Imaging properties of a positron tomograph with 280 BGO crystals

Conference · Sat Nov 01 04:00:00 EST 1980

OSTI ID:6526951

Derenzo, S E; Budinger, T F; Huesman, R H; Cahoon, J L; Vuletich, T

The basic imaging properties of the Donner 280-BGO-Crystal positron tomograph were measured and compared with the same system when it was equipped with 280 NaI(T1) crystals. The NaI(T1) crystals were 8 mm x 30 mm x 50 mm deep, sealed in 10 mm wide stainless steel cans. The BGO crystals are 9.5 mm x 32 mm x 32 mm deep and as they are not hygroscopic do not require sealed cans. With a shielding gap of 3 cm (section thickness 1.7 cm FWHM) the sensitivity of the BGO system is 55,000 events per sec for 1 ..mu..Ci per cm/sup 3/ in a 20 cm cylinder of water, which is 2.3 times higher than the NaI(T1) system. For a 200 ..mu..Ci/cm line source on the ring axis in a 20 cm diameter water cylinder, the BGO system records 86% of the scatter fraction and 66% of the accidental fraction of the NaI(T1) system. The lower light yield and poorer time resolution of BGO requires a wider coincidence timing window than NaI(T1). However, the ability to use full-energy pulse height selection with a 2.3-fold improvement in sensitivity results in an overall reduction in the fraction of accidental events recorded. The in-plane resolution of the BGO system is 9 to 10 mm FWHM within the central 30 cm diameter field, and the radial elongation at the edge of the field in the NaI(T1) system has been nearly eliminated.

• Research Organization: Lawrence Berkeley Lab., CA (USA); California Univ., Berkeley (USA). Donner Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6526951
• Report Number(s): LBL-11858; CONF-801103-56
• Country of Publication: United States
• Language: English

Related Subjects

550602* -- Medicine-- External Radiation in Diagnostics-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
BISMUTH COMPOUNDS
COMPARATIVE EVALUATIONS
COMPUTERIZED TOMOGRAPHY
COUNTING TECHNIQUES
DIAGNOSTIC TECHNIQUES
EMISSION COMPUTED TOMOGRAPHY
GERMANATES
GERMANIUM COMPOUNDS
IMAGES
MEASURING INSTRUMENTS
NAI DETECTORS
OXYGEN COMPOUNDS
POSITRON COMPUTED TOMOGRAPHY
RADIATION DETECTORS
RADIOISOTOPE SCANNING
SCINTILLATION COUNTERS
SENSITIVITY
SOLID SCINTILLATION DETECTORS
TOMOGRAPHY