53-0.95; only human epidermal growth factor receptor 2+ and triple negative). In conclusion, no association between the primary tumor SUVmax on baseline [ 18 F]FDG PET/CT and axillary pCR was found. Concerning the axilla, based on limited scientific evidence, the axillary SUVmax on baseline [ 18 F]FDG PET/CT may be associated with axillary pCR after NST in cN+ breast cancer patients, however, potential differences between clinical subtypes should be considered.

In the UK, the Administration of Radioactive Substances Advisory Committee (ARSAC) sets and publishes National Diagnostic Reference Levels (NDRLs) for diagnostic nuclear medicine (NM) and Positron Emission Tomography procedures. This article summarises how these NDRLs should be applied and used within the UK and proposes a new model on how they are set. As an exemplar, the results of a recent survey of administered activities in the UK for 18 F-fluorodeoxyglucose (FDG) for whole-body tumour imaging and infection inflammation imaging are presented here. ARSAC recommends that the UK NDRLs for NM or PET examinations are set as either a fixed activity (MBq) or by administered activity per body weight (MBq/kg). ARSAC proposes setting the first weight-based activity scaling NDRLs for 18 F-FDG whole-body tumour imaging and 18 F-FDG infection inflammation imaging to 3.5 MBq/kg.

Objective: This study aimed to refine the 99m Tc-dimercaptosuccinic acid (Tc-99m DMSA) renal static imaging (DMSA) rating method and evaluate its prognostic value in children with urinary tract infections (UTIs) associated with vesicoureteral reflux (VUR).

Methods: Retrospective analysis was conducted on DMSA data (DMSA1 at the initial visit and DMSA2 at follow-up; imaging interval ≥ 6 months) and clinical data from 117 children. Each kidney was divided into three regions: upper, middle, and lower. Lesions were graded in a blinded manner based on the distribution of the imaging agent and whether the defect area exceeded 50% of the region. Lesion grades were classified as 0 (normal) to 5 (complete defect). DMSA2 ratings were categorized as complete recovery, improvement, similar, or deterioration, and clinical factors influencing each group were analyzed.

Results: A total of 160 diseased kidneys were identified in 117 children. The DMSA1 and DMSA2 image ratings were highly consistent (kappa coefficients: 0.806, 0.839, 0.813, 0.820 for left and right kidneys, respectively). A statistically significant difference in image ratings was observed between DMSA1 and DMSA2 when DMSA1 rating was ≥3b. Changes in DMSA2 ratings were associated only with the initial DMSA1 rating and the presence of breakthrough urinary sensation at follow-up.

Conclusion: Image changes were related solely to breakthrough urinary sensation. When the initial DMSA lesion grade exceeds 3b, improvement in the lesion is unlikely, regardless of subsequent breakthrough urinary sensation. The modified DMSA rating method is effective and can predict prognosis in children with UTIs.

Purpose: The study aimed to investigate the imaging parameters of 18F-fluorodeoxyglucose ( 18 F-FDG) PET/computed tomography (PET/CT) in nasopharyngeal carcinoma (NPC), specifically examining the relationship between mean standardized uptake value (SUVmean), maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) with Ki-67 expression, T-stage, and tumor node metastasis (TNM) stage.

Methods: A retrospective analysis was conducted on 143 consecutive NPC patients from January 2015 to December 2023 who underwent 18 F-FDG PET/CT for initial disease assessment. SUVmax, SUVmean, MTV, and TLG were quantified from PET/CT images. Immunohistochemical staining was used to assess Ki-67 protein expression. Correlations between 18 F-FDG PET/CT metabolic parameters, Ki-67 expression, T-stage, and TNM-stage were evaluated using statistical methods, with significance set at P  < 0.05.

Results: All primary NPC lesions demonstrated elevated 18 F-FDG uptake. Significant positive correlations were observed between SUVmax ( r  = 0.234, P  = 0.005), SUVmean ( r  = 0.223, P  = 0.007), MTV ( r  = 0.218, P  = 0.009), and TLG ( r  = 0.232, P  = 0.005) with Ki-67 labeling index. The univariate analysis indicated that all the parameters (SUVmax, SUVmean, MTV, and TLG) in the group with Ki-67 ≥ 50% were significantly higher than those in the group with Ki-67 < 50% ( P  = 0.001). Additionally, binary logistic regression analysis revealed that SUVmax was an independent risk factor for the group with Ki-67 ≥ 50% ( P  = 0.003). The univariate analysis revealed that all parameters (SUVmax, SUVmean, MTV, and TLG) in the T3-4 group and clinical stage IV group were significantly higher than those in the T1-2 group and stages I-III group ( P both <0.05), respectively. Furthermore, binary logistic regression analysis demonstrated that MTV was an independent risk factor for both comparisons ( P both <0.05).

Conclusion: The metabolic parameters derived from 18 F-FDG PET/CT in NPC indirectly reflect tumor biological behavior, suggesting their potential utility in guiding individualized comprehensive treatment strategies.

Objective: The objective of this study is to investigate the risk and prognostic factors for radioactive iodine (RAI)-refractory (RAIR) differentiated thyroid cancer (DTC) with distant metastasis.

Methods: A total of 128 patients with distant metastasis-DTC who underwent iodine-131 radiotherapy were included in this cohort study. After exclusion, 75 DTC patients who were resistant to radioiodine therapy and 53 patients in whom the treatment was successful were finally included. Clinical data as well as BRAF V600E and telomerase reverse transcriptase (TERT) promoter mutations were compared between these two groups to predict the risk of RAIR. Patients with RAIR-distant metastasis-DTC were followed up to further investigate the risk factors for disease progression after the cancer became iodine-refractory.

Results: Univariate analysis showed that TERTp mutation, age at diagnosis, mean maximum tumor diameter, lymph node metastasis, synchronous metastasis or heterochronous metastasis, mean cumulative dose of RAI, and preoperative Tg were statistically different between the RAIR and RAIE (radioiodine efficient) groups. Logistic regression analysis further found that the TERTp mutation may be risk factor for iodine refractory occurrence. During the follow-up of RAIR-distant metastasis-DTC patients, 41 patients developed disease progression, and 24 patients had good disease control.

Conclusion: We found that TERTp mutation is correlated with the poor curative effect of RAI therapy in distant metastasis-DTC. Once iodine refractory occurs, patients aged 55 years or older are more likely to develop disease progression.

Background and objective: Yttrium-90 plays a significant role in managing drug-resistant inflammatory arthritis through radionuclide synovectomy, where the radioisotope is injected into the affected joint to alleviate pain and inflammation by targeting the synovial tissue. This study aims to evaluate the effectiveness and safety of Yttrium-90 hydroxyapatite radionuclide synovectomy in improving joint functionality, as judged by physicians, in patients with inflammatory arthritis who had not responded to conventional treatments.

Methods: Patients with inflammatory arthritis were recruited from the orthopedics department and referred to the nuclear medicine department for evaluation. A three-phase bone scan was conducted to identify eligible patients, who then received intra-articular injections of Yttrium-90 hydroxyapatite along with triamcinolone. After 48 h, patients underwent PET-CT imaging, followed by two follow-ups at 2 and 6 months to assess improvements in joint functionality and monitor for adverse reactions.

Results: Fifteen patients underwent radionuclide synovectomy. Significant improvements were observed between baseline and 2 months in joint restriction ( P  = 0.001), pain severity ( P  = 0.037), visual analog scale (VAS) ( P  = 0.004), and swelling ( P  = 0.002). At 6 months, further improvements were noted in joint restriction ( P  = 0.002), pain severity ( P  = 0.019), VAS ( P  = 0.013), and swelling ( P  = 0.023). However, no significant changes occurred between the 2- and 6-month follow-ups. One patient experienced radiation-induced skin necrosis, which resolved with conservative treatment, and another had self-limited skin rashes.

Conclusion: Yttrium-90 hydroxyapatite radionuclide synovectomy proved to be an effective and safe treatment for improving joint functionality in patients with drug-resistant inflammatory arthritis of the knee for up to 6 months.

Objective: The appropriate clinical management of indeterminate small renal masses can be improved based on accurate risk stratification. This study aimed to investigate the impact of renal function on the uptake of technetium-99m ( 99m Tc)-sestamibi, a widely available imaging agent that can be utilized to identify oncocytomas and other benign/indolent renal masses.

Methods: A retrospective cohort study was conducted, involving 100 consecutive patients who underwent 99m Tc-sestamibi single-photon emission computed tomography/computed tomography. Renal function was evaluated based on creatinine levels and glomerular filtration rate (GFR). Statistical analyses, including correlation and regression analyses, were performed to explore the relationship between renal function and 99m Tc-sestamibi uptake.

Results: The results revealed that discrepancies can occur between imaging and pathology results, emphasizing the need for careful interpretation of imaging findings. Correlation analysis demonstrated no significant correlation between relative tumor uptake of 99m Tc-sestamibi and GFR or serum creatinine levels. These findings highlight the relative independence of renal function and 99m Tc-sestamibi uptake and suggest sestamibi may be of use even in patients with relatively poor renal function.

Conclusions: However, further research with larger sample sizes is required to validate and generalize these findings. Ultimately, understanding the broad variety of applicability of 99m Tc-sestamibi uptake for risk stratification of renal malignancy could aid in appropriate clinical decision-making.