A GSO tweezers-type coincidence detector for tumor detection

Seiichi Yamamoto*, Tatsuya Higashi, Michio Senda

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A Gd2SiO5 (GSO) tweezers-type coincidence detector was developed and tested for tumor detection in procedures such as 18F-fluorodeoxyglucose (FDG)-guided surgery. The detector consists of a pair of GSO scintillators, a pair of metal-packaged small-sized photomultiplier tubes (PMTs), and a coincidence circuit. Because the GSO scintillators are located on the tips of tweezers, a target organ such as a lymph node or the colon can be easily positioned between them. The size of a single GSO was 8 × 14 × 14 mm. The results show that the energy resolution was 30 % full-width at half-maximum (FWHM) and the timing resolution was 6 ns FWHM for 511-keV gamma photons. The point-spread function perpendicular to the detector was 4.5 mm FWHM, and the point-spread function parallel to the detector was 7.5 mm FWHM. The absolute sensitivity of the coincidence detector was 0.6 % at the center of the detector when the two GSOs were 5 mm apart. Background counts due to the accidental and scatter coincidence were 2 cps up to 48 MBq from the positron source contained in a 20-cm-diameter, 20-cm-high cylindrical phantom. From these results, we conclude that the proposed tweezers-type coincidence detector is useful for tumor detection by the use of FDG, such as that in radio-guided surgery.

Original languageEnglish
Pages (from-to)293-298
Number of pages6
JournalRadiological Physics and Technology
Issue number2
Publication statusPublished - 2013 Jul
Externally publishedYes


  • Coincidence
  • GdSiO (GSO)
  • Tumor detection
  • Tweezers-type

ASJC Scopus subject areas

  • Radiation
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Radiology Nuclear Medicine and imaging


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