title: A GSO tweezers-type coincidence detector for tumor detection.
abstract: A Gd2SiO5 (GSO) tweezers-type coincidence detector was developed and tested for tumor detection in procedures such as (18)F-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.
authors.affiliation: Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya 461-8673, Japan. s-yama@met.nagoya-u.ac.jp
authors.forename: Seiichi
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Higashi
authors.forename: Michio
authors.initials: M
authors.lastname: Senda
mesh_terms: D004867:Equipment Design; D019788:Fluorodeoxyglucose F18; D006801:Humans; D009369:Neoplasms / Q000175:diagnosis*; D019047:Phantoms, Imaging; D017785:Photons; D049268:Positron-Emission Tomography; D017640:Silicates; D014159:Transducers
chemical_list: D017640:Silicates; C477725:gadolinium oxyorthosilicate; D019788:Fluorodeoxyglucose F18