TY - JOUR A1 - Brumberg, Joachim A1 - Küsters, Sebastian A1 - Al-Momani, Ehab A1 - Marotta, Giorgio A1 - Cosgrove, Kelly P. A1 - van Dyck, Christopher H. A1 - Herrmann, Ken A1 - Homola, György A. A1 - Pezzoli, Gianni A1 - Buck, Andreas K. A1 - Volkmann, Jens A1 - Samnick, Samuel A1 - Isaias, Ioannis U. T1 - Cholinergic activity and levodopa-induced dyskinesia: a multitracer molecular imaging study JF - Annals of Clinical and Translational Neurology N2 - Objective: To investigate the association between levodopa‐induced dyskinesias and striatal cholinergic activity in patients with Parkinson's disease. Methods: This study included 13 Parkinson's disease patients with peak‐of‐dose levodopa‐induced dyskinesias, 12 nondyskinetic patients, and 12 healthy controls. Participants underwent 5‐[\(^{123}\)I]iodo‐3‐[2(S)‐2‐azetidinylmethoxy]pyridine single‐photon emission computed tomography, a marker of nicotinic acetylcholine receptors, [\(^{123}\)I]N‐ω‐fluoropropyl‐2β‐carbomethoxy‐3β‐(4‐iodophenyl)nortropane single‐photon emission computed tomography, to measure dopamine reuptake transporter density and 2‐[\(^{18}\)F]fluoro‐2‐deoxyglucose positron emission tomography to assess regional cerebral metabolic activity. Striatal binding potentials, uptake values at basal ganglia structures, and correlations with clinical variables were analyzed. Results: Density of nicotinic acetylcholine receptors in the caudate nucleus of dyskinetic subjects was similar to that of healthy controls and significantly higher to that of nondyskinetic patients, in particular, contralaterally to the clinically most affected side. Interpretation: Our findings support the hypothesis that the expression of dyskinesia may be related to cholinergic neuronal excitability in a dopaminergic‐depleted striatum. Cholinergic signaling would play a role in maintaining striatal dopaminergic responsiveness, possibly defining disease phenotype and progression. KW - levodopa-induced dyskinesia KW - cholinergic activity KW - Parkinson’s disease Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170406 VL - 4 IS - 9 ER - TY - JOUR A1 - Lückerath, Katharina A1 - Lapa, Constantin A1 - Albert, Christa A1 - Herrmann, Ken A1 - Jörg, Gerhard A1 - Samnick, Samuel A1 - Einsele, Herrmann A1 - Knop, Stefan A1 - Buck, Andreas K. T1 - \(^{11}\)C-Methionine-PET: a novel and sensitive tool for monitoring of early response to treatment in multiple myeloma JF - Oncotarget N2 - Multiple myeloma (MM) remains an essentially incurable hematologic malignancy. However, new treatment modalities and novel drugs have been introduced and thus additional tools for therapy monitoring are increasingly needed. Therefore, we evaluated the radiotracers \(^{11}\)C-Methionine (paraprotein-biosynthesis) and \(^{18}\)F-FDG (glucose-utilization) for monitoring response to anti-myeloma-therapy and outcome prediction. Influence of proteasome-inhibition on radiotracer-uptake of different MM cell-lines and patient-derived CD138\(^{+}\) plasma cells was analyzed and related to tumor-biology. Mice xenotransplanted with MM. 1S tumors underwent MET- and FDG-\(\mu\)PET. Tumor-to-background ratios before and after 24 h, 8 and 15 days treatment with bortezomib were correlated to survival. Treatment reduced both MET and FDG uptake; changes in tracer-retention correlated with a switch from high to low CD138-expression. In xenotransplanted mice, MET-uptake significantly decreased by 30-79% as early as 24 h after bortezomib injection. No significant differences were detected thus early with FDG. This finding was confirmed in patient-derived MM cells. Importantly, early reduction of MET-but not FDG-uptake correlated with improved survival and reduced tumor burden in mice. Our results suggest that MET is superior to FDG in very early assessment of response to anti-myeloma-therapy. Early changes in MET-uptake have predictive potential regarding response and survival. MET-PET holds promise to individualize therapies in MM in future. KW - positron emission tomography KW - imaging techniques KW - experience KW - \(^{11}\)C-Methionine-PET KW - treatment response KW - molecular imaging KW - multiple myeloma KW - management KW - \(^{18}\)F-FDG PET/CT KW - bone disease KW - stem-cell transplantation KW - esophagogastric junction Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148688 VL - 6 IS - 10 ER - TY - JOUR A1 - Israel, Ina A1 - Ohsiek, Andrea A1 - Al-Momani, Ehab A1 - Albert-Weissenberger, Christiane A1 - Stetter, Christian A1 - Mencl, Stine A1 - Buck, Andreas K. A1 - Kleinschnitz, Christoph A1 - Samnick, Samuel A1 - Sirén, Anna-Leena T1 - Combined [\(^{18}\)F]DPA-714 micro-positron emission tomography and autoradiography imaging of microglia activation after closed head injury in mice JF - Journal of Neuroinflammation N2 - Background Traumatic brain injury (TBI) is a major cause of death and disability. Neuroinflammation contributes to acute damage after TBI and modulates long-term evolution of degenerative and regenerative responses to injury. The aim of the present study was to evaluate the relationship of microglia activation to trauma severity, brain energy metabolism, and cellular reactions to injury in a mouse closed head injury model using combined in vivo PET imaging, ex vivo autoradiography, and immunohistochemistry. Methods A weight-drop closed head injury model was used to produce a mixed diffuse and focal TBI or a purely diffuse mild TBI (mTBI) in C57BL6 mice. Lesion severity was determined by evaluating histological damage and functional outcome using a standardized neuroscore (NSS), gliosis, and axonal injury by immunohistochemistry. Repeated intra-individual in vivo μPET imaging with the specific 18-kDa translocator protein (TSPO) radioligand [\(^{18}\)F]DPA-714 was performed on day 1, 7, and 16 and [\(^{18}\)F]FDG-μPET imaging for energy metabolism on days 2–5 after trauma using freshly synthesized radiotracers. Immediately after [\(^{18}\)F]DPA-714-μPET imaging on days 7 and 16, cellular identity of the [\(^{18}\)F]DPA-714 uptake was confirmed by exposing freshly cut cryosections to film autoradiography and successive immunostaining with antibodies against the microglia/macrophage marker IBA-1. Results Functional outcome correlated with focal brain lesions, gliosis, and axonal injury. [\(^{18}\)F]DPA-714-μPET showed increased radiotracer uptake in focal brain lesions on days 7 and 16 after TBI and correlated with reduced cerebral [\(^{18}\)F]FDG uptake on days 2–5, with functional outcome and number of IBA-1 positive cells on day 7. In autoradiography, [\(^{18}\)F]DPA-714 uptake co-localized with areas of IBA1-positive staining and correlated strongly with both NSS and the number of IBA1-positive cells, gliosis, and axonal injury. After mTBI, numbers of IBA-1 positive cells with microglial morphology increased in both brain hemispheres; however, uptake of [\(^{18}\)F]DPA-714 was not increased in autoradiography or in μPET imaging. Conclusions [\(^{18}\)F]DPA-714 uptake in μPET/autoradiography correlates with trauma severity, brain metabolic deficits, and microglia activation after closed head TBI. KW - neuroinflammation KW - TBI KW - immunohistochemistry KW - weight drop KW - PET KW - diffuse KW - focal KW - TSPO KW - autoradiography KW - IBA-1 Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146606 VL - 13 IS - 140 ER - TY - JOUR A1 - Mencacci, Niccoló E. A1 - Isaias, Ioannis U. A1 - Reich, Martin M. A1 - Ganos, Christos A1 - Plagnol, Vincent A1 - Polke, James M. A1 - Bras, Jose A1 - Hersheson, Joshua A1 - Stamelou, Maria A1 - Pittman, Alan M. A1 - Noyce, Alastair J. A1 - Mok, Kin Y. A1 - Opladen, Thomas A1 - Kunstmann, Erdmute A1 - Hodecker, Sybille A1 - Münchau, Alexander A1 - Volkmann, Jens A1 - Samnick, Samuel A1 - Sidle, Katie A1 - Nanji, Tina A1 - Sweeney, Mary G. A1 - Houlden, Henry A1 - Batla, Amit A1 - Zecchinelli, Anna L. A1 - Pezzoli, Gianni A1 - Marotta, Giorgio A1 - Lees, Andrew A1 - Alegria, Paulo A1 - Krack, Paul A1 - Cormier-Dequaire, Florence A1 - Lesage, Suzanne A1 - Brice, Alexis A1 - Heutink, Peter A1 - Gasser, Thomas A1 - Lubbe, Steven J. A1 - Morris, Huw R. A1 - Taba, Pille A1 - Koks, Sulev A1 - Majounie, Elisa A1 - Gibbs, J. Raphael A1 - Singleton, Andrew A1 - Hardy, John A1 - Klebe, Stephan A1 - Bhatia, Kailash P. A1 - Wood, Nicholas W. T1 - Parkinson’s disease in GTP cyclohydrolase 1 mutation carriers JF - Brain N2 - GTP cyclohydrolase 1, encoded by the GCH1 gene, is an essential enzyme for dopamine production in nigrostriatal cells. Loss-of-function mutations in GCH1 result in severe reduction of dopamine synthesis in nigrostriatal cells and are the most common cause of DOPA-responsive dystonia, a rare disease that classically presents in childhood with generalized dystonia and a dramatic long-lasting response to levodopa. We describe clinical, genetic and nigrostriatal dopaminergic imaging ([(123)I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) tropane single photon computed tomography) findings of four unrelated pedigrees with DOPA-responsive dystonia in which pathogenic GCH1 variants were identified in family members with adult-onset parkinsonism. Dopamine transporter imaging was abnormal in all parkinsonian patients, indicating Parkinson's disease-like nigrostriatal dopaminergic denervation. We subsequently explored the possibility that pathogenic GCH1 variants could contribute to the risk of developing Parkinson's disease, even in the absence of a family history for DOPA-responsive dystonia. The frequency of GCH1 variants was evaluated in whole-exome sequencing data of 1318 cases with Parkinson's disease and 5935 control subjects. Combining cases and controls, we identified a total of 11 different heterozygous GCH1 variants, all at low frequency. This list includes four pathogenic variants previously associated with DOPA-responsive dystonia (Q110X, V204I, K224R and M230I) and seven of undetermined clinical relevance (Q110E, T112A, A120S, D134G, I154V, R198Q and G217V). The frequency of GCH1 variants was significantly higher (Fisher's exact test P-value 0.0001) in cases (10/1318 = 0.75%) than in controls (6/5935 = 0.1%; odds ratio 7.5; 95% confidence interval 2.4-25.3). Our results show that rare GCH1 variants are associated with an increased risk for Parkinson's disease. These findings expand the clinical and biological relevance of GTP cycloydrolase 1 deficiency, suggesting that it not only leads to biochemical striatal dopamine depletion and DOPA-responsive dystonia, but also predisposes to nigrostriatal cell loss. Further insight into GCH1-associated pathogenetic mechanisms will shed light on the role of dopamine metabolism in nigral degeneration and Parkinson's disease. KW - DOPA-responsive-dystonia KW - GCH1 KW - Parkinson's disease KW - dopamine KW - exome sequencing Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121268 VL - 137 IS - 9 ER - TY - JOUR A1 - Lapa, Constantin A1 - Linsenmann, Thomas A1 - Lückerath, Katharina A1 - Samnick, Samuel A1 - Herrmann, Ken A1 - Stoffer, Carolin A1 - Ernestus, Ralf-Ingo A1 - Buck, Andreas K. A1 - Löhr, Mario A1 - Monoranu, Camelia-Maria T1 - Tumor-Associated Macrophages in Glioblastoma Multiforme—A Suitable Target for Somatostatin Receptor-Based Imaging and Therapy? JF - PLoS One N2 - Background Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. Tumor-associated macrophages (TAM) have been shown to promote malignant growth and to correlate with poor prognosis. [1,4,7,10-tetraazacyclododecane-NN′,N″,N′″-tetraacetic acid]-d-Phe1,Tyr3-octreotate (DOTATATE) labeled with Gallium-68 selectively binds to somatostatin receptor 2A (SSTR2A) which is specifically expressed and up-regulated in activated macrophages. On the other hand, the role of SSTR2A expression on the cell surface of glioma cells has not been fully elucidated yet. The aim of this study was to non-invasively assess SSTR2A expression of both glioma cells as well as macrophages in GBM. Methods 15 samples of patient-derived GBM were stained immunohistochemically for macrophage infiltration (CD68), proliferative activity (Ki67) as well as expression of SSTR2A. Anti-CD45 staining was performed to distinguish between resident microglia and tumor-infiltrating macrophages. In a subcohort, positron emission tomography (PET) imaging using \(^{68}Ga-DOTATATE\) was performed and the semiquantitatively evaluated tracer uptake was compared to the results of immunohistochemistry. Results The amount of microglia/macrophages ranged from <10% to >50% in the tumor samples with the vast majority being resident microglial cells. A strong SSTR2A immunostaining was observed in endothelial cells of proliferating vessels, in neurons and neuropile. Only faint immunostaining was identified on isolated microglial and tumor cells. Somatostatin receptor imaging revealed areas of increased tracer accumulation in every patient. However, retention of the tracer did not correlate with immunohistochemical staining patterns. Conclusion SSTR2A seems not to be overexpressed in GBM samples tested, neither on the cell surface of resident microglia or infiltrating macrophages, nor on the surface of tumor cells. These data suggest that somatostatin receptor directed imaging and treatment strategies are less promising in GBM. KW - glioma KW - positron emission tomography KW - glioblastoma multiforme KW - macrophages KW - somatostatin KW - microglial cells KW - immunostaining KW - magnetic resonance imaging Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125498 VL - 10 IS - 3 ER - TY - JOUR A1 - Isaias, Ioannis Ugo A1 - Spiegel, Jörg A1 - Brumberg, Joachim A1 - Cosgrove, Kelly P. A1 - Marotta, Giorgio A1 - Oishi, Naoya A1 - Higuchi, Takahiro A1 - Küsters, Sebastian A1 - Schiller, Markus A1 - Dillmann, Ulrich A1 - van Dyck, Christopher H. A1 - Buck, Andreas A1 - Herrmann, Ken A1 - Schloegl, Susanne A1 - Volkmann, Jens A1 - Lassmann, Michael A1 - Fassbender, Klaus A1 - Lorenz, Reinhard A1 - Samnick, Samuel T1 - Nicotinic acetylcholine receptor density in cognitively intact subjects at an early stage of Parkinson's disease JF - Frontiers in Aging Neuroscience N2 - We investigated in vivo brain nicotinic acetylcholine receptor (nAChR) distribution in cognitively intact subjects with Parkinson's disease (PD) at an early stage of the disease. Fourteen patients and 13 healthy subjects were imaged with single photon emission computed tomography and the radiotracer 5-[(123)I]iodo-3-[2(S)-2-azetidinylmethoxy]pyridine ([(123)I]5IA). Patients were selected according to several criteria, including short duration of motor signs (<7 years) and normal scores at an extensive neuropsychological evaluation. In PD patients, nAChR density was significantly higher in the putamen, the insular cortex and the supplementary motor area and lower in the caudate nucleus, the orbitofrontal cortex, and the middle temporal gyrus. Disease duration positively correlated with nAChR density in the putamen ipsilateral (ρ = 0.56, p < 0.05) but not contralateral (ρ = 0.49, p = 0.07) to the clinically most affected hemibody. We observed, for the first time in vivo, higher nAChR density in brain regions of the motor and limbic basal ganglia circuits of subjects with PD. Our findings support the notion of an up-regulated cholinergic activity at the striatal and possibly cortical level in cognitively intact PD patients at an early stage of disease. KW - nicotinic receptors KW - Parkinson disease KW - 5IA-SPECT KW - dopamine acetylcholine KW - cognitive decline Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119351 VL - 6 ER - TY - JOUR A1 - Lückerath, Katharina A1 - Lapa, Constantin A1 - Malzahn, Uwe A1 - Samnick, Samuel A1 - Einsele, Herrmann A1 - Buck, Andreas K. A1 - Herrmann, Ken A1 - Knop, Stefan T1 - 18FDG-PET/CT for prognostic stratification of patients with multiple myeloma relapse after stem cell transplantation N2 - The aim of this study was to investigate the prognostic value of 18F-fluoro-deoxyglucose positron emission tomography–computed tomography (18F-FDG-PET/CT) in 37 patients with a history of multiple myeloma (MM) and suspected or confirmed recurrence after stem cell transplantation (SCT). All patients had been heavily pre-treated. Time to progression (TTP) and overall survival (OS) were correlated to a number of different PET-derived as well as clinical parameters. Impact on patient management was assessed. Absence of FDG-avid MM foci was a positive prognostic factor for both TTP and OS (p<0.01). Presence of >10 focal lesions correlated with both TTP (p<0.01) and OS (p<0.05). Interestingly, presence of >10 lesions in the appendicular skeleton proved to have the strongest association with disease progression. Intensity of glucose uptake and presence of extramedullary disease were associated with shorter TTP (p=0.037 and p=0.049, respectively). Manifestations in soft tissue structures turned out to be a strong negative predictor for both, TTP and OS (p<0.01, respectively). PET resulted in a change of management in 30% of patients. Our data underline the prognostic value of 18F-FDG-PET/CT in MM patients also in the setting of post-SCT relapse. PET/CT has a significant impact on patient management. KW - 18FDG-PET/CT KW - Multiple myeloma KW - molecular imaging KW - FDG-PET/CT Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113107 ER - TY - JOUR A1 - Lückerath, Katharina A1 - Lapa, Constantin A1 - Spahmann, Annika A1 - Jörg, Gerhard A1 - Samnick, Samuel A1 - Rosenwald, Andreas A1 - Einsele, Herrmann A1 - Knop, Stefan A1 - Buck, Andreas T1 - Targeting Paraprotein Biosynthesis for Non-Invasive Characterization of Myeloma Biology N2 - Purpose Multiple myeloma is a hematologic malignancy originating from clonal plasma cells. Despite effective therapies, outcomes are highly variable suggesting marked disease heterogeneity. The role of functional imaging for therapeutic management of myeloma, such as positron emission tomography with 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG-PET), remains to be determined. Although some studies already suggested a prognostic value of 18F-FDG-PET, more specific tracers addressing hallmarks of myeloma biology, e.g. paraprotein biosynthesis, are needed. This study evaluated the amino acid tracers L-methyl-[11C]-methionine (11C-MET) and [18F]-fluoroethyl-L-tyrosine (18F-Fet) for their potential to image myeloma and to characterize tumor heterogeneity. Experimental Design To study the utility of 11C-MET, 18F-Fet and 18F-FDG for myeloma imaging, time activity curves were compared in various human myeloma cell lines (INA-6, MM1.S, OPM-2) and correlated to cell-biological characteristics, such as marker gene expression and immunoglobulin levels. Likewise, patient-derived CD138+ plasma cells were characterized regarding uptake and biomedical features. Results Using myeloma cell lines and patient-derived CD138+ plasma cells, we found that the relative uptake of 11C-MET exceeds that of 18F-FDG 1.5- to 5-fold and that of 18F-Fet 7- to 20-fold. Importantly, 11C-MET uptake significantly differed between cell types associated with worse prognosis (e.g. t(4;14) in OPM-2 cells) and indolent ones and correlated with intracellular immunoglobulin light chain and cell surface CD138 and CXCR4 levels. Direct comparison of radiotracer uptake in primary samples further validated the superiority of 11C-MET. Conclusion These data suggest that 11C-MET might be a versatile biomarker for myeloma superior to routine functional imaging with 18F-FDG regarding diagnosis, risk stratification, prognosis and discrimination of tumor subtypes. KW - Myelomas KW - Antibodies KW - Positron emission tomography KW - Myeloma cells KW - cell staining KW - lesions KW - biosynthesis KW - bone marrow cells Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-111319 ER - TY - JOUR A1 - Lassmann, Michael A1 - Preylowski, Veronika A1 - Schlögl, Susanne A1 - Schoenahl, Frédéric A1 - Jörg, Gerhard A1 - Samnick, Samuel A1 - Buck, Andreas K. T1 - Is the Image Quality of I-124-PET Impaired by an Automatic Correction of Prompt Gammas? JF - PLoS ONE N2 - Objectives The aim of this study is to evaluate the quality of I-124 PET images with and without prompt gamma compensation (PGC) by comparing the recovery coefficients (RC), the signal to noise ratios (SNR) and the contrast to F-18 and Ga-68. Furthermore, the influence of the PGC on the quantification and image quality is evaluated. Methods For measuring the image quality the NEMA NU2-2001 PET/SPECT-Phantom was used containing 6 spheres with a diameter between 10 mm and 37 mm placed in water with different levels of background activity. Each sphere was filled with the same activity concentration measured by an independently cross-calibrated dose calibrator. The “hot” sources were acquired with a full 3D PET/CT (Biograph mCT®, Siemens Medical USA). Acquisition times were 2 min for F-18 and Ga-68, and 10 min for I-124. For reconstruction an OSEM algorithm was applied. For I-124 the images were reconstructed with and without PGC. For the calculation of the RCs the activity concentrations in each sphere were determined; in addition, the influence of the background correction was studied. Results The RCs of Ga-68 are the smallest (79%). I-124 reaches similar RCs (87% with PGC, 84% without PGC) as F-18 (84%). showing that the quantification of I-124 images is similar to F-18 and slightly better than Ga-68. With background activity the contrast of the I-124 PGC images is similar to Ga-68 and F-18 scans. There was lower background activity in the I-124 images without PGC, which probably originates from an overcorrection of the scatter contribution. Consequently, the contrast without PGC was much higher than with PGC. As a consequence PGC should be used for I-124. Conclusions For I-124 there is only a slight influence on the quantification depending on the use of the PGC. However, there are considerable differences with respect to I-124 image quality. KW - cancer treatment KW - health care KW - isotopes KW - photons KW - positron emission tomography KW - signal to noise ratio KW - super ultraviolet KW - thyroid carcinomas Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96863 ER - TY - JOUR A1 - Li, Xiang A1 - Samnick, Samuel A1 - Lapa, Constantin A1 - Israel, Ina A1 - Buck, Andreas K. A1 - Kreissl, Michael C. A1 - Bauer, Wolfgang T1 - 68Ga-DOTATATE PET/CT for the detection of inflammation of large arteries: correlation with18F-FDG, calcium burden and risk factors N2 - Background: Ga-[1,4,7,10-tetraazacyclododecane-N,N0,N00,N000-tetraacetic acid]-d-Phe1,Tyr3-octreotate (DOTATATE) positron emission tomography (PET) is commonly used for the visualization of somatostatin receptor (SSTR)-positive neuroendocrine tumors. SSTR is also known to be expressed on macrophages, which play a major role in inflammatory processes in the walls of coronary arteries and large vessels. Therefore, imaging SSTR expression has the potential to visualize vulnerable plaques. We assessed 68Ga-DOTATATE accumulation in large vessels in comparison to 18F-2-fluorodeoxyglucose (FDG) uptake, calcified plaques (CPs), and cardiovascular risk factors. Methods: Sixteen consecutive patients with neuroendocrine tumors or thyroid cancer underwent both 68Ga-DOTATATE and 18F-FDG PET/CT for staging or restaging purposes. Detailed clinical data, including common cardiovascular risk factors, were recorded. For a separate assessment, they were divided into a high-risk and a low-risk group. In each patient, we calculated the maximum target-to-background ratio (TBR) of eight arterial segments. The correlation of the TBRmean of both tracers with risk factors including plaque burden was assessed. Results: The mean TBR of 68Ga-DOTATATE in all large arteries correlated significantly with the presence of CPs (r = 0.52; p < 0.05), hypertension (r = 0.60; p < 0.05), age (r = 0.56; p < 0.05), and uptake of 18F-FDG (r = 0.64; p < 0.01). There was one significant correlation between 18F-FDG uptake and hypertension (0.58; p < 0.05). Out of the 37 sites with the highest focal 68Ga-DOTATATE uptake, 16 (43.2%) also had focal 18F-FDG uptake. Of 39 sites with the highest 18F-FDG uptake, only 11 (28.2%) had a colocalized 68Ga-DOTATATE accumulation. Conclusions: In this series of cancer patients, we found a stronger association of increased 68Ga-DOTATATE uptake with known risk factors of cardiovascular disease as compared to 18F-FDG, suggesting a potential role for plaque imaging in large arteries. Strikingly, we found that focal uptake of 68Ga-DOTATATE and 18F-FDG does not colocalize in a significant number of lesions. KW - Medizin KW - Atherosclerotic plaque KW - 68Ga-DOTATATE KW - Somatostatin receptor KW - Cardiovascular risk factors KW - Macrophage Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-76231 ER - TY - JOUR A1 - Kreissl, Michael C. A1 - Hänscheid, Heribert A1 - Löhr, Mario A1 - Verburg, Frederik A. A1 - Schiller, Markus A1 - Lassmann, Michael A1 - Reiners, Christoph A1 - Samnick, Samuel S. A1 - Buck, Andreas K. A1 - Flentje, Michael A1 - Sweeney, Reinhart A. T1 - Combination of peptide receptor radionuclide therapy with fractionated external beam radiotherapy for treatment of advanced symptomatic meningioma N2 - Background: External beam radiotherapy (EBRT) is the treatment of choice for irresectable meningioma. Due to the strong expression of somatostatin receptors, peptide receptor radionuclide therapy (PRRT) has been used in advanced cases. We assessed the feasibility and tolerability of a combination of both treatment modalities in advanced symptomatic meningioma. Methods: 10 patients with irresectable meningioma were treated with PRRT (177Lu-DOTA0,Tyr3 octreotate or - DOTA0,Tyr3 octreotide) followed by external beam radiotherapy (EBRT). EBRT performed after PRRT was continued over 5–6 weeks in IMRT technique (median dose: 53.0 Gy). All patients were assessed morphologically and by positron emission tomography (PET) before therapy and were restaged after 3–6 months. Side effects were evaluated according to CTCAE 4.0. Results: Median tumor dose achieved by PRRT was 7.2 Gy. During PRRT and EBRT, no side effects>CTCAE grade 2 were noted. All patients reported stabilization or improvement of tumor-associated symptoms, no morphologic tumor progression was observed in MR-imaging (median follow-up: 13.4 months). The median pre-therapeutic SUVmax in the meningiomas was 14.2 (range: 4.3–68.7). All patients with a second PET after combined PRRT + EBRT showed an increase in SUVmax (median: 37%; range: 15%–46%) to a median value of 23.7 (range: 8.0–119.0; 7 patients) while PET-estimated volume generally decreased to 81 ± 21% of the initial volume. Conclusions: The combination of PRRT and EBRT is feasible and well tolerated. This approach represents an attractive strategy for the treatment of recurring or progressive symptomatic meningioma, which should be further evaluated. KW - Medizin KW - PRRT KW - Peptide receptor radionuclide therapy KW - Meningioma KW - Radiotherapy KW - EBRT KW - Combination Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75540 ER - TY - JOUR A1 - Lapa, Constantin A1 - Herrmann, Ken A1 - Schirbel, Andreas A1 - Hänscheid, Heribert A1 - Lückerath, Katharina A1 - Schottelius, Margret A1 - Kircher, Malte A1 - Werner, Rudolf A. A1 - Schreder, Martin A1 - Samnick, Samuel A1 - Kropf, Saskia A1 - Knop, Stefan A1 - Buck, Andreas K. A1 - Einsele, Hermann A1 - Wester, Hans-Juergen A1 - Kortüm, K. Martin T1 - CXCR4-directed endoradiotherapy induces high response rates in extramedullary relapsed multiple myeloma JF - Theranostics N2 - C-X-C-motif chemokine receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer. We have recently reported promising first-in-man experience with CXCR4-directed endoradiotherapy (ERT) in multiple myeloma (MM). Eight heavily pretreated MM patients underwent a total of 10 ERT cycles (7 patients with 1 cycle and a single patient with 3 cycles). ERT was administered in combination with chemotherapy and autologous stem cell support. End points were occurrence and timing of adverse events, progression-free and overall survival. ERT was overall well tolerated without any unexpected acute adverse events or changes in vital signs. With absorbed tumor doses >30-70 Gy in intra- or extramedullary lesions, significant anti-myeloma activity was observed with 1 patient achieving complete remission and 5/8 partial remission. Directly after ERT major infectious complications were seen in one patient who died from sepsis 22 days after ERT, another patient with high tumor burden experienced lethal tumor lysis syndrome. Median progression-free survival was 54 days (range, 13-175), median overall survival was 223 days (range, 13-313). During follow-up (6 patients available), one patient died from infectious complications, 2/8 from disease progression, the remaining 3/8 patients are still alive. CXCR4-directed ERT was well-tolerated and exerted anti-myeloma activity even at very advanced stage MM with presence of extramedullary disease. Further assessment of this novel treatment option is highly warranted. KW - medicine KW - multiple myeloma KW - PET KW - CXCR4 KW - theranostics Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-172095 VL - 7 IS - 6 ER - TY - JOUR A1 - Schadt, Fabian A1 - Israel, Ina A1 - Samnick, Samuel T1 - Development and Validation of a Semi-Automated, Preclinical, MRI-Template Based PET Image Data Analysis Tool for Rodents JF - Frontiers in Neuroinformatics N2 - AimIn PET imaging, the different types of radiotracers and accumulations, as well as the diversity of disease patterns, make the analysis of molecular imaging data acquired in vivo challenging. Here, we evaluate and validate a semi-automated MRI template-based data analysis tool that allows preclinical PET images to be aligned to a self-created PET template. Based on the user-defined volume-of-interest (VOI), image data can then be evaluated using three different semi-quantitative parameters: normalized activity, standardized uptake value, and uptake ratio. Materials and MethodsThe nuclear medicine Data Processing Analysis tool (NU_DPA) was implemented in Matlab. Testing and validation of the tool was performed using two types of radiotracers in different kinds of stroke-related brain diseases in rat models. The radiotracers used are 2-[\(^{18}\)F]fluoro-2-deoxyglucose ([\(^{18}\)F]FDG), a metabol\(^{68}\)Ga]Ga-Fucoidan, a target-selective radioligand specifically binding to p-selectin. After manual image import, the NU_DPA tool automatically creates an averaged PET template out of the acquired PET images, to which all PET images are then aligned onto. The added MRI template-based information, resized to the lower PET resolution, defines the VOI and also allows a precise subdivision of the VOI into individual sub-regions. The aligned PET images can then be evaluated semi-quantitatively for all regions defined in the MRI atlas. In addition, a statistical analysis and evaluation of the semi-quantitative parameters can then be performed in the NU_DPA tool. ResultsUsing ischemic stroke data in Wistar rats as an example, the statistical analysis of the tool should be demonstrated. In this [\(^{18}\)F]FDG-PET experiment, three different experimental states were compared: healthy control state, ischemic stroke without electrical stimulation, ischemic stroke with electrical stimulation. Thereby, statistical data evaluation using the NU_DPA tool showed that the glucose metabolism in a photothrombotic lesion can be influenced by electrical stimulation. ConclusionOur NU_DPA tool allows a very flexible data evaluation of small animal PET data in vivo including statistical data evaluation. Using the radiotracers [\(^{18}\)F]FDG and [\(^{68}\)Ga]Ga-Fucoidan, it was shown that the semi-automatic MRI-template based data analysis of the NU_DPA tool is potentially suitable for both metabolic radiotracers as well as target-selective radiotracers. KW - data analysis KW - Matlab KW - MRI KW - PET KW - positron emission tomography KW - preclinical imaging Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240289 SN - 1662-5196 VL - 15 ER - TY - JOUR A1 - Lapa, Constantin A1 - Schreder, Martin A1 - Schirbel, Andreas A1 - Samnick, Samuel A1 - Kortüm, Klaus Martin A1 - Herrmann, Ken A1 - Kropf, Saskia A1 - Einsele, Herrmann A1 - Buck, Andreas K. A1 - Wester, Hans-Jürgen A1 - Knop, Stefan A1 - Lückerath, Katharina T1 - [\(^{68}\)Ga]Pentixafor-PET/CT for imaging of chemokine receptor CXCR4 expression in multiple myeloma - comparison to [\(^{18}\)F]FDG and laboratory values JF - Theranostics N2 - Chemokine (C-X-C motif) receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer including multiple myeloma (MM). Proof-of-concept of CXCR4-directed radionuclide therapy in MM has recently been reported. This study assessed the diagnostic performance of the CXCR4-directed radiotracer [\(^{68}\)Ga]Pentixafor in MM and a potential role for stratifying patients to CXCR4-directed therapies. Thirty-five patients with MM underwent [\(^{68}\)Ga]Pentixafor-PET/CT for evaluation of eligibility for endoradiotherapy. In 19/35 cases, [\(^{18}\)F]FDG-PET/CT for correlation was available. Scans were compared on a patient and on a lesion basis. Tracer uptake was correlated with standard clinical parameters of disease activity. [\(^{68}\)Ga]Pentixafor-PET detected CXCR4-positive disease in 23/35 subjects (66%). CXCR4-positivity at PET was independent from myeloma subtypes, cytogenetics or any serological parameters and turned out as a negative prognostic factor. In the 19 patients in whom a comparison to [\(^{18}\)F]FDG was available, [\(^{68}\)Ga]Pentixafor-PET detected more lesions in 4/19 (21%) subjects, [\(^{18}\)F]FDG proved superior in 7/19 (37%). In the remaining 8/19 (42%) patients, both tracers detected an equal number of lesions. [\(^{18}\)F]FDG-PET positivity correlated with [\(^{68}\)Ga]Pentixafor-PET positivity (p=0.018). [\(^{68}\)Ga]Pentixafor-PET provides further evidence that CXCR4 expression frequently occurs in advanced multiple myeloma, representing a negative prognostic factor and a potential target for myeloma specific treatment. However, selecting patients for CXCR4 directed therapies and prognostic stratification seem to be more relevant clinical applications for this novel imaging modality, rather than diagnostic imaging of myeloma. KW - medicine KW - multiple myeloma KW - FDG KW - molecular imaging KW - CXCR4 KW - PET KW - radionuclide therapy KW - theranostics Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-172106 VL - 7 IS - 1 ER - TY - JOUR A1 - Zhou, Xiang A1 - Dierks, Alexander A1 - Kertels, Olivia A1 - Kircher, Malte A1 - Schirbel, Andreas A1 - Samnick, Samuel A1 - Buck, Andreas K. A1 - Knorz, Sebastian A1 - Böckle, David A1 - Scheller, Lukas A1 - Messerschmidt, Janin A1 - Barakat, Mohammad A1 - Kortüm, K. Martin A1 - Rasche, Leo A1 - Einsele, Hermann A1 - Lapa, Constantin T1 - 18F-FDG, 11C-Methionine, and 68Ga-Pentixafor PET/CT in patients with smoldering multiple myeloma: imaging pattern and clinical features JF - Cancers N2 - This study aimed to explore the correlation between imaging patterns and clinical features in patients with smoldering multiple myeloma (SMM) who simultaneously underwent 18F-FDG, 11C-Methionine, and 68Ga-Pentixafor positron emission tomography/computed tomography (PET/CT). We retrieved and analyzed clinical characteristics and PET imaging data of 10 patients with SMM. We found a significant correlation between bone marrow (BM) plasma cell (PC) infiltration and mean standardized uptake values (SUV\(_{mean}\)) of lumbar vertebrae L2-L4 on 11C-Methionine PET/CT scans (r = 0.676, p = 0.031) and 68Ga-Pentixafor PET/CT scans (r = 0.839, p = 0.002). However, there was no significant correlation between BM involvement and SUV\(_{mean}\) of lumbar vertebrae L2-L4 on 18F-FDG PET/CT scans (r = 0.558, p = 0.093). Similarly, mean target-to-background ratios (TBR\(_{mean}\)) of lumbar vertebrae L2-L4 also correlated with bone marrow plasma cell (BMPC) infiltration in 11C-Methionine PET/CT (r = 0.789, p = 0.007) and 68Ga-Pentixafor PET/CT (r = 0.724, p = 0.018) PET/CT. In contrast, we did not observe a significant correlation between BMPC infiltration rate and TBR\(_{mean}\) in 18F-FDG PET/CT (r = 0.355, p = 0.313). Additionally, on 11C-Methionine PET/CT scans, we found a significant correlation between BMPC infiltration and TBR\(_{max}\) of lumbar vertebrae L2-L4 (r = 0.642, p = 0.045). In conclusion, 11C-Methionine and 68Ga-Pentixafor PET/CT demonstrate higher sensitivity than 18F-FDG PET/CT in detecting BM involvement in SMM. KW - 18F-FDG PET/CT KW - 11C-Methionine PET/CT KW - 68Ga-Pentixafor PET/CT KW - smoldering myeloma Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-211240 SN - 2072-6694 VL - 12 IS - 8 ER - TY - JOUR A1 - Schadt, Fabian A1 - Israel, Ina A1 - Beez, Alexandra A1 - Alushi, Kastriot A1 - Weiland, Judith A1 - Ernestus, Ralf-Ingo A1 - Westermaier, Thomas A1 - Samnick, Samuel A1 - Lilla, Nadine T1 - Analysis of cerebral glucose metabolism following experimental subarachnoid hemorrhage over 7 days JF - Scientific Reports N2 - Little is known about changes in brain metabolism following SAH, possibly leading towards secondary brain damage. Despite sustained progress in the last decade, analysis of in vivo acquired data still remains challenging. The present interdisciplinary study uses a semi-automated data analysis tool analyzing imaging data independently from the administrated radiotracer. The uptake of 2-[18F]Fluoro-2-deoxy-glucose ([\(^{18}\)F]FDG) was evaluated in different brain regions in 14 male Sprague–Dawley rats, randomized into two groups: (1) SAH induced by the endovascular filament model and (2) sham operated controls. Serial [\(^{18}\)F]FDG-PET measurements were carried out. Quantitative image analysis was performed by uptake ratio using a self-developed MRI-template based data analysis tool. SAH animals showed significantly higher [\(^{18}\)F]FDG accumulation in gray matter, neocortex and olfactory system as compared to animals of the sham group, while white matter and basal forebrain region showed significant reduced tracer accumulation in SAH animals. All significant metabolic changes were visualized from 3 h, over 24 h (day 1), day 4 and day 7 following SAH/sham operation. This [\(^{18}\)F]FDG-PET study provides important insights into glucose metabolism alterations following SAH—for the first time in different brain regions and up to day 7 during course of disease. KW - SAH KW - metabolism KW - brain Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300725 VL - 13 IS - 1 ER - TY - JOUR A1 - Morales-Lozano, Maria I. A1 - Viering, Oliver A1 - Samnick, Samuel A1 - Rodriguez-Otero, Paula A1 - Buck, Andreas K. A1 - Marcos-Jubilar, Maria A1 - Rasche, Leo A1 - Prieto, Elena A1 - Kortüm, K. Martin A1 - San-Miguel, Jesus A1 - Garcia-Velloso, Maria J. A1 - Lapa, Constantin T1 - \(^{18}\)F-FDG and \(^{11}\)C-methionine PET/CT in newly diagnosed multiple myeloma patients: comparison of volume-based PET biomarkers JF - Cancers N2 - \(^{11}\)C-methionine (\(^{11}\)C-MET) is a new positron emission tomography (PET) tracer for the assessment of disease activity in multiple myeloma (MM) patients, with preliminary data suggesting higher sensitivity and specificity than \(^{18}\)F-fluorodeoxyglucose (\(^{18}\)F-FDG). However, the value of tumor burden biomarkers has yet to be investigated. Our goals were to corroborate the superiority of \(^{11}\)C-MET for MM staging and to compare its suitability for the assessment of metabolic tumor burden biomarkers in comparison to \(^{18}\)F-FDG. Twenty-two patients with newly diagnosed, treatment-naïve symptomatic MM who had undergone \(^{11}\)C-MET and \(^{18}\)F-FDG PET/CT were evaluated. Standardized uptake values (SUV) were determined and compared with total metabolic tumor volume (TMTV) for both tracers: total lesion glycolysis (TLG) and total lesion \(^{11}\)C-MET uptake (TLMU). PET-derived values were compared to Revised International Staging System (R-ISS), cytogenetic, and serologic MM markers such as M component, beta 2 microglobulin (B2M), serum free light chains (FLC), albumin, and lactate dehydrogenase (LDH). In 11 patients (50%), \(^{11}\)C-MET detected more focal lesions (FL) than FDG (p < 0.01). SUVmax, SUVmean, SUVpeak, TMTV, and TLMU were also significantly higher in \(^{11}\)C-MET than in \(^{18}\)F-FDG (p < 0.05, respectively). \(^{11}\)C-MET PET biomarkers had a better correlation with tumor burden (bone marrow plasma cell infiltration, M component; p < 0.05 versus p = n.s. respectively). This pilot study suggests that \(^{11}\)C-MET PET/CT is a more sensitive marker for the assessment of myeloma tumor burden than \(^{18}\)F-FDG. Its implications for prognosis evaluation need further investigation. KW - multiple myeloma KW - methionine KW - total lesion glycolysis (TLG) KW - metabolic tumor volume (MTV) KW - total lesion methionine uptake (TLMU) Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203686 SN - 2072-6694 VL - 12 IS - 4 ER - TY - JOUR A1 - Lapa, Constantin A1 - Garcia-Velloso, Maria J. A1 - Lückerath, Katharina A1 - Samnick, Samuel A1 - Schreder, Martin A1 - Otero, Paula Rodriguez A1 - Schmid, Jan-Stefan A1 - Herrmann, Ken A1 - Knop, Stefan A1 - Buck, Andreas K. A1 - Einsele, Hermann A1 - San-Miguel, Jesus A1 - Kortüm, Klaus Martin T1 - \(^{11}\)C-methionine-PET in multiple myeloma: a combined study from two different institutions JF - Theranostics N2 - \(^{11}\)C-methionine (MET) has recently emerged as an accurate marker of tumor burden and disease activity in patients with multiple myeloma (MM). This dual-center study aimed at further corroboration of the superiority of MET as positron emission tomography (PET) tracer for staging and re-staging MM, as compared to \(^{18}\)F-2`-deoxy-2`-fluoro-D-glucose (FDG). 78 patients with a history of solitary plasmacytoma (n=4), smoldering MM (SMM, n=5), and symptomatic MM (n=69) underwent both MET- and FDG-PET/computed tomography (CT) at the University Centers of Würzburg, Germany and Navarra, Spain. Scans were compared on a patient and on a lesion basis. Inter-reader agreement was also evaluated. In 2 patients, tumor biopsies for verification of discordant imaging results were available. MET-PET detected focal lesions (FL) in 59/78 subjects (75.6%), whereas FDG-PET/CT showed lesions in only 47 patients (60.3%; p<0.01), accordingly disease activity would have been missed in 12 patients. Directed biopsies of discordant results confirmed MET-PET/CT results in both cases. MET depicted more FL in 44 patients (56.4%; p<0.01), whereas in two patients (2/78), FDG proved superior. In the remainder (41.0%, 32/78), both tracers yielded comparable results. Inter-reader agreement for MET was higher than for FDG (κ = 0.82 vs κ = 0.72). This study demonstrates higher sensitivity of MET in comparison to standard FDG to detect intra- and extramedullary MM including histologic evidence of FDG-negative, viable disease exclusively detectable by MET-PET/CT. MET holds the potential to replace FDG as functional imaging standard for staging and re-staging of MM. KW - medicine KW - PET/CT KW - \(^{11}\)C-methionine KW - multiple myeloma KW - FDG Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-172038 VL - 7 IS - 11 ER - TY - JOUR A1 - Zhou, Xiang A1 - Dierks, Alexander A1 - Kertels, Olivia A1 - Samnick, Samuel A1 - Kircher, Malte A1 - Buck, Andreas K. A1 - Haertle, Larissa A1 - Knorz, Sebastian A1 - Böckle, David A1 - Scheller, Lukas A1 - Messerschmidt, Janin A1 - Barakat, Mohammad A1 - Truger, Marietta A1 - Haferlach, Claudia A1 - Einsele, Hermann A1 - Rasche, Leo A1 - Kortüm, K. Martin A1 - Lapa, Constantin T1 - The link between cytogenetics/genomics and imaging patterns of relapse and progression in patients with relapsed/refractory multiple myeloma: a pilot study utilizing 18F-FDG PET/CT JF - Cancers N2 - Utilizing 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT), we performed this pilot study to evaluate the link between cytogenetic/genomic markers and imaging patterns in relapsed/refractory (RR) multiple myeloma (MM). We retrospectively analyzed data of 24 patients with RRMM who were treated at our institution between November 2018 and February 2020. At the last relapse/progression, patients had been treated with a median of three (range 1–10) lines of therapy. Six (25%) patients showed FDG avid extramedullary disease without adjacency to bone. We observed significantly higher maximum standardized uptake values (SUV\(_{max}\)) in patients harboring del(17p) compared with those without del(17p) (p = 0.025). Moreover, a high SUV\(_{max}\) of >15 indicated significantly shortened progression-free survival (PFS) (p = 0.01) and overall survival (OS) (p = 0.0002). One female patient exhibited biallelic TP53 alteration, i.e., deletion and mutation, in whom an extremely high SUV\(_{max}\) of 37.88 was observed. In summary, this pilot study suggested a link between del(17p)/TP53 alteration and high SUV\(_{max}\) on 18F-FDG PET/CT in RRMM patients. Further investigations are highly warranted at this point. KW - radiogenomics KW - 18F-FDG PET/CT KW - multiple myeloma KW - relapse KW - progression KW - pattern Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-211157 SN - 2072-6694 VL - 12 IS - 9 ER - TY - JOUR A1 - Lapa, Constantin A1 - Kircher, Malte A1 - Hänscheid, Heribert A1 - Schirbel, Andreas A1 - Grigoleit, Götz Ulrich A1 - Klinker, Erdwine A1 - Böck, Markus A1 - Samnick, Samuel A1 - Pelzer, Theo A1 - Buck, Andreas K T1 - Peptide receptor radionuclide therapy as a new tool in treatment-refractory sarcoidosis - initial experience in two patients JF - Theranostics N2 - Sarcoidosis is a multisystem granulomatous disorder of unknown etiology that can involve virtually all organ systems. Whereas most patients present without symptoms, progressive and disabling organ failure can occur in up to 10% of subjects. Somatostatin receptor (SSTR)-directed peptide receptor radionuclide therapy (PRRT) has recently received market authorization for treatment of SSTR-positive neuroendocrine tumors. Methods: We describe the first case series comprising two patients with refractory multi-organ involvement of sarcoidosis who received 4 cycles of PRRT. Results: PRRT was well-tolerated without any acute adverse effects. No relevant toxicities could be recorded during follow-up. Therapy resulted in partial response accompanied by a pronounced reduction in pain (patient #1) and stable disease regarding morphology as well as disease activity (patient #2), respectively. Conclusion: Peptide receptor radionuclide therapy in sarcoidosis is feasible and might be a new valuable tool in patients with otherwise treatment-refractory disease. Given the long experience with and good tolerability of PRRT, further evaluation of this new treatment option for otherwise treatment-refractory sarcoidosis in larger patient cohorts is warranted. KW - peptide receptor KW - PRRT KW - sarcoidosis KW - somatostatin receptors KW - radionuclide therapy Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158983 VL - 8 IS - 3 ER -