Synthesis of piperazine-based fluorinated fibroblast activation protein inhibitors for the development of a novel 18F-labeled PET imaging probe

Radiolabeled probes addressing the fibroblast activation protein (FAP) expressed among others by cancer associated fibroblasts in the microenvironment of tumors emerged as promising drugs for diagnostic imaging and therapy of tumors. 68Ga-chelator-based FAP inhibitors are clinically used for the diagnosis of various tumor types. To enhance the imaging quality and improve the applicability, we started to develop covalently 18F-labeled PET tracers for imaging of FAP in various diseases. For this purpose, four fluorinated quinolinecarboxamides 4a-d were synthesized and biologically evaluated. The seven-step synthesis of 4a comprised a Pd-catalyzed Buchwald-Hartwig reaction of bromoquinoline 6 and a Cu-catalyzed 1,3-dipolar cycloaddition of alkyne 12 with 1-azido-2-fluoroethane (Click reaction) as key steps. The fluorinated quinolinecarboxamides 4a-d showed low nanomolar inhibitory activity on FAP and high selectivity against related enzymes. Due to its low lipophilicity (logD7.4 = 0.08) and high metabolic stability (78 % intact after incubation with murine liver microsomes for 90 min), fluoroethyltriazole 4a (IC50 = 1.7 nM) was selected for radiosynthesis. The two-step radiosynthesis with [18F]-1-azido-2-fluoroethane provided the PET tracer [18F]4a in acceptable radiochemical yields (10.8 %) and high radiochemical purities (>97.0 %) within a total synthesis time of 156 min. The molar activities were 0.1-5.8 GBq/μmol. In vitro [18F]4a was stable in human and mouse serum over 90 min. In the biodistribution studies in mice [18F]4a showed fast renal and hepatobiliary elimination. In a mouse xenograft model with a tumor expressing FAP only very low accumulation in the tumor tissue was observed. This unexpected result was confirmed by the relative low uptake of [18F]4a by FAP expressing HT1080 cells.

Comparative Evaluation of ( 18 F)AlF-PSMA-HBED-CC and 68 Ga-PSMA-HBED-CC in Staging Intermediate-/High-Risk Prostate Cancer: A Prospective Study

Objective   68 Ga-PSMA-HBED-CC positron emission tomography (PET)/computed tomography (CT) represents a clinically relevant technique for the evaluation of prostate cancer (PCa) patients, whereas 18 F-AIF-PSMA-HBED-CC is a novel tracer produced in our center, with suitable radiochemical purity for clinical purposes. We prospectively compared the diagnostic values of both tracers for the detection of metastatic disease in patients with intermediate-/high-risk PCa at initial staging. Materials and Methods  Sixty-six patients (mean age: 63 years; range: 52-78 years) with PCa at initial staging (Gleason score ≥6; median prostate-specific antigen [PSA]: 10 ng/mL; range:1.7-152 ng/mL) prospectively underwent routine 68 Ga-PSMA-11 and 18 F-AlF-PSMA-11 PET/CT scanning with a 64-slice PET/CT scan with time-of-flight (TOF) correction. We measured the maximum standardized uptake value (SUVmax) and lesion-to-background ratio (LBR) in all coincidentally detected lesions. Open prostatectomy and pelvic lymph node dissection were performed in nonmetastatic patients. Histopathology, correlative imaging, and/or clinical follow-up were considered the gold standard. Follow-up was conducted at least 4 months after PET/CT scanning (median: 6.4 months; range: 4-11 months). Sensitivity, specificity, and predictive values were calculated. Results  The overall detection rate was 85% (56/66) for both tracers. At least one suspicious lesion indicating potential PCa metastasis was detected in 20 (30%) and 21 (32%) of 66 patients for 68 Ga-PSMA-11 and 18 F-AIF-PSMA-11 tracers, respectively. A total of 145 extra-prostatic lesions were detected in the bone ( n  = 56), lymph nodes ( n  = 88), and lung ( n  = 1) by at least one radiopharmaceutical: 131 (90%) for 68 Ga-PSMA-11 and 123 (85%) for 18 F-AlF-PSMA-11. In concordant lesions, a significant correlation was found between the SUVmax of both tracers ( r  = 0.90, p  = 0.001). The SUVmax and LBR for 18 F-AlF-PSMA-11 were higher in bone foci ( n  = 39) compared with 68 Ga-PSMA-11 (7.2 vs. 8.9 and 14 vs. 13, respectively, p  = 0.02). For the detection of systemic metastasis, the sensitivity values were the same for both techniques: 0.90 (95% confidence interval [CI]: 0.68-0.98). We calculated specificities of 0.96 (95% CI: 0.85-0.99) and 0.94 (95% CI: 0.82-0.98) for 68 Ga-PSMA-11 and 18 F-AlF-PSMA-11, respectively. Conclusions   68 Ga-PSMA-11 and 18 F-AlF-PSMA-11 PET/CT seem to be clinically equivalent imaging techniques for the assessment of primary intermediate-/high-risk PCa with promising potential for the detection of metastatic spread that would impact patient management.

Preliminary study on detection and diagnosis of focal liver lesions based on a deep learning model using multimodal PET/CT images

Objectives

To develop and validate a deep learning model using multimodal PET/CT imaging for detecting and classifying focal liver lesions (FLL).

Methods

This study included 185 patients who underwent 18F-FDG PET/CT imaging at our institution from March 2022 to February 2023. We analyzed serological data and imaging. Liver lesions were segmented on PET and CT, serving as the "reference standard". Deep learning models were trained using PET and CT images to generate predicted segmentations and classify lesion nature. Model performance was evaluated by comparing the predicted segmentations with the reference segmentations, using metrics such as Dice, Precision, Recall, F1-score, ROC, and AUC, and compared it with physician diagnoses.

Results

This study finally included 150 patients, comprising 46 patients with benign liver nodules, 51 patients with malignant liver nodules, and 53 patients with no FLLs. Significant differences were observed among groups for age, AST, ALP, GGT, AFP, CA19-9and CEA. On the validation set, the Dice coefficient of the model was 0.740. For the normal group, the recall was 0.918, precision was 0.904, F1-score was 0.909, and AUC was 0.976. For the benign group, the recall was 0.869, precision was 0.862, F1-score was 0.863, and AUC was 0.928. For the malignant group, the recall was 0.858, precision was 0.914, F1-score was 0.883, and AUC was 0.979. The model's overall diagnostic performance was between that of junior and senior physician.

Conclusion

This deep learning model demonstrated high sensitivity in detecting FLLs and effectively differentiated between benign and malignant lesions.

Importance of oxyphil cells for 99mTc-sestamibi uptake in primary hyperparathyroidism: a retrospective observational study

In patients with primary hyperparathyroidism (pHPT), the importance of oxyphil cells for 99mTc-sestamibi uptake is uncertain.This retrospective observational study of pHPT patients evaluated independent associations between oxyphil cell content (OCC) and preoperative scintigraphic (SC) findings, using logistic regression analyses.We studied 76 patients with pHPT before and after operation. Preoperative SC was able to definitively identify abnormal parathyroid tissue in 47 patients (61.8%). The median relative OCC (postoperative histopathological examination) was 10% (IQR 0.25% - 40%) and the median absolute OCC was 0.09 cm3 (IQR 0.00 - 0.59 cm3). After adjustment for confounders, an iPTH concentration >200 pg/ml and increasing OCC was the only significant independent predictor of a definitively positive SC result (per category of relative OCC: adjusted odds ratio (aOR) 2.40, 95% confidence interval (CI) 1.02 - 5.65, p=0.045).In patients with pHPT, a higher OCC was associated with a significantly higher probability of a clearly positive SC finding.

Predictive value of machine learning for PD-L1 expression in NSCLC: a systematic review and meta-analysis

BACKGROUND

As machine learning (ML) continuously develops in cancer diagnosis and treatment, some researchers have attempted to predict the expression of programmed death ligand-1 (PD-L1) in non-small cell lung cancer (NSCLC) by ML. However, there is a lack of systematic evidence on the effectiveness of ML.

METHODS

We conducted a thorough search across Embase, PubMed, the Cochrane Library, and Web of Science from inception to December 14th, 2023.A systematic review and meta-analysis was conducted to assess the value of ML for predicting PD-L1 expression in NSCLC.

RESULTS

Totally 30 studies with 12,898 NSCLC patients were included. The thresholds of PD-L1 expression level were < 1%, 1-49%, and ≥ 50%. In the validation set, in the binary classification for PD-L1 ≥ 1%, the pooled C-index was 0.646 (95%CI: 0.587-0.705), 0.799 (95%CI: 0.782-0.817), 0.806 (95%CI: 0.753-0.858), and 0.800 (95%CI: 0.717-0.883), respectively, for the clinical feature-, radiomics-, radiomics + clinical feature-, and pathomics-based ML models; in the binary classification for PD-L1 ≥ 50%, the pooled C-index was 0.649 (95%CI: 0.553-0.744), 0.771 (95%CI: 0.728-0.814), and 0.826 (95%CI: 0.783-0.869), respectively, for the clinical feature-, radiomics-, and radiomics + clinical feature-based ML models.

CONCLUSIONS

At present, radiomics- or pathomics-based ML methods are applied for the prediction of PD-L1 expression in NSCLC, which both achieve satisfactory accuracy. In particular, the radiomics-based ML method seems to have wider clinical applicability as a non-invasive diagnostic tool. Both radiomics and pathomics serve as processing methods for medical images. In the future, we expect to develop medical image-based DL methods for intelligently predicting PD-L1 expression.

PET/MR for predicting extranodal extension of head and neck cancer

PURPOSE

To analyze the diagnostic accuracy of multiparametric FDG-PET/MR in identifying pathologic extranodal extension (pENE) of lymph node metastases (LNM) in head and neck squamous cell carcinoma (HNSCC) patients.

METHODS AND MATERIALS

Retrospective analysis of 57 HNSCC patients who underwent preoperative FDG-PET/MR imaging. PET parameters of LNM SUVmax and MTV, lymph node size as well as MR parameters flare sign, shaggy margin sign and vanishing border sign were analyzed. Histopathological assessment of neck dissection specimens served as standard of reference.

RESULTS

A logistic regression model consisting of lymph node size (p = 0.029), shaggy margin sign (p = 0.031) and MTV (p = 0.035) proved that all three parameters significantly contributed to the prediction of pENE (χ²(3) = 54.23, p < 0.001). A second model without the reader-dependent parameter shaggy margin sign yielded similar results (χ²(2) = 45.36, p < 0.001), with every increase in lymph node size (p = 0.006) by 1 mm increasing the likelihood of pENE by a factor of 1.41 (95%-CI[1.11, 1.81]), and every increase in MTV (p = 0.023) by 1 cm3 increasing the likelihood of pENE by a factor of 1.64 (95%-CI[1.07, 2.50]). This model yielded an accuracy of 94.7% (95%-CI [85.4, 98.9]) for predicting pENE, with a specificity of 97.3% (95%-CI [85.8, 99.9]) and a sensitivity of 90.0% (95%-CI [68.3, 98.8]). Internal validation using a test dataset confirmed high accuracy of this model.

CONCLUSION

PET/MR-based multivariate binomial logistic regression models consisting of MTV, lymph node size and/or shaggy lymph node margins predict pENE with high accuracy.

FAPI PET Versus FDG PET/CT in Gastrointestinal Cancers: An Overview

Fibroblast activation protein (FAP) is a type II transmembrane serine protease that is highly expressed in cancer-associated fibroblasts (CAFs) but absent in quiescent fibroblasts. Its overexpression is associated with poor prognosis in various cancers and contributes to treatment resistance. In recent years, radiolabeled FAP inhibitors (FAPI) for PET imaging have shown promising clinical value across a range of cancers. Gastrointestinal (GI) malignancies, which often exhibit a desmoplastic reaction with a high density of FAP-expressing CAFs, are particularly well-suited for FAPI PET. Given the limitations of [18F]FDG PET in GI cancers, such as low sensitivity in certain histological subtypes and high physiological background uptake, FAPI PET is expected to serve as a complementary method, potentially enhancing both diagnostic accuracy and treatment guidance. This review provides a comprehensive comparison of the clinical applications of FAPI PET and [18F]FDG PET in various GI cancers, including their value in diagnosis, staging, and treatment guidance. Additionally, this review summarizes studies on the expanding role of FAPI PET, including its use in assessing treatment response and predicting prognosis, aiming to provide insights into its potential contribution to the improved management of GI malignancies.

Combined gamma radiation source detector and ultrasound imaging system: Proof of concept and first results

BACKGROUND

The examination of lymphogenic metastasis is the basis for the treatment of tumors. It primarily targets the sentinel lymph nodes (SLN). Common imaging techniques to identify SLNs expose patients to high doses of radiation. Ultrasound imaging supported by radiation detectors is a more patient-friendly alternative that can be used intraoperatively. This work aims to develop a gamma source detector which can localize the source and can be combined with a commercial ultrasound system to a dual-modality system.

METHODS

The problem is modeled, and a localization algorithm is developed that robustly determines position estimates from noisy sensor readings. An accuracy optimized arrangement of sensors is determined. The concept is verified by using a test setup based on infrared radiation. Furthermore first tests with gamma radiation are performed.

RESULTS

An infrared radiation source with unknown radiant flux is localized with a spatial deviation of 3.64 ± 1.66 mm (2σ) on average within a wide measurement range of 40 × 20 × 60 mm3. A visualization setup to combine and display data from the developed sensor system and an ultrasound system is shown, that achieves a display rate of 3 frames/s. Tests with gamma radiation show that two gamma source positions can be distinguished.

CONCLUSIONS

The system presented allows 3D localization of a gamma radiation source with reduced radiation exposure to patients. The measurements are combined registration-free with ultrasound imaging to a dual-modality system and provide an enriched database for SLN identification. To reduce measurement times, more efficient sensors must be used.

Role of selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors and psychedelics in the treatment of major depressive disorder: A perspective on mechanistic insight and current status

Globally, depression affects millions of people of all ages, making it one of the significant contributors to deteriorating quality of life by causing neurological impairments that eventually weaken cognition, learning, and memory. According to the monoamine hypothesis, depression is associated with decreased serotonin, dopamine, and norepinephrine levels in the central nervous system. Drugs that inhibit serotonin (5-HT) and norepinephrine (NE) transporters have gained recognition in drug discoveries concerning antidepressants. Both the serotonin-norepinephrine reuptake inhibitors (SNRIs) and selective serotonin reuptake inhibitors (SSRIs) have been significantly involved as the primary medication for major depressive disorder. Recently, the use of psychedelics has gained much importance in antidepressant medications. In this review, we explore a comprehensive overview of different types of antidepressants like SSRIs, SNRIs, and psychedelics, along with their respective target receptors, and their role in recent advancements in treating depression. Furthermore, we discuss the polypharmacology of psychedelics and functional magnetic resonance imaging (fMRI) studies to enhance our understanding of the brain dynamics due to psychedelics.

Simultaneous Identification of Tc-99m-Sestamibi-Positive Autonomous Thyroid Adenoma and Adjacent F-18-Ethylcholine-Positive Parathyroid Adenoma in Patient with Graves' Disease Using Real-Time Ultrasound Fusion Imaging

A 49-year-old female presented for nuclear medicine diagnostics of a sonographically suspected parathyroid adenoma dorsal to the cranial pole of the right thyroid lobe. The patient received Tc-99m-pertechnetate and Tc-99m-sestamibi (including SPECT/CT) scans, revealing no sestamibi uptake by the suspected parathyroid adenoma but a ventrally adjacent autonomous thyroid adenoma. Additional F-18-ethylcholine-PET/CT as well as subsequent Tc-99m-sestamibi-SPECT/US and F-18-ethylcholine-PET/US fusion imaging confirmed the suspected diagnosis of simultaneous autonomous thyroid adenoma and parathyroid adenoma. A blood analysis showed additional Graves' disease.

[The Medical Atom: Radioisotopes in Internal Medicine in the Federal Republic of Germany, 1945-1965]

Radioisotopes were one of the defining innovations in clinical internal medicine in the post-war period. Medical university clinics used radioisotopes in the treatment of previously untreatable diseases and at the same time used them to study physiological processes in the laboratory. In the mid-1950s, new technical methods-such as scintigraphy-expanded the diagnostic and therapeutic repertoire of internal medicine. The article uses the example of isotope research to highlight the significance of technology-driven processes of change for the internal medicine clinic in West Germany. In addition, transfer processes between basic medical research and clinical research are examined and analyzed as a form of translational medicine avant la lettre.

Potent candidates for Targeted Alpha Therapy (TAT)

Targeted Alpha Therapy (TAT) holds significant promise as a localized treatment for cancer. Encouraging clinical results from using peptides and antibodies labeled with alpha emitters to treat patients with metastatic cancers, particularly those who have not responded to other therapies, provide compelling evidence of TAT's potential. To fully realize the benefits of TAT, it is essential to carefully select appropriate radionuclides and targeting delivery systems to maximize therapeutic efficacy while minimizing nonspecific toxicity to healthy tissues. This review explores key radiochemical, radiopharmaceutical, and radiation-biological considerations for current TAT candidates, and proposes additional potential candidates, establishing a foundation and criteria for the ongoing development of TAT radiopharmaceuticals.

Scintigraphy for the diagnosis of primary unrecognised fractures in multiple trauma patients - a prospective, blinded, monocentric study

INTRODUCTION

After structured (S3 guideline, ATLS®) acute care of multiple trauma patients in trauma centers, post-acute missed injuries continue to occur with incidence rates ranging from 1.3 to 39% as described in literature. The aim of the tertiary survey was the reduction of these rates. However, high numbers of missed injuries continue to be reported. The aim of this prospective, single-center, blinded clinical diagnostic study was to determine whether the standardised use of 3-phase whole-body skeletal scintigraphy in severely injured patients can reduce the number of missed injuries compared with the established standard procedure for polytrauma diagnosis.

METHODS

26 patients aged 18 years or older (median 53.5 years, 4 female, 22 male) with an ISS ≥ 9 were evaluated by an orthopaedic and trauma surgeon using skeletal scintigraphy after completion of standardised trauma room diagnostics and tertiary survey, a median of 7 days after trauma. All clinical and diagnostic examinations were then analysed and a final consensus was reached on the bony injuries. An evaluation of each procedure against the consensus was performed for the whole body and five body regions.

RESULTS

Skeletal scintigraphy was clearly superior to the established method (sensitivity 98.8% vs. 75.4%). Of the 60 additional bony injuries identified, 25 were treated without therapeutic consequences. Twenty-nine were treated conservatively without additional immobilisation and five with additional immobilisation. One unnecessary immobilisation was ended and no surgical treatment was required.

CONCLUSION

Three-phase whole-body skeletal scintigraphy is a low-risk, highly sensitive tool for reducing the incidence of missed injuries. A more liberal indication for skeletal scintigraphy should be given for injuries of increasing severity and in persons with impaired consciousness or paralysis, to avoid sequelae of missed injuries.

CLINICAL TRIAL REGISTRATION

The study was registered at the German Clinical Trails Register (DRKS) with the identifier DRKS00029402.

Revolutionizing cancer diagnosis and dose biodistribution: a meta-analysis of [68ga] FAPI- 46 vs. [18f] FDG imaging

BACKGROUND

Advancements in novel peptides significantly affect cancer diagnosis by targeting cancer-specific markers, thereby improving imaging modalities, such as positron emission tomography combined with computed tomography (PET/CT) for more accurate tumor detection. This systematic review and meta-analysis aimed to assess the diagnostic accuracy of [18F] Fluorodeoxyglucose (FDG) and 68Ga-fibroblast activation protein inhibitor (FAPI- 46) PET/CT for early cancer detection.

METHODS

A comprehensive search was conducted in Scopus, MEDLINE, Web of Science, and Embase databases up to March 28, 2024, using MeSH keywords. Titles and abstracts were screened to identify studies on hybrid [68Ga] FAPI- 46 and [18F] FDG, followed by a detailed full-text evaluation. Only cohort or cross-sectional studies published in English, focusing on the clinical diagnosis of cancer patients, were included, while reviews, case reports, conference proceedings, and abstracts were excluded. Random-effects meta-analysis was used for the estimation of pooled specificity and sensitivity with 95% confidence intervals (CIs). In addition, the heterogeneity was assessed across studies and subgroup meta-analyses for the detection rate via Stata.

RESULTS

Among the 615 retrieved studies, nine articles were incorporated in the present systematic review, with five (n = 144 patients) eligible for meta-analysis. For [68Ga] FAPI- 46, the pooled sensitivity and specificity compared with immunohistopathology were 0.96 (95% CI 0.84, 0.99) and 0.92 (95% CI 0.53, 0.99), respectively, with a positive likelihood ratio (LR +) of 4.41 (95% CI 1.64, 11.79) and a negative likelihood ratio (LR -) of 3.07 (95% CI 1.01, 9.37). For [18F] FDG, pooled sensitivity and specificity compared with immunohistopathology were 0.73 (95% CI 0.34, 0.93) and 0.83 (95% CI 0.57, 0.95), with an LR + of 12.73 (95% CI 1.43, 113.45) and an LR - of 0.32 (95% CI 0.11, 0.17). The pooled odds ratio for the detection rate on a per-lesion basis was 1.73 (95% CI 0.99, 3.02) for [68Ga] FAPI- 46 compared with [18F] FDG. The pooled weighted mean differences in the standardized uptake value (SUVmax) for primary tumor uptake and the tumor-to-background ratio (TBR) in [68Ga] FAPI- 46 vs. 18F-FDG were 4.40 (95% CI - 0.7, 9.5) and 6.18 (95% CI 1.74, 10.61), respectively. Moderate to high heterogeneity was noted because of the variations in patient selection, interpretation criteria, and scanning procedures.

CONCLUSIONS

This study revealed that [68Ga] FAPI- 46 outperforms [18F] FDG in cancer diagnosis, with higher sensitivity (0.96 vs. 0.73) and specificity (0.92 vs. 0.83). [Ga] FAPI- 46 improved tumor detection with higher SUVmax and TBR. While FDG had a higher LR +, its lower LR - highlighted more false negatives. Accordingly, [68Ga] FAPI- 46 exhibited superior accuracy and reliability than FDG in cancer diagnosis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD 42023472270.

Determination of the Intralesional Distribution of Theranostic 124I-Omburtamab Convection-Enhanced Delivery in Treatment of Diffuse Intrinsic Pontine Glioma

This phase 1, dose-escalation study examined the use of the radiolabeled antibody 124I-Omburtamab delivered directly to brain-stem tumors via convection-enhanced delivery (CED). CED bypasses the blood-brain barrier by injecting the agent under the pressure of a peristaltic pump to convectively drive the therapeutic agent through the brain tissue and tumor compartment, enabling high concentrations at the target site. We evaluated 124I-Omburtamab's potential to deliver therapeutic radiation doses to diffuse intrinsic pontine glioma in children. PET and MRI were used to assess the alignment between the intended and actual distribution of the agent, with an analysis of tumor coverage and radiation absorbed doses. Methods: 124I-Omburtamab doses ranging from 9.25 to 370 MBq were administered to 36 patients. Tumor distribution volumes were derived from PET images by placing volumes of interest over lesions and overlaying them onto T2-weighted fluid-attenuated inversion recovery MRI-delineated tumor volumes. Dosimetry metrics evaluated after CED included dose-volume histograms, tumor coverage percentage, and the Dice similarity coefficient between the antibody distribution and tumor volume. A 4-quadrant scatter plot of Dice similarity versus tumor coverage was used to classify treatment variations among patients. Results: Serial PET scans showed 124I-Omburtamab localization in brain-stem lesions from 1 h to 7 d ± 1 d after dose administration. Coverage analysis revealed that 29 patients had tumor volume coverage greater than 50%, and 28 had a Dice similarity coefficient over 50%. The 4-quadrant statistical analysis-percentage of coverage versus Dice similarity coefficient-showed that 27 patients had acceptable coverage for treatment, and 4 patients experiencing suboptimal tumor coverage. Conclusion: CED of 124I-Omburtamab is a novel approach for delivering radiolabeled therapies into brain-stem tumors. Imaging enabled quantification of radiation dose coverage within the MRI-defined tumor target, highlighting the importance of precise alignment between therapeutic agent distribution and tumor volume.

Dopamine D2 receptor upregulation in dorsal striatum in the LRRK2-R1441C rat model of early Parkinson's disease revealed by in vivo PET imaging

We conducted PET imaging with [18F]FDOPA and dopamine D2/3 receptor ligand [18F]fallypride in aged transgenic rats carrying human pathogenic LRRK2 R1441C or G2019S mutations. These rats have mild age-dependent deficits in dopamine release restricted to dorsal striatum despite no overt loss of dopamine neurons or dopamine content and demonstrate L-DOPA-responsive movement deficits.LRRK2 mutant rats displayed no deficit in [18F]FDOPA uptake, consistent with intact dopamine synthesis in striatal axons. However, LRRK2-R1441C rats demonstrated greater binding of [18F]fallypride than LRRK2-G2019S or non-transgenic controls, from a regionally selective increase in dorsal striatum. Immunocytochemical labelling post-mortem confirmed a greater density of D2 receptors in LRRK2-R1441C than other genotypes restricted to dorsal striatum, consistent with upregulation of D2-receptors as a compensatory response to the greater dopamine release deficit previously demonstrated in this genotype.These results show that [18F]fallypride PET imaging is sensitive to dysregulation of dopamine signalling in the LRRK2-R1441C rat, revealing upregulation of D2 receptors that parallels observations in human putamen in early sporadic PD. Future studies of candidate therapies could exploit this non-invasive approach to assess treatment efficacy.

Toxicities of radioligand and radioisotope therapy in prostate cancer: a systematic review and meta-analysis

PURPOSE OF REVIEW

This systematic review and meta-analysis investigate the toxicities of radioligand and radioisotope therapies - [177Lu]lutetium-prostate-specific membrane antigen (PSMA) (Lu-PSMA), [225Ac]actinium-PSMA (Ac-PSMA), and [223Ra]radium-dichloride (223-Radium) - in metastatic prostate cancer. While previous studies have explored this topic, most failed to differentiate between treatment-emergent adverse events (TEAEs) and preexisting conditions, leading to inflated toxicity rates. By focusing exclusively on TEAEs, this study provides a more accurate and clinically relevant assessment.

RECENT FINDINGS

This meta-analysis of 65 studies including 8706 patients identified haematotoxicities as the most frequent TEAEs across all therapies, affecting 10-20% of patients. Fatigue is a common nonhematologic adverse event in all treatments. Low grade xerostomia is specifically associated with Lu-PSMA and Ac-PSMA therapies, occurring in 30% and 84% of patients, respectively, while 223-Radium is uniquely linked to an increased fracture risk. Severe toxicities (Common Terminology Criteria for Adverse Events ≥ 3) are rare across all therapies. By clearly distinguishing TEAEs from baseline conditions, this study addresses a gap in the existing literature.

SUMMARY

Severe TEAEs are uncommon across Lu-PSMA, Ac-PSMA, and 223-Radium therapies. Still, monitoring and managing specific toxicities to optimize the safety and tolerability of these therapies in clinical practice is mandatory, especially concerning xerostomia in Ac-PSMA therapy.

PET imaging utilization and trends in Germany: a comprehensive survey

INTRODUCTION

PET imaging is a key diagnostic procedure in clinical routine worldwide. While public figures on PET volume are available in many countries, until now these numbers were not publicly known for Germany.

METHODS

On behalf of the PET committee of the German Society of Nuclear Medicine, we conducted a comprehensive survey among PET centers in Germany to collect data on PET imaging, including the total PET volume and indication groups.

RESULTS

National total PET volume in 2021 was 154,400 scans (94% PET/CT, 6% PET/MRI). PET volume in 2021 normalized to total population was lower in Germany (1,857 scans per 1 million inhabitants) when compared to public figures from France (10,182 scans), Belgium (9,866 scans), or Italy (4,312 scans). PET volume in Germany demonstrated significant growth 2017 to 2021 (+ 48%). Top three indication fields were oncological (re)staging (76%), theranostic (13%), and neurology (4%). The top three indications were lung cancer (31%), prostate cancer (16%), and lymphoma/leukemia (12%). The top three radiotracers used were [18F]FDG (75%), PSMA radioligands (17%), and somatostatin-receptor radioligands (8%).

CONCLUSIONS

Clinical adoption of PET imaging in Germany is behind compared to Italy, France, and Belgium. However, newly established outpatient reimbursement seems to contribute to recent growth in PET volume. We observe considerable shift towards theranostic applications.

Reinstating respiratory heart rate variability improves hemodynamic responses during exercise in heart failure with reduced ejection fraction

Individuals with heart failure have significantly reduced exercise capacity, a critical life-limiting symptom for those living with the disease. Heart failure is negatively correlated with decreased heart rate variability, including the loss of heart rate variability in tune with breathing-termed respiratory heart rate variability (RespHRV). We tested the hypothesis that restoration of RespHRV would improve exercise tolerance. Heart failure was induced in adult female sheep using a microembolization technique, and the sheep were divided into two groups: RespHRV paced and monotonically paced. Following a 1-week baseline recording, the sheep underwent 2 weeks of pacing. Direct recordings of hemodynamic parameters, including arterial pressure, cardiac output, coronary artery blood flow, and heart rate, were taken at rest and during treadmill exercise. Reinstating RespHRV significantly increased resting cardiac output, a change not observed in monotonically paced sheep. Neither group showed a change in resting coronary artery blood flow. During exercise, RespHRV-paced sheep showed increased cardiac output, coronary artery blood flow, cardiac power output, and faster heart rate recovery post-exercise. In contrast, monotonically paced sheep showed no changes in exercise-induced cardiac function. A separate group of heart failure animals were studied to determine if these benefits would persist alongside heart failure medications. RespHRV pacing continued to improve resting cardiac output with concurrent heart failure medications. Our results indicate that reinstating RespHRV may be a novel approach for improving outcomes in heart failure, including exercise capacity.

Consensus Nomenclature for Radionuclide Therapy: Initial Recommendations from Nuclear Medicine Global Initiative

Since its inception in 2012, the Nuclear Medicine Global Initiative (NMGI) of the Society of Nuclear Medicine and Molecular Imaging has played an important role in addressing significant challenges in the field of nuclear medicine and molecular imaging. The first 3 projects were dedicated to standardizing pediatric nuclear medicine practices, addressing the global challenges of radionuclide access and availability, and assessing the educational and training initiatives on theranostics across the globe. These efforts aimed to advance human health, foster worldwide educational collaboration, and standardize procedural guidelines to enhance quality and safety in nuclear medicine practice. In its latest project, NMGI aimed to develop a unified nomenclature for systemic radionuclide therapy in nuclear medicine, addressing the diverse terminology currently used. An online survey was distributed to NMGI member organizations, drawing participation from various geographical locations and disciplines. The survey anonymously collected responses from physicians, physicists, scientists, radiopharmacists, radiopharmaceutical scientists, dosimetrists, technologists, and nurse managers, totaling 240 responses from 30 countries. Findings revealed a prevailing use of the term targeted radionuclide therapy for radionuclide therapy, with 52% of respondents expressing a preference for this term. In contrast, approximately 37% favored "radiopharmaceutical therapy," whereas 11% favored "molecular radionuclide therapy." Other key terms under the umbrella of targeted radionuclide therapy were also discussed to achieve a consensus on terminology. NMGI efforts to standardize terminology in this dynamic and fluid field should improve communication within the field, better reflect the technology used, enable comparison of results, and ultimately lead to improved patient outcomes.

177Lu-FAPI-2286 Therapy in a Patient With Radio-iodine Refractory Papillary Thyroid Carcinoma: A Favorable Clinical and Biochemical Response

We report a 38-year-old man with radio-iodine refractory papillary thyroid carcinoma (RAIR PTC) who experienced significant relief from symptoms and showed a positive biochemical response after undergoing a single cycle of 177Lu-FAPI-2286 therapy. A pretreatment 99mTc-FAPI-46 scan showed diffuse uptake throughout both lungs and subsequent serial post-treatment scans demonstrated sustained uptake in pulmonary metastases. After treatment, there was a significant decline in serum thyroglobulin levels, accompanied by a remarkable improvement in symptoms, leading to near-complete resolution. This case highlights the potential of 177Lu-FAPI-2286 therapy as an effective treatment option for RAIR PTC patients.

D-Glucuronolactone Supplementation Enhances Production Performance, Eggshell Quality, and Liver Health in Laying Hens

The liver of hens bears a very heavy workload in handling lipogenesis as well as carbohydrate, protein, and other nutrient metabolism to maintain a high laying rate. D-glucuronolactone (DGL) is a naturally occurring chemical metabolite produced from glucose and exhibits a hepatoprotective effect as a food ingredient. This study aimed to evaluate the effect of DGL on production performance, egg quality, and liver health in laying hens during their peak period. Four hundred and eighty Hy-Line brown hens (aged 42 weeks), with comparable high-laying performance, were randomly assigned to four groups, with each group consisting of eight replicates. The control group was fed a basal diet, while the treatment groups were supplemented with DGL at 70, 140, and 280 mg/kg in the basal diet, respectively. The results indicated that DGL supplementation significantly increases the laying rate and egg mass of hens (p < 0.05). The brown color of the eggshell was significantly deepened by DGL administration (p < 0.05). Additionally, DGL supplementation significantly decreased the serum levels of aspartate aminotransferase and γ-glutamyl transpeptidase (p < 0.05). The liver index, liver fat, and triglyceride levels in the liver had also significantly decreased (p < 0.05). Liver histopathological results showed that the control group exhibited yellow coloration with large gaps and numerous vacuolar cells, while DGL supplementation improved the compactness of liver parenchyma. Antioxidant activity was enhanced, showing a significant increase in the activity of total antioxidant capacity and catalase in the liver (p < 0.05). The inflammatory response was alleviated, with a significant decrease in expressions of interleukin-β, tumor necrosis factor-α, interferon-α, interleukin-6, and interleukin-8 genes in the liver (p < 0.05). Moreover, DGL supplementation significantly reduced cell apoptosis-related genes, including factor-related apoptosis, Caspase 7, and BCL2 associated X protein in the liver (p < 0.05). Overall, these findings indicate that dietary DGL enhanced the laying performance of hens by maintaining liver health, with the best results achieved at a dose of 280 mg/kg in this trial.

"Mood, psychosis and suicidal behavior in epilepsy"

Epilepsy is a chronic neurological disorder that has complex relations with social, vocational and psychological functioning. Multiple studies showed that frequency of mood disorders in patients with epilepsy is increased and include depression, anxiety and psychosis. We present data from a neurobiological prospective having clinical relevance for epilepsy and comorbidities, including studies in people with late onset epilepsies. Better understanding of neurobiological mechanisms, anatomical, functional, neuroendocrine and molecular basis of psychiatric comorbidities in persons with epilepsy, can advance therapeutic responses. Epilepsy patients have a significantly higher prevalence of depressive symptoms. Many studies showed that depressive symptoms reduce their quality of life. Psychosis in epilepsy is a rare but severe disorder that usually occurs in patients with early onset of seizures, less localised ictal EEG recordings and seizure clustering. Suicide behavior presents an important problem in managing people with epilepsy. Suicidal ideation is not uncommon, and patients also have an increased risk for suicidal attempt or completed suicide. Psychiatric comorbidities present a significant problem and ask for a multidisciplinary approach to optimize treatment of people with epilepsy.

Exploring the Role of [68Ga]Ga-DOTAGA-IAC and Comparison of Its Diagnostic Performance with [18F]F-FDG PET/CT in Radioiodine Refractory Differentiated Thyroid Carcinoma

Introduction: Integrin antagonist complex (IAC), a novel αvβ3 integrin antagonist peptidomimetic, has emerged as a promising agent for molecular imaging of tumor angiogenesis. This study evaluates the biodistribution and clinical efficacy of [68Ga]Ga-DOTAGA-IAC PET/CT in detecting radioiodine-refractory differentiated thyroid carcinoma (RAIR-DTC), comparing its diagnostic performance with [18F]F-FDG PET/CT. Materials and Methods: In this prospective pilot study, RAIR-DTC patients underwent whole-body imaging with [18F] F-FDG PET/CT, followed by [68Ga]Ga-DOTAGA-IAC PET/CT. Biodistribution patterns of [68Ga]Ga-DOTAGA-IAC were assessed. Lesions with abnormal, nonphysiologic tracer uptake (showing activity exceeding mediastinal blood pool) were considered positive for disease. Imaging findings were compared between the two modalities, and quantitative metrics, including SUVmax, metabolic tumor volume, and total lesion glycolysis, were analyzed statistically. Results: Among 30 patients with RAIR-DTC, [68Ga]Ga-DOTAGA-IAC PET/CT revealed predominant physiological tracer uptake in the kidneys. [18F]F-FDG PET/CT identified 97 lesions, predominantly nodal (73.2%), while [68Ga]Ga-DOTAGA-IAC PET/CT detected 34 lesions, 50% of which were nodal. Few patients exhibited multiple lesions with varying uptake grades, with 20% showing coexisting higher-grade lesions (grade II or above) on [68Ga]Ga-DOTAGA-IAC PET/CT. Conclusion: Angiogenesis imaging using [68Ga]Ga-DOTAGA-IAC PET/CT demonstrates limited sensitivity for lesion detection in patients with RAIR-DTC compared with [18F]F-FDG PET/CT. However, the potential of [68Ga]Ga-DOTAGA-IAC as a diagnostic tool for other cancers has been used in other cancers with positive imaging characteristics warranting further exploration.

The Evolution of Artificial Intelligence in Nuclear Medicine

Nuclear medicine has continuously evolved since its beginnings, constantly improving the diagnosis and treatment of various diseases. The integration of artificial intelligence (AI) is one of the latest revolutionizing chapters, promising significant advancements in diagnosis, prognosis, segmentation, image quality enhancement, and theranostics. Early AI applications in nuclear medicine focused on improving diagnostic accuracy, leveraging machine learning algorithms for disease classification and outcome prediction. Advances in deep learning, including convolutional and more recently transformer-based neural networks, have further enabled more precise diagnosis and image segmentation as well as low-dose imaging, and patient-specific dosimetry for personalized treatment. Generative AI, driven by large language models and diffusion techniques, is now allowing the process, interpretation, and generation of complex medical language and images. Despite these achievements, challenges such as data scarcity, heterogeneity, and ethical concerns remain barriers to clinical translation. Addressing these issues through interdisciplinary collaboration will pave the way for a broader adoption of AI in nuclear medicine, potentially enhancing patient care and optimizing diagnosis and therapeutic outcomes.

Can PSMA PET detect intratumour heterogeneity in histological PSMA expression of primary prostate cancer? Analysis of [68Ga]Ga-PSMA-11 and [18F]PSMA-1007

PURPOSE

Prostate-specific membrane-antigen positron emission tomography (PSMA PET) is a promising candidate for non-invasive characterization of prostate cancer (PCa). This study evaluated whether PET with tracers [68Ga]Ga-PSMA-11 or [18F]PSMA-1007 is capable to depict intratumour heterogeneity of histological PSMA expression.

METHODS

Thirty-five patients with biopsy-proven primary PCa without evidence of metastatic disease nor prior interventions were prospectively enrolled. All patients underwent PSMA PET combined with computer tomography (CT) with either [68Ga]Ga-PSMA-11 (cohort I, 20 patients) or [18F]PSMA-1007 (cohort II, 15 patients) followed by radical prostatectomy. Specimens were scanned by ex-vivo CT and histologically prepared. On digitized whole-mount prostate sections, PCa areas with different morphologies were manually defined and H-Score of immunohistochemical PSMA expression was calculated with assistance by artificial intelligence (AI). PCa areas with similar H-Score were unified in segmentation on ex-vivo CT. After co-registration on PSMA PET-CT, Spearman's coefficients of PSMA expression to mean and maximum standardized uptake value (SUVmean and SUVmax) were calculated. Furthermore, the agreement of the co-registered tumour areas to gross tumour volume (GTV) in PSMA PET was analysed.

RESULTS

Thirty-two patients were included in the final analysis. For histological PCa areas, immunohistochemical PSMA expression correlated significantly to SUVmean and SUVmax (p < 0.001, p = 0.001). An approximate linear correlation between H-Score and SUVmean / SUVmax was found for tumour areas larger than 400 μm² in histology (p < 0.001). Tumour areas with strong PSMA expression showed a significantly larger overlap to GTV in PSMA PET after co-registration than tumour areas with very low PSMA expression (p < 0.01). No significant differences were found between the two tracer cohorts (p = 0.72).

CONCLUSION

PSMA PET with both [68Ga]Ga-PSMA-11 or [18F]PSMA-1007 is able to detect changes in histological PSMA expression within PCa lesions allowing biologically targeted radiotherapy.

Microbial Cytotoxic Effect of 212Pb in Radiopharmaceuticals

Background: The cytotoxic effect of 212Pb on microbial growth was examined, using six microorganisms, at clinically relevant time points, to determine the potency of 212Pb as a self-sterilizing agent in radiopharmaceuticals using [212Pb]Pb-DOTAMTATE. Materials and Methods: Vials of radiolabeled [212Pb]Pb-DOTAMTATE, nonradiolabeled DOTAMTATE, and appropriate media were inoculated with Bacillus spizizenii, Candida albicans, Clostridium sporogenes, Pseudomonas aeruginosa, Staphylococcus aureus, or Aspergillus brasiliensis. Samples from each vial type were plated onto tryptic soy agar or Sabouraud dextrose plates and allowed to grow at optimal temperature for each strain to obtain quantifiable colony forming units (CFU). Results: Each microbial organism observed at least a 6 log reduction in total CFUs after 6 h of exposure to [212Pb]Pb-DOTAMTATE drug product vials, showing no remaining colonies as compared to the vials containing only media and drug formulation with no radiolabeled material, utilizing a low absorbed dose of no greater than 1.01 kGy. A sterility assessment of the two [212Pb]Pb-DOTAMTATE drug product vials containing the lowest total CFUs per vial displayed no microbial growth upon incubation for 14 d. Conclusions: This study suggests that 212Pb in radiopharmaceuticals is a potent microbial cytotoxic agent with self-sterilizing properties.

GPOH Guidelines for Diagnosis and First-line Treatment of Patients with Neuroblastic Tumors, update 2025

The clinical course of neuroblastoma is more heterogeneous than any other malignant disease. Many low-risk patients experience regression after limited or even no chemotherapy. However, more than half of high-risk patients die from disease despite intensive multimodal treatment. Precise disease characterization for each patient at diagnosis is key for risk-adapted treatment. The guidelines presented here incorporate results from national and international clinical trials to produce recommendations for diagnosing and treating neuroblastoma patients in German hospitals outside of clinical trials.

Radiomic features and tumor immune microenvironment associated with anaplastic lymphoma kinase-rearranged lung adenocarcinoma and their prognostic value

Purpose

To identify radiomic features from preoperative computed tomography (CT) images and characteristics of the tumor immune microenvironment (TIME) associated with anaplastic lymphoma kinase (ALK) rearrangement in patients with lung adenocarcinomas and their prognostic value in predicting recurrence or metastases after surgery.

Materials and methods

This retrospective study included 66 ALK-positive and 66 ALK-negative patients who underwent surgical resected lung adenocarcinoma. The number of CD8+ T cells and Human leukocyte antigen class I (HLA-I)/programmed death ligand 1 (PD-L1) expression were determined using immunohistochemistry. Radiomic features were extracted from the preoperative CT images. Combined radiomic, clinicopathological, and clinicopathological-radiomic models were built to predict ALK rearrangements. The models' prediction performance was analyzed using receiver operating characteristic (ROC) curves with five-fold cross-validation. Prediction models for determining disease-free survival (DFS) of ALK-rearranged patients were developed, and the C-index after internal cross-validation was calculated to evaluate the performance of the models.

Results

HLA-I and PD-L1 expression were negatively associated with ALK rearrangement (both P < 0.001). The ROC curve indicated areas under the curve of 0.763, 0.817, and 0.878 for the radiomics, clinicopathology, and combined models in predicting ALK rearrangement, respectively. The combined model showed significant improvement compared to the clinicopathological (P = 0.02) and radiomics (P < 0.001) models alone. The validation C-indices were 0.752, 0.712, and 0.808 for the radiomic, clinicopathological, and combined models in predicting the DFS of ALK-rearranged patients, respectively. The combined model showed a significant improvement (P < 0.001) compared to the clinicopathological model alone.

Conclusion

This study demonstrated the potential role of radiomics and TIME characteristics in identifying ALK rearrangements in lung adenocarcinomas and the prognostic value of radiomics in predicting DFS in patients with ALK rearrangements.

Evaluating Bone Marrow Involvement in Pediatric Neuroblastoma: Traditional Methods and Emerging Technologies-A Systematic Review

Neuroblastoma (NB) is the most common extracranial solid neoplasm affecting the pediatric population. It shows a high prevalence of bone marrow infiltration (BMI), which substantially impacts the disease's staging and prognostic assessment. Conventional methodologies, including bone marrow biopsy (BMB) and aspirate (BMA), have been extensively employed; nevertheless, the advent of novel technologies presents a promising avenue for diagnostic accuracy. This systematic review is designed to critically analyze and compare the established techniques (BMB and BMA) versus novel diagnostic approaches-such as immunocytology, RT-qPCR, and multiparametric flow cytometry (FCM), along with functional imaging like MIBG scintigraphy and FDG-PET/CT-in assessing BMI in pediatric NB. An exhaustive search was performed across the PubMed and Embase databases, identifying 2694 scholarly articles. Following a meticulous screening process and the application of inclusion criteria centered on diagnostic accuracy, sensitivity, and specificity about BMI, a total of 140 articles were selected for qualitative analysis. While BMB remains the gold standard for diagnosing and staging BMI in NB, recent advances in molecular techniques and functional imaging have shown superior sensitivity and specificity. Immunocytology and RT-qPCR can detect minimal residual disease (MRD) with higher sensitivity compared to traditional methods. Functional imaging modalities, particularly FDG-PET/CT and MIBG scintigraphy, have demonstrated improved accuracy in assessing bone marrow involvement with the added advantage of evaluating the entire bone marrow, overcoming the limitations of focal sampling in BMB. The integration of advanced molecular diagnostics and functional imaging with traditional biopsy methods enhances the accuracy of BMI in NB.

The Role of AI in Lymphoma: An Update

Malignant lymphomas encompass a range of malignancies with incidence rising globally, particularly with age. In younger populations, Hodgkin and Burkitt lymphomas predominate, while older populations more commonly experience subtypes such as diffuse large B-cell, follicular, marginal zone, and mantle cell lymphomas. Positron emission tomography/computed tomography (PET/CT) using [18F] fluorodeoxyglucose (FDG) is the gold standard for staging, treatment response assessment, and prognostication in lymphoma. However, interpretation of PET/CT is complex, time-consuming, and reliant on expert imaging specialists, exacerbating challenges associated with workforce shortages worldwide. Artificial intelligence (AI) offers transformative potential across multiple aspects of PET/CT imaging in this setting. AI applications in appointment planning have demonstrated utility in reducing nonattendance rates and improving departmental efficiency. Advanced reconstruction techniques leveraging convolutional neural networks (CNNs) enable reduced injected activities of radiopharmaceutical and patient dose whilst maintaining diagnostic accuracy, particularly benefiting younger patients requiring multiple scans. Automated segmentation tools, predominantly using 3D U-Net architectures, have improved quantification of metrics such as total metabolic tumour volume (TMTV) and total lesion glycolysis (TLG), facilitating prognostication and treatment stratification. Despite these advancements, challenges remain, including variability in segmentation performance, impact on Deauville Score interpretation, and standardization of TMTV/TLG measurements. Emerging large language models (LLMs) also show promise in enhancing PET/CT reporting, converting free-text reports into structured formats, and improving patient communication. Further research is required to address limitations such as AI-induced errors, physiological uptake differentiation, and the integration of AI models into clinical workflows. With robust validation and harmonization, AI integration could significantly enhance lymphoma care, improving diagnostic precision, workflow efficiency, and patient outcomes.

Precision matters: the value of PET/CT and PET/MRI in the clinical management of cervical cancer

The incidence of cervical cancer has been increasing recently, becoming an essential factor threatening patients' health. Positron emission computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI) are multimodal molecular imaging methods that combine functional imaging (PET) and anatomical imaging (CT) with MRI fusion technology. They play an important role in the clinical management of patients with cervical cancer. Precision radiotherapy refers to the use of advanced intensive modulated radiotherapy (IMRT) to give different doses of radiation to different treatment areas to achieve the purpose of killing tumors and protecting normal tissues to the greatest extent. At present, pelvic target delineation is mostly based on CT and MRI, but these mostly provide anatomical morphological information, which is difficult to show the internal metabolism of tumors. PET/CT and PET/MRI combine information on biological function, metabolism and anatomical structure, thereby more accurately distinguishing the boundaries between tumor and non-tumor tissues and playing a positive guiding role in improving radiotherapy planning (RTP) for cervical cancer and evaluating treatment effect.

Expert Panel on Vascular Imaging, Kokabi N, Dabbous H, Khaja MS, Baker JB, Brixey AG, Browne WF, Contrella BN, Faiz SA, Gunn AJ, Keefe NA, Kendi AT, Linden PA, Litt H, Sharma AM, Vijay K, Wang DS, Majdalany BS. ACR Appropriateness Criteria® Chylothorax Treatment Planning: 2024 Update

Chylothoraces are encountered at a rate of up to 1 in 6,000 in all hospital admissions. The etiology of these chylothoraces can be categorized into traumatic or nontraumatic. Traumatic or iatrogenic chylothorax can be seen in up to half of all chylothoraces with nontraumatic or unknown etiology constituting the remaining majority. Treatment planning is essential in chylothorax due to the varying etiologies. Lymphangiography continues to be usually appropriate, as it is both an effective diagnostic and a therapeutic intervention. Additionally, with development in MR technology, MR lymphangiography has advanced rapidly in the last decade and is an additional radiological procedure that is usually appropriate in all etiologies of chylothoraces. Ultrasound is not appropriate for treatment planning in all etiologies and CT chest without contrast is not appropriate in nontraumatic etiologies of chylothoraces. All other radiological procedures may be appropriate based on individual cases. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Autonomously Functioning Thyroid Nodule With 99mTc-PSMA Uptake in a Patient With Prostate Cancer

We present the findings of a 99mTc-PSMA scan in a 76-year-old man with a history of prostate cancer. He was referred for re-staging and response to treatment. The 99mTc-HYNIC PSMA scan incidentally detected an area of increased uptake in the neck region. Subsequent SPECT/CT imaging revealed a large, heterogeneous PSMA-avid thyroid nodule with macrocalcification, suggesting a benign thyroid nodule. Comprehensive imaging confirmed hyperthyroidism with a large autonomously functioning nodule. The case underscores the importance of recognizing PSMA uptake in benign thyroid lesions, emphasizing the need for a thorough evaluation to prevent misdiagnosis and ensure appropriate management.

Influence of visual objects and music on anxiety levels and imaging process in patients undergoing coronary CT angiography

OBJECTIVE

High anxiety during coronary computed tomography angiography (CCTA) can compromise imaging quality, increase radiation exposure, and elevate medication use. Therefore, optimizing waiting room environments to reduce patient anxiety is important for clinical outcomes. This study examines the effects of music and visual stimuli in the waiting rooms on patients' anxiety levels, heart rate, radiation dose, and beta-blocker use prior to CCTA.

METHODS

This study, designed as a prospective and randomized trial, was conducted between April 15 and August 15, 2024, with 216 patients randomized into two groups: a standard waiting room (SWR) and a designed waiting room (DWR) featuring music and visual objects. Anxiety and depression levels were measured using the Hospital Anxiety and Depression Scale (HADS) and the State-Trait Anxiety Inventory (STAI). Additional parameters, such as heart rate, radiation dose, and beta-blocker requirement, were also recorded.

RESULTS

In the DWR group, anxiety scores and heart rates were significantly lower compared to the SWR group (p < 0.001). Additionally, a notable reduction in radiation dose and beta-blocker use was observed in the DWR group (p < 0.05). In the general patient population, higher anxiety scores were associated with poorer imaging quality. Imaging quality was significantly better in the DWR group (p < 0.001).

CONCLUSION

It has been demonstrated that waiting room designs enriched with music and visual stimuli reduce anxiety during CCTA scanning, enhancing patient comfort, improving imaging quality, and enabling imaging with lower radiation doses. The design of such waiting rooms can improve patient experience while optimizing outcomes.

KEY POINTS

Question Can a waiting room with music and visual stimuli reduce anxiety and heart rate in CCTA patients, improving imaging quality and reducing beta-blocker use? Findings Music and visual stimuli reduced anxiety and heart rate, lowering beta-blocker use and radiation doses while improving imaging quality in CCTA. Clinical relevance Integrating music and visual stimuli in waiting rooms helps reduce anxiety and heart rate, leading to less medication use and radiation exposure while enhancing imaging quality. This simple, cost-effective approach improves patient comfort and optimizes outcomes in CCTA procedures.

Assessing the Clinical Effectiveness of Radioimmunotherapy with Combined Radionuclide/Monoclonal Antibody Conjugates in Cancer Treatment: Insights from Randomised Clinical Trials

Background: Despite the development of advanced cancer therapies, achieving cancer eradication remains challenging. Radioimmunotherapy (RIT) is an innovative approach that combines radionuclides with monoclonal antibodies targeting tumour-associated antigens or those expressed by the tumour microenvironment. Over the past two decades, RIT has been extensively researched, along with two RIT products-90Y-ibritumomab tiuxetan and 131I-tositumomab. However, despite its demonstrated efficacy in non-solid tumours, RIT's clinical use remains limited, and its effectiveness in solid tumours is inconclusive. This study aimed to analyse randomised controlled trials (RCTs) to evaluate the overall clinical effectiveness of RIT across different cancer types and its impact on treatment outcomes. Methods: A systematic search of PubMed, EMBASE, Scopus, CENTRAL, and Google Scholar was conducted from January 2000 to October 2024 in accordance with PRISMA guidelines and the PICOS framework. Studies were included if they were RCTs evaluating RIT for cancer treatment and reported treatment outcomes such as overall survival (OS), progression-free survival (PFS), disease-free survival, or time to progression (TTP). Data extraction was performed using a standardised Excel form, and study quality was assessed with the Joanna Briggs Institute Critical Appraisal Tool for RCTs. A narrative synthesis of the data was complemented by meta-analyses where feasible, particularly for progression- and survival-related endpoints. Results: Out of 2241 records identified, 20 RCTs encompassing approximately 3562 patients were included. The majority of trials focused on non-solid tumours, particularly non-Hodgkin's lymphoma (NHL), while a smaller subset evaluated solid tumours such as lung, pancreatic, ovarian, and prostate cancers. Most non-solid tumour studies employed 90Y-ibritumomab tiuxetan or 131I-tositumomab, targeting the CD20 antigen, whereas limited evidence exists for RIT efficacy in solid tumours. Meta-analysis of progression-related outcomes yielded a pooled hazard ratio (HR) of 0.48 (95% CI: 0.39-0.59), indicating a 52% reduction in the risk of progression. In contrast, overall survival outcomes were more variable, with a pooled OS HR of 0.80 (95% CI: 0.60-1.07). Adverse events, predominantly haematological and nonhaematological toxicities, were common yet generally reversible. The findings suggest that RIT, especially when used as part of combination regimens, significantly improves treatment outcomes in non-solid tumours but has an inconsistent effect in solid tumour settings. Conclusions: The results underscore the clinical promise of RIT in treating non-solid tumours like NHL, where combination regimens yield superior outcomes compared to monotherapy. However, the inconclusive evidence in solid tumours highlights the need for further large-scale, well-designed RCTs to define the optimal use, dosing, and patient selection for RIT in these settings. Additionally, standardisation in outcome reporting and longer follow-up periods are essential for more accurate economic and clinical assessments. Overall, RIT represents a valuable therapeutic modality, yet its integration into cancer treatment regimens should be guided by further research aimed at mitigating toxicity and optimising combination strategies.

Small Animal Positron Emission Tomography Imaging of a Triple-Negative Breast Cancer Model Using the 68Ga-Labeled pH (Low) Insertion Peptide-Like Peptide YJL-11

Objectives: To prepare a novel 68Ga-labeled pH (low) insertion peptide-like peptide, YJL-11, and study its ability to be used as a probe for the diagnosis of triple-negative breast cancer (TNBC) via in vivo imaging of tumor-bearing nude mice. Methods: Circular dichroism (CD) analysis of YJL-11 was performed to assess its secondary structure. YJL-11 was labeled with 68Ga, and the in vivo biodistribution of 68Ga-YJL-11 in MDA-MB-231 xenograft mice was evaluated. This probe was then applied for small animal positron emission tomography (PET) imaging of tumor-bearing nude mice. Results: CD analysis of YJL-11 confirmed a typical pH-dependent transition in its secondary structure. The radiochemical yield of 68Ga-YJL-11 was 75.5 ± 0.25%, and the radiochemical purity was 95.75 ± 0.15%. Biodistribution studies showed that the tumor uptake of 68Ga-YJL-11 was significantly higher than in the control group, 1 and 2 h after injection. Small animal PET imaging results were consistent with the biodistribution data, showing clear images of the tumors and livers 1 and 2 h after injection of 68Ga-YJL-11, whereas tumors were not detected in the control group. Conclusion: 68Ga-YJL-11 was prepared with high radiochemical yield and can target TNBC tissues, indicating that it has great potential in the diagnosis of TNBC.

Influence of fever on 18F-FDG PET/CT in vivo: Utilizing a quantitative parameter SUL

INTRODUCTION

Fever can affect the identification and efficacy evaluation of tumors on the 18F-FDG PET/CT, and this effect can be reduced by referring to normal tissue metabolism. The aim of the study was to analyze the influence of fever on glucose metabolism in the mediastinal blood pool, liver, spleen, and bone marrow utilizing PET/CT quantitative parameter SUV normalized by lean body mass (SUL).

MATERIALS AND METHODS

30 patients with fever of unknown origin and 24 patients for tumor screening with normal body temperature within 3 weeks, who underwent 18F-FDG PET/CT in our department, were analyzed retrospectively. The SULmax and SULmean of the mediastinal blood pool, liver, spleen, and bone marrow were respectively measured in the two groups, and the differences between the two groups were compared by independent sample t test or Wilcoxon-Mann-Whitney test.

RESULTS

The SULmax and SULmean of the liver in the fever group were lower than those in the control group (p = 0.001, 0.013). The SULmax and SULmean of spleen and bone marrow in the fever group were higher than in the control group (all p < 0.05). The SULmax of the mediastinal blood pool in the fever group was lower than that in the control group (p = 0.007), but there was no significant difference in SULmean of the mediastinal between the fever group and the control group (t = 1.181, p = 0.221).

CONCLUSION

The fever can affect the glucose metabolism in internal organs. But there was no significant difference in the SULmean of mediastinal blood pool. Perhaps the SULmean of the blood pool can be invoked as a calibration parameter in the evaluation of efficacy in tumor patients with fever.

Treatments and cancer: implications for radiologists

This review highlights the critical role of radiologists in personalized cancer treatment, focusing on the evaluation of treatment outcomes using imaging tools like Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Ultrasound. Radiologists assess the effectiveness and complications of therapies such as chemotherapy, immunotherapy, and ablative treatments. Understanding treatment mechanisms and consistent imaging protocols are essential for accurate evaluation, especially in managing complex cases like liver cancer. Collaboration between radiologists and oncologists is key to optimizing patient outcomes through precise imaging assessments.

The Status of Neuroimaging with SPECT and PET in Germany: Results from the 1st Survey on Nuclear Neuroimaging in Germany in 2023

The advent of disease-modifying therapies for neurodegenerative diseases may result in a growing demand for nuclear neuroimaging procedures presenting opportunities but also challenges to the nuclear medicine community. Whether capacity and expertise in Germany are sufficient to meet an increasing demand for nuclear neuroimaging is under discussion. Against this background, the Neuroimaging Working Group of the German Society of Nuclear Medicine initiated the first survey on the status of nuclear neuroimaging in Germany in 2023. 82 institutions participated in the survey: 33 practices, 15 community hospitals, 34 university hospitals. Primary findings were the following. In practices, brain scans are less frequently performed than in hospitals and are often limited to dopamine transporter SPECT. Brain PET is mainly performed in hospitals, and in community hospitals it is often restricted to FDG PET. Nevertheless, availability of amyloid PET with well-certified quality can be taken for granted. Thus, access to amyloid PET will not be a major bottleneck for new treatments of Alzheimer's disease. Adequate reimbursement and clear anchoring in clinical guidelines have the greatest potential to advance nuclear neuroimaging in Germany. Clinical dopamine transporter SPECT is largely in agreement with procedure guidelines. An area for improvement is the limited availability of MR images to avoid misinterpretation of structural/vascular lesions as nigrostriatal degeneration. The survey provides the first systematic assessment of the status of nuclear neuroimaging in Germany. It underscores the capacity of the German nuclear medicine community to meet an increasing demand for neuroimaging procedures, its adherence to procedure guidelines and identifies topics for improvement.

18F labeled myocardial perfusion PET: New precision in cardiac imaging

The rising global burden of coronary artery disease (CAD) underscores the need for advanced diagnostic tools. While single-photon emission computed tomography (SPECT) has been the cornerstone for myocardial perfusion imaging (MPI), it is increasingly being supplemented by positron emission tomography (PET) due to superior spatial resolution, sensitivity, and the ability to quantify myocardial blood flow. However, current PET tracers, including Rubidium-82, 13N-Ammonia, and 15O-Water, face limitations due to their short half-lives and logistical challenges. The advent of 18F labeled PET tracers, such as Flurpiridaz F18, promises a new era in cardiac imaging by offering a longer half-life (110 minutes), compatibility with exercise stress testing, and high diagnostic accuracy. This review explores the current landscape of MPI, evaluates the clinical performance of novel 18F tracers, and discusses their transformative potential in expanding access to PET imaging and improving CAD diagnostics.

Diagnostic reference level, achievable dose, and effective dose estimation in adult hybrid SPECT myocardial perfusion imaging in Institut Jantung Negara

This study aims to establish the diagnostic reference level (DRL), achievable dose (AD), and effective dose (ED) estimation for adult hybrid SPECT myocardial perfusion imaging (MPI) procedures at Institut Jantung Negara (IJN). 737 subjects referred for MPI studies from January to June 2024 were included in the analysis. These subjects underwent either a one-day or two-day Tc-99 m tetrofosmin protocol using a cardiac-dedicated single-photon emission computed tomography (SPECT), either GE SPECT Discovery NM530c or GE SPECT Ventri. All subjects also underwent a cardiac CT scan via an external positron emission tomography/computed tomography (PET/CT) system, GE Discovery MI Digital Ready for either CT attenuation correction (CTAC) or CT coronary artery calcium score (CAC) protocol, depending on their clinical condition. The one-day protocol showed AD of 240.50 MBq and 691.90 MBq for the first and second injections, respectively, with corresponding DRL of 263.63 MBq and 777.93 MBq. The two-day protocol involved higher ADs of 1106.30 MBq and 1073.00 MBq for the first and second injections, with DRL of 1239.50 MBq and 1221.00 MBq, respectively. In the CTAC protocol, the AD for CT dose index volume (CTDIvol) was 2.8 mGy, with a DRL of 4.3 mGy. The dose length product (DLP) had an AD of 53.1 mGy.cm, compared to a DRL of 78.6 mGy.cm. For the CAC protocol, the CTDIvol had an AD of 4.8 mGy, matching the DRL of 4.8 mGy. The DLP showed an AD of 67.8 mGy.cm, with a DRL of 77.5 mGy.cm. The mean cumulated effective dose (EDCUMULATED) for one-day/CTAC, one-day/CAC, two-day/CTAC, and two-day/CAC was 6.69 ± 1.76 mSv, 7.32 ± 1.37 mSv, 10.13 ± 5.31 mSv, and 13.99 ± 3.24 mSv respectively. The average ED relative contribution by SPECT and CT were found to be 78.3% and 21.7% respectively. The DRL, AD, and ED data were successfully established for local MPI practice, contributing to global efforts to harmonize and enhance radiation safety in MPI practices.

Neovascular prostate specific membrane antigen (PSMA) expression in bone and soft tissue sarcoma: a systematic analysis

Bone and soft tissue sarcomas are a highly heterogeneous group of rare cancers of mesenchymal origin. Treatment options other than surgery have limited efficacy due to low response rates with some exceptions. Radioligand therapy targeting prostate-specific membrane antigen (PSMA) may provide a novel treatment option, as it was recently suggested that soft tissue sarcomas express PSMA in the neovasculature, and on PET/CT imaging, multiple sarcomas have shown intense PSMA-tracer accumulation. Moreover, in prostate cancer patients, incidental PSMA uptake was seen in hemangiomas. In addition to confirming previous results in soft tissue sarcoma, the current study aims to systematically explore the expression of PSMA in bone tumors and in vascular tumors. Immunohistochemistry for PSMA was performed on a total of 706 tumors. High PSMA expression in the neovasculature was seen in 29% of the soft tissue sarcomas and 33% of the bone sarcomas. Malignant tumors showed a higher frequency of PSMA expression (score 2) as compared to benign tumors, with a high frequency in rhabdomyosarcoma (2 of 2, 100%), mesenchymal chondrosarcoma (14 of 20, 70%), undifferentiated sarcoma of bone (4 of 6, 67%) and of soft tissue (13 of 20, 65%), and osteosarcoma (46 of 81, 57%). In addition, giant cell tumor of bone displayed a high PSMA labelling in 67% of the cases. In contrast, high PSMA expression was seen in only 0-40% of the non-neoplastic vessels in vascular tumors, while 8% of them expressed PSMA in the tumor cells. Thus, with variable frequency among the different subtypes, a subset of bone and soft tissue tumors, both malignant and intermediate behavior, express PSMA and these patients may benefit from PSMA-targeting PET/CT scans or PSMA targeted radioligand therapy.

Radioiodine Exhalation Following Oral I-131 Administration in a Mouse Model

Background: The exhalation of radioiodine following radioiodine therapy (RIT) presents a challenge in radiation protection, though the mechanisms remain incompletely understood. Previous studies have indicated that radioiodine is predominantly exhaled in an organically bound form in humans. Methods: This study investigates the chemical composition and exhaled amounts of radioiodine, as well as the impact of thyroid-targeted pharmacological interventions, using a controlled mouse model. Female Balb/c mice (25 g) were administered oral doses of radioiodine (0.1, 1, 2, 10, and 23 MBq per animal) with and without prior treatment using thyroid-blocking agents (stable iodine, perchlorate) or antithyroid drugs (carbimazole). Exhaled radioiodine was collected in metabolic cages, separating chemical forms (aerosolized iodine, elemental iodine, organically bound iodine), and quantified via scintillation counter. Results: The exhaled radioiodine activity was proportional to the administered dose (0.2-0.3%). Thyroid-blocking agents increased exhalation, shifting toward elemental iodine. Antithyroid drugs reduced exhalation but increased aerosol formation, particularly at higher I-131 doses. Organically bound iodine remained the predominant exhaled species in all groups. Conclusions: These results highlight the critical role of the thyroid in radioiodine organification. The blockade of thyroid uptake disrupted the formation of organically bound iodine, suggesting that iodine organification requires passage through the thyroid. Additionally, the results support the hypothesis that iodine metabolism outside the thyroid is less efficient, contributing to the formation of organic iodine species. Radical formation is likely a key factor in generating these volatile iodine species, with radiation-induced iodine and methyl radicals playing a role in their formation.

Fibroblast Activation Protein Inhibitor (FAPI)-Based Theranostics

Fibroblast activation protein (FAP) is a serine protease selectively expressed in cancer-associated fibroblasts (CAFs), fibrotic tissues, and areas of active tissue remodeling, making it an attractive target for diagnostic imaging across a spectrum of disease. FAP inhibitors (FAPIs) labeled with PET tracers have rapidly advanced as a novel imaging modality with broad clinical applications that offers several advantages, including rapid tumor accumulation, low background uptake, and high tumor-to-background ratios. In oncology, FAPI PET has demonstrated excellent performance in visualizing a wide range of malignancies, including those with low glycolytic activity, such as pancreatic cancer, cholangiocarcinoma, and certain sarcomas. Its high sensitivity and specificity for the stromal component enables improved tumor delineation, staging, and response assessment. Additionally, the potential to guide theranostic approaches, where the same tracer can be labeled with therapeutic radionuclides, positions FAPI as a key player in precision oncology. Beyond oncology, FAPI PET has shown promise in imaging conditions characterized by fibrotic and inflammatory processes. In the cardiovascular field, FAPI PET imaging is being investigated for its ability to detect myocardial fibrosis and active cardiac remodeling, crucial in conditions like heart failure, post-myocardial infarction remodeling, and hypertrophic cardiomyopathy. This review highlights the expanding clinical applications of FAPI-based PET imaging across oncology, inflammation, and cardiovascular disease. While the current data are promising, further large-scale studies and multicenter trials are essential to validate these findings and establish standardized protocols. The versatility and broad applicability of FAPI PET underscore its potential as a transformative tool in precision medicine.

Construction of the preoperative staging prediction model for cervical cancer based on deep learning and MRI: a retrospective study

Background

Cervical cancer remains a significant global health concern, particularly for women. Accurate preoperative staging is crucial for treatment planning and long-term prognosis. Traditional staging methods rely on manual imaging analysis, which is subjective and time-consuming. Deep learning-based automated staging models offer a promising approach to enhance both accuracy and efficiency.

Methods

This study retrospectively analyzed preoperative MRI scans (T1 and T2 stages) from 112 cervical cancer patients. Seven deep learning models-DenseNet, FBNet, HRNet, RegNet, ResNet50, ShuffleNet, and ViT-were trained and validated using standardized preprocessing, data augmentation, and manual annotation techniques. Convolutional neural networks were employed to extract multidimensional imaging features, forming the basis of an automated staging prediction model.

Results

Among all tested models, HRNet demonstrated the best performance, achieving an accuracy of 69.70%, recall of 68.89%, F1-score of 68.98%, and precision of 69.62%. ShuffleNet ranked second, with slightly lower performance, while ViT exhibited the weakest predictive ability. The ROC curve analysis confirmed HRNet's superior classification capability, with an AUC of 0.7778, highlighting its effectiveness in small-sample datasets.

Conclusion

This study confirms that deep learning models utilizing MRI images can enable automated cervical cancer staging with improved accuracy and efficiency. HRNet, in particular, demonstrates strong potential as a clinical decision-support tool, contributing to the advancement of precision medicine and personalized treatment strategies for cervical cancer.

Prediction of PD-L1 expression in NSCLC patients using PET/CT radiomics and prognostic modelling for immunotherapy in PD-L1-positive NSCLC patients

AIM

To develop a positron emission tomography/computed tomography (PET/CT)-based radiomics model for predicting programmed cell death ligand 1 (PD-L1) expression in non-small cell lung cancer (NSCLC) patients and estimating progression-free survival (PFS) and overall survival (OS) in PD-L1-positive patients undergoing first-line immunotherapy.

MATERIALS AND METHODS

We retrospectively analysed 143 NSCLC patients who underwent pretreatment 18F-fluorodeoxyglucose (18F-FDG) PET/CT scans, of whom 86 were PD-L1-positive. Clinical data collected included gender, age, smoking history, Tumor-Node-Metastases (TNM) staging system, pathologic types, laboratory parameters, and PET metabolic parameters. Four machine learning algorithms-Bayes, logistic, random forest, and Supportsupport vector machine (SVM)-were used to build models. The predictive performance was validated using receiver operating characteristic (ROC) curves. Univariate and multivariate Cox analyses identified independent predictors of OS and PFS in PD-L1-positive expression patients undergoing immunotherapy, and a nomogram was created to predict OS.

RESULTS

A total of 20 models were built for predicting PD-L1 expression. The clinical combined PET/CT radiomics model based on the SVM algorithm performed best (area under curve for training and test sets: 0.914 and 0.877, respectively). The Cox analyses showed that smoking history independently predicted PFS. SUVmean, monocyte percentage and white blood cell count were independent predictors of OS, and the nomogram was created to predict 1-year, 2-year, and 3-year OS based on these three factors.

CONCLUSION

We developed PET/CT-based machine learning models to help predict PD-L1 expression in NSCLC patients and identified independent predictors of PFS and OS in PD-L1-positive patients receiving immunotherapy, thereby aiding precision treatment.