Performance characteristics of a compact position-sensitive LSO detector module.
We assembled a compact detector module comprised of an array of small, individual crystals of lutetium oxyorthosilicate:Ce (LSO) coupled directly to a miniature, metal-can, position-sensitive photomultiplier tube (PSPMT). We exposed this module to sources of 511-keV annihilation radiation and beams of 30- and 140-keV photons and measured spatial linearity; spatial variations in module gain, energy resolution, and event positioning; coincidence timing; the accuracy and sensitivity of identifying the crystal-of-first-interaction at 511 keV; and the effects of intercrystal scatter and LSO background radioactivity. The results suggest that this scintillator/phototube combination should be highly effective in the coincidence mode and can be used, with some limitations, to image relatively low-energy single photon emitters. Photons that are completely absorbed on their first interaction at 511 keV are positioned by the module at the center of a crystal. Intercrystal scatter events, even those that lead to total absorption of the incident photon, are placed by the module in a regular "connect-the-dot" pattern that joins crystal centers. As a result, the accuracy of event positioning can be made to exceed 90%, though at significantly reduced sensitivity, by retaining only events that occur within small regions-of-interest around each crystal center and rejecting events that occur outside these regions in the connect-the-dot pattern.
Nuclear Medicine Department, National Institutes of Health, Bethesda, MD 20892, USA.
J J
JJ
Vaquero
J
J
Seidel
S
S
Siegel
W R
WR
Gandler
M V
MV
Green
D000818:Animals; D004307:Dose-Response Relationship, Radiation; D004583:Electrons; D004867:Equipment Design; D005462:Fluorine Radioisotopes; D008187:Lutetium / Q000528:radiation effects; D016011:Normal Distribution; D017785:Photons; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D013997:Time Factors; D014055:Tomography, Emission-Computed / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data
D005462:Fluorine Radioisotopes; D008187:Lutetium