A high-field 3He metastability exchange optical pumping polarizer operating in a 1.5 T medical scanner for lung magnetic resonance imaging

G. Collier , T. Pałasz , A. Wojna , Bartosz Głowacz , Mateusz Suchanek , Zbigniew Olejniczak , T. Dohnalik

Abstract

After being hyperpolarized using the technique of Metastability Exchange Optical Pumping (MEOP), 3He can be used as a contrast agent for lung magnetic resonance imaging (MRI). MEOP is usually performed at low magnetic field (~ 1 mT) and low pressure (~ 1 mbar), which results in a low magnetization production rate. A delicate polarization-preserving step of compression is also required. It was demonstrated in sealed cells that high nuclear polarization values can be obtained at higher pressures with MEOP, if performed at high magnetic field (non-standard conditions). In this work the feasibility of building a high-field polarizer that operates within a commercial 1.5 T scanner was evaluated. Preliminary measurements of nuclear polarization with sealed cells filled at different 3He gas pressures (1.33 to 267 mbar) were performed. The use of an annular shape for the laser beam increased by 25 % the achievable nuclear polarization equilibrium value (Meq) at 32 and 67 mbar as compared to a Gaussian beam shape. Meq values of 66.4 and 31 % were obtained at 32 and 267 mbar respectively and the magnetization production rate was increased by a factor of 10 compared to the best results obtained under standard conditions. To study the reproducibility of the method in a polarizing system, the same experiments were performed with small cells connected to a gas handling system. The polarization build-up times were approximately 3 times longer in the 20-30 mbar range of pressure than those obtained for the 32 mbar sealed cell. However, reasonable Meq values of 40-60 % were achieved in a 90 mL open cell. Based on these findings, a novel compact polarizing system was designed and built. Its typical output is a 3He gas flow rate of 15 sccm with a polarization of 33 %. In-vivo lung MRI ventilation images were acquired to demonstrate the polarizer s application.
Author G. Collier
G. Collier,,
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, T. Pałasz
T. Pałasz,,
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, A. Wojna
A. Wojna,,
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, Bartosz Głowacz
Bartosz Głowacz,,
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, Mateusz Suchanek (FoAaE / DoChaP)
Mateusz Suchanek,,
- Department of Chemistry and Physics
, Zbigniew Olejniczak
Zbigniew Olejniczak,,
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, T. Dohnalik
T. Dohnalik,,
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Journal seriesJournal of Applied Physics, ISSN 0021-8979, (A 35 pkt)
Issue year2013
Vol113
No20
Pages1-23
Publication size in sheets1.1
ASJC Classification3100 General Physics and Astronomy
DOIDOI:10.1063/1.4807836
URL http://arxiv.org/ftp/arxiv/papers/1302/1302.4863.pdf
Internal identifierWRE/2013/291
Languageen angielski
Score (nominal)35
Score sourcejournalList
Publication indicators WoS Citations = 6; Scopus SNIP (Source Normalised Impact per Paper): 2013 = 1.289; WoS Impact Factor: 2013 = 2.185 (2) - 2013=2.259 (5)
Citation count*2 (2015-10-05)
Additional fields
FinansowanieMNiSW - SPUB 547/6.PRUE/2008/07
FinansowanieRTN (Marie Curie Research Training Networks) - PHeLINet (MRTN-CT-2006-036002
FinansowanieProgram Operacyjny Innowacyjna Gospodarka (POIG) - Program NLTK (POIG.02.02.00-00-003/08
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.
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