Search results for " Nuclear Medicine and imaging"
showing 10 items of 2516 documents
Biodosimetry Based on γ-H2AX Quantification and Cytogenetics after Partial- and Total-Body Irradiation during Fractionated Radiotherapy
2015
The aim of this current study was to quantitatively describe radiation-induced DNA damage and its distribution in leukocytes of cancer patients after fractionated partial- or total-body radiotherapy. Specifically, the impact of exposed anatomic region and administered dose was investigated in breast and prostate cancer patients receiving partial-body radiotherapy. DNA double-strand breaks (DSBs) were quantified by γ-H2AX immunostaining. The frequency of unstable chromosomal aberrations in stimulated lymphocytes was also determined and compared with the frequency of DNA DSBs in the same samples. The frequency of radiation-induced DNA damage was converted into dose, using ex vivo generated ca…
Covariations among fMRI, skin conductance, and behavioral data during processing of concealed information.
2007
Imaging techniques have been used to elucidate the neural correlates that underlie deception. The scientifically best understood paradigm for the detection of deception, however, the guilty knowledge test (GKT), was rarely used in imaging studies. By transferring a GKT‐paradigm to a functional magnetic resonance imaging (fMRI) study, while additionally quantifying reaction times and skin conductance responses (SCRs), this study aimed at identifying the neural correlates of the behavioral and electrodermal response pattern typically found in GKT examinations. Prior to MR scanning, subjects viewed two specific items (probes) and were instructed to hide their knowledge of these. Two other spec…
Ventral striatal prediction error signaling is associated with dopamine synthesis capacity and fluid intelligence.
2012
Fluid intelligence represents the capacity for flexible problem solving and rapid behavioral adaptation. Rewards drive flexible behavioral adaptation, in part via a teaching signal expressed as reward prediction errors in the ventral striatum, which has been associated with phasic dopamine release in animal studies. We examined a sample of 28 healthy male adults using multimodal imaging and biological parametric mapping with 1) functional magnetic resonance imaging during a reversal learning task and 2) in a subsample of 17 subjects also with positron emission tomography using 6-[18F]fluoro-L-DOPA to assess dopamine synthesis capacity. Fluid intelligence was measured using a battery of nine…
Color-coded duplex ultrasonography of the origin of the vertebral artery: normal values of flow velocities.
2000
The introduction of color-coded duplex ultrasonography has improved the ease of performing ultrasound investigations of the vertebral arteries. So far, normal values of flow velocities have been reported only for the intertransverse region of the vertebral artery (V2 segments). Atherosclerotic disease at the origin of the vertebral arteries (V0 segment) is frequent and is one of the risk factors for vertebrobasilar ischemic disease. Normal values of flow velocities of the vertebral artery origin are needed to assess pathologic findings, such as vertebral artery origin stenosis or dissection. The aim of this study was to describe the normal flow velocities of vertebral artery origin (V0 segm…
Human sleep under the influence of pulsed radiofrequency electromagnetic fields: A polysomnographic study using standardized conditions
1998
To investigate the influence of radiofrequency electromagnetic fields (EMFs) of cellular phone GSM signals on human sleep electroencephalographic (EEG) pattern, all-night polysomnographies of 24 healthy male subjects were recorded, both with and without exposure to a circular polarized EMF (900 MHz, pulsed with a frequency of 217 Hz, pulse width 577 μs, power flux density 0.2 W/m2. Suppression of rapid eye movement (REM) sleep as well as a sleep-inducing effect under field exposure did not reach statistical significance, so that previous results indicating alterations of these sleep parameters could not be replicated. Spectral power analysis also did not reveal any alterations of the EEG rh…
'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET inves…
2006
Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron‐emission‐tomography (PET) studies, net blood‐brain clearance of [(18)F]‐fluoro‐l‐DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood‐brain clearance of FDOPA (K [Formula: see text]) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes‐of‐interest. The Wisconsin‐Card‐Sorting‐Test (WCST), Stroop‐T…
Pregnancy Outcome in Maternal Crigler-Najjar Syndrome Type II: A Case Report and Systematic Review of the Literature
2008
<i>Objective:</i> To report a case of maternal Crigler-Najjar syndrome (CNS) type II in pregnancy, systematically review the literature for similar case reports, and to evaluate whether pregnancy is safe in patients with the disease. Data sources included the PubMed and uptodate databases. <i>Results:</i> A 37-year-old mother with CNS type II was treated with phenobarbital during her pregnancy and her bilirubin levels were monitored. Her newborn had mild direct hyperbilirubinemia, did not require any treatment and his postnatal follow-up showed normal growth and development as well as normal hearing. <i>Conclusion:</i> CNS type II is rare, and only a few …
Mini-Laparoscopically Guided Percutaneous Gastrostomy and Jejunostomy
2003
Abstract Background: Percutaneous endoscopic tube placement can be problematic under certain circumstances: absence of transillumination of the abdominal wall, percutaneous jejunostomy in patients with a PEG tube and recurrent aspiration, enteral feeding access after gastrectomy, and obstruction of the upper GI tract. As an alternative in these problematic situations, a technique was developed for placing feeding tubes under visual control by using mini-laparoscopy. Methods: Placement of a feeding tube with mini-laparoscopy with the patient under conscious sedation was considered for 17 patients in whom standard PEG placement was impossible. Techniques used were the following: combined mini…
Double-balloon enteroscopy (push-and-pull enteroscopy) of the small bowel: feasibility and diagnostic and therapeutic yield in patients with suspecte…
2005
Background Double-balloon enteroscopy (push-and-pull enteroscopy) is a new method that allows complete visualization, biopsy, and treatment in the small bowel. This study evaluated the feasibility and the diagnostic and the therapeutic yield of double-balloon enteroscopy (push-and-pull enteroscopy) in comparison with current imaging methods. Methods Between March 2003 and November 2004, 248 consecutive double-balloon enteroscopies (push-and-pull enteroscopies) were performed in a prospective study in 137 patients with suspected small-bowel disease (60 women, 77 men; mean age 56.6 ± 17.8 years), most with chronic GI bleeding (66%). The examinations were carried out after negative evaluations…
Automatic fuzzy classification of the washout curves from magnetic resonance first-pass perfusion imaging after myocardial infarction.
2005
International audience; Abstract: Objectives: We sought to investigate the diagnostic ability of cardiac magnetic resonance imaging (MRI) perfusion in acute reper-fused myocardial infarction. The study used fuzzy logic to automatically classify signal intensity-time curves from myocardial segments into 3 categories: normal, hypointense, and Hyperintense. Materials and Methods: Thirty-eight patients with myocardial infarction underwent short-axis cine-MRI and contrast-enhanced MRI to provide data on wall thickening and the transmural extent of infarction. Of these, 17 had a second cardiac MRI to ascertain the functional recovery in each segment. Results: The fuzzy logic based classification …