Study of mechanical compression of spin-polarized 3He gas

Becker, Jan; Heil, W.; Krug, Brian; Leduc, Michèle; Meyerhoff, M.; Nacher, Pierre-Jean; Otten, Ernst W.; Prokscha, T.; Schearer, L. D.; Surkau, R.

doi:10.1016/0168-9002(94)90687-4

Cited by 78 publications

(46 citation statements)

References 11 publications

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“…This direct process excites the He nucleus with circularly polarized laser light at a wavelength of 1083 nm and allows more rapid production of polarized gas, 0.4 liter/hour of up to 60% polarized He-3 at atmospheric pressure (36,37). Production capacity with either technique is sufficient to provide He-3 by either local or central production (36,38) with transport in specialized containers (39) and is comparable in preparation time to clinical radiochemistry processes.…”

Section: Hyperpolarized Gas Agentsmentioning

confidence: 99%

Functional lung imaging using hyperpolarized gas MRI

Fain

Korosec

Holmes

et al. 2007

Magnetic Resonance Imaging

178

158

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The noninvasive assessment of lung function using imaging is increasingly of interest for the study of lung diseases, including chronic obstructive pulmonary disease (COPD) and asthma. Hyperpolarized gas MRI (HP MRI) has demonstrated the ability to detect changes in ventilation, perfusion, and lung microstructure that appear to be associated with both normal lung development and disease progression. The physical characteristics of HP gases and their application to MRI are presented with an emphasis on current applications. Clinical investigations using HP MRI to study asthma, COPD, cystic fibrosis, pediatric chronic lung disease, and lung transplant are reviewed. Recent advances in polarization, pulse sequence development for imaging with Xe-129, and prototype low magnetic field systems dedicated to lung imaging are highlighted as areas of future development for this rapidly evolving technology.

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Section: Hyperpolarized Gas Agentsmentioning

confidence: 99%

Functional lung imaging using hyperpolarized gas MRI

Fain

Korosec

Holmes

et al. 2007

Magnetic Resonance Imaging

178

158

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“…14b). The typical OP power densities presently used for production of polarized gas lie between 0.2 and 2.4 W/cm 2 [11,12,23,42,43]. Our results suggest that optimal performances should be achieved with 2 GHz-broad lasers at the upper end of that power range, while 1.2-1.5 GHz FWHMs might be preferred at the lower end.…”

Section: Laser Optimization For Op Applicationsmentioning

confidence: 91%

“…Most current schemes are based on gas flow through one or several OP cells, where it gets optically pumped at low pressure and mT magnetic field, and accumulation of compressed polarized gas in appropriate storage vessels [11,12,23]. Cell dimensions, materials, and gas flow rates are optimized to achieve the best efficiency with the available laser source, which usually results from a tradeoff between high nuclear polarizations and fast production rates.…”

Section: Metastability Exchange Optical Pumping and Laser Requirementsmentioning

confidence: 99%

“…Large nuclear polarizations can be prepared in a low-pressure gas at room temperature within a few seconds [9,10]. Polarization-preserving compression is performed after OP to obtain dense gas, with a choice of possible schemes depending on the targeted application [11,12,13]. Home-built 1083 nm light sources [1,14] are now replaced by commercial lasers [10,15,16,17].…”

Section: Introductionmentioning

confidence: 99%

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A broadband ytterbium-doped tunable fiber laser for 3He optical pumping at 1083�nm

Tastevin

Grot

Courtade

et al. 2004

Applied Physics B: Lasers and Optics

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Large amounts of hyperpolarized 3 He gas with high nuclear polarization rates are required for use in neutron spin filters or nuclear magnetic resonance imaging of human lung. Very high efficiency can be obtained by metastability exchange optical pumping using multimode lasers to excite the 2 3 S-2 3 P transition at 1083 nm. Broadband Ytterbium-doped tunable fiber lasers have been designed for that particular application. Different options for the architecture of the fiber oscillator are presented and compared. Emphasis is given to a linear cavity configuration that includes a high reflectivity fiber mirror and a low reflectivity tunable fiber Bragg grating. Optical measurements are performed to finely characterize the spectral behavior of the lasers. Atomic response is also quantitatively probed to assess the optimal design of the oscillator for optical pumping. Multimode operation matching the 2 GHz Doppler-broadened helium resonance line and tunability over more than 200 GHz are demonstrated. Boosting the output of this fiber laser with a Yb-doped fiber power amplifier, allfiber devices are built to provide robust, high power turn-key sources at 1083 nm for improved production of laser polarized 3 He. 42.55.Wd; 32.80.Bx PACS

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“…3 He was polarized at the Laü e-Langevin Institute (Grenoble, France) using the metastable-exchange method (3,17). The typical polarization level varied between 50% and 55% at the end of the optical pumping process.…”

Section: Helium Polarization and Microbubble Preparationmentioning

confidence: 99%

MR perfusion imaging using encapsulated laser‐polarized ³He

Callot¹,

Canet²,

Brochot³

et al. 2001

Magnetic Resonance in Med

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In this work, the use of a new carrier agent for intravascular laser-polarized 3 He imaging is reported. Lipid-based helium microbubbles were investigated. Their average diameter of 3 m, which is smaller than that of the capillaries, makes it possible to conduct in vivo studies. The NMR relaxation parameters T 1 , T 2 , and T* 2 of a microbubble suspension were measured as 90 s, 300 ms, and 4.5 ms, respectively, and in vivo images of encapsulated 3 He with signal-to-noise ratios (SNRs) larger than 30 were acquired. Dynamic cardiac images and vascular images of encapsulated 3 He were obtained in rats using intravenous injections of microbubble suspensions. Excellent preservation of Several optical pumping techniques (1-3) have been developed for polarization of the nuclear magnetic moments of two noble gas isotopes, 3 He and 129 Xe. These techniques offer NMR signal enhancements of five orders of magnitude compared to thermally polarized nuclei at room temperature.One important biomedical application of these hyperpolarized (HP) gases is the visualization by MRI of cavities such as the lungs (4 -7). Another potential application is their use as intravascular contrast agents. Initial in vivo NMR studies of blood-dissolved HP gas have already been performed on animals using polarized 129 Xe. The polarized nuclei can be delivered to blood and tissues directly from inhaled gas (7-11) or can be alternatively dissolved (12,13) in an appropriate emulsion (typically a lipid-enriched solution) and injected in a venous or arterial vessel.3 He possesses a larger nuclear magnetic moment value than 129 Xe and, at present, higher levels of polarization can be achieved with 3 He. Hence, for an equivalent number of nuclear spins, a typical gain of 10 in NMR signal amplitude can be achieved using 3 He instead of 129 Xe. Furthermore, due to the threefold-larger magnetic moment of helium, there is less demand on gradient magnetic field strength in 3 He MRI. Finally, xenon is well known for its lipophilic and anesthetic properties that may limit the amount of dissolved xenon acceptable in the blood.However, compared to xenon, helium is characterized by a much lower solubility (ϳ0.01 ml of dissolved gas per ml of fluid in blood and water (14) vs. ϳ0.1 for xenon). This precludes an efficient delivery of helium to the intravascular system from inhaled polarized helium. Similarly, major difficulties are encountered in the preparation of an injectable solution of dissolved helium. The first in vivo intravascular helium images were obtained (15) using helium microbubble suspensions. However, the large mean bubble diameter of these suspensions reported by the authors (on the order of 30 m) represented a major limitation for the safe in vivo use of these solutions.Fortunately, the problem of low dissolution coefficient can be overcome using an appropriate carrier agent. Recently, in vivo vascular images have been reported using encapsulated 3 He in microspheres of 5.3 m diameter (16) formed from human serum albumin.In this work, we propose...

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Study of mechanical compression of spin-polarized 3He gas

Cited by 78 publications

References 11 publications

Functional lung imaging using hyperpolarized gas MRI

Functional lung imaging using hyperpolarized gas MRI

A broadband ytterbium-doped tunable fiber laser for 3He optical pumping at 1083�nm

MR perfusion imaging using encapsulated laser‐polarized ³He

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Study of mechanical compression of spin-polarized 3He gas

Cited by 78 publications

References 11 publications

Functional lung imaging using hyperpolarized gas MRI

Functional lung imaging using hyperpolarized gas MRI

A broadband ytterbium-doped tunable fiber laser for 3He optical pumping at 1083�nm

MR perfusion imaging using encapsulated laser‐polarized 3He

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MR perfusion imaging using encapsulated laser‐polarized ³He