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Purpose: The purpose of this study was to investigate whether (44)Sc-labeled puromycin can be utilized for imaging of protein synthesis in vivo.Methods: For micro-positron emission tomographic (μPET) studies, 20-25 MBq of [(44)Sc]-DOTA-puromycin was administered to tumor-bearing rats, and animals were scanned for 1 h dynamically. Results were further validated by dissecting organs and tissues of the animals after the measurement and in vitro blocking experiments using puromycin or cycloheximide to block protein synthesis.Results: μPET images of tumor-bearing rats showed significant tumor uptake of [(44)Sc]-DOTA-puromycin and a clear-cut tumor visualization. In both blocking experiments, cellular uptake of [(44)Sc]-DOTA-puromycin ([(44)Sc]-DOTA-Pur) could be suppressed by blocking protein synthesis.Conclusions: We report for the first time successful μPET imaging with (44)Sc obtained from a (44)Ti/(44)Sc generator, as well as noninvasive μPET imaging of ribosomal activity, respectively protein synthesis, with a puromycin-based radiopharmaceutical and the direct correlation between cellular uptake of [(44)Sc]-DOTA-Pur and protein synthesis. [ABSTRACT FROM AUTHOR]

Purpose: Prostate-specific membrane antigen (PSMA)-targeted radioguided surgery (RGS) has gained increased interest in prostate cancer (PCa). This analysis aims to evaluate the feasibility, safety, and limitations of RGS with a novel drop-in gamma probe in primary PCa., Patients and Methods: The data of 13 patients with primary PCa undergoing RGS were analyzed retrospectively. After preoperative administration of 99m Tc-PSMA-I&S, a SPECT/CT was conducted and a robotic radical prostatectomy was performed the following day including intraoperative assessment of the lymph node stations using a novel robotic drop-in gamma probe. This was followed by an extended pelvic lymph node dissection (ePLND) with ex vivo control measurement using the drop-in and a conventional rigid gamma probe., Results: Eleven patients (median PSA value of 11 ng/mL) had high-risk and 2 patients had intermediate-risk PCa. Overall, a median of 22 ePLND lymph nodes were dissected. In 1 patient, preoperative SPECT/CT imaging showed suspicious lymph nodes, which could be confirmed intraoperatively with the robotic drop-in probe and subsequently in the final histopathological analysis. RGS failed to identify 2 patients with micrometastases (<3 mm) preoperatively and intraoperatively. No postoperative complications related to 99m Tc-PSMA-I&S RGS or ePLND occurred., Conclusions: RGS with the novel drop-in gamma probe and 99m Tc-PSMA-I&S allows for a reliable intraoperative screening for lymph node metastases in robot-assisted radical prostatectomy for primary PCa with an acceptable safety profile. However, limitations in the detection of micrometastases need to be overcome before omitting extended ePLND in patients at risk for lymphatic spread., Competing Interests: Conflicts of interest and sources of funding: No external funding or sponsorship was received for this study or publication of this article. N.N.H. has received honoraria for presentations from Intuitive Surgical, Janssen, and Pajunk, and compensation for travel from Bayer, Astellas, Pfizer, and Janssen. C.F. has obtained compensation for travel by Lightpoint. O.K. has received compensation for travel from Astellas., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

The serotonergic system has shown to be altered during epileptogenesis and in chronic epilepsy, making selective serotonin reuptake inhibitors interesting candidates for antiepileptogenic therapy. In this study, we aimed to evaluate disease-modifying effects of fluoxetine during experimental epileptogenesis. Status epilepticus (SE) was induced by lithium-pilocarpine, and female rats were treated either with vehicle or fluoxetine over 15 days. Animals were subjected to 18 F-FDG (7 days post-SE), 18 F-GE180 (15 days post-SE) and 18 F-flumazenil positron emission tomography (PET, 21 days post-SE). Uptake ( 18 F-FDG), volume of distribution ( 18 F-GE180) and binding potential ( 18 F-flumazenil) were calculated. In addition, hyperexcitability testing and video-EEG monitoring were performed. Fluoxetine treatment did not alter brain glucose metabolism. 18 F-GE180 PET indicated lower neuroinflammation in the hippocampus of treated animals (-22.6%, p = 0.042), but no differences were found in GABA A receptor density. Video-EEG monitoring did not reveal a treatment effect on seizure frequency. However, independently of the treatment, hippocampal FDG uptake 7 days after SE correlated with seizure frequency during the chronic phase (r = -0.58; p = 0.015). Fluoxetine treatment exerted anti-inflammatory effects in rats during epileptogenesis. However, this effect did not alter disease outcome. Importantly, FDG-PET in early epileptogenesis showed biomarker potential as higher glucose metabolism correlated to lower seizure frequency in the chronic phase., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To evaluate if exercise and sitting time during chemotherapy were associated with chemotherapy side-effects, completion of planned chemotherapy and survival., Methods: We used data from the Ovarian cancer Prognosis And Lifestyle (OPAL) Study, a national prospective cohort of adults with newly-diagnosed epithelial ovarian cancer. At 3-monthly questionnaires we asked about exercise and sitting time in the past week, and treatment-related side-effects. Details about treatment, toxicities, progression and death were abstracted from medical records. We used linear, logistic and Cox regression, respectively, to assess associations between both exercise and sitting time, and chemotherapy side-effects and completion (≥85% relative dose intensity) and survival., Results: 503 eligible participants were included in one or more analyses. Patients participating in higher-intensity exercise (≥30 min of moderate-vigorous exercise/week; 24%) reported significantly better Functional Assessment of Chronic Illness/Cancer Therapy (FACIT)-Fatigue (32.2 vs. 26.7) and FACT-Trial Outcome Index (69.4 vs. 61.7) scores, and were less likely to have clinician-reported moderate-severe neurotoxicity (odds ratio [OR]:0.50; 95% confidence interval [95%CI]:0.29-0.88), than minimal exercisers (<30 min moderate-vigorous exercise/week & <120 min walking/week; 52%). Participating in higher-intensity exercise was also possibly associated with greater chemotherapy completion (OR:1.70; 95%CI:0.90-3.20), particularly for paclitaxel. Sitting time was not associated with chemotherapy completion. For patients with advanced disease who underwent cytoreduction and received first-line carboplatin and paclitaxel, there was a suggestion higher-intensity exercise during chemotherapy may improve survival (HR:0.68; 95%CI:0.47-1.01)., Conclusions: Patients with ovarian cancer who carry out moderate-vigorous exercise during chemotherapy have fewer side-effects and potentially better completion of planned chemotherapy and overall survival., Competing Interests: Declaration of competing interest A DeFazio, PM Webb and ML Friedlander have received grant funding from AstraZeneca for an unrelated study of ovarian cancer. Outside of the submitted work PM Webb received a speaker's fee from AstraZeneca, A DeFazio's institution received honoraria from AstraZeneca and ML Friedlander received consulting/speakers fees from AstraZeneca, Novartis GSK and MSD as well as institutional research grants from AstraZeneca, Novartis and Beigene. All remaining authors have declared no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Pure-tone audiograms often poorly predict elderly humans' ability to communicate in everyday complex acoustic scenes. Binaural processing is crucial for discriminating sound sources in such complex acoustic scenes. The compromised perception of communication signals presented above hearing threshold has been linked to both peripheral and central age-related changes in the auditory system. Investigating young and old Mongolian gerbils of both sexes, an established model for human hearing, we demonstrate age-related supra-threshold deficits in binaural hearing using behavioral, electrophysiological, anatomical, and imaging methods. Binaural processing ability was measured as the binaural masking level difference (BMLD), an established measure in human psychophysics. We tested gerbils behaviorally with "virtual headphones," recorded single-unit responses in the auditory midbrain and evaluated gross midbrain and cortical responses using positron emission tomography (PET) imaging. Furthermore, we obtained additional measures of auditory function based on auditory brainstem responses, auditory-nerve synapse counts, and evidence for central inhibitory processing revealed by PET. BMLD deteriorates already in middle-aged animals having normal audiometric thresholds and is even worse in old animals with hearing loss. The magnitude of auditory brainstem response measures related to auditory-nerve function and binaural processing in the auditory brainstem also deteriorate. Furthermore, central GABAergic inhibition is affected by age. Because the number of synapses in the apical turn of the inner ear was not reduced in middle-aged animals, we conclude that peripheral synaptopathy contributes little to binaural processing deficits. Exploratory analyses suggest increased hearing thresholds, altered binaural processing in the brainstem and changed central GABAergic inhibition as potential contributors., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 the authors.)

The immune-fibrosis axis plays a critical role in cardiac remodeling after acute myocardial infarction. Imaging approaches to monitor temporal inflammation and fibroblast activation in mice have seen wide application in recent years. However, the repeatability of quantitative measurements remains challenging, particularly across multiple imaging centers. We aimed to determine reproducibility of quantitative inflammation and fibroblast activation images acquired at 2 facilities after myocardial infarction in mice. Methods: Mice underwent coronary artery ligation and sequential imaging with 68 Ga-DOTA-ECL1i to assess chemokine receptor type 2 expression at 3 d after myocardial infarction and 68 Ga-FAPI-46 to assess fibroblast activation protein expression at 7 d after myocardial infarction. Images were acquired at 1 center using either a local or a consensus protocol developed with the second center; the protocols differed in the duration of isoflurane anesthesia and the injected tracer dose. A second group of animals were scanned at the second site using the consensus protocol. Image analyses performed by each site and just by 1 site were also compared. Results: The uptake of 68 Ga-DOTA-ECL1i in the infarct territory tended to be higher when the consensus protocol was used ( P = 0.03). No difference was observed between protocol acquisitions for 68 Ga-FAPI-46. Compared with the local protocol, the consensus protocol decreased variability between individual animals. When a matched consensus protocol was used, the 68 Ga-DOTA-ECL1i infarct territory percentage injected dose per gram of tissue was higher on images acquired at site B than on those acquired at site A ( P = 0.006). When normalized to body weight as SUV, this difference was mitigated. Both the percentage injected dose per gram of tissue and the SUV were comparable between sites for 68 Ga-FAPI-46. Image analyses at the sites differed significantly, but this difference was mitigated when all images were analyzed at site A. Conclusion: The application of a standardized acquisition protocol may lower variability within datasets and facilitate comparison of molecular radiotracer distribution between preclinical imaging centers. Like clinical studies, multicenter preclinical studies should use centralized core-based image analysis to maximize reproducibility across sites., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: Five-year relative survival for ovarian cancer remains below 50%. Strategies to improve outcomes are needed. Higher serum 25-hydroxyvitamin D [25(OH)D] concentrations [measure of vitamin D status] at and before diagnosis have been associated with longer survival in cancer patients; however, data for ovarian cancer are limited. We aimed to determine if 25(OH)D concentrations during and after primary treatment were associated with ovarian cancer-specific survival., Methods: We used data from a nationwide prospective cohort study of women with ovarian cancer. Among 886 participants treated with chemotherapy, 700 (79%) had a blood sample collected during (n = 591) and/or after (n = 458) primary treatment. These were tested for 25(OH)D. Clinical and survival data were abstracted from medical records. We used multivariable Cox proportional hazards regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between 25(OH)D and ovarian cancer-specific survival., Results: Mean 25(OH)D concentrations were lower during than after primary treatment (82 and 91 nmol/L, respectively); only 14% and 8% had concentrations below 50 nmol/L during and after primary treatment, respectively. There was no association between 25(OH)D and ovarian cancer-specific survival during five years of follow-up [HR 1.10 (95% CI: 0.76, 1.61) and 0.95 (0.54, 1.68) for the highest vs. lowest quintile during and after treatment, respectively]., Conclusions: We did not observe any association between serum 25(OH)D concentration and ovarian cancer-specific survival. Our results suggest that, in the absence of vitamin D deficiency, vitamin D supplementation to improve ovarian cancer survival is not warranted., (© 2023. The Author(s).)

Background: Implant infections caused by biofilm forming bacteria are a major threat in orthopedic surgery. Delivering antibiotics directly to an implant affected by a bacterial biofilm via superparamagnetic nanoporous silica nanoparticles could present a promising approach. Nevertheless, short blood circulation half-life because of rapid interactions of nanoparticles with the host's immune system hinder them from being clinically used. The aim of this study was to determine the temporal in vivo resolution of magnetic nanoporous silica nanoparticle (MNPSNP) distribution and the effect of PEGylation and clodronate application using PET/CT imaging and gamma counting in an implant mouse model., Methods: PEGylated and non-PEGylated MNPSNPs were radiolabeled with gallium-68 ( 68 Ga), implementing the chelator tris(hydroxypyridinone). 36 mice were included in the study, 24 mice received a magnetic implant subcutaneously on the left and a titanium implant on the right hind leg. MNPSNP pharmacokinetics and implant accumulation was analyzed in dependence on PEGylation and additional clodronate application. Subsequently gamma counting was performed for further final analysis., Results: The pharmacokinetics and biodistribution of all radiolabeled nanoparticles could clearly be visualized and followed by dynamic PET/CT imaging. Both variants of 68 Ga-labeled MNPSNP accumulated mainly in liver and spleen. PEGylation of the nanoparticles already resulted in lower liver uptakes. Combination with macrophage depletion led to a highly significant effect whereas macrophage depletion alone could not reveal significant differences. Although MNPSNP accumulation around implants was low in comparison to the inner organs in PET/CT imaging, gamma counting displayed a significantly higher %I.D./g for the tissue surrounding the magnetic implants compared to the titanium control. Additional PEGylation and/or macrophage depletion revealed no significant differences regarding nanoparticle accumulation at the implantation site., Conclusion: Tracking of 68 Ga-labeled nanoparticles in a mouse model in the first critical hours post-injection by PET/CT imaging provided a better understanding of MNPSNP distribution, elimination and accumulation. Although PEGylation increases circulation time, nanoparticle accumulation at the implantation site was still insufficient for infection treatment and additional efforts are needed to increase local accumulation., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: We explored the interrelation between prostate-specific membrane antigen (PSMA) expression on circulating tumor cells (CTCs) and that of solid metastatic lesions as determined by whole-body PSMA-targeted positron emission tomography (PET) to refine the prediction of response to subsequent PSMA-targeted radioligand therapy (RLT)., Methods: A prospective study was performed in 20 patients with advanced mCRPC. Of these, 16 underwent subsequent RLT with [ 177 Lu]Lu-PSMA-617 at a dose of 7.4 GBq every 6-8 weeks. PSMA expression on CTCs using the CellSearch system was compared to clinical and serological results, and to marker expression in targeted imaging and available histological sections of prostatectomy specimens (19% of RLT patients). Clinical outcome was obtained after two cycles of RLT., Results: Marked heterogeneity of PSMA expression was observed already at first diagnosis in available histological specimens. Targeted whole-body imaging also showed heterogeneous inter- and intra-patient PSMA expression between metastases. Heterogeneity of CTC PSMA expression was partially paralleled by heterogeneity of whole-body tumor burden PSMA expression. Twenty percent of CTC samples showed no PSMA expression, despite unequivocal PSMA expression of solid metastases at PET. A high fraction of PSMA-negative CTCs emerged as the sole predictor of poor RLT response (odds ratio [OR]: 0.9379 [95% confidence interval, CI, 0.8558-0.9902]; p = 0.0160), and was prognostic for both shorter progression-free survival (OR: 1.236 [95% CI, 1.035-2.587]; p = 0.0043) and overall survival (OR: 1.056 [95% CI, 1.008-1.141]; p = 0.0182)., Conclusion: This proof-of-principle study suggests that liquid biopsy for CTC PSMA expression is complementary to PET for individual PSMA phenotyping of mCRPC., (© 2023 The Authors. The Prostate published by Wiley Periodicals LLC.)

Using multimodal imaging, we investigated the extent and functional correlates of myocardial fibroblast activation in patients with aortic stenosis (AS) scheduled for transcatheter aortic valve replacement (TAVR). AS may cause myocardial fibrosis, which is associated with disease progression and may limit response to TAVR. Novel radiopharmaceuticals identify upregulation of fibroblast activation protein (FAP) as a cellular substrate of cardiac profibrotic activity. Methods: Twenty-three AS patients underwent 68 Ga-FAP inhibitor 46 ( 68 Ga-FAPI) PET, cardiac MRI, and echocardiography within 1-3 d before TAVR. Imaging parameters were correlated and then were integrated with clinical and blood biomarkers. Control cohorts of subjects without a history of cardiac disease and with ( n = 5) and without ( n = 9) arterial hypertension were compared with matched AS subgroups. Results: Myocardial FAP volume varied significantly among AS subjects (range, 1.54-138 cm 3 , mean ± SD, 42.2 ± 35.6 cm 3 ) and was significantly higher than in controls with (7.42 ± 8.56 cm 3 , P = 0.007) and without (2.90 ± 6.67 cm 3 ; P < 0.001) hypertension. FAP volume correlated with N-terminal prohormone of brain natriuretic peptide ( r = 0.58, P = 0.005), left ventricular ejection fraction ( r = -0.58, P = 0.02), mass ( r = 0.47, P = 0.03), and global longitudinal strain ( r = 0.55, P = 0.01) but not with cardiac MRI T1 (spin-lattice relaxation time) and extracellular volume ( P = not statistically significant). In-hospital improvement in left ventricular ejection fraction after TAVR correlated with pre-TAVR FAP volume ( r = 0.440, P = 0.035), N-terminal prohormone of brain natriuretic peptide, and strain but not with other imaging parameters. Conclusion: FAP-targeted PET identifies varying degrees of left ventricular fibroblast activation in TAVR candidates with advanced AS. 68 Ga-FAPI signal does not match other imaging parameters, generating the hypothesis that it may become useful as a tool for personalized selection of optimal TAVR candidates., (© 2023 by the Society of Nuclear Medicine and Molecular Imaging.)

Background: A quantitative imaging biomarker is desirable to provide a comprehensive measure of whole-body tumor burden in patients with metastatic neuroendocrine tumors, and to standardize the evaluation of treatment-related changes. Therefore, we evaluated volumetric parameters for quantification of whole-body tumor burden from somatostatin receptor (SSR)-targeted PET/CT., Methods: Thirty-two patients with metastastic grade1/grade 2 gastroenteropancreatic neuroendocrine tumors who underwent a 68 Ga-DOTA-TATE PET/CT for staging of disease before initiation of peptide receptor radionuclide therapy were included in this retrospective cohort analysis. Volumetric parameters of tumor lesions, SSR-derived tumor volume (SSR-TV) and total lesion SSR (TL-SSR), were calculated for each patient using a computerized volumetric technique with a 40% SUVmax cut-off, and compared with serum chromogranin A (CgA) levels. Progression-free survival (PFS) was determined in relation to volumetric parameters. In a subgroup of 18 patients, the feasibility of volumetric parameters for treatment monitoring was evaluated., Results: Mean SSR-TV was 178±214 cm 3 (range, 9-797 cm 3 ), whereas mean TL-SSR was 4096±5191 cm 3 (range, 61-19,203 cm 3 ). Baseline CgA levels were associated with whole-body tumor burden (SSR-TV, r=0.57, P=0.0008; and TL-SSR, r=0.43, P=0.01, respectively). PFS was shorter in patients with high SSR-TV and high TL-SSR (HR 5.16, 95% CI, 1.61-29.67), P=0.009), and SSR-TV (P=0.0067) and TL-SSR (P=0.0215) emerged as the sole predictors of progression in regression analysis. Changes in CgA did not correctly identify treatment response (P=0.25)., Conclusions: SSR-derived volumetric parameters provide a quantitative imaging biomarker for whole-body tumor burden, and may hold potential as a clear-cut measure for assessment of treatment response.

Ischemic stroke imparts elevated risk of heart failure though the underlying mechanisms remain poorly described. We aimed to characterize the influence of cerebral ischemic injury on cardiac function using multimodality molecular imaging to investigate brain and cardiac morphology and tissue inflammation in two mouse models of variable stroke severity. Transient middle cerebral artery occlusion (MCAo) generated extensive stroke damage (56.31 ± 40.39 mm 3 ). Positron emission tomography imaging of inflammation targeting the mitochondrial translocator protein (TSPO) revealed localized neuroinflammation at 7 days after stroke compared to sham (3.8 ± 0.8 vs 2.6 ± 0.7 %ID/g max, p < 0.001). By contrast, parenchyma topical application of vasoconstrictor endothelin-1 did not generate significant stroke damage or neuroinflammatory cell activity. MCAo evoked a modest reduction in left ventricle ejection fraction at both 1 weeks and 3 weeks after stroke (LVEF at 3 weeks: 54.3 ± 5.7 vs 66.1 ± 3.5%, p < 0.001). This contractile impairment was paralleled by elevated cardiac TSPO PET signal compared to sham (8.6 ± 2.4 vs 5.8 ± 0.7%ID/g, p = 0.022), but was independent of leukocyte infiltration defined by flow cytometry. Stroke size correlated with severity of cardiac dysfunction (r = 0.590, p = 0.008). Statistical parametric mapping identified a direct association between neuroinflammation at 7 days in a cluster of voxels including the insular cortex and reduced ejection fraction (ρ = - 0.396, p = 0.027). Suppression of microglia led to lower TSPO signal at 7 days which correlated with spared late cardiac function after MCAo (r = - 0.759, p = 0.029). Regional neuroinflammation early after cerebral ischemia influences subsequent cardiac dysfunction. Total body TSPO PET enables monitoring of neuroinflammation, providing insights into brain-heart inter-organ communication and may guide therapeutic intervention to spare cardiac function post-stroke., (© 2022. The Author(s).)

After acute myocardial infarction (AMI), fibroblast activation protein (FAP) upregulation exceeds the infarct region. We sought further insights into the physiologic relevance by correlating FAP-targeted PET with tissue characteristics from cardiac MRI (CMR) and functional outcome. Methods: Thirty-five patients underwent CMR, perfusion SPECT, and 68 Ga-FAP inhibitor (FAPI)-46 PET/CT within 11 d after AMI. Infarct size was determined from SPECT by comparison to a reference database. For PET, regional SUVs and isocontour volumes of interest determined the extent of cardiac FAP upregulation (FAP volume). CMR yielded functional parameters, area of injury (late gadolinium enhancement [LGE]) and T1/T2 mapping. Follow-up was available from echocardiography or CMR after 139.5 d (interquartile range, 80.5-188.25 d) ( n = 14). Results: The area of FAP upregulation was significantly larger than the SPECT perfusion defect size (58% ± 15% vs. 23% ± 17%, P < 0.001) and infarct area by LGE (28% ± 11%, P < 0.001). FAP volume significantly correlated with CMR parameters at baseline (all P < 0.001): infarct area ( r = 0.58), left ventricle (LV) mass ( r = 0.69), end-systolic volume ( r = 0.62), and end-diastolic volume ( r = 0.57). Segmental analysis revealed FAP upregulation in 308 of 496 myocardial segments (62%). Significant LGE was found in only 56% of FAP-positive segments, elevated T1 in 74%, and elevated T2 in 68%. Fourteen percent (44/308) of FAP-positive segments exhibited neither prolonged T1 or T2 nor significant LGE. Of note, FAP volume correlated only weakly with simultaneously measured LV ejection fraction at baseline ( r = -0.32, P = 0.07), whereas there was a significant inverse correlation with LV ejection fraction obtained at later follow-up ( r = -0.58, P = 0.007). Conclusion: Early after AMI and reperfusion therapy, activation of fibroblasts markedly exceeds the hypoperfused infarct region and involves noninfarcted myocardium. The 68 Ga-FAPI PET signal does not match regional myocardial tissue characteristics as defined by CMR but is predictive of the evolution of ventricular dysfunction. FAP-targeted imaging may provide a novel biomarker of LV remodeling that is complementary to existing techniques., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Background: Cyclotrons form a central infrastructure and are a resource of medical radionuclides for the development of new radiotracers as well as the production and supply of clinically established radiopharmaceuticals for patient care in nuclear medicine., Aim: To provide an updated overview of the number and characteristics of cyclotrons that are currently in use within radiopharmaceutical sciences and for the development of radiopharmaceuticals to be used for patient care in Nuclear Medicine in Germany (D), Austria (A) and Switzerland (CH)., Methods: Publicly available information on the cyclotron infrastructure was (i) consolidated and updated, (ii) supplemented by selective desktop research and, last but not least, (iii) validated by members of the committee of the academic "Working Group Radiochemistry and Radiopharmacy" (AGRR), consisting of radiochemists and radiopharmacists of the D-A-CH countries and belonging to the German Society of Nuclear Medicine (DGN), as well as the Radiopharmaceuticals Committee of the DGN., Results: In total, 42 cyclotrons were identified that are currently being operated for medical radionuclide production for imaging and therapy in Nuclear Medicine clinics, 32 of them in Germany, 4 in Austria and 6 in Switzerland. Two thirds of the cyclotrons reported (67%) are operated by universities, university hospitals or research institutions close to a university hospital, less by/in cooperation with industrial partners (29%) or a non-academic clinic/ PET-center (5%). Most of the cyclotrons (88%) are running with up to 18 MeV proton beams, which is sufficient for the production of the currently most common cyclotron-based radionuclides for PET imaging., Discussion: The data presented provide an academically-updated overview of the medical cyclotrons operated for the production of radiopharmaceuticals and their use in Nuclear Medicine in the D-A-CH countries. In this context, we discuss current developments and trends with a view to the cyclotron infrastructure in these countries, with a specific focus on organizational aspects., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zippel, Ermert, Patt, Gildehaus, Ross, Reischl, Kuwert, Solbach, Neumaier, Kiss, Mitterhauser, Wadsak, Schibli and Kopka.)

Persistent inflammation following myocardial infarction (MI) precipitates adverse outcome including acute ventricular rupture and chronic heart failure. Molecular imaging allows longitudinal assessment of immune cell activity in the infarct territory and predicts severity of remodeling. We utilized a multiparametric imaging platform to assess the immune response and cardiac healing following MI in mice. Suppression of circulating macrophages prior to MI paradoxically resulted in higher total leukocyte content in the heart, demonstrated by increased CXC motif chemokine receptor 4 (CXCR4) positron emission tomography imaging. This supported the formation of a thrombus overlying the injured region, as identified by magnetic resonance imaging. The injured and thrombotic region in macrophage depeleted mice subsequently showed active calcification, as evidenced by accumulation of 18 F-fluoride and by cardiac computed tomography. Importantly, macrophage suppression triggered a prolonged inflammatory response confirmed by post-mortem tissue analysis that was associated with higher mortality from ventricular rupture early after occlusion and with increased infarct size and worse chronic contractile function at 6 weeks after reperfusion. These findings establish a molecular imaging toolbox for monitoring the interplay between adverse immune response and tissue repair after MI. This may serve as a foundation for development and monitoring of novel targeted therapies that may include immune modulation and endogenous healing support., (© 2022. The Author(s).)

Objectives: Knowledge on the course of symptoms patients with ovarian cancer experience is limited. We documented the prevalence and trajectories of symptoms after first-line chemotherapy using the Measure of Ovarian Symptoms and Treatment concerns (MOST)., Methods: A total of 726 patients who received platinum-based chemotherapy for ovarian cancer were asked to complete the MOST every 3 months, beginning 6 months post-diagnosis and continuing for up to 4 years. We used descriptive statistics to examine temporal changes in MOST-S26 index scores for disease or treatment-related (MOST-DorT), neurotoxicity (MOST-NTx), abdominal (MOST-Abdo), and psychological (MOST-Psych) symptoms, and wellbeing (MOST-Wellbeing) and selected individual symptoms. We used group-based trajectory models to identify groups with persistently poor symptoms., Results: The median MOST-Abdo, MOST-DorT and MOST-Wellbeing score were worst at chemotherapy-end but improved and stabilised by 1, 3 and 12 months after treatment, respectively. The median MOST-NTx score peaked at 1 month after treatment before improving, while the median MOST-Psych score did not change substantially over time. Long-term moderate-to-severe fatigue (32%), trouble sleeping (31%), sore hands and feet (21%), pins and needles (20%) and anxiety (18%) were common. Trajectory models revealed groups of patients with persistent symptoms had MOST-DorT scores above 30 and MOST-NTx scores above 40 at treatment-end., Conclusions: Although many patients report improvements in symptoms by 3 months after first-line chemotherapy for ovarian cancer, patients who score > 30/100 on MOST-S26-DorT or > 40/100 on MOST-S26-NTx at the end of chemotherapy are likely to have persistent symptoms. The MOST could triage this at-risk subset for early intervention., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) may be associated with renal toxicity. We aimed to identify predictive parameters for the development of chronic kidney disease (CKD) in patients with metastatic castration resistant prostate cancer (mCRPC) undergoing RLT., Methods: In 46 mCRPC patients scheduled for Lu-177-PSMA-RLT, pretherapeutic estimated glomerular filtration rate (eGFR [ml/min/1.73 m 2 ]), Tc-99m-mercaptoacetyltriglycine (Tc-99m-MAG3) clearance and baseline Ga-68-PSMA-ligand positron emission tomography (PET)-derived renal cortical uptake and PSMA-tumor volume (TV) were determined. We tested the predictive capability of these parameters and clinical risk factors for the occurrence of CKD (defined as CTCAE vers. 5.0 grade 2 or higher) during follow-up., Results: After 4 ± 3 cycles of RLT average eGFR declined from 76 ± 17 to 72 ± 20 ml/min/1.73 m 2 (p = 0.003). Increased estimated renal radiation dose (eRRD) was significantly associated with renal functional decline (p = 0.008). During follow-up, 16/46 (30.4%) developed CKD grade 2 (no grade 3 or higher). In receiver operating characteristic (ROC) analysis, pretherapeutic eGFR was highly accurate in identifying the occurrence of CKD vs no CKD with an area under the curve (AUC) of 0.945 (p < 0.001; best threshold, 77 ml/min/1.73 m 2 ), followed by Tc-99m-MAG3-derived tubular extraction rate (TER; AUC, 0.831, p < 0.001; best threshold, 200 ml/min/1.73 m 2 ). Renal PET signal (p = 0.751) and PSMA-TV (p = 0.942), however, were not predictive. Kaplan-Meier analyses revealed adverse renal outcome for patients with lower eGFR (p = 0.001) and lower scintigraphy-derived TER (p = 0.009), with pretherapeutic eGFR emerging as the sole predictive parameter in multivariate analysis (p = 0.007)., Conclusion: Serious adverse renal events are not a frequent phenomenon after PSMA-targeted RLT. However, in patients developing moderate CKD after RLT, pretherapeutic eGFR is an independent predictor for renal impairment during follow-up., (© 2021 Authors. The Prostate published by Wiley Periodicals LLC.)

Purpose: Calcineurin inhibitors (CNI) can cause long-term impairment of brain function. Possible pathomechanisms include alterations of the cerebral immune system. This study used positron emission tomography (PET) imaging with the translocator protein (TSPO) ligand 18 F-GE-180 to evaluate microglial activation in liver-transplanted patients under different regimens of immunosuppression., Methods: PET was performed in 22 liver-transplanted patients (3 CNI free, 9 with low-dose CNI, 10 with standard-dose CNI immunosuppression) and 9 healthy controls. The total distribution volume (V T ) estimated in 12 volumes-of-interest was analyzed regarding TSPO genotype, CNI therapy, and cognitive performance., Results: In controls, V T was about 80% higher in high affinity binders (n = 5) compared to mixed affinity binders (n = 3). Mean V T corrected for TSPO genotype was significantly lower in patients compared to controls, especially in patients in whom CNI dose had been reduced because of nephrotoxic side effect., Conclusion: Our results provide evidence of chronic suppression of microglial activity in liver-transplanted patients under CNI therapy especially in patients with high sensitivity to CNI toxicity., (© 2021. The Author(s).)

Status epilepticus (SE) is a clinical emergency with high mortality. SE can trigger neuronal death or injury and alteration of neuronal networks resulting in long-term cognitive decline or epilepsy. Among the multiple factors contributing to this damage, imbalance between oxygen and glucose requirements and brain perfusion during SE has been proposed. Herein, we aimed to quantify by neuroimaging the spatiotemporal course of brain perfusion during and after lithium-pilocarpine-induced SE in rats. To this purpose, animals underwent 99m Tc-HMPAO SPECT imaging at different time points during and after SE using a small animal SPECT/CT system. 99m Tc-HMPAO regional uptake was normalized to the injected dose. In addition, voxel-based statistical parametric mapping was performed. SPECT imaging showed an increase of cortical perfusion before clinical seizure activity onset followed by regional hypo-perfusion starting with the first convulsive seizure and during SE. Twenty-four hours after SE, brain 99m Tc-HMPAO uptake was widely decreased. Finally, chronic epileptic animals showed regionally decreased perfusion affecting hippocampus and cortical sub-regions. Despite elevated energy and oxygen requirements, brain hypo-perfusion is present during SE. Our results suggest that insufficient compensation of required blood flow might contribute to neuronal damage and neuroinflammation, and ultimately to chronic epilepsy generated by SE., (© 2021. The Author(s).)

Purpose: Alterations in brain glucose metabolism detected by 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) positron emission tomography (PET) may serve as an early predictive biomarker and treatment target for epileptogenesis. Here, we aimed to investigate changes in cerebral glucose metabolism before induction of epileptogenesis, during epileptogenesis as well as during chronic epilepsy. As anesthesia is usually unavoidable for preclinical PET imaging and influences the distribution of the radiotracer, four different protocols were compared., Procedures: We investigated 18F-FDG uptake phase in conscious rats followed by a static scan as well as dynamic scans under continuous isoflurane, medetomidine-midazolam-fentanyl (MMF), or propofol anesthesia. Furthermore, we applied different analysis approaches: atlas-based regional analysis, statistical parametric mapping, and kinetic analysis., Results: At baseline and compared to uptake in conscious rats, isoflurane and propofol anesthesia resulted in decreased cortical 18F-FDG uptake while MMF anesthesia led to a globally decreased tracer uptake. During epileptogenesis, MMF anesthesia was clearly best distinctive for visualization of prominently increased glucometabolism in epilepsy-related brain areas. Kinetic modeling further increased sensitivity, particularly for continuous isoflurane anesthesia. During chronic epilepsy, hypometabolism affecting more or less the whole brain was detectable with all protocols., Conclusion: This study reveals evaluation of anesthesia protocols for preclinical 18F-FDG PET imaging as a critical step in the study design. Together with an appropriate data analysis workflow, the chosen anesthesia protocol may uncover otherwise concealed disease-associated regional glucometabolic changes., Competing Interests: The authors have declared that no competing interests exist.

Objective: The Measure of Ovarian Symptoms and Treatment (MOST-T35) is a patient-reported symptom index, developed and validated in the context of palliative chemotherapy for recurrent ovarian cancer (OC). We aimed to develop and validate a version suitable for surveillance of symptoms following first-line treatment for OC to support clinical follow-up., Methods: In a prospective study of women following completion of first-line chemotherapy for OC, patients completed MOST-T35 every 3 months for up to 3.5 years and other patient-reported outcome measures. Construct validity (Spearman's correlations), discriminative validity (t-tests/ANOVAs assessing differences between clinically distinct groups), ability to detect clinically important symptoms (receiver operating characteristic analysis), and responsiveness (t-tests examining change) were assessed., Results: Data from 726 women who received ≥3 cycles of chemotherapy, did not progress within 3 months, and completed ≥one MOST-T35 were analysed. The revised version, MOST-S26, has 26 items and 5 multi-item indexes: peripheral neuropathy (MOST-NTx), disease or treatment-related (MOST-DorT), abdominal (MOST-Abdo), and psychological symptoms (MOST-Psych), and MOST-Wellbeing, plus 9 individual items. Construct validity was confirmed (r range = 0.43-0.88). Discriminative validity confirmed expected differences between groups. MOST-NTx and MOST-Psych detected improvements in peripheral neuropathy and psychological symptoms respectively, whereas MOST-Abdo detected worsening of abdominal symptoms pre-recurrence., Conclusions: This study developed and validated the MOST-S26, for surveillance of women in follow-up after first-line chemotherapy for OC. MOST-S26 reliably detected improvement in symptoms of peripheral neuropathy, psychological distress and may detect symptoms of relapse. Administration of MOST-S26 in follow-up consultations could identify concerning symptoms and facilitate timely and appropriate intervention., Competing Interests: Declaration of Competing Interest PMW and MF have received funding from Astra Zeneca for an unrelated study of ovarian cancer. MF has received personal fees from Astra Zeneca, MSD, GSK, Lilly, Novartis, Takeda and ACT Genomics; and research support from Beigene. PC has received personal fees from Seqirus and Astra Zeneca,outside the submitted work. All remaining authors have declared no conflicts of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: Hematotoxicity is a potentially dose-limiting adverse event in patients with metastasized castration-resistant prostate cancer (mCRPC) undergoing prostate-specific membrane antigen (PSMA)-directed radioligand therapy (RLT). We aimed to identify clinical or PSMA-targeted imaging-derived parameters to predict hematological adverse events at early and late stages in the treatment course., Methods: In 67 patients with mCRPC scheduled for 177 Lu-PSMA-617 RLT, pretherapeutic osseous tumor volume (TV) from 68 Ga-PSMA-11 PET/CT and laboratory values were assessed. We then tested the predictive capability of these parameters for early and late hematotoxicity (according to CTCAE vers. 5.0) after one cycle of RLT and in a subgroup of 32/67 (47.8%) patients after four cycles of RLT., Results: After one cycle, 10/67 (14.9%) patients developed leukocytopenia (lymphocytopenia, 39/67 [58.2%]; thrombocytopenia, 17/67 [25.4%]). A cut-off of 5.6 × 10 3 /mm 3 for baseline leukocytes was defined by receiver operating characteristics (ROC) and separated between patients with and without leukocytopenia (P < 0.001). Baseline leukocyte count emerged as a stronger predictive factor in multivariate analysis (hazard ratio [HR], 33.94, P = 0.001) relative to osseous TV (HR, 14.24, P = 0.01). After four cycles, 4/32 (12.5%) developed leukocytopenia and the pretherapeutic leukocyte cut-off (HR, 9.97, P = 0.082) tended to predict leukocytopenia better than TV (HR, 8.37, P = 0.109). In addition, a cut-off of 1.33 × 10 3 /mm 3 for baseline lymphocytes separated between patients with and without lymphocytopenia (P < 0.001), which was corroborated in multivariate analysis (HR, 21.39, P < 0.001 vs. TV, HR, 4.57, P = 0.03). After four cycles, 19/32 (59.4%) developed lymphocytopenia and the pretherapeutic cut-off for lymphocytes (HR, 46.76, P = 0.007) also demonstrated superior predictive performance for late lymphocytopenia (TV, HR, 5.15, P = 0.167). Moreover, a cut-off of 206 × 10 3 /mm 3 for baseline platelets separated between patients with and without thrombocytopenia (P < 0.001) and also demonstrated superior predictive capability in multivariate analysis (HR, 115.02, P < 0.001 vs.TV, HR, 12.75, P = 0.025). After four cycles, 9/32 (28.1%) developed thrombocytopenia and the pretherapeutic cut-off for platelets (HR, 5.44, P = 0.048) was also superior for the occurrence of late thrombocytopenia (TV, HR, 1.44, P = 0.7)., Conclusions: Pretherapeutic leukocyte, lymphocyte, and platelet levels themselves are strong predictors for early and late hematotoxicity under PSMA-directed RLT, and are better suited than PET-based osseous TV for this purpose., (© 2021. The Author(s).)

The automated plate assessment system (APAS Independence; Clever Culture System, Bäch, Switzerland) is an automated imaging station linked with interpretive software that detects target colonies of interest on chromogenic media and sorts samples as negative or presumptive positive. We evaluated the accuracy of the APAS to triage methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus cultures using chromogenic medium compared to that by human interpretation. Patient samples collected from the nares on ESwabs were plated onto BD BBL CHROMagar MRSA II and BD BBL CHROMagar Staph aureus and allowed to incubate for 20 to 24 h at 37°C in a non-CO 2 incubator. Mauve colonies are suggestive of S. aureus and were confirmed with latex agglutination. Following incubation, samples were first interrogated by APAS before being read by a trained technologist blinded to the APAS interpretation. The triaging by both APAS and the technologists was compared for accuracy. Any discordant results required further analysis by a third reader. Over a 5-month period, 5,913 CHROMagar MRSA cultures were evaluated. Of those, 236 were read as concordantly positive, 5,525 were read as concordantly negative, and 152 required discordant analysis. Positive and negative percent agreements (PPA and NPA, respectively) were 100% and 97.3%, respectively. The APAS detected 5 positive cultures that were missed by manual reading and determined to be true positives. In a separate analysis, 744 CHROMagar Staph aureus plates were read in parallel. Of these, 133 were concordantly positive, 585 were concordantly negative, and 26 required discordant analysis. PPA and NPA were 95.7% and 96.7%, respectively. This study confirmed the high sensitivity of digital image analysis by the APAS Independence such that negative cultures can be reliably reported without technologist intervention (negative predictive values [NPVs] of 100% for CHROMagar MRSA and 99.0% for CHROMagar Staph aureus). Triaging using the APAS Independence may provide great efficiency in a laboratory with high throughput of MRSA and S. aureus surveillance cultures.

The diagnosis of bacterial infections at deep body sites benefits from noninvasive imaging of molecular probes that can be traced by positron emission tomography (PET). We specifically labeled bacteria by targeting their iron transport system with artificial siderophores. The cyclen-based probes contain different binding sites for iron and the PET nuclide gallium-68. A panel of 11 siderophores with different iron coordination numbers and geometries was synthesized in up to 8 steps, and candidates with the best siderophore potential were selected by a growth recovery assay. The probes [ 68 Ga] 7 and [ 68 Ga] 15 were found to be suitable for PET imaging based on their radiochemical yield, radiochemical purity, and complex stability in vitro and in vivo. Both showed significant uptake in mice infected with Escherichia coli and were able to discern infection from lipopolysaccharide-triggered, sterile inflammation. The study qualifies cyclen-based artificial siderophores as readily accessible scaffolds for the in vivo imaging of bacteria.

Importance: The demand for medications for opioid use disorder (MOUD) in rural US counties far outweighs their availability. Novel approaches to extend treatment capacity include telemedicine (TM) and mobile treatment on demand; however, their combined use has not been reported or evaluated., Objective: To evaluate the use of a TM mobile treatment unit (TM-MTU) to improve access to MOUD for individuals living in an underserved rural area., Design, Setting, and Participants: This quality improvement study evaluated data collected from adult outpatients with a diagnosis of OUD enrolled in the TM-MTU initiative from February 2019 (program inception) to June 2020. Program staff traveled to rural areas in a modified recreational vehicle equipped with medical, videoconferencing, and data collection devices. Patients were virtually connected with physicians based more than 70 miles (112 km) away. Data analysis was performed from June to October 2020., Intervention: Patients received buprenorphine prescriptions after initial teleconsultation and follow-up visits from a study physician specialized in addiction psychiatry and medicine., Main Outcomes and Measures: The primary outcome was 3-month treatment retention, and the secondary outcome was opioid-positive urine screens. Exploratory outcomes included use of other drugs and patients' travel distance to treatment., Results: A total of 118 patients were enrolled in treatment, of whom 94 were seen for follow-up treatment predominantly (at least 2 of 3 visits [>50%]) on the TM-MTU; only those 94 patients' data are considered in all analyses. The mean (SD) age of patients was 36.53 (9.78) years, 59 (62.77%) were men, 71 (75.53%) identified as White, and 90 (95.74%) were of non-Hispanic ethnicity. Fifty-five patients (58.51%) were retained in treatment by 3 months (90 days) after baseline. Opioid use was reduced by 32.84% at 3 months, compared with baseline, and was negatively associated with treatment duration (F = 12.69; P = .001). In addition, compared with the nearest brick-and-mortar treatment location, TM-MTU treatment was a mean of 6.52 miles (range, 0.10-58.70 miles) (10.43 km; range, 0.16-93.92 km) and a mean of 10 minutes (range, 1-49 minutes) closer for patients., Conclusions and Relevance: These data demonstrate the feasibility of combining TM with mobile treatment, with outcomes (retention and opioid use) similar to those obtained from office-based TM MOUD programs. By implementing a traveling virtual platform, this clinical paradigm not only helps fill the void of rural MOUD practitioners but also facilitates access to underserved populations who are less likely to reach traditional medical settings, with critical relevance in the context of the COVID-19 pandemic.

Background: Leukocyte subtypes bear distinct pro-inflammatory, reparative, and regulatory functions. Imaging inflammation provides information on disease prognosis and may guide therapy, but the cellular basis of the signal remains equivocal. We evaluated leukocyte subtype specificity of characterized clinically relevant inflammation-targeted radiotracers., Methods and Results: Leukocyte populations were purified from blood- and THP-1-derived macrophages were polarized into M1-, reparative M2a-, or M2c-macrophages. In vitro uptake assays were conducted using tracers of enhanced glucose or amino acid metabolism and molecular markers of inflammatory cells. Both 18 F-deoxyglucose ( 18 F-FDG) and the labeled amino acid 11 C-methionine ( 11 C-MET) displayed higher uptake in neutrophils and monocytes compared to other leukocytes (P = 0.005), and markedly higher accumulation in pro-inflammatory M1-macrophages compared to reparative M2a-macrophages (P < 0.001). Molecular tracers 68 Ga-DOTATATE targeting the somatostatin receptor type 2 and 68 Ga-pentixafor targeting the chemokine receptor type 4 (CXCR4) exhibited broad uptake by leukocyte subpopulations and polarized macrophages with highest uptake in T-cells/natural killer cells and B-cells compared to neutrophils. Mitochondrial translocator protein (TSPO)-targeted 18 F-flutriciclamide selectively accumulated in monocytes and pro-inflammatory M1 macrophages (P < 0.001). Uptake by myocytes and fibroblasts tended to be higher for metabolic radiotracers., Conclusions: The different in vitro cellular uptake profiles may allow isolation of distinct phases of the inflammatory pathway with specific inflammation-targeted radiotracers. The pathogenetic cell population in specific inflammatory diseases should be considered in the selection of an appropriate imaging agent., (© 2019. American Society of Nuclear Cardiology.)

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