PET and Cyclotron Unit

Copenhagen, Denmark

PET and Cyclotron Unit

Copenhagen, Denmark

Time filter

Source Type

Marner L.,Neurobiology Research Unit | Marner L.,Center for Integrated Molecular Brain Imaging | Frokjaer V.G.,Neurobiology Research Unit | Frokjaer V.G.,Center for Integrated Molecular Brain Imaging | And 12 more authors.
Neurobiology of Aging | Year: 2012

In patients with Alzheimer's disease (AD), postmortem and imaging studies have revealed early and prominent reductions in cerebral serotonin 2A (5-HT 2A) receptors. To establish if this was due to a selective disease process of the serotonin system, we investigated the cerebral 5-HT 2A receptor and the serotonin transporter binding, the latter as a measure of serotonergic projections and neurons. Twelve patients with AD (average Mini Mental State Examination [MMSE]: 24) and 11 healthy age-matched subjects underwent positron emission tomography (PET) scanning with [ 18F]altanserin and [ 11C]N,N-Dimethyl-2-(2-amino-4-cyanopheylthio)benzylamine ([ 11C]DASB). Overall [ 18F]altanserin binding was markedly reduced in AD by 28%-39% (p = 0.02), whereas the reductions in [ 11C]DASB binding were less prominent and mostly insignificant, except for a marked reduction of 33% in mesial temporal cortex (p = .0005). No change in [ 11C]DASB binding was found in the midbrain. We conclude that the prominent reduction in neocortical 5-HT 2A receptor binding in early AD is not caused by a primary loss of serotonergic neurons or their projections. © 2012 Elsevier Inc..


Jakobsen G.R.,Neurobiology Research Unit | Jakobsen G.R.,Copenhagen University | Fisher P.M.,Neurobiology Research Unit | Dyssegaard A.,Neurobiology Research Unit | And 10 more authors.
Psychoneuroendocrinology | Year: 2016

Serotonin signalling is considered critical for an appropriate and dynamic adaptation to stress. Previously, we have shown that prefrontal serotonin transporter (SERT) binding is positively associated with the cortisol awakening response (CAR) (. Frokjaer et al., 2013), which is an index of hypothalamic-pituitary-adrenal (HPA)-axis output dynamics. Here, we investigated in healthy individuals if cerebral serotonin 4 receptor (5-HT4r) binding, reported to be a proxy for serotonin levels, is associated with CAR.Thirty healthy volunteers (25 males, age range 20-56 years) underwent 5-HT4r PET imaging with [11C]-SB207145, genotyping of the SERT-linked polymorphic region (5-HTTLPR), and performed serial home sampling of saliva (5 time points from 0 to 60 min from awakening) to assess CAR. The association between 5-HT4r binding in 4 regions of interest (prefrontal cortex, anterior cingulate cortex, pallidostriatum, and hippocampus) and CAR was tested using multiple linear regression with adjustment for age and 5-HTTLPR genotype. Finally, an exploratory voxel-based analysis of the association was performed.CAR was negatively associated with 5-HT4r binding in pallidostriatum (p = 0.01), prefrontal cortex (p = 0.03), and anterior cingulate cortex (p = 0.002), respectively, but showed no association in hippocampus. The results remained significant when taking into account other potentially relevant covariates.In conclusion, our finding reinforces an association between HPA-axis function and serotonin signaling in vivo in humans. We suggest that higher synaptic serotonin concentration, here indexed by lower 5-HT4r binding, supports HPA-axis dynamics, which in healthy volunteers is reflected by a robust CAR. © 2016 Elsevier Ltd.


Risum S.,Copenhagen University | Hogdall C.,Rigshospitalet | Loft A.,PET and Cyclotron Unit | Berthelsen A.K.,PET and Cyclotron Unit | And 4 more authors.
Gynecologic Oncology | Year: 2010

Objective: To investigate if the use of diagnostic FDG-PET/CT leads to stage migration in patients with advanced ovarian cancer and to evaluate the prognostic significance of FDG-PET/CT. Methods: From September 2004 to August 2007, 201 patients with a Risk of Malignancy Index (RMI) > 150 based on serum CA-125, ultrasound examinations and menopausal state, underwent PET/CT within 2 weeks prior to standard surgery/debulking of a pelvic tumor. On 15 August, 2009 overall survival and prognostic variables were analysed in 66 ovarian cancer patients (64 stage III and 2 stage IV). Results: Median follow-up was 30.2 months; median age was 62.5 years (range 35-85 years); 97% (64/66) had a performance status ≤ 2; 38% (25/66) underwent complete debulking (no macroscopic residual tumor); 51% (39/66) was diagnosed with PET/CT stage III and 41% (27/66) was diagnosed with PET/CT stage IV. Survival was significantly longer for patients with PET/CT stage III than for patients with PET/CT stage IV (P = 0.03). Using univariate analysis, PET/CT stage III (P = 0.03), complete debulking (no macroscopic residual tumor) (P = 0.002), and GOG performance status ≤ 2 (P = 0.04) were statistically significant prognostic variables. Using multivariate Cox regression analysis, complete debulking was the only statistically significant independent prognostic variable (P = 0.02). Conclusion: In primary advanced ovarian cancer the use of diagnostic FDG-PET/CT leads to stage migration. Adequate staging is the foundation for ovarian cancer treatment and advanced imaging for optimal evaluation of metastases should be promoted in clinical trials. The strongest determinant of patient outcome is residual abdominal tumor after primary surgery. © 2009 Elsevier Inc. All rights reserved.


Jensen T.K.,University of Southern Denmark | Holt P.,University of Southern Denmark | Gerke O.,PET and Cyclotron Unit | Gerke O.,University of Southern Denmark | And 5 more authors.
Scandinavian Journal of Urology and Nephrology | Year: 2011

Objective: The treatment and prognosis of bladder cancer are based on the depth of primary tumour invasion and the presence of metastases. A highly accurate preoperative tumour, node, metastasis (TNM) staging is critical to proper patient management and treatment. This study retrospectively investigated the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed axial tomography ( 18F-FDG PET/CT) and magnetic resonance imaging (MRI) for preoperative N staging of bladder cancer. Material and methods. From June 2006 to January 2008, 48 consecutive patients diagnosed with bladder cancer were referred to preoperative staging including MRI and 18F-FDG PET/CT. Eighteen out of 48 patients underwent radical cystoprostatectomy including removal of lymph nodes for histology, and were included in the study. Values of 18F-FDG PET/CT and MRI for regional N staging were compared to histopathology findings, the gold standard. Results. 18F-FDG PET/CT and MRI were performed in 18 patients. The specificities for detection of lymph-node metastases for MRI and 18F-FDG PET/CT were 80% (n = 15) and 93.33% (n = 15), respectively. The negative predictive values were 80% (n = 15) and 87.5% (n = 16) for MRI and 18F-FDG PET/CT, respectively. The differences in specificity and negative predictive values were not statistically significant. Conclusions. No significant statistical difference between 18F-FDG PET/CT and MRI for preoperative N staging of urothelial bladder cancer was found in the study. However, the trend of the data indicates an advantage of 18F-FDG PET/CT over MRI. Larger prospective studies are needed to elucidate the role of 18F-FDG PET/CT in N staging of bladder cancer. © 2011 Informa Healthcare.


PubMed | PET and Cyclotron Unit, Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging and Copenhagen University
Type: | Journal: Psychoneuroendocrinology | Year: 2016

Serotonin signalling is considered critical for an appropriate and dynamic adaptation to stress. Previously, we have shown that prefrontal serotonin transporter (SERT) binding is positively associated with the cortisol awakening response (CAR) (Frokjaer et al., 2013), which is an index of hypothalamic-pituitary-adrenal (HPA)-axis output dynamics. Here, we investigated in healthy individuals if cerebral serotonin 4 receptor (5-HT4r) binding, reported to be a proxy for serotonin levels, is associated with CAR. Thirty healthy volunteers (25 males, age range 20-56 years) underwent 5-HT4r PET imaging with [(11)C]-SB207145, genotyping of the SERT-linked polymorphic region (5-HTTLPR), and performed serial home sampling of saliva (5 time points from 0 to 60min from awakening) to assess CAR. The association between 5-HT4r binding in 4 regions of interest (prefrontal cortex, anterior cingulate cortex, pallidostriatum, and hippocampus) and CAR was tested using multiple linear regression with adjustment for age and 5-HTTLPR genotype. Finally, an exploratory voxel-based analysis of the association was performed. CAR was negatively associated with 5-HT4r binding in pallidostriatum (p=0.01), prefrontal cortex (p=0.03), and anterior cingulate cortex (p=0.002), respectively, but showed no association in hippocampus. The results remained significant when taking into account other potentially relevant covariates. In conclusion, our finding reinforces an association between HPA-axis function and serotonin signaling in vivo in humans. We suggest that higher synaptic serotonin concentration, here indexed by lower 5-HT4r binding, supports HPA-axis dynamics, which in healthy volunteers is reflected by a robust CAR.

Loading PET and Cyclotron Unit collaborators
Loading PET and Cyclotron Unit collaborators