Spolaryzowany ksenon do celów medycznych

The hyperpolarized noble gases (xenon 129Xe and helium 3He) delivered a great tool for the growing number of applications, spanning nuclear physics, Medical Resonance Imaging (MRI) and Nuclear Magnetic Resonance (NMR) spectroscopy studies. Hyperpolarization may be achieved via the Spin Exchange Optical Pumping (SEOP, for 129Xe or 3He) or the Metastability Exchange Optical Pumping (MEOP, 3He). The main aim of this thesis is to present the design of a novel large scale SEOP polarizer, built in the frame of the PhD thesis, for producing hyperpolarized 129Xe for further medical imaging of lungs. Increasing requirements for large volumes of hyperpolarized gases could be realized by e cient polarizers, such as the novel polarizer presented here. The thesis characterizes the optimum operating parameters of the polarizer. The polarizer works basing on the SEOP method, resulting in a high-yield of the polarized gas. The main parts of the unit are presented: the coil system producing magnetic eld, the gas (129Xe and bu er gases: N2, 4He) and rubidium distribution system, the high-power laser diode system spectrally narrowed with Volume Bragg Gratings for rubidium optical pumpin and the high-volume SEOP cell. The SEOP polarizer was designed to work at the pressure close to the atmospheric pressure with a low content of the 129Xe gas in the SEOP mixture, contained in a large SEOP cell (about 6 L inner volume). This is unique comparing to majority of other SEOP designs, which use the high-pressure and small-volume cells. The motivation, a brief overview of the state of the art in the hyper-polarized gases techniques, the current status of the SEOP polarizer project and the future research plans are also part of this work

Radon Mitigation Applications at the Laboratorio Subterraneo de Canfranc (LSC)

The Laboratorio Subterraneo de Canfranc (LSC) is the Spanish national hub for low radioactivity techniques and the associated scientific and technological applications. The concentration of the airborne radon is a major component of the radioactive budget in the neighborhood of the detectors. The LSC hosts a Radon Abatement System, which delivers a radon suppressed air with 1.1 & PLUSMN;0.2 mBq/m(3) of Rn-222. The radon content in the air is continuously monitored with an Electrostatic Radon Monitor. Measurements with the double beta decay demonstrators NEXT-NEW and CROSS and the gamma HPGe detectors show the important reduction of the radioactive background due to the purified air in the vicinity of the detectors. We also discuss the use of this facility in the LSC current program which includes NEXT-100, low background biology experiments and radiopure copper electroformation equipment placed in the radon-free clean room

Principles of diffusion kurtosis imaging and its role in early diagnosis of neurodegenerative disorders

Pathology of neurodegenerative diseases can be correlated with intra-neuronal as well as extracellular changes which lead to neuronal degeneration. The central nervous system (CNS) is a complex structure comprising of many biological barriers. These microstructural barriers might be affected by a variety of pathological processes. Specifically, changes in the brain tissue's microstructure affect the diffusion of water which can be assessed non invasively by diffusion weighted (DW) magnetic resonance imaging (MRI) techniques. Diffusion tensor imaging (DTI) is a diffusion MRI technique that considers diffusivity as a Gaussian process, i.e. does not account for any diffusion hindrance. However, environment of the brain tissues is characterized by a non-Gaussian diffusion. Therefore, diffusion kurtosis imaging (DKI) was developed as an extension of DTI method in order to quantify the non-Gaussian distribution of water diffusion. This technique represents a promising approach for early diagnosis of neurodegenerative diseases when the neurodegenerative process starts. Hence, the purpose of this article is to summarize the ongoing clinical and preclinical research on Parkinson's, Alzheimer's and Huntington diseases, using DKI and to discuss the role of this technique as an early stage biomarker of neurodegenerative conditions

Metastability exchange optical pumping low field polarizer for lung magnetic resonance imaging

An extensive improvement of our low field polarizer is described. It produces 3He gas polarized up to 40% in a 6 h decay time storage cell. Production rate was raised by a factor of 10 to 4–5 scc/min thanks to the implementation of a new 10 W laser and a new design of a peristaltic compressor, easier to handle. Some applications of polarized gas are also presented: dynamic images of gas inhalation in the rat as well as a static image of human lungs using hyperpolarized gas were obtained