title: Recycling of 3He from lung magnetic resonance imaging.
abstract: We have developed the means to recycle (3) He exhaled by patients after imaging the lungs using magnetic resonance of hyperpolarized (3) He. The exhaled gas is collected in a helium leak proof bag and further compressed into a steel bottle. The collected gas contains about 1-2% of (3) He, depending on the amount administered and the number of breaths collected to wash out the (3) He gas from the lungs. (3) He is separated from the exhaled air using zeolite molecular sieve adsorbent at 77 K followed by a cold head at 8 K. Residual gaseous impurities are finally absorbed by a commercial nonevaporative getter. The recycled (3) He gas features high purity, which is required for repolarization by metastability exchange optical pumping. At present, we achieve a collection efficiency of 80-84% for exhaled gas from healthy volunteers and cryogenic separation efficiency of 95%.
authors.affiliation: Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany. salhi@uni-mainz.de
authors.forename: Z
authors.initials: Z
authors.lastname: Salhi
authors.forename: T
authors.initials: T
authors.lastname: Grossmann
authors.forename: M
authors.initials: M
authors.lastname: Gueldner
authors.forename: W
authors.initials: W
authors.lastname: Heil
authors.forename: S
authors.initials: S
authors.lastname: Karpuk
authors.forename: E W
authors.initials: EW
authors.lastname: Otten
authors.forename: D
authors.initials: D
authors.lastname: Rudersdorf
authors.forename: R
authors.initials: R
authors.lastname: Surkau
authors.forename: U
authors.initials: U
authors.lastname: Wolf
mesh_terms: D000280:Administration, Inhalation; D003287:Contrast Media / Q000302:isolation & purification*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D045853:Exhalation; D006371:Helium / Q000008:administration & dosage / Q000302:isolation & purification*; D006801:Humans; D007554:Isotopes / Q000008:administration & dosage / Q000302:isolation & purification; D008168:Lung / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000302:isolation & purification; D059027:Recycling / Q000379:methods*
chemical_list: D003287:Contrast Media; D007554:Isotopes; D019275:Radiopharmaceuticals; D006371:Helium