Document Detail


Positron emission tomography within a magnetic field using photomultiplier tubes and lightguides.
MedLine Citation:
PMID:  7610123     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The spatial resolution of positron emission tomography (PET) improves when positron annihilation takes place in a strong magnetic field. In a magnetic field, the Lorentz force restricts positron range perpendicular to the field. Since positron annihilation occurs closer to its point of origin, the positron annihilation point spread function decreases. This was verified experimentally by measuring the spread function of positron annihilation from a 500 mm 68Ge bead imbedded in tissue-equivalent wax. At 5 T the spread function full width at half maximum (FWHM) and the full width at tenth maximum (FWTM) decrease by a factor of 1.42 and 2.09, respectively. Two NaI(Tl) scintillation crystals that interface to a pair of photomultiplier tubes (PMTS) through long lightguides detect positron annihilation at zero field and 5.0 T. Photomultiplier tubes, inoperable in strong magnetic fields, are functional if lightguides bring the photons produced by scintillators within the field to a minimal magnetic field. These tests also demonstrate techniques necessary for combining magnetic resonance imaging (MRI) and PET into one scanner.
Authors:
N L Christensen; B E Hammer; B G Heil; K Fetterly
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Physics in medicine and biology     Volume:  40     ISSN:  0031-9155     ISO Abbreviation:  Phys Med Biol     Publication Date:  1995 Apr 
Date Detail:
Created Date:  1995-08-16     Completed Date:  1995-08-16     Revised Date:  2011-02-11    
Medline Journal Info:
Nlm Unique ID:  0401220     Medline TA:  Phys Med Biol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  691-7     Citation Subset:  IM    
Affiliation:
School of Physics and Astronomy, University of Minnesota, Minneapolis 55455, USA.
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MeSH Terms
Descriptor/Qualifier:
Gamma Rays
Germanium
Humans
Magnetics*
Radioisotopes
Tomography, Emission-Computed / instrumentation*,  methods
Grant Support
ID/Acronym/Agency:
R29 CA065523-05/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Radioisotopes; 7440-56-4/Germanium

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