Current Medical Imaging - Volume 7, Issue 2, 2011

Dynamic molecular imaging methods now allow detection of acute changes in neurotransmission in the live human brain (neurotransmitter imaging) during task performance. These methods have extended the scope of neuroimaging by allowing study of neurochemical changes associated with cognitive and behavior processing. The neurotransmitter imaging methods however are at the initial stages of develop Read More

Neurochemistry of human cognition remains uninvestigated because neuroimaging techniques have limited ability to detect neurochemical changes associated with cognitive processing. In recent years investigators have used molecular imaging to develop methods for detection, mapping and measurement of neurotransmitters released acutely during cognitive processing in the live human brain. Most of these me Read More

This review depicts characteristics of nuclear neuroimaging investigations of dopamine release in response to non-pharmacological stimuli. Investigations of dopamine release in response to pharmacological challenges have focused mainly on the striatum, a region with a relatively high density of dopamine D2/D3 receptors. Non-pharmacological stimuli likely elicit dopamine release in extrastriatal regions with a relatively Read More

Neuronal nicotinic acetylcholine receptors (nAChRs) have been implicated in a spectrum of cognitive functions as well as psychiatric and neurodegenerative disorders, including tobacco addiction and Alzheimer's Disease. The examination of neuronal nAChRs in living humans is a relatively new field. Researchers have developed brain-imaging radiotracers for nAChRs, with radiolabeled A-85380 compounds having t Read More

Individual images in dynamic molecular imaging studies are noisy because of short duration of frames. To reduce noise in these studies we used a method that employed the Hilbert transform and Singular Value Decomposition (SVD) processing. Use of this method, which we call the Complex Singular Value Decomposition (CSVD), significantly reduces noise while preserving signal intensity of dynamic images. Further, we used s Read More

Over the last two decades, using PET imaging to assess changes in endogenous dopamine has become a standard neurochemical research technique. Initially, investigators focused on the in vivo study of direct pharmacological manipulation of the dopamine system (e.g., amphetamine, cocaine, methylphenidate). More recently, there has been a shift toward studying the role that dopamine plays in cognitive processes an Read More

In three dimensional (3D) imaging, the field of view (FOV) is a significant factor that defines the ability of the system. Due to the small flat detector, the size of the FOV is limited. It is known that the FOV can be enlarged by using a horizontally shifted detector and x-ray source, but the projection data are horizontally truncated at each view angle. We have developed a dual-helical cone-beam computed tomography (CT), in which t Read More

A variety of medications can produce severe abdominal pain simulating an acute abdomen and, in some cases, a surgical abdomen. Nonsteroidal anti-inflammatory drugs are a well-established cause of peptic ulcer. Hemorrhage is the most serious complication of antithrombotic therapy. Pseudomembraneous colitis after use of antibiotics or chemotherapeutic agents can result in acute abdominal pain. Neutropenic entero Read More

To better understand the temporal pattern of hsp70 transcription, three tumor cell lines (M21, SCCVII, NIH3T3) were transfected with a Hsp70A.1 promoter to express luciferase (luc). The cells were exposed to a range of temperatures (38-52°C) for 20 minutes and luciferase activity was measured using a CCD camera. Luciferase activity was assessed every 2 h for 12 h, then every 6 h for another 12 h, and finally every 1 Read More

Radiotherapy aims to deliver the prescribed radiation dose to the entire volume of moving tumor while avoiding high radiation to the adjacent healthy tissues. Due to the physiological factors, (e.g. respiratory and, to a lesser extent, cardiac motion) the tumor and its surrounding tissue inside the thorax or abdomen move dynamically. Thus the subsequent targeting uncertainty existing in intra-fractional tumor motion an Read More