Investigation of crystal geometries for fiber coupled gamma imaging intra-operative probes

Author

Tornai, Martin P. ; Levin, Craig S. ; MacDonald, Lawrence R. ; Hoffman, Edward J.

Author_Institution

Sch. of Med., California Univ., Los Angeles, CA, USA

Volume

44

Issue

3

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

1254

Lastpage

1261

Abstract

CsI(Na), CsI(Tl) and NaI(Tl) scintillators coupled through optical fibers were investigated with simulations and measurements to evaluate their potential as gamma imaging intraoperative probes. Three coupling methods were employed: discrete crystals coupled one-to-one with the fibers; discrete crystals coupled through a light diffuser to an unmatched fiber array; and continuous crystals coupled directly to the fiber optic array. The discrete crystals were 4×4 element arrays ranging in size from 1×1×2.5 mm³ to 2×2×6 mm³. CsI(Na) produced the best pulse height and single crystal energy resolution (44% at 140 keV) when coupled through fibers to the photodetector. All elements of the arrays were completely resolved, indicating that the intrinsic spatial resolution will be determined by the crystal size. The spatial resolution for the 12.5 mm φ×3.5 mm continuous crystals was ~1.33 mm FWHM. Preliminary imaging measurements faithfully reproduced the activity distributions and compared favorably with simulations

Keywords

biomedical equipment; caesium compounds; fibre optic sensors; optical fibre couplers; radioisotope imaging; sodium compounds; solid scintillation detectors; surgery; 1 mm; 12.5 mm; 140 keV; 2 mm; 2.5 mm; 3.5 mm; 6 mm; CsI(Na) scintillators; CsI(Tl) scintillators; CsI:Na; CsI:Tl; NaI(Tl) scintillators; NaI:Tl; activity distributions; continuous crystals; coupling methods; crystal geometries; crystal size; discrete crystals; fiber coupled gamma imaging intra-operative probes; fiber optic array; gamma imaging; intrinsic spatial resolution; light diffuser; optical fibers; photodetector; pulse height; simulations; single crystal energy resolution; unmatched fiber array; Crystals; Energy resolution; Geometrical optics; Geometry; Optical arrays; Optical coupling; Optical fibers; Optical imaging; Probes; Spatial resolution;

fLanguage

English

Journal_Title

Nuclear Science, IEEE Transactions on

Publisher

ieee

ISSN

0018-9499

Type

jour

DOI

10.1109/23.596997

Filename

596997