Journal of Radioanalytical and Nuclear Chemistry

, Volume 291, Issue 2, pp 493–496 | Cite as

Measurement of three gamma annihilation by lanthanum-based crystals compared with NaI(Tl) and HPGe

  • M. Alkhorayef
  • K. Alzimami
  • A. Alfuraih
  • M. Alnafea
  • N. M. Spyrou


The relative yield of 3γ to 2γ annihilation was measured for a positron emitter, 22Na, with the new scintillator detectors lanthanum chloride (LaCl3:Ce) and lanthanum bromide (LaBr3:Ce), which had been characterised for comparison with high-purity germanium (HPGe) and sodium iodide (NaI(Tl)) detectors. The information obtained from the ortho-positronium 3γ decay in positron emission tomography (PET) can be a measure of the oxygen content in biological tissues by determination of this relative yield. However, it requires high resolution spectroscopy and detection efficiency. Characterisation of the new generation of scintillator detectors determines whether they could replace conventional scintillators and semiconductors. A series of experiments was carried out with different samples in order to study the effect of ortho-positronium formation. The peak-to-peak and the peak-to-valley methods were compared in the measurement of the relative yield of 3γ to 2γ annihilation.


Positron emission tomography (PET) Lanthanum-based crystals Three gamma annihilation Peak-to-peak method Peak-to-valley method Relative yield of 3γ to 2γ annihilation 



The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding the work through the research group project number RGP-VPP-085.


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2011

Authors and Affiliations

  • M. Alkhorayef
    • 1
  • K. Alzimami
    • 1
  • A. Alfuraih
    • 1
  • M. Alnafea
    • 1
  • N. M. Spyrou
    • 1
    • 2
  1. 1.Department of Radiological SciencesCollege of Applied Medical Sciences, King Saud UniversityRiyadhSaudi Arabia
  2. 2.Department of PhysicsCentre for Nuclear and Radiation Physics, University of SurreyGuildfordUK

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