Annals of Nuclear Medicine最新文献

Recent advancements in the development of positron emission tomography (PET) tracers have significantly enhanced our ability to image neuroinflammatory processes and neurotransmitter systems, which are vital for understanding and treating neurodegenerative and psychiatric disorders. Similarly, innovative tracers in oncology provide detailed images of the metabolic and molecular characteristics of tumors, which are crucial for tailoring targeted therapies and monitoring responses, including radiotherapy. Notable advancements include programmed death ligand 1 (PD-L1)-targeting agents for lung cancer, prostate-specific membrane antigen-based tracers for prostate cancer, chemokine receptor-targeting agents for hematological malignancies, human epidermal growth factor receptor 2 (HER2)-targeting tracers for various cancers, Claudin 18 based tracers for epithelial tumors, glutamine tracers for colorectal cancer, and ascorbic acid analogs for assessing cancer metabolism and therapy efficacy. Additionally, novel tracers have been developed for non-neurological and non-oncological applications, including adrenal imaging, amyloidosis, and human immunodeficiency virus (HIV) infection. This overview focuses on the newly developed tracers, particularly those used in neurology and oncology.

This review explores the potential applications of Large Language Models (LLMs) in nuclear medicine, especially nuclear medicine examinations such as PET and SPECT, reviewing recent advancements in both fields. Despite the rapid adoption of LLMs in various medical specialties, their integration into nuclear medicine has not yet been sufficiently explored. We first discuss the latest developments in nuclear medicine, including new radiopharmaceuticals, imaging techniques, and clinical applications. We then analyze how LLMs are being utilized in radiology, particularly in report generation, image interpretation, and medical education. We highlight the potential of LLMs to enhance nuclear medicine practices, such as improving report structuring, assisting in diagnosis, and facilitating research. However, challenges remain, including the need for improved reliability, explainability, and bias reduction in LLMs. The review also addresses the ethical considerations and potential limitations of AI in healthcare. In conclusion, LLMs have significant potential to transform existing frameworks in nuclear medicine, making it a critical area for future research and development.

Objective

The purpose of this study was to validate the concordance of visual ratings of [18F] flutemetamol amyloid positron emission tomography (PET) images and to investigate the correlation between the agreement of each rater and the Centiloid (CL) scale.

Methods

A total of 192 participants, clinically classified as cognitively normal (CN) (n = 59), mild cognitive impairment (MCI) (n = 65), Alzheimer’s disease (AD) (n = 55), or non-AD dementia (n = 13), participated in this study. Three experts conducted visual ratings of the amyloid PET images for all 192 patients, assigning a confidence level to each rating on a three-point scale (certain, probable, or neither). The positive or negative determination of amyloid PET results was made by majority vote. The CL value was calculated using the CapAIBL pipeline.

Results

Overall, 101 images were determined to be positive, and 91 images were negative. Of the 101 positive images, the three raters were in complete agreement for 92 images and in disagreement for 9 images. Of the 91 negative images, the three raters were in complete agreement for 75 images and in disagreement for 16 images. Interrater reliability among the three experts was particularly high, with both Fleiss’ kappa and Conger’s kappa measuring 0.83 (0.76–0.89). The CL values of the unanimous positive group were significantly greater than those of the other groups, whereas the CL values of the unanimous negative group were significantly lower than those of the other groups. Images with rater disagreement had intermediate CLs. In cases with a high confidence level, the positive or negative visual ratings were in almost complete agreement. However, as confidence levels decreased, experts’ visual ratings became more variable. The lower the confidence level was, the greater the number of cases with disagreement in the visual ratings.

Conclusion

Three experts independently rated 192 amyloid PET images, achieving a high level of interrater agreement. However, in patients with intermediate amyloid accumulation, visual ratings varied. Therefore, determining positive and negative decisions in these patients should be performed with caution.

Objectives

The use of ¹⁸F-Sodium fluoride (NaF) PET/CT is established in the detection of metastatic bone disease, yet its utility in osteoporosis remains underexplored. This research aims to assess the variations in ¹⁸F-NaF uptake among individuals with differing bone mineral density (BMD) and to examine the relationship between ¹⁸F-NaF uptake and BMD.

Methods

In this retrospective study, 199 patients (average age 56 ± 6, comprising 52 males and 147 females) with a history of cancer were analyzed. Each participant underwent both ¹⁸F-NaF PET/CT and lumbar dual-energy X-ray absorptiometry (DXA) scans within a span of 7 days. Based on DXA outcomes, patients and their lumbar vertebrae were categorized into normal BMD, osteopenia, and osteoporosis groups. The lumbar ¹⁸F-NaF uptake across these groups were compared, and to explore the association between lumbar standardized uptake values (SUV) values and BMD. The efficacy of ¹⁸F-NaF uptake in diagnosing osteoporosis or osteopenia was also evaluated. Analysis was conducted using Mann–Whitney U tests, Spearman regression, and receiver operating characteristic (ROC) curve analysis through GraphPad Prism 10.0.

Results

A total of 796 lumbar vertebrae from 199 patients were measured. It was observed that osteoporotic patients had significantly lower ¹⁸F-NaF uptake than those with osteopenia and normal BMD across the L1–L4 lumbar vertebrae (P < 0.0001). In a vertebra-based analysis, normal BMD vertebrae exhibited the highest maximum SUV(SUV_max) compared to osteopenic (8.13 ± 1.28 vs. 6.61 ± 1.01, P < 0.0001) and osteoporotic vertebrae (8.13 ± 1.28 vs. 4.82 ± 1.01, P < 0.0001). There was a positive correlation between lumbar ¹⁸F-NaF uptake and BMD across all vertebrae, with correlation coefficients exceeding 0.5 (range: 0.57–0.8). The area under the ROC curve values were notably high, at 0.96 for osteoporosis and 0.83 for osteopenia diagnosis.

Conclusion

This study demonstrates distinct ¹⁸F-NaF uptake patterns among individuals with varying BMD levels, with a positive correlation between ¹⁸F-NaF uptake and BMD. These findings highlight the potential of ¹⁸F-NaF PET/CT as a supportive diagnostic method in the management of osteoporosis.

Background

The efficacy of a second radioactive iodine-131 (¹³¹I) treatment in patients with differentiated thyroid cancer (DTC) who did not achieve an excellent response (ER) following initial ¹³¹I therapy remains controversy and the population that would derive limited benefit from it is currently unclear.

Objectives

The aim of this retrospective study was to assess the efficacy of the second ¹³¹I treatment in DTC patients with non-ER after the initial ¹³¹I therapy, and to identify potential risk factors associated with non-benefit of the second ¹³¹I treatment.

Methods

127 DTC patients who underwent two ¹³¹I treatments following thyroidectomy were included in this study, and the therapeutic response was evaluated after each ¹³¹I treatment. Beneficial treatment was defined as an improvement in therapy response grade (e.g. from indeterminate response to ER) after the second ¹³¹I treatment, while unbeneficial treatment was defined as no change or a downgrade in therapy response grade. The potential risk factors associated with the non-benefit of the second ¹³¹I treatment were identified using univariate and multivariate logistic regression models.

Results

Following the second ¹³¹I treatment, therapy responses of 55.12% (70/127) of patients were reclassified to a better grade indicating treatment benefit, while 44.88% (57/127) showed no change or were reclassified to a worse grade suggesting no benefit from treatment. The non-benefit of the second ¹³¹I treatment was significantly associated with potential risk factors including stimulated thyroglobulin (sTg) level ≥ 11.46 ng/mL before the second ¹³¹I treatment, primary tumor size > 2 cm, status T2 or higher, N1b status and ATA high risk.

Conclusions

The study results demonstrated that more than half of DTC patients could potentially benefit from a second ¹³¹I therapy. However, over 40% of patients exhibited no benefit in response to the second ¹³¹I treatment, suggesting potential overtreatment for this subgroup. Therefore, clinicians should exercise meticulous and precise decision-making based on identified risk factors when considering the necessity of a second ¹³¹I treatment.

The gastrin-releasing peptide receptor (GRPr) has gained recognition as a promising target for both diagnostic and therapeutic applications in a variety of human cancers. This study aims to explore the primary tumor detection capabilities of [⁶⁸Ga] Ga-GRPr PET imaging, specifically in newly diagnosed intra-prostatic prostate cancer lesions (PCa). Following PRISMA-DTA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy Studies) guidelines, a systematic literature search was conducted using the Medline, Embase, Scopus, and Web of Science databases. Data regarding patient characteristics and imaging procedure details—including the type of radiotracer used, administered activity, image acquisition time, scanner modality, criteria, and detection rate of index test—were extracted from the included studies. The pooled patient-and lesion-based detection rates, along with their corresponding 95% confidence intervals (CI), were calculated using a random effects model. The final analysis included 9 studies involving 291 patients and 350 intra-prostatic lesions with [⁶⁸Ga] Ga-GRPr PET imaging in primary PCa. In per-patient-based analysis of [⁶⁸Ga] Ga-GRPr PET imaging, the pooled detection rates of overall and patients with Gleason score ≥ 7 were 87.09% (95% CI 74.98–93.82) and 89.01% (95% CI 68.17–96.84), respectively. In per-lesion-based analysis, the pooled detection rate [⁶⁸Ga] Ga-GRPr PET imaging was 78.54% (95% CI 69.8–85.29). The pooled detection rate mpMRI (multiparametric magnetic resonance imaging) in patient-based analysis was 91.85% (95% CI 80.12–96.92). The difference between the detection rates of the mpMRI and [⁶⁸Ga] Ga-GRPr PET imaging was not statistically significant (OR 0.90, 95% CI 0.23–3.51). Our findings suggest that [⁶⁸Ga] Ga-GRPr PET imaging has the potential as a diagnostic target for primary PCa. Future research is needed to determine the effectiveness of [⁶⁸Ga] Ga-GRPr PET in delivering additional imaging data and guiding therapeutic decisions.

Objective

Sentinel Lymph Node Biopsy (SLNB) is an important management tool for early-stage melanoma. Different radiopharmaceuticals are used internationally to localise the sentinel node using lymphoscintigraphy (LSG) before surgery. Recent reports have suggested that a delayed interval between LSG and SLNB using ^99mTc-labelled nanocolloid tracer has an adverse survival impact, but not with ^99mTc-labelled antimony sulphide colloid. This study aims to analyse survival outcome in a prospective cohort of melanoma patients undergoing same day or next day SLNB after LSG using ^99mTc-labelled nanocolloid.

Methods

Outcome data were reviewed for patients undergoing SLNB, stratified by time interval between LSG and SLNB at a single UK academic centre. Kaplan–Meier survival analysis was used to assess overall survival (OS), melanoma-specific survival (MSS) and progression-free survival (PFS). Cox multivariable regression analysis identified independent risk factors.

Results

925 patients had LSG using the ^99mTc-nanocolloid tracer between 2009 and 2019, with a median follow-up of 6.36 years. No difference was seen on univariate analysis in OS, MSS, PFS, or nodal recurrence between patients undergoing same day or next day SLNB (Log-rank P = 0.437, 0.293, 0.587, 0.342 respectively). In addition, nodal recurrence as first site or anytime site of recurrence in SLNB negative patients was similar between the groups (Log-rank P = 0.093 and 0.457 respectively). Stratified analysis of time did not demonstrate an outcome difference (MSS Log-rank P = 0.938). Cox multivariable regression did not show time interval to independently influence OS, MSS or PFS.

Conclusions

We do not find a significant effect on long-term outcomes when SLNB is performed the day after LSG with ^99mTc-labelled nanocolloid tracer. We infer that tracer migration is not clinically significant within 24 h of injection based on long term clinical outcome data.

Purpose

This study evaluated the usefulness of SUV analysis of 99mTc-galactosyl human serum albumin (99mTc-GSA) scintigraphy including SUV analysis of the cardiac blood pool normalized by blood volume as a predictor of short-term survival in severe liver failure.

Patients and methods

We enrolled 24 patients with severe liver failure who underwent 99mTc-GSA scintigraphy and were admitted to the intensive care unit. Patients were divided into survival and non-survival groups at 7, 14, and 28 days from the performance of 99mTc-GSA scintigraphy. From SPECT images we calculated SUVs of the cardiac blood pool, performing normalization for body weight, lean body weight, Japanese lean body weight, and blood volume and we calculated SUVs of the liver, normalizing by body weight, lean body weight, and Japanese lean body weight. We also calculated the uptake ratio of the heart at 15 min to that at 3 min (HH15) and the uptake ratio of the liver at 15 min to the liver plus the heart at 15 min (LHL15) from planar images of 99mTc-GSA scintigraphy.

Results

There were significant differences between the 7 day survival and non-survival groups for all SUVs of the heart and the liver and HH15, for 14 day survival groups in SUVs of the heart normalized by Japanese lean body weight and blood volume, and no significant differences between 28 day survival groups for any SUVs, HH15, or LHL15. Although the difference was not significant, SUV analysis of the heart normalized by blood volume showed the highest value for the area under the receiver-operating-characteristics curve for both 7 day and 14 day survival.

Conclusion

SUV analysis of 99mTc-GSA including SUV analysis of cardiac blood pool normalized by blood volume is of value for prediction of short-term survival in cases with severe liver failure.

Objective

Transient ischaemic dilatation (TID) had incremental diagnostic and prognostic value in obstructive coronary artery disease (CAD), but its clinical significance in patients with non-obstructive CAD remains unknown. We aimed to explore the prognostic value of TID in patients with non-obstructive CAD by ¹³N-ammonia PET imaging.

Methods

We retrospectively studied 131 consecutive patients with non-obstructive CAD undergoing one-day rest-stress ¹³N-ammonia PET myocardial perfusion imaging (MPI). TID was automatically generated using CardIQ Physio software. The receiver operative characteristic (ROC) curve was used to determine the optimal threshold of TID. The follow-up outcome was major adverse cardiac events (MACE), a composite of re-hospitalization for heart failure or unstable angina, late revascularization, non-fatal myocardial infarction, and cardiac death. Cardiac event-free survivals for normal and abnormal TID were compared using Kaplan–Meier plots and log-rank tests.

Results

During a median follow-up of 42.08 ± 17.67 months, 22 (16.7%) patients occurred MACE. The optimal cut-off value of TID was 1.03 based on MACE. Our preliminary outcome analysis suggests that TID-abnormal subjects had a lower overall survival probability. Furthermore, our multivariate analysis reveals abnormal TID was the only independent predictor for MACE in non-obstructive CAD. In the subgroup analysis, an abnormal TID was an independent predictor for MACE in patients with abnormal perfusion patterns.

Conclusion

Among patients with non-obstructive CAD, PET-derived TID ≥ 1.03 may identify those with a high risk of subsequent MACE independently. It was also an independent risk factor for poor prognosis in patients with abnormal perfusion.

Graphical abstract

CAD coronary artery disease, PET positron emission tomography, MPI myocardial perfusion imaging, TID transient ischaemic dilatation, MACE major adverse cardiac events, ROC receiver operative characteristic.

Objective

Myocardial blood flow (MBF) assessment can provide incremental diagnostic and prognostic information and thus the validation of dynamic SPECT is of high importance. We recently developed a novel cardiac phantom for dynamic SPECT validation and compared its performance against the GE Discovery NM 530c. We now report its use for validation of a new hybrid SPECT/CT System featuring advanced cadmium zinc telluride (CZT) technology in a ring array detector design (StarGuide™, GE HealthCare).

Methods

Our recently developed cardiac phantom with injected technetium-99m radiotracer was used to create physiological time activity curves (TACs) for the left ventricular (LV) cavity and the myocardium. The TACs allow the calculation of uptake rate (K1) and MBF. The StarGuide system was used to acquire and process the TACs, and these were compared to the TACs produced by the phantom and its mathematical model. Fifteen (15) experiments with different doses representing various MBF values were conducted, and a standard statistic tool was applied for significance.

Results

The TACs produced by the StarGuide system had a significant correlation (p < 0.001) with the reference TACs generated by the phantom both for the LV (r = 0.94) and for the myocardium (r = 0.89). The calculated MBF difference between the system and the phantom was 0.14 ± 0.16 ml/min/g and the average relative absolute difference was 13.2 ± 8.1%. A coefficient of variance of ≤ 11% was observed for all MBF subranges. The regional uptake rate values were similar to the global one with a maximum difference of 5%.

Conclusions

Our newly developed dynamic cardiac phantom was used for validation of the dynamic hybrid SPECT/CT CZT-based system (StarGuide™, GE). The accuracy and precision of the system for assessing MBF values were high. The new StarGuide system can reliably perform dynamic SPECT acquisitions over a wide range of myocardial perfusion flow rates.