Geological Carbon Sequestration: A New Approach for Near-Surface Assurance Monitoring

There are two distinct objectives in monitoring geological carbon sequestration (GCS): Deep monitoring of the reservoir’s integrity and plume movement and near-surface monitoring (NSM) to ensure public health and the safety of the environment. However, the minimum detection limits of the current instrumentation for NSM is too high for detecting weak signals that are embedded in the background levels of the natural variations, and the data obtained represents point measurements in space and time. A new approach for NSM, based on gamma-ray spectroscopy induced by inelastic neutron scatterings (INS), offers novel and unique characteristics providing the following: (1) High sensitivity with a reducible error of measurement and detection limits, and, (2) temporal- and spatial-integration of carbon in soil that results from underground CO2 seepage. Preliminary field results validated this approach showing carbon suppression of 14% in the first year and 7% in the second year. In addition the temporal behavior of the error propagation is presented and it is shown that for a signal at the level of the minimum detection level the error asymptotically approaches 47%

Breath-hold MR cholangiopancreatography with three-dimensional, segmented, echo-planar imaging and volume rendering

End-expiration, 21-second breath-hold, three-dimensional magnetic resonance (MR) cholangiopancreatography (MRCP) was developed with segmented echo-planar imaging. In 15 healthy subjects and 14 randomly selected patients undergoing liver studies, three-dimensional MRCP images were obtained and volume rendered. In 15 (100%) healthy subjects and 13 (93%) patients, clear depiction of biliary, hepatic, and pancreatic ducts (with lumen diameter of at least 2 mm) was possible with good signal-to-noise ratio

Neutron Generator Output Monitoring for Normalization of Gamma-Ray Spectra

Neutron generators (NG) being devices where neutron outputs are accomplished electrically, suffer from fluctuations in their outputs. Of particular importance are the short term variations that may affect individual data acquisition runs. Thus when using NGs for quantitative neutron-induced gamma-ray spectroscopy, the neutron output must be continuously monitored in real time, and normalization procedures subsequently applied to properly evaluate the gamma-ray spectra. Using a plastic scintillator, we developed a scheme for detecting fast neutrons that relies firstly, on recording a spectrum and, secondly, on establishing a region-of-interest (ROI) that may effectively discriminate against gamma rays that are always present in a neutron field. We discuss the optimization of these procedures for a field system to measure carbon in soil

Monitoring Neutron Generator Output in a Mixed Neutron-Gamma Field Using a Plastic Scintillator.

Quantitative neutron-induced gamma-ray spectroscopy employing neutron generators (NGs) entails monitoring them for possible fluctuations in their neutron output. We accomplished this using a plastic scintillator and recording a spectrum from which we selected a neutron region-of-interest (nROI) to discriminate between neutrons and the accompanying high-energy gamma-rays. We show that the selected nROI is insensitive to changes in the gamma-ray background, thus allowing satisfactory normalization of the gamma-ray spectra of an in-situ system for analyzing soil carbon

Magnetic resonance imaging in children: common problems and possible solutions for lung and airways imaging

Pediatric chest MRI is challenging. High-resolution scans of the lungs and airways are compromised by long imaging times, low lung proton density and motion. Low signal is a problem of normal lung. Lung abnormalities commonly cause increased signal intenstities. Among the most important factors for a successful MRI is patient cooperation, so the long acquisition times make patient preparation crucial. Children usually have problems with long breath-holds and with the concept of quiet breathing. Young children are even more challenging because of higher cardiac and respiratory rates giving motion blurring. For these reasons, CT has often been preferred over MRI for chest pediatric imaging. Despite its drawbacks, MRI also has advantages over CT, which justifies its further development and clinical use. The most important advantage is the absence of ionizing radiation, which allows frequent scanning for short- and long-term follow-up studies of chronic diseases. Moreover, MRI allows assessment of functional aspects of the chest, such as lung perfusion and ventilation, or airways and diaphragm mechanics. In this review, we describe the most common MRI acquisition techniques on the verge of clinical translation, their problems and the possible solutions to make chest MRI feasible in children

Cell labelling with superparamagnetic iron oxide has no effect on chondrocyte behaviour

SummaryBackgroundTissue engineering and regenerative medicine are two rapidly advancing fields of research offering potential for effective treatment of cartilage lesions. Today, chondrocytes are the cell type of choice for use in cartilage repair approaches such as autologous chondrocyte implantation. To verify the safety and efficacy of such approaches it is necessary to determine the fate of these transplanted cells. One way of doing this is prelabelling cells before implantation and tracking them using imaging techniques. The use of superparamagnetic iron oxide (SPIO) for tracking of cells with magnetic resonance imaging (MRI) is ideal for this purpose. It is non-radioactive, does not require viral transfection and is already approved for clinical use as a contrast agent.ObjectiveThe purpose of this study was to assess the effect of SPIO labelling on adult human chondrocyte behaviour.MethodsCells were culture expanded and dedifferentiated for two passages and then labelled with SPIO. Effect on cell proliferation was tested. Furthermore, cells were cultured for 21 days in alginate beads in redifferentiation medium. Following this period, cells were analysed for expression of cartilage-related genes, proteoglycan production and collagen protein expression.ResultsSPIO labelling did not significantly affect any of these parameters relative to unlabelled controls. We also demonstrated SPIO retention within the cells for the full duration of the experiment.ConclusionsThis paper demonstrates for the first time the effects of SPIO labelling on chondrocyte behaviour, illustrating its potential for in vivo tracking of implanted chondrocytes

Labelling of mammalian cells for visualisation by MRI

Through labelling of cells with magnetic contrast agents it is possible to follow the fate of transplanted cells in vivo with magnetic resonance imaging (MRI) as has been demonstrated in animal studies as well as in a clinical setting. A large variety of labelling strategies are available that allow for prolonged and sensitive detection of the labelled cells with MRI. The various protocols each harbour specific advantages and disadvantages. In choosing a particular labelling strategy it is also important to ascertain that the labelling procedure does not negatively influence cell functionality, for which a large variety of assays are available. In order to overcome the challenges still faced in fully exploiting the benefits of in vivo cell tracking by MRI a good understanding and standardisation of the procedures and assays used will be crucial